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<div id="app" data-server-rendered="true"><div class="theme-container"><header class="navbar"><div class="inner"><div class="sidebar-button"><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" role="img" viewBox="0 0 448 512" class="icon"><path fill="currentColor" d="M436 124H12c-6.627 0-12-5.373-12-12V80c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12zm0 160H12c-6.627 0-12-5.373-12-12v-32c0-6.627 5.373-12 12-12h424c6.627 0 12 5.373 12 12v32c0 6.627-5.373 12-12 12z"></path></svg></div> <a href="/learn-wgpu/" class="home-link router-link-active"><!----> <span class="site-name">Learn Wgpu</span></a> <div class="links"><!----> <div class="search-box"><input aria-label="Search" autocomplete="off" spellcheck="false" value=""> <!----></div></div></div></header> <div class="sidebar-mask"></div> <div class="docs-layout"><aside class="sidebar"><!----> <ul class="sidebar-links"><li><a href="/learn-wgpu/" aria-current="page" class="sidebar-link">Introduction</a></li><li><section class="sidebar-group depth-0"><p class="sidebar-heading"><span>Beginner</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/learn-wgpu/beginner/tutorial1-window/" class="sidebar-link">Dependencies and the window</a></li><li><a href="/learn-wgpu/beginner/tutorial2-surface/" class="sidebar-link">The Surface</a></li><li><a href="/learn-wgpu/beginner/tutorial3-pipeline/" class="sidebar-link">The Pipeline</a></li><li><a href="/learn-wgpu/beginner/tutorial4-buffer/" class="sidebar-link">Buffers and Indices</a></li><li><a href="/learn-wgpu/beginner/tutorial5-textures/" class="sidebar-link">Textures and bind groups</a></li><li><a href="/learn-wgpu/beginner/tutorial6-uniforms/" class="sidebar-link">Uniform buffers and a 3d camera</a></li><li><a href="/learn-wgpu/beginner/tutorial7-instancing/" class="sidebar-link">Instancing</a></li><li><a href="/learn-wgpu/beginner/tutorial8-depth/" class="sidebar-link">The Depth Buffer</a></li><li><a href="/learn-wgpu/beginner/tutorial9-models/" class="sidebar-link">Model Loading</a></li></ul></section></li><li><section class="sidebar-group depth-0"><p class="sidebar-heading open"><span>Intermediate</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/learn-wgpu/intermediate/tutorial10-lighting/" aria-current="page" class="active sidebar-link">Working with Lights</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#ray-path-tracing" class="sidebar-link">Ray/Path Tracing</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#the-blinn-phong-model" class="sidebar-link">The Blinn-Phong Model</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#seeing-the-light" class="sidebar-link">Seeing the light</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#ambient-lighting" class="sidebar-link">Ambient Lighting</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#diffuse-lighting" class="sidebar-link">Diffuse Lighting</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#the-normal-matrix" class="sidebar-link">The normal matrix</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#specular-lighting" class="sidebar-link">Specular Lighting</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/intermediate/tutorial10-lighting/#the-half-direction" class="sidebar-link">The half direction</a></li></ul></li><li><a href="/learn-wgpu/intermediate/tutorial11-normals/" class="sidebar-link">Normal Mapping</a></li><li><a href="/learn-wgpu/intermediate/tutorial12-camera/" class="sidebar-link">A Better Camera</a></li><li><a href="/learn-wgpu/intermediate/tutorial13-hdr/" class="sidebar-link">High Dynamic Range Rendering</a></li></ul></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>Showcase</span> <span class="arrow right"></span></p> <!----></section></li><li><section class="sidebar-group collapsable depth-0"><p class="sidebar-heading"><span>News</span> <span class="arrow right"></span></p> <!----></section></li></ul> </aside> <main class="page"> <div class="theme-default-content content__default"><h1 id="working-with-lights"><a href="#working-with-lights" class="header-anchor">#</a> Working with Lights</h1> <p>While we can tell that our scene is 3d because of our camera, it still feels very flat. That's because our model stays the same color regardless of how it's oriented. If we want to change that we need to add lighting to our scene.</p> <p>In the real world, a light source emits photons that bounce around until they enter our eyes. The color we see is the light's original color minus whatever energy it lost while it was bouncing around.</p> <p>In the computer graphics world, modeling individual photons would be hilariously computationally expensive. A single 100 Watt light bulb emits about 3.27 x 10^20 photons <em>per second</em>. Just imagine that for the sun! To get around this, we're gonna use math to cheat.</p> <p>Let's discuss a few options.</p> <h2 id="ray-path-tracing"><a href="#ray-path-tracing" class="header-anchor">#</a> Ray/Path Tracing</h2> <p>This is an <em>advanced</em> topic, and we won't be covering it in depth here. It's the closest model to the way light really works so I felt I had to mention it. Check out the <a href="/learn-wgpu/todo/">ray tracing tutorial</a> if you want to learn more.</p> <h2 id="the-blinn-phong-model"><a href="#the-blinn-phong-model" class="header-anchor">#</a> The Blinn-Phong Model</h2> <p>Ray/path tracing is often too computationally expensive for most real-time applications (though that is starting to change), so a more efficient, if less accurate method based on the <a href="https://en.wikipedia.org/wiki/Phong_shading" target="_blank" rel="noopener noreferrer">Phong reflection model<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a> is often used. It splits up the lighting calculation into three (3) parts: ambient lighting, diffuse lighting, and specular lighting. We're going to be learning the <a href="https://en.wikipedia.org/wiki/Blinn%E2%80%93Phong_reflection_model" target="_blank" rel="noopener noreferrer">Blinn-Phong model<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a>, which cheats a bit at the specular calculation to speed things up.</p> <p>Before we can get into that though, we need to add a light to our scene.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// lib.rs</span>
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<span class="token attribute attr-name">#[repr(C)]</span>
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<span class="token attribute attr-name">#[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]</span>
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<span class="token keyword">struct</span> <span class="token type-definition class-name">LightUniform</span> <span class="token punctuation">{</span>
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position<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token comment">// Due to uniforms requiring 16 byte (4 float) spacing, we need to use a padding field here</span>
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_padding<span class="token punctuation">:</span> <span class="token keyword">u32</span><span class="token punctuation">,</span>
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color<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token comment">// Due to uniforms requiring 16 byte (4 float) spacing, we need to use a padding field here</span>
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_padding2<span class="token punctuation">:</span> <span class="token keyword">u32</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>Our <code>LightUniform</code> represents a colored point in space. We're just going to use pure white light, but it's good to allow different colors of light.</p> <div class="note"><p>The rule of thumb for alignment with WGSL structs is field alignments are
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always powers of 2. For example, a <code>vec3</code> may only have 3 float fields giving
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it a size of 12, the alignment will be bumped up to the next power of 2 being
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16. This means that you have to be more careful with how you layout your struct
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in Rust.</p> <p>Some developers choose the use <code>vec4</code>s instead of <code>vec3</code>s to avoid alignment
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issues. You can learn more about the alignment rules in the <a href="https://www.w3.org/TR/WGSL/#alignment-and-size" target="_blank" rel="noopener noreferrer">wgsl spec<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a></p></div> <p>We're going to create another buffer to store our light in.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> light_uniform <span class="token operator">=</span> <span class="token class-name">LightUniform</span> <span class="token punctuation">{</span>
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position<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token number">2.0</span><span class="token punctuation">,</span> <span class="token number">2.0</span><span class="token punctuation">,</span> <span class="token number">2.0</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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_padding<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
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color<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token number">1.0</span><span class="token punctuation">,</span> <span class="token number">1.0</span><span class="token punctuation">,</span> <span class="token number">1.0</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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_padding2<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token comment">// We'll want to update our lights position, so we use COPY_DST</span>
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<span class="token keyword">let</span> light_buffer <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_buffer_init</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span>util<span class="token punctuation">::</span></span><span class="token class-name">BufferInitDescriptor</span> <span class="token punctuation">{</span>
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label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Light VB"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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contents<span class="token punctuation">:</span> <span class="token namespace">bytemuck<span class="token punctuation">::</span></span><span class="token function">cast_slice</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token punctuation">[</span>light_uniform<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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usage<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferUsages</span><span class="token punctuation">::</span><span class="token constant">UNIFORM</span> <span class="token operator">|</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferUsages</span><span class="token punctuation">::</span><span class="token constant">COPY_DST</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>Don't forget to add the <code>light_uniform</code> and <code>light_buffer</code> to <code>State</code>. After that, we need to create a bind group layout and bind group for our light.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> light_bind_group_layout <span class="token operator">=</span>
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device<span class="token punctuation">.</span><span class="token function">create_bind_group_layout</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroupLayoutDescriptor</span> <span class="token punctuation">{</span>
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entries<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroupLayoutEntry</span> <span class="token punctuation">{</span>
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binding<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
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visibility<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderStages</span><span class="token punctuation">::</span><span class="token constant">VERTEX</span> <span class="token operator">|</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderStages</span><span class="token punctuation">::</span><span class="token constant">FRAGMENT</span><span class="token punctuation">,</span>
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ty<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindingType</span><span class="token punctuation">::</span><span class="token class-name">Buffer</span> <span class="token punctuation">{</span>
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ty<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferBindingType</span><span class="token punctuation">::</span><span class="token class-name">Uniform</span><span class="token punctuation">,</span>
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has_dynamic_offset<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
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min_binding_size<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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count<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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label<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> light_bind_group <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_bind_group</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroupDescriptor</span> <span class="token punctuation">{</span>
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layout<span class="token punctuation">:</span> <span class="token operator">&</span>light_bind_group_layout<span class="token punctuation">,</span>
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entries<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroupEntry</span> <span class="token punctuation">{</span>
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binding<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
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resource<span class="token punctuation">:</span> light_buffer<span class="token punctuation">.</span><span class="token function">as_entire_binding</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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label<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>Add those to <code>State</code>, and also update the <code>render_pipeline_layout</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> render_pipeline_layout <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_pipeline_layout</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PipelineLayoutDescriptor</span> <span class="token punctuation">{</span>
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bind_group_layouts<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span>
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<span class="token operator">&</span>texture_bind_group_layout<span class="token punctuation">,</span>
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<span class="token operator">&</span>camera_bind_group_layout<span class="token punctuation">,</span>
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<span class="token operator">&</span>light_bind_group_layout<span class="token punctuation">,</span>
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<span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>Let's also update the light's position in the <code>update()</code> method, so we can see what our objects look like from different angles.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// Update the light</span>
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<span class="token keyword">let</span> old_position<span class="token punctuation">:</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Vector3</span><span class="token operator"><</span>_<span class="token operator">></span> <span class="token operator">=</span> <span class="token keyword">self</span><span class="token punctuation">.</span>light_uniform<span class="token punctuation">.</span>position<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span>light_uniform<span class="token punctuation">.</span>position <span class="token operator">=</span>
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<span class="token punctuation">(</span><span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Quaternion</span><span class="token punctuation">::</span><span class="token function">from_axis_angle</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token number">0.0</span><span class="token punctuation">,</span> <span class="token number">1.0</span><span class="token punctuation">,</span> <span class="token number">0.0</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Deg</span><span class="token punctuation">(</span><span class="token number">1.0</span><span class="token punctuation">)</span><span class="token punctuation">)</span>
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<span class="token operator">*</span> old_position<span class="token punctuation">)</span>
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<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span>queue<span class="token punctuation">.</span><span class="token function">write_buffer</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>light_buffer<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> <span class="token namespace">bytemuck<span class="token punctuation">::</span></span><span class="token function">cast_slice</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token punctuation">[</span><span class="token keyword">self</span><span class="token punctuation">.</span>light_uniform<span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>This will have the light rotate around the origin one degree every frame.</p> <h2 id="seeing-the-light"><a href="#seeing-the-light" class="header-anchor">#</a> Seeing the light</h2> <p>For debugging purposes, it would be nice if we could see where the light is to make sure that the scene looks correct. We could adapt our existing render pipeline to draw the light, but it will likely get in the way. Instead, we are going to extract our render pipeline creation code into a new function called <code>create_render_pipeline()</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">fn</span> <span class="token function-definition function">create_render_pipeline</span><span class="token punctuation">(</span>
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device<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Device</span><span class="token punctuation">,</span>
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layout<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PipelineLayout</span><span class="token punctuation">,</span>
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|
color_format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">TextureFormat</span><span class="token punctuation">,</span>
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depth_format<span class="token punctuation">:</span> <span class="token class-name">Option</span><span class="token operator"><</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">TextureFormat</span><span class="token operator">></span><span class="token punctuation">,</span>
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vertex_layouts<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexBufferLayout</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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shader<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderModuleDescriptor</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">-></span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">RenderPipeline</span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> shader <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_shader_module</span><span class="token punctuation">(</span>shader<span class="token punctuation">)</span><span class="token punctuation">;</span>
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device<span class="token punctuation">.</span><span class="token function">create_render_pipeline</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">RenderPipelineDescriptor</span> <span class="token punctuation">{</span>
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label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Render Pipeline"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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layout<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span>layout<span class="token punctuation">)</span><span class="token punctuation">,</span>
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vertex<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexState</span> <span class="token punctuation">{</span>
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module<span class="token punctuation">:</span> <span class="token operator">&</span>shader<span class="token punctuation">,</span>
|
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entry_point<span class="token punctuation">:</span> <span class="token string">"vs_main"</span><span class="token punctuation">,</span>
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buffers<span class="token punctuation">:</span> vertex_layouts<span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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fragment<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">FragmentState</span> <span class="token punctuation">{</span>
|
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module<span class="token punctuation">:</span> <span class="token operator">&</span>shader<span class="token punctuation">,</span>
|
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entry_point<span class="token punctuation">:</span> <span class="token string">"fs_main"</span><span class="token punctuation">,</span>
|
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targets<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ColorTargetState</span> <span class="token punctuation">{</span>
|
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format<span class="token punctuation">:</span> color_format<span class="token punctuation">,</span>
|
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blend<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BlendState</span> <span class="token punctuation">{</span>
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alpha<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BlendComponent</span><span class="token punctuation">::</span><span class="token constant">REPLACE</span><span class="token punctuation">,</span>
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color<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BlendComponent</span><span class="token punctuation">::</span><span class="token constant">REPLACE</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
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write_mask<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ColorWrites</span><span class="token punctuation">::</span><span class="token constant">ALL</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
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primitive<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PrimitiveState</span> <span class="token punctuation">{</span>
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topology<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PrimitiveTopology</span><span class="token punctuation">::</span><span class="token class-name">TriangleList</span><span class="token punctuation">,</span>
|
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strip_index_format<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
|
|
front_face<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">FrontFace</span><span class="token punctuation">::</span><span class="token class-name">Ccw</span><span class="token punctuation">,</span>
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cull_mode<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Face</span><span class="token punctuation">::</span><span class="token class-name">Back</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
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<span class="token comment">// Setting this to anything other than Fill requires Features::NON_FILL_POLYGON_MODE</span>
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polygon_mode<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PolygonMode</span><span class="token punctuation">::</span><span class="token class-name">Fill</span><span class="token punctuation">,</span>
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<span class="token comment">// Requires Features::DEPTH_CLIP_CONTROL</span>
|
|
unclipped_depth<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
|
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<span class="token comment">// Requires Features::CONSERVATIVE_RASTERIZATION</span>
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conservative<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
|
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depth_stencil<span class="token punctuation">:</span> depth_format<span class="token punctuation">.</span><span class="token function">map</span><span class="token punctuation">(</span><span class="token closure-params"><span class="token closure-punctuation punctuation">|</span>format<span class="token closure-punctuation punctuation">|</span></span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">DepthStencilState</span> <span class="token punctuation">{</span>
|
|
format<span class="token punctuation">,</span>
|
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depth_write_enabled<span class="token punctuation">:</span> <span class="token boolean">true</span><span class="token punctuation">,</span>
|
|
depth_compare<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">CompareFunction</span><span class="token punctuation">::</span><span class="token class-name">Less</span><span class="token punctuation">,</span>
|
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stencil<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">StencilState</span><span class="token punctuation">::</span><span class="token function">default</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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bias<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">DepthBiasState</span><span class="token punctuation">::</span><span class="token function">default</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
|
multisample<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">MultisampleState</span> <span class="token punctuation">{</span>
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count<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span>
|
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mask<span class="token punctuation">:</span> <span class="token operator">!</span><span class="token number">0</span><span class="token punctuation">,</span>
|
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alpha_to_coverage_enabled<span class="token punctuation">:</span> <span class="token boolean">false</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
|
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multiview<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">)</span>
|
|
<span class="token punctuation">}</span>
|
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</code></pre></div><p>We also need to change <code>State::new()</code> to use this function.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> render_pipeline <span class="token operator">=</span> <span class="token punctuation">{</span>
|
|
<span class="token keyword">let</span> shader <span class="token operator">=</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderModuleDescriptor</span> <span class="token punctuation">{</span>
|
|
label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Normal Shader"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
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source<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderSource</span><span class="token punctuation">::</span><span class="token class-name">Wgsl</span><span class="token punctuation">(</span><span class="token macro property">include_str!</span><span class="token punctuation">(</span><span class="token string">"shader.wgsl"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
|
|
<span class="token function">create_render_pipeline</span><span class="token punctuation">(</span>
|
|
<span class="token operator">&</span>device<span class="token punctuation">,</span>
|
|
<span class="token operator">&</span>render_pipeline_layout<span class="token punctuation">,</span>
|
|
config<span class="token punctuation">.</span>format<span class="token punctuation">,</span>
|
|
<span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token namespace">texture<span class="token punctuation">::</span></span><span class="token class-name">Texture</span><span class="token punctuation">::</span><span class="token constant">DEPTH_FORMAT</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token operator">&</span><span class="token punctuation">[</span><span class="token namespace">model<span class="token punctuation">::</span></span><span class="token class-name">ModelVertex</span><span class="token punctuation">::</span><span class="token function">desc</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token class-name">InstanceRaw</span><span class="token punctuation">::</span><span class="token function">desc</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
|
|
shader<span class="token punctuation">,</span>
|
|
<span class="token punctuation">)</span>
|
|
<span class="token punctuation">}</span><span class="token punctuation">;</span>
|
|
</code></pre></div><p>We're going to need to modify <code>model::DrawModel</code> to use our <code>light_bind_group</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// model.rs</span>
|
|
<span class="token keyword">pub</span> <span class="token keyword">trait</span> <span class="token type-definition class-name">DrawModel</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token operator">></span> <span class="token punctuation">{</span>
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|
<span class="token keyword">fn</span> <span class="token function-definition function">draw_mesh</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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material<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Material</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
|
|
light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
|
|
<span class="token punctuation">)</span><span class="token punctuation">;</span>
|
|
<span class="token keyword">fn</span> <span class="token function-definition function">draw_mesh_instanced</span><span class="token punctuation">(</span>
|
|
<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
|
|
mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
|
|
material<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Material</span><span class="token punctuation">,</span>
|
|
instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
|
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
|
|
light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
|
|
<span class="token punctuation">)</span><span class="token punctuation">;</span>
|
|
|
|
<span class="token keyword">fn</span> <span class="token function-definition function">draw_model</span><span class="token punctuation">(</span>
|
|
<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
|
|
model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
|
|
camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
|
|
light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
|
|
<span class="token punctuation">)</span><span class="token punctuation">;</span>
|
|
<span class="token keyword">fn</span> <span class="token function-definition function">draw_model_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">impl</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token punctuation">,</span> <span class="token lifetime-annotation symbol">'b</span><span class="token operator">></span> <span class="token class-name">DrawModel</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'b</span><span class="token operator">></span> <span class="token keyword">for</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">RenderPass</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token operator">></span>
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<span class="token keyword">where</span>
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<span class="token lifetime-annotation symbol">'b</span><span class="token punctuation">:</span> <span class="token lifetime-annotation symbol">'a</span><span class="token punctuation">,</span>
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<span class="token punctuation">{</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_mesh</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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material<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Material</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_mesh_instanced</span><span class="token punctuation">(</span>mesh<span class="token punctuation">,</span> material<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">..</span><span class="token number">1</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> light_bind_group<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_mesh_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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material<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Material</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_vertex_buffer</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> mesh<span class="token punctuation">.</span>vertex_buffer<span class="token punctuation">.</span><span class="token function">slice</span><span class="token punctuation">(</span><span class="token punctuation">..</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_index_buffer</span><span class="token punctuation">(</span>mesh<span class="token punctuation">.</span>index_buffer<span class="token punctuation">.</span><span class="token function">slice</span><span class="token punctuation">(</span><span class="token punctuation">..</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">IndexFormat</span><span class="token punctuation">::</span><span class="token class-name">Uint32</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_bind_group</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> <span class="token operator">&</span>material<span class="token punctuation">.</span>bind_group<span class="token punctuation">,</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_bind_group</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_bind_group</span><span class="token punctuation">(</span><span class="token number">2</span><span class="token punctuation">,</span> light_bind_group<span class="token punctuation">,</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_indexed</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">..</span>mesh<span class="token punctuation">.</span>num_elements<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> instances<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_model</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_model_instanced</span><span class="token punctuation">(</span>model<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">..</span><span class="token number">1</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> light_bind_group<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_model_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">for</span> mesh <span class="token keyword">in</span> <span class="token operator">&</span>model<span class="token punctuation">.</span>meshes <span class="token punctuation">{</span>
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<span class="token keyword">let</span> material <span class="token operator">=</span> <span class="token operator">&</span>model<span class="token punctuation">.</span>materials<span class="token punctuation">[</span>mesh<span class="token punctuation">.</span>material<span class="token punctuation">]</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_mesh_instanced</span><span class="token punctuation">(</span>mesh<span class="token punctuation">,</span> material<span class="token punctuation">,</span> instances<span class="token punctuation">.</span><span class="token function">clone</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> light_bind_group<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>With that done we can create another render pipeline for our light.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// lib.rs</span>
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<span class="token keyword">let</span> light_render_pipeline <span class="token operator">=</span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> layout <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_pipeline_layout</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PipelineLayoutDescriptor</span> <span class="token punctuation">{</span>
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label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Light Pipeline Layout"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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bind_group_layouts<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token operator">&</span>camera_bind_group_layout<span class="token punctuation">,</span> <span class="token operator">&</span>light_bind_group_layout<span class="token punctuation">]</span><span class="token punctuation">,</span>
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push_constant_ranges<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> shader <span class="token operator">=</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderModuleDescriptor</span> <span class="token punctuation">{</span>
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label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Light Shader"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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source<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderSource</span><span class="token punctuation">::</span><span class="token class-name">Wgsl</span><span class="token punctuation">(</span><span class="token macro property">include_str!</span><span class="token punctuation">(</span><span class="token string">"light.wgsl"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token function">create_render_pipeline</span><span class="token punctuation">(</span>
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<span class="token operator">&</span>device<span class="token punctuation">,</span>
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<span class="token operator">&</span>layout<span class="token punctuation">,</span>
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config<span class="token punctuation">.</span>format<span class="token punctuation">,</span>
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<span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token namespace">texture<span class="token punctuation">::</span></span><span class="token class-name">Texture</span><span class="token punctuation">::</span><span class="token constant">DEPTH_FORMAT</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token operator">&</span><span class="token punctuation">[</span><span class="token namespace">model<span class="token punctuation">::</span></span><span class="token class-name">ModelVertex</span><span class="token punctuation">::</span><span class="token function">desc</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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shader<span class="token punctuation">,</span>
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<span class="token punctuation">)</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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</code></pre></div><p>I chose to create a separate layout for the <code>light_render_pipeline</code>, as it doesn't need all the resources that the regular <code>render_pipeline</code> needs (main just the textures).</p> <p>With that in place, we need to write the actual shaders.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token comment">// light.wgsl</span>
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<span class="token comment">// Vertex shader</span>
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<span class="token keyword">struct</span> <span class="token class-name">Camera</span> <span class="token punctuation">{</span>
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view_proj<span class="token punctuation">:</span> <span class="token builtin">mat4x4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">group</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> <span class="token punctuation">@</span><span class="token attributes attr-name">binding</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span>
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<span class="token keyword">var</span><span class="token punctuation"><</span><span class="token keyword">uniform</span><span class="token punctuation">></span> camera<span class="token punctuation">:</span> <span class="token class-name">Camera</span><span class="token punctuation">;</span>
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<span class="token keyword">struct</span> <span class="token class-name">Light</span> <span class="token punctuation">{</span>
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position<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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color<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">group</span><span class="token punctuation">(</span><span class="token int-literal number">1</span><span class="token punctuation">)</span> <span class="token punctuation">@</span><span class="token attributes attr-name">binding</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span>
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<span class="token keyword">var</span><span class="token punctuation"><</span><span class="token keyword">uniform</span><span class="token punctuation">></span> light<span class="token punctuation">:</span> <span class="token class-name">Light</span><span class="token punctuation">;</span>
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<span class="token keyword">struct</span> <span class="token class-name">VertexInput</span> <span class="token punctuation">{</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> position<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token keyword">struct</span> <span class="token class-name">VertexOutput</span> <span class="token punctuation">{</span>
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<span class="token punctuation">@</span><span class="token builtin-attribute"><span class="token attribute attr-name">builtin</span><span class="token punctuation">(</span><span class="token built-in-values attr-value">position</span><span class="token punctuation">)</span></span> clip_position<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> color<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">vertex</span>
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<span class="token keyword">fn</span> <span class="token functions function">vs_main</span><span class="token punctuation">(</span>
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model<span class="token punctuation">:</span> <span class="token class-name">VertexInput</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">VertexOutput</span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> scale <span class="token operator">=</span> <span class="token decimal-float-literal number">0.25</span><span class="token punctuation">;</span>
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<span class="token keyword">var</span> out<span class="token punctuation">:</span> <span class="token class-name">VertexOutput</span><span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>clip_position <span class="token operator">=</span> camera<span class="token punctuation">.</span>view_proj <span class="token operator">*</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>model<span class="token punctuation">.</span>position <span class="token operator">*</span> scale <span class="token operator">+</span> light<span class="token punctuation">.</span>position<span class="token punctuation">,</span> <span class="token decimal-float-literal number">1.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>color <span class="token operator">=</span> light<span class="token punctuation">.</span>color<span class="token punctuation">;</span>
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<span class="token keyword">return</span> out<span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token comment">// Fragment shader</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">fragment</span>
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<span class="token keyword">fn</span> <span class="token functions function">fs_main</span><span class="token punctuation">(</span>in<span class="token punctuation">:</span> <span class="token class-name">VertexOutput</span><span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span> <span class="token punctuation">{</span>
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<span class="token keyword">return</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>in<span class="token punctuation">.</span>color<span class="token punctuation">,</span> <span class="token decimal-float-literal number">1.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>Now we could manually implement the draw code for the light in <code>render()</code>, but to keep with the pattern we developed, let's create a new trait called <code>DrawLight</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// model.rs</span>
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<span class="token keyword">pub</span> <span class="token keyword">trait</span> <span class="token type-definition class-name">DrawLight</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token operator">></span> <span class="token punctuation">{</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_mesh</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_mesh_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_model</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_model_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'a</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">impl</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token punctuation">,</span> <span class="token lifetime-annotation symbol">'b</span><span class="token operator">></span> <span class="token class-name">DrawLight</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'b</span><span class="token operator">></span> <span class="token keyword">for</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">RenderPass</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'a</span><span class="token operator">></span>
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<span class="token keyword">where</span>
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<span class="token lifetime-annotation symbol">'b</span><span class="token punctuation">:</span> <span class="token lifetime-annotation symbol">'a</span><span class="token punctuation">,</span>
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<span class="token punctuation">{</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_mesh</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_light_mesh_instanced</span><span class="token punctuation">(</span>mesh<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">..</span><span class="token number">1</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> light_bind_group<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_mesh_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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mesh<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Mesh</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_vertex_buffer</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> mesh<span class="token punctuation">.</span>vertex_buffer<span class="token punctuation">.</span><span class="token function">slice</span><span class="token punctuation">(</span><span class="token punctuation">..</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_index_buffer</span><span class="token punctuation">(</span>mesh<span class="token punctuation">.</span>index_buffer<span class="token punctuation">.</span><span class="token function">slice</span><span class="token punctuation">(</span><span class="token punctuation">..</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">IndexFormat</span><span class="token punctuation">::</span><span class="token class-name">Uint32</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_bind_group</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">set_bind_group</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> light_bind_group<span class="token punctuation">,</span> <span class="token operator">&</span><span class="token punctuation">[</span><span class="token punctuation">]</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_indexed</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">..</span>mesh<span class="token punctuation">.</span>num_elements<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">,</span> instances<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_model</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_light_model_instanced</span><span class="token punctuation">(</span>model<span class="token punctuation">,</span> <span class="token number">0</span><span class="token punctuation">..</span><span class="token number">1</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> light_bind_group<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">draw_light_model_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span>
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model<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token class-name">Model</span><span class="token punctuation">,</span>
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instances<span class="token punctuation">:</span> <span class="token class-name">Range</span><span class="token operator"><</span><span class="token keyword">u32</span><span class="token operator">></span><span class="token punctuation">,</span>
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camera_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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light_bind_group<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token lifetime-annotation symbol">'b</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroup</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token keyword">for</span> mesh <span class="token keyword">in</span> <span class="token operator">&</span>model<span class="token punctuation">.</span>meshes <span class="token punctuation">{</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span><span class="token function">draw_light_mesh_instanced</span><span class="token punctuation">(</span>mesh<span class="token punctuation">,</span> instances<span class="token punctuation">.</span><span class="token function">clone</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> camera_bind_group<span class="token punctuation">,</span> light_bind_group<span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>Finally, we want to add Light rendering to our render passes.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">impl</span> <span class="token class-name">State</span> <span class="token punctuation">{</span>
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<span class="token comment">// ...</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">render</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-></span> <span class="token class-name">Result</span><span class="token operator"><</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">SurfaceError</span><span class="token operator">></span> <span class="token punctuation">{</span>
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<span class="token comment">// ...</span>
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render_pass<span class="token punctuation">.</span><span class="token function">set_vertex_buffer</span><span class="token punctuation">(</span><span class="token number">1</span><span class="token punctuation">,</span> <span class="token keyword">self</span><span class="token punctuation">.</span>instance_buffer<span class="token punctuation">.</span><span class="token function">slice</span><span class="token punctuation">(</span><span class="token punctuation">..</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">use</span> <span class="token keyword">crate</span><span class="token module-declaration namespace"><span class="token punctuation">::</span>model<span class="token punctuation">::</span></span><span class="token class-name">DrawLight</span><span class="token punctuation">;</span> <span class="token comment">// NEW!</span>
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render_pass<span class="token punctuation">.</span><span class="token function">set_pipeline</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>light_render_pipeline<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// NEW!</span>
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render_pass<span class="token punctuation">.</span><span class="token function">draw_light_model</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>obj_model<span class="token punctuation">,</span>
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<span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>camera_bind_group<span class="token punctuation">,</span>
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<span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>light_bind_group<span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span> <span class="token comment">// NEW!</span>
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render_pass<span class="token punctuation">.</span><span class="token function">set_pipeline</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>render_pipeline<span class="token punctuation">)</span><span class="token punctuation">;</span>
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render_pass<span class="token punctuation">.</span><span class="token function">draw_model_instanced</span><span class="token punctuation">(</span>
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<span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>obj_model<span class="token punctuation">,</span>
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<span class="token number">0</span><span class="token punctuation">..</span><span class="token keyword">self</span><span class="token punctuation">.</span>instances<span class="token punctuation">.</span><span class="token function">len</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token keyword">u32</span><span class="token punctuation">,</span>
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<span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>camera_bind_group<span class="token punctuation">,</span>
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<span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">.</span>light_bind_group<span class="token punctuation">,</span> <span class="token comment">// NEW</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>With all that, we'll end up with something like this.</p> <p><img src="/learn-wgpu/assets/img/light-in-scene.7c329d72.png" alt="./light-in-scene.png"></p> <h2 id="ambient-lighting"><a href="#ambient-lighting" class="header-anchor">#</a> Ambient Lighting</h2> <p>Light has a tendency to bounce around before entering our eyes. That's why you can see in areas that are in shadow. Actually modeling this interaction is computationally expensive, so we cheat. We define an ambient lighting value that stands for the light bouncing off other parts of the scene to light our objects.</p> <p>The ambient part is based on the light color as well as the object color. We've already added our <code>light_bind_group</code>, so we just need to use it in our shader. In <code>shader.wgsl</code>, add the following below the texture uniforms.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">struct</span> <span class="token class-name">Light</span> <span class="token punctuation">{</span>
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position<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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color<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">group</span><span class="token punctuation">(</span><span class="token int-literal number">2</span><span class="token punctuation">)</span> <span class="token punctuation">@</span><span class="token attributes attr-name">binding</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span>
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<span class="token keyword">var</span><span class="token punctuation"><</span><span class="token keyword">uniform</span><span class="token punctuation">></span> light<span class="token punctuation">:</span> <span class="token class-name">Light</span><span class="token punctuation">;</span>
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</code></pre></div><p>Then we need to update our main shader code to calculate and use the ambient color value.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token punctuation">@</span><span class="token attributes attr-name">fragment</span>
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<span class="token keyword">fn</span> <span class="token functions function">fs_main</span><span class="token punctuation">(</span>in<span class="token punctuation">:</span> <span class="token class-name">VertexOutput</span><span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> object_color<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span> <span class="token operator">=</span> <span class="token builtin">textureSample</span><span class="token punctuation">(</span>t_diffuse<span class="token punctuation">,</span> s_diffuse<span class="token punctuation">,</span> in<span class="token punctuation">.</span>tex_coords<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token comment">// We don't need (or want) much ambient light, so 0.1 is fine</span>
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<span class="token keyword">let</span> ambient_strength <span class="token operator">=</span> <span class="token decimal-float-literal number">0.1</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> ambient_color <span class="token operator">=</span> light<span class="token punctuation">.</span>color <span class="token operator">*</span> ambient_strength<span class="token punctuation">;</span>
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<span class="token keyword">let</span> result <span class="token operator">=</span> ambient_color <span class="token operator">*</span> object_color<span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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<span class="token keyword">return</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>result<span class="token punctuation">,</span> object_color<span class="token punctuation">.</span>a<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>With that, we should get something like this.</p> <p><img src="/learn-wgpu/assets/img/ambient_lighting.8bece8d1.png" alt="./ambient_lighting.png"></p> <h2 id="diffuse-lighting"><a href="#diffuse-lighting" class="header-anchor">#</a> Diffuse Lighting</h2> <p>Remember the normal vectors that were included with our model? We're finally going to use them. Normals represent the direction a surface is facing. By comparing the normal of a fragment with a vector pointing to a light source, we get a value of how light/dark that fragment should be. We compare the vector using the dot product to get the cosine of the angle between them.</p> <p><img src="/learn-wgpu/assets/img/normal_diagram.dfa577f7.png" alt="./normal_diagram.png"></p> <p>If the dot product of the normal and light vector is 1.0, that means that the current fragment is directly in line with the light source and will receive the light's full intensity. A value of 0.0 or lower means that the surface is perpendicular or facing away from the light, and therefore will be dark.</p> <p>We're going to need to pull in the normal vector into our <code>shader.wgsl</code>.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">struct</span> <span class="token class-name">VertexInput</span> <span class="token punctuation">{</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> position<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">1</span><span class="token punctuation">)</span> tex_coords<span class="token punctuation">:</span> <span class="token builtin">vec2</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">2</span><span class="token punctuation">)</span> normal<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span> <span class="token comment">// NEW!</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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</code></pre></div><p>We're also going to want to pass that value, as well as the vertex's position to the fragment shader.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">struct</span> <span class="token class-name">VertexOutput</span> <span class="token punctuation">{</span>
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<span class="token punctuation">@</span><span class="token builtin-attribute"><span class="token attribute attr-name">builtin</span><span class="token punctuation">(</span><span class="token built-in-values attr-value">position</span><span class="token punctuation">)</span></span> clip_position<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> tex_coords<span class="token punctuation">:</span> <span class="token builtin">vec2</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">1</span><span class="token punctuation">)</span> world_normal<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">2</span><span class="token punctuation">)</span> world_position<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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</code></pre></div><p>For now, let's just pass the normal directly as-is. This is wrong, but we'll fix it later.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token punctuation">@</span><span class="token attributes attr-name">vertex</span>
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<span class="token keyword">fn</span> <span class="token functions function">vs_main</span><span class="token punctuation">(</span>
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model<span class="token punctuation">:</span> <span class="token class-name">VertexInput</span><span class="token punctuation">,</span>
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instance<span class="token punctuation">:</span> <span class="token class-name">InstanceInput</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">VertexOutput</span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> model_matrix <span class="token operator">=</span> <span class="token builtin">mat4x4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>
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instance<span class="token punctuation">.</span>model_matrix_0<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>model_matrix_1<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>model_matrix_2<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>model_matrix_3<span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">var</span> out<span class="token punctuation">:</span> <span class="token class-name">VertexOutput</span><span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>tex_coords <span class="token operator">=</span> model<span class="token punctuation">.</span>tex_coords<span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>world_normal <span class="token operator">=</span> model<span class="token punctuation">.</span>normal<span class="token punctuation">;</span>
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<span class="token keyword">var</span> world_position<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span> <span class="token operator">=</span> model_matrix <span class="token operator">*</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>model<span class="token punctuation">.</span>position<span class="token punctuation">,</span> <span class="token decimal-float-literal number">1.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>world_position <span class="token operator">=</span> world_position<span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>clip_position <span class="token operator">=</span> camera<span class="token punctuation">.</span>view_proj <span class="token operator">*</span> world_position<span class="token punctuation">;</span>
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<span class="token keyword">return</span> out<span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>With that, we can do the actual calculation. Below the <code>ambient_color</code> calculation, but above <code>result</code>, add the following.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">let</span> light_dir <span class="token operator">=</span> <span class="token builtin">normalize</span><span class="token punctuation">(</span>light<span class="token punctuation">.</span>position <span class="token operator">-</span> in<span class="token punctuation">.</span>world_position<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> diffuse_strength <span class="token operator">=</span> <span class="token builtin">max</span><span class="token punctuation">(</span><span class="token builtin">dot</span><span class="token punctuation">(</span>in<span class="token punctuation">.</span>world_normal<span class="token punctuation">,</span> light_dir<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token decimal-float-literal number">0.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> diffuse_color <span class="token operator">=</span> light<span class="token punctuation">.</span>color <span class="token operator">*</span> diffuse_strength<span class="token punctuation">;</span>
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</code></pre></div><p>Now we can include the <code>diffuse_color</code> in the <code>result</code>.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">let</span> result <span class="token operator">=</span> <span class="token punctuation">(</span>ambient_color <span class="token operator">+</span> diffuse_color<span class="token punctuation">)</span> <span class="token operator">*</span> object_color<span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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</code></pre></div><p>With that, we get something like this.</p> <p><img src="/learn-wgpu/assets/img/ambient_diffuse_wrong.dab00d9a.png" alt="./ambient_diffuse_wrong.png"></p> <h2 id="the-normal-matrix"><a href="#the-normal-matrix" class="header-anchor">#</a> The normal matrix</h2> <p>Remember when I said passing the vertex normal directly to the fragment shader was wrong? Let's explore that by removing all the cubes from the scene except one that will be rotated 180 degrees on the y-axis.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">const</span> <span class="token constant">NUM_INSTANCES_PER_ROW</span><span class="token punctuation">:</span> <span class="token keyword">u32</span> <span class="token operator">=</span> <span class="token number">1</span><span class="token punctuation">;</span>
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<span class="token comment">// In the loop we create the instances in</span>
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<span class="token keyword">let</span> rotation <span class="token operator">=</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Quaternion</span><span class="token punctuation">::</span><span class="token function">from_axis_angle</span><span class="token punctuation">(</span><span class="token punctuation">(</span><span class="token number">0.0</span><span class="token punctuation">,</span> <span class="token number">1.0</span><span class="token punctuation">,</span> <span class="token number">0.0</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Deg</span><span class="token punctuation">(</span><span class="token number">180.0</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>We'll also remove the <code>ambient_color</code> from our lighting <code>result</code>.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">let</span> result <span class="token operator">=</span> <span class="token punctuation">(</span>diffuse_color<span class="token punctuation">)</span> <span class="token operator">*</span> object_color<span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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</code></pre></div><p>That should give us something that looks like this.</p> <p><img src="/learn-wgpu/assets/img/diffuse_wrong.ce856a2c.png" alt="./diffuse_wrong.png"></p> <p>This is clearly wrong as the light is illuminating the wrong side of the cube. This is because we aren't rotating our normals with our object, so no matter what direction the object faces, the normals will always face the same way.</p> <p><img src="data:image/png;base64,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" alt="./normal_not_rotated.png"></p> <p>We need to use the model matrix to transform the normals to be in the right direction. We only want the rotation data though. A normal represents a direction and should be a unit vector throughout the calculation. We can get our normals in the right direction using what is called a normal matrix.</p> <p>We could compute the normal matrix in the vertex shader, but that would involve inverting the <code>model_matrix</code>, and WGSL doesn't actually have an inverse function. We would have to code our own. On top of that computing, the inverse of a matrix is actually really expensive, especially doing that computation for every vertex.</p> <p>Instead, we're going to add a <code>normal</code> matrix field to <code>InstanceRaw</code>. Instead of inverting the model matrix, we'll just be using the instance's rotation to create a <code>Matrix3</code>.</p> <div class="note"><p>We are using <code>Matrix3</code> instead of <code>Matrix4</code> as we only really need the rotation component of the matrix.</p></div> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token attribute attr-name">#[repr(C)]</span>
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<span class="token attribute attr-name">#[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]</span>
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<span class="token attribute attr-name">#[allow(dead_code)]</span>
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<span class="token keyword">struct</span> <span class="token type-definition class-name">InstanceRaw</span> <span class="token punctuation">{</span>
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model<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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normal<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token number">3</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">impl</span> <span class="token namespace">model<span class="token punctuation">::</span></span><span class="token class-name">Vertex</span> <span class="token keyword">for</span> <span class="token class-name">InstanceRaw</span> <span class="token punctuation">{</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">desc</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">-></span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexBufferLayout</span><span class="token operator"><</span><span class="token lifetime-annotation symbol">'static</span><span class="token operator">></span> <span class="token punctuation">{</span>
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<span class="token keyword">use</span> <span class="token namespace">std<span class="token punctuation">::</span></span>mem<span class="token punctuation">;</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexBufferLayout</span> <span class="token punctuation">{</span>
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array_stride<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token class-name">InstanceRaw</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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<span class="token comment">// We need to switch from using a step mode of Vertex to Instance</span>
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<span class="token comment">// This means that our shaders will only change to use the next</span>
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<span class="token comment">// instance when the shader starts processing a new instance</span>
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step_mode<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexStepMode</span><span class="token punctuation">::</span><span class="token class-name">Instance</span><span class="token punctuation">,</span>
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attributes<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
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<span class="token comment">// While our vertex shader only uses locations 0, and 1 now, in later tutorials we'll</span>
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<span class="token comment">// be using 2, 3, and 4, for Vertex. We'll start at slot 5 not conflict with them later</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">5</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x4</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token comment">// A mat4 takes up 4 vertex slots as it is technically 4 vec4s. We need to define a slot</span>
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<span class="token comment">// for each vec4. We don't have to do this in code though.</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">6</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x4</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">8</span><span class="token punctuation">]</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">7</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x4</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">12</span><span class="token punctuation">]</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">8</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x4</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token comment">// NEW!</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">16</span><span class="token punctuation">]</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">9</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x3</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">19</span><span class="token punctuation">]</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">10</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x3</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexAttribute</span> <span class="token punctuation">{</span>
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offset<span class="token punctuation">:</span> <span class="token namespace">mem<span class="token punctuation">::</span></span><span class="token function">size_of</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">22</span><span class="token punctuation">]</span><span class="token operator">></span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token keyword">as</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferAddress</span><span class="token punctuation">,</span>
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shader_location<span class="token punctuation">:</span> <span class="token number">11</span><span class="token punctuation">,</span>
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format<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">VertexFormat</span><span class="token punctuation">::</span><span class="token class-name">Float32x3</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>We need to modify <code>Instance</code> to create the normal matrix.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">struct</span> <span class="token type-definition class-name">Instance</span> <span class="token punctuation">{</span>
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position<span class="token punctuation">:</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Vector3</span><span class="token operator"><</span><span class="token keyword">f32</span><span class="token operator">></span><span class="token punctuation">,</span>
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rotation<span class="token punctuation">:</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Quaternion</span><span class="token operator"><</span><span class="token keyword">f32</span><span class="token operator">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">impl</span> <span class="token class-name">Instance</span> <span class="token punctuation">{</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">to_raw</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token keyword">self</span><span class="token punctuation">)</span> <span class="token punctuation">-></span> <span class="token class-name">InstanceRaw</span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> model <span class="token operator">=</span>
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<span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Matrix4</span><span class="token punctuation">::</span><span class="token function">from_translation</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>position<span class="token punctuation">)</span> <span class="token operator">*</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Matrix4</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>rotation<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token class-name">InstanceRaw</span> <span class="token punctuation">{</span>
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model<span class="token punctuation">:</span> model<span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token comment">// NEW!</span>
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normal<span class="token punctuation">:</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Matrix3</span><span class="token punctuation">::</span><span class="token function">from</span><span class="token punctuation">(</span><span class="token keyword">self</span><span class="token punctuation">.</span>rotation<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>Now we need to reconstruct the normal matrix in the vertex shader.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">struct</span> <span class="token class-name">InstanceInput</span> <span class="token punctuation">{</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">5</span><span class="token punctuation">)</span> model_matrix_0<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">6</span><span class="token punctuation">)</span> model_matrix_1<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">7</span><span class="token punctuation">)</span> model_matrix_2<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">8</span><span class="token punctuation">)</span> model_matrix_3<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token comment">// NEW!</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">9</span><span class="token punctuation">)</span> normal_matrix_0<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">10</span><span class="token punctuation">)</span> normal_matrix_1<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">11</span><span class="token punctuation">)</span> normal_matrix_2<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token keyword">struct</span> <span class="token class-name">VertexOutput</span> <span class="token punctuation">{</span>
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<span class="token punctuation">@</span><span class="token builtin-attribute"><span class="token attribute attr-name">builtin</span><span class="token punctuation">(</span><span class="token built-in-values attr-value">position</span><span class="token punctuation">)</span></span> clip_position<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span> tex_coords<span class="token punctuation">:</span> <span class="token builtin">vec2</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">1</span><span class="token punctuation">)</span> world_normal<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">location</span><span class="token punctuation">(</span><span class="token int-literal number">2</span><span class="token punctuation">)</span> world_position<span class="token punctuation">:</span> <span class="token builtin">vec3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">vertex</span>
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<span class="token keyword">fn</span> <span class="token functions function">vs_main</span><span class="token punctuation">(</span>
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model<span class="token punctuation">:</span> <span class="token class-name">VertexInput</span><span class="token punctuation">,</span>
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instance<span class="token punctuation">:</span> <span class="token class-name">InstanceInput</span><span class="token punctuation">,</span>
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<span class="token punctuation">)</span> <span class="token operator">-></span> <span class="token class-name">VertexOutput</span> <span class="token punctuation">{</span>
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<span class="token keyword">let</span> model_matrix <span class="token operator">=</span> <span class="token builtin">mat4x4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>
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instance<span class="token punctuation">.</span>model_matrix_0<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>model_matrix_1<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>model_matrix_2<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>model_matrix_3<span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token comment">// NEW!</span>
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<span class="token keyword">let</span> normal_matrix <span class="token operator">=</span> <span class="token builtin">mat3x3</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>
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instance<span class="token punctuation">.</span>normal_matrix_0<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>normal_matrix_1<span class="token punctuation">,</span>
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instance<span class="token punctuation">.</span>normal_matrix_2<span class="token punctuation">,</span>
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<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">var</span> out<span class="token punctuation">:</span> <span class="token class-name">VertexOutput</span><span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>tex_coords <span class="token operator">=</span> model<span class="token punctuation">.</span>tex_coords<span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>world_normal <span class="token operator">=</span> normal_matrix <span class="token operator">*</span> model<span class="token punctuation">.</span>normal<span class="token punctuation">;</span> <span class="token comment">// UPDATED!</span>
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<span class="token keyword">var</span> world_position<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span> <span class="token operator">=</span> model_matrix <span class="token operator">*</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>model<span class="token punctuation">.</span>position<span class="token punctuation">,</span> <span class="token decimal-float-literal number">1.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>world_position <span class="token operator">=</span> world_position<span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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out<span class="token punctuation">.</span>clip_position <span class="token operator">=</span> camera<span class="token punctuation">.</span>view_proj <span class="token operator">*</span> world_position<span class="token punctuation">;</span>
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<span class="token keyword">return</span> out<span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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</code></pre></div><div class="note"><p>I'm currently doing things in <a href="https://gamedev.stackexchange.com/questions/65783/what-are-world-space-and-eye-space-in-game-development" target="_blank" rel="noopener noreferrer">world space<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a>. Doing things in view-space also known as eye-space, is more standard as objects can have lighting issues when they are further away from the origin. If we wanted to use view-space, we would have included the rotation due to the view matrix as well. We'd also have to transform our light's position using something like <code>view_matrix * model_matrix * light_position</code> to keep the calculation from getting messed up when the camera moves.</p> <p>There are advantages to using view space. The main one is when you have massive worlds doing lighting and other calculations in model spacing can cause issues as floating-point precision degrades when numbers get really large. View space keeps the camera at the origin meaning all calculations will be using smaller numbers. The actual lighting math ends up the same, but it does require a bit more setup.</p></div> <p>With that change, our lighting now looks correct.</p> <p><img src="/learn-wgpu/assets/img/diffuse_right.e3a6b793.png" alt="./diffuse_right.png"></p> <p>Bringing back our other objects, and adding the ambient lighting gives us this.</p> <p><img src="/learn-wgpu/assets/img/ambient_diffuse_lighting.98735034.png" alt="./ambient_diffuse_lighting.png">;</p> <div class="note"><p>If you can guarantee that your model matrix will always apply uniform scaling to your objects, you can get away with just using the model matrix. Github user @julhe pointed shared this code with me that does the trick:</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code>out<span class="token punctuation">.</span>world_normal <span class="token operator">=</span> <span class="token punctuation">(</span>model_matrix <span class="token operator">*</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">(</span>model<span class="token punctuation">.</span>normal<span class="token punctuation">,</span> <span class="token decimal-float-literal number">0.0</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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</code></pre></div><p>This works by exploiting the fact that by multiplying a 4x4 matrix by a vector with 0 in the w component, only the rotation and scaling will be applied to the vector. You'll need to normalize this vector though as normals need to be unit length for the calculations to work.</p> <p>The scaling factor <em>needs</em> to be uniform in order for this to work. If it's not the resulting normal will be skewed as you can see in the following image.</p> <p><img src="/learn-wgpu/assets/img/normal-scale-issue.7631ac97.png" alt="./normal-scale-issue.png"></p></div> <h2 id="specular-lighting"><a href="#specular-lighting" class="header-anchor">#</a> Specular Lighting</h2> <p>Specular lighting describes the highlights that appear on objects when viewed from certain angles. If you've ever looked at a car, it's the super bright parts. Basically, some of the light can reflect off the surface like a mirror. The location of the highlight shifts depending on what angle you view it at.</p> <p><img src="data:image/png;base64,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" alt="./specular_diagram.png"></p> <p>Because this is relative to the view angle, we are going to need to pass in the camera's position both into the fragment shader and into the vertex shader.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">struct</span> <span class="token class-name">Camera</span> <span class="token punctuation">{</span>
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view_pos<span class="token punctuation">:</span> <span class="token builtin">vec4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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view_proj<span class="token punctuation">:</span> <span class="token builtin">mat4x4</span><span class="token punctuation"><</span><span class="token builtin">f32</span><span class="token punctuation">></span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">@</span><span class="token attributes attr-name">group</span><span class="token punctuation">(</span><span class="token int-literal number">1</span><span class="token punctuation">)</span> <span class="token punctuation">@</span><span class="token attributes attr-name">binding</span><span class="token punctuation">(</span><span class="token int-literal number">0</span><span class="token punctuation">)</span>
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<span class="token keyword">var</span><span class="token punctuation"><</span><span class="token keyword">uniform</span><span class="token punctuation">></span> camera<span class="token punctuation">:</span> <span class="token class-name">Camera</span><span class="token punctuation">;</span>
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</code></pre></div><div class="note"><p>Don't forget to update the <code>Camera</code> struct in <code>light.wgsl</code> as well, as if it doesn't match the <code>CameraUniform</code> struct in rust, the light will render wrong.</p></div> <p>We're going to need to update the <code>CameraUniform</code> struct as well.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// lib.rs</span>
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<span class="token attribute attr-name">#[repr(C)]</span>
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<span class="token attribute attr-name">#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]</span>
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<span class="token keyword">struct</span> <span class="token type-definition class-name">CameraUniform</span> <span class="token punctuation">{</span>
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view_position<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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view_proj<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token punctuation">[</span><span class="token keyword">f32</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">impl</span> <span class="token class-name">CameraUniform</span> <span class="token punctuation">{</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">new</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">-></span> <span class="token keyword">Self</span> <span class="token punctuation">{</span>
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<span class="token keyword">Self</span> <span class="token punctuation">{</span>
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view_position<span class="token punctuation">:</span> <span class="token punctuation">[</span><span class="token number">0.0</span><span class="token punctuation">;</span> <span class="token number">4</span><span class="token punctuation">]</span><span class="token punctuation">,</span>
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view_proj<span class="token punctuation">:</span> <span class="token namespace">cgmath<span class="token punctuation">::</span></span><span class="token class-name">Matrix4</span><span class="token punctuation">::</span><span class="token function">identity</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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<span class="token keyword">fn</span> <span class="token function-definition function">update_view_proj</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token keyword">mut</span> <span class="token keyword">self</span><span class="token punctuation">,</span> camera<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token class-name">Camera</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token comment">// We're using Vector4 because of the uniforms 16 byte spacing requirement</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span>view_position <span class="token operator">=</span> camera<span class="token punctuation">.</span>eye<span class="token punctuation">.</span><span class="token function">to_homogeneous</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">self</span><span class="token punctuation">.</span>view_proj <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token constant">OPENGL_TO_WGPU_MATRIX</span> <span class="token operator">*</span> camera<span class="token punctuation">.</span><span class="token function">build_view_projection_matrix</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">into</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token punctuation">}</span>
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<span class="token punctuation">}</span>
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</code></pre></div><p>Since we want to use our uniforms in the fragment shader now, we need to change its visibility.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// lib.rs</span>
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<span class="token keyword">let</span> camera_bind_group_layout <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_bind_group_layout</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroupLayoutDescriptor</span> <span class="token punctuation">{</span>
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entries<span class="token punctuation">:</span> <span class="token operator">&</span><span class="token punctuation">[</span>
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<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BindGroupLayoutBinding</span> <span class="token punctuation">{</span>
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<span class="token comment">// ...</span>
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visibility<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderStages</span><span class="token punctuation">::</span><span class="token constant">VERTEX</span> <span class="token operator">|</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderStages</span><span class="token punctuation">::</span><span class="token constant">FRAGMENT</span><span class="token punctuation">,</span> <span class="token comment">// Updated!</span>
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<span class="token comment">// ...</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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<span class="token comment">// ...</span>
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<span class="token punctuation">]</span><span class="token punctuation">,</span>
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label<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>We're going to get the direction from the fragment's position to the camera, and use that with the normal to calculate the <code>reflect_dir</code>.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token comment">// shader.wgsl</span>
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<span class="token comment">// In the fragment shader...</span>
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<span class="token keyword">let</span> view_dir <span class="token operator">=</span> <span class="token builtin">normalize</span><span class="token punctuation">(</span>camera<span class="token punctuation">.</span>view_pos<span class="token punctuation">.</span>xyz <span class="token operator">-</span> in<span class="token punctuation">.</span>world_position<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> reflect_dir <span class="token operator">=</span> <span class="token builtin">reflect</span><span class="token punctuation">(</span><span class="token operator">-</span>light_dir<span class="token punctuation">,</span> in<span class="token punctuation">.</span>world_normal<span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>Then we use the dot product to calculate the <code>specular_strength</code> and use that to compute the <code>specular_color</code>.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">let</span> specular_strength <span class="token operator">=</span> <span class="token builtin">pow</span><span class="token punctuation">(</span><span class="token builtin">max</span><span class="token punctuation">(</span><span class="token builtin">dot</span><span class="token punctuation">(</span>view_dir<span class="token punctuation">,</span> reflect_dir<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token decimal-float-literal number">0.0</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token decimal-float-literal number">32.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> specular_color <span class="token operator">=</span> specular_strength <span class="token operator">*</span> light<span class="token punctuation">.</span>color<span class="token punctuation">;</span>
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</code></pre></div><p>Finally, we add that to the result.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">let</span> result <span class="token operator">=</span> <span class="token punctuation">(</span>ambient_color <span class="token operator">+</span> diffuse_color <span class="token operator">+</span> specular_color<span class="token punctuation">)</span> <span class="token operator">*</span> object_color<span class="token punctuation">.</span>xyz<span class="token punctuation">;</span>
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</code></pre></div><p>With that, you should have something like this.</p> <p><img src="/learn-wgpu/assets/img/ambient_diffuse_specular_lighting.76386148.png" alt="./ambient_diffuse_specular_lighting.png"></p> <p>If we just look at the <code>specular_color</code> on its own we get this.</p> <p><img src="/learn-wgpu/assets/img/specular_lighting.b3869eb1.png" alt="./specular_lighting.png"></p> <h2 id="the-half-direction"><a href="#the-half-direction" class="header-anchor">#</a> The half direction</h2> <p>Up to this point, we've actually only implemented the Phong part of Blinn-Phong. The Phong reflection model works well, but it can break down under <a href="https://learnopengl.com/Advanced-Lighting/Advanced-Lighting" target="_blank" rel="noopener noreferrer">certain circumstances<span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></a>. The Blinn part of Blinn-Phong comes from the realization that if you add the <code>view_dir</code>, and <code>light_dir</code> together, normalize the result and use the dot product of that and the <code>normal</code>, you get roughly the same results without the issues that using <code>reflect_dir</code> had.</p> <div class="language-wgsl extra-class"><pre class="language-wgsl"><code><span class="token keyword">let</span> view_dir <span class="token operator">=</span> <span class="token builtin">normalize</span><span class="token punctuation">(</span>camera<span class="token punctuation">.</span>view_pos<span class="token punctuation">.</span>xyz <span class="token operator">-</span> in<span class="token punctuation">.</span>world_position<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> half_dir <span class="token operator">=</span> <span class="token builtin">normalize</span><span class="token punctuation">(</span>view_dir <span class="token operator">+</span> light_dir<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> specular_strength <span class="token operator">=</span> <span class="token builtin">pow</span><span class="token punctuation">(</span><span class="token builtin">max</span><span class="token punctuation">(</span><span class="token builtin">dot</span><span class="token punctuation">(</span>in<span class="token punctuation">.</span>world_normal<span class="token punctuation">,</span> half_dir<span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token decimal-float-literal number">0.0</span><span class="token punctuation">)</span><span class="token punctuation">,</span> <span class="token decimal-float-literal number">32.0</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>It's hard to tell the difference, but here are the results.</p> <p><img src="/learn-wgpu/assets/img/half_dir.bbcc23b8.png" alt="./half_dir.png"></p> <div id="wasm-example"><!----> <button>Try Tutorial10_lighting!</button></div> <div class="auto-github-link"><a href="https://github.com/sotrh/learn-wgpu/tree/master/code/intermediate/tutorial10-lighting/" target="_blank" rel="noopener noreferrer">Check out the code!</a> <span><svg xmlns="http://www.w3.org/2000/svg" aria-hidden="true" focusable="false" x="0px" y="0px" viewBox="0 0 100 100" width="15" height="15" class="icon outbound"><path fill="currentColor" d="M18.8,85.1h56l0,0c2.2,0,4-1.8,4-4v-32h-8v28h-48v-48h28v-8h-32l0,0c-2.2,0-4,1.8-4,4v56C14.8,83.3,16.6,85.1,18.8,85.1z"></path> <polygon fill="currentColor" points="45.7,48.7 51.3,54.3 77.2,28.5 77.2,37.2 85.2,37.2 85.2,14.9 62.8,14.9 62.8,22.9 71.5,22.9"></polygon></svg> <span class="sr-only">(opens new window)</span></span></div></div> <footer class="page-edit"><!----> <div class="last-updated"><span class="prefix">Last Updated: </span> <span class="time">11/28/2023, 12:41:28 AM</span></div></footer> <div class="page-nav"><p class="inner"><span class="prev">
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