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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"><span>Intermediate</span> <!----></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/learn-wgpu/intermediate/tutorial10-lighting/" class="sidebar-link">Working with Lights</a></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 open"><span>Showcase</span> <span class="arrow down"></span></p> <ul class="sidebar-links sidebar-group-items"><li><a href="/learn-wgpu/showcase/" aria-current="page" class="sidebar-link">Foreword</a></li><li><a href="/learn-wgpu/showcase/windowless/" aria-current="page" class="active sidebar-link">Wgpu without a window</a><ul class="sidebar-sub-headers"><li class="sidebar-sub-header"><a href="/learn-wgpu/showcase/windowless/#so-what-do-we-need-to-do" class="sidebar-link">So what do we need to do?</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/showcase/windowless/#a-triangle-without-a-window" class="sidebar-link">A triangle without a window</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/showcase/windowless/#getting-data-out-of-a-buffer" class="sidebar-link">Getting data out of a buffer</a></li><li class="sidebar-sub-header"><a href="/learn-wgpu/showcase/windowless/#main-is-not-asyncable" class="sidebar-link">Main is not asyncable</a></li></ul></li><li><a href="/learn-wgpu/showcase/gifs/" class="sidebar-link">Creating gifs</a></li><li><a href="/learn-wgpu/showcase/pong/" class="sidebar-link">Pong</a></li><li><a href="/learn-wgpu/showcase/compute/" class="sidebar-link">Compute Example: Tangents and Bitangents</a></li><li><a href="/learn-wgpu/showcase/alignment/" class="sidebar-link">Memory Layout in WGSL</a></li></ul></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="wgpu-without-a-window"><a href="#wgpu-without-a-window" class="header-anchor">#</a> Wgpu without a window</h1> <p>Sometimes we just want to leverage the gpu. Maybe we want to crunch a large set of numbers in parallel. Maybe we're working on a 3D movie, and need to create a realistic-looking scene with path tracing. Maybe we're mining a cryptocurrency. In all these situations, we don't necessarily <em>need</em> to see what's going on.</p> <h2 id="so-what-do-we-need-to-do"><a href="#so-what-do-we-need-to-do" class="header-anchor">#</a> So what do we need to do?</h2> <p>It's actually quite simple. We don't <em>need</em> a window to create an <code>Instance</code>, we don't <em>need</em> a window to select an <code>Adapter</code>, nor do we <em>need</em> a window to create a <code>Device</code>. We only needed the window to create a <code>Surface</code> which we needed to create the <code>SwapChain</code>. Once we have a <code>Device</code>, we have all we need to start sending commands to the gpu.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> adapter <span class="token operator">=</span> instance
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<span class="token punctuation">.</span><span class="token function">request_adapter</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">RequestAdapterOptions</span> <span class="token punctuation">{</span>
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power_preference<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">PowerPreference</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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compatible_surface<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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<span class="token punctuation">.</span><span class="token keyword">await</span>
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<span class="token punctuation">.</span><span class="token function">unwrap</span><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> <span class="token punctuation">(</span>device<span class="token punctuation">,</span> queue<span class="token punctuation">)</span> <span class="token operator">=</span> adapter
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<span class="token punctuation">.</span><span class="token function">request_device</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token class-name">Default</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> <span class="token class-name">None</span><span class="token punctuation">)</span>
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<span class="token punctuation">.</span><span class="token keyword">await</span>
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<span class="token punctuation">.</span><span class="token function">unwrap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><h2 id="a-triangle-without-a-window"><a href="#a-triangle-without-a-window" class="header-anchor">#</a> A triangle without a window</h2> <p>Now we've talked about not needing to see what the gpu is doing, but we do need to see the results at some point. If we look back to talking about the <a href="/learn-wgpu/beginner/tutorial2-surface/#render">surface</a> we see that we use <code>surface.get_current_texture()</code> to grab a texture to draw to. We'll skip that step by creating the texture ourselves. One thing to note here is we need to specify <code>wgpu::TextureFormat::Rgba8UnormSrgb</code> to <code>format</code> instead of <code>surface.get_preferred_format(&adapter)</code> since PNG uses RGBA, not BGRA.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> texture_size <span class="token operator">=</span> <span class="token number">256u32</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> texture_desc <span class="token operator">=</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">TextureDescriptor</span> <span class="token punctuation">{</span>
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size<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Extent3d</span> <span class="token punctuation">{</span>
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width<span class="token punctuation">:</span> texture_size<span class="token punctuation">,</span>
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height<span class="token punctuation">:</span> texture_size<span class="token punctuation">,</span>
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depth_or_array_layers<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span>
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<span class="token punctuation">}</span><span class="token punctuation">,</span>
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mip_level_count<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span>
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sample_count<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span>
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dimension<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">TextureDimension</span><span class="token punctuation">::</span><span class="token constant">D2</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">TextureFormat</span><span class="token punctuation">::</span><span class="token class-name">Rgba8UnormSrgb</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">TextureUsages</span><span class="token punctuation">::</span><span class="token constant">COPY_SRC</span>
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<span class="token operator">|</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">TextureUsages</span><span class="token punctuation">::</span><span class="token constant">RENDER_ATTACHMENT</span>
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<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>
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<span class="token keyword">let</span> texture <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_texture</span><span class="token punctuation">(</span><span class="token operator">&</span>texture_desc<span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> texture_view <span class="token operator">=</span> texture<span class="token punctuation">.</span><span class="token function">create_view</span><span class="token punctuation">(</span><span class="token operator">&</span><span class="token class-name">Default</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><span class="token punctuation">;</span>
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</code></pre></div><p>We're using <code>TextureUsages::RENDER_ATTACHMENT</code> so wgpu can render to our texture. The <code>TextureUsages::COPY_SRC</code> is so we can pull data out of the texture so we can save it to a file.</p> <p>While we can use this texture to draw our triangle, we need some way to get at the pixels inside it. Back in the <a href="/learn-wgpu/beginner/tutorial5-textures/">texture tutorial</a> we used a buffer to load color data from a file that we then copied into our buffer. Now we are going to do the reverse: copy data into a buffer from our texture to save into a file. We'll need a buffer big enough for our data.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// we need to store this for later</span>
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<span class="token keyword">let</span> u32_size <span class="token operator">=</span> <span class="token namespace">std<span class="token punctuation">::</span>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 keyword">u32</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 keyword">u32</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> output_buffer_size <span class="token operator">=</span> <span class="token punctuation">(</span>u32_size <span class="token operator">*</span> texture_size <span class="token operator">*</span> texture_size<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 keyword">let</span> output_buffer_desc <span class="token operator">=</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">BufferDescriptor</span> <span class="token punctuation">{</span>
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size<span class="token punctuation">:</span> output_buffer_size<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">COPY_DST</span>
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<span class="token comment">// this tells wpgu that we want to read this buffer from the cpu</span>
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<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">MAP_READ</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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mapped_at_creation<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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<span class="token keyword">let</span> output_buffer <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_buffer</span><span class="token punctuation">(</span><span class="token operator">&</span>output_buffer_desc<span class="token punctuation">)</span><span class="token punctuation">;</span>
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</code></pre></div><p>Now that we have something to draw to, let's make something to draw. Since we're just drawing a triangle, let's grab the shader code from the <a href="/learn-wgpu/beginner/tutorial3-pipeline/#writing-the-shaders">pipeline tutorial</a>.</p> <div class="language-glsl extra-class"><pre class="language-glsl"><code><span class="token comment">// shader.vert</span>
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<span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">version</span> <span class="token expression"><span class="token number">450</span></span></span>
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<span class="token keyword">const</span> <span class="token keyword">vec2</span> positions<span class="token punctuation">[</span><span class="token number">3</span><span class="token punctuation">]</span> <span class="token operator">=</span> <span class="token keyword">vec2</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 keyword">vec2</span><span class="token punctuation">(</span><span class="token number">0.0</span><span class="token punctuation">,</span> <span class="token number">0.5</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token keyword">vec2</span><span class="token punctuation">(</span><span class="token operator">-</span><span class="token number">0.5</span><span class="token punctuation">,</span> <span class="token operator">-</span><span class="token number">0.5</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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<span class="token keyword">vec2</span><span class="token punctuation">(</span><span class="token number">0.5</span><span class="token punctuation">,</span> <span class="token operator">-</span><span class="token number">0.5</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">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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gl_Position <span class="token operator">=</span> <span class="token keyword">vec4</span><span class="token punctuation">(</span>positions<span class="token punctuation">[</span>gl_VertexIndex<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 punctuation">;</span>
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<span class="token punctuation">}</span>
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</code></pre></div><div class="language-glsl extra-class"><pre class="language-glsl"><code><span class="token comment">// shader.frag</span>
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<span class="token macro property"><span class="token directive-hash">#</span><span class="token directive keyword">version</span> <span class="token expression"><span class="token number">450</span></span></span>
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<span class="token keyword">layout</span><span class="token punctuation">(</span>location<span class="token operator">=</span><span class="token number">0</span><span class="token punctuation">)</span> <span class="token keyword">out</span> <span class="token keyword">vec4</span> f_color<span class="token punctuation">;</span>
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<span class="token keyword">void</span> <span class="token function">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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f_color <span class="token operator">=</span> <span class="token keyword">vec4</span><span class="token punctuation">(</span><span class="token number">0.3</span><span class="token punctuation">,</span> <span class="token number">0.2</span><span class="token punctuation">,</span> <span class="token number">0.1</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 punctuation">}</span>
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</code></pre></div><p>Update dependencies to support SPIR-V module.</p> <div class="language-toml extra-class"><pre class="language-toml"><code><span class="token punctuation">[</span><span class="token table class-name">dependencies</span><span class="token punctuation">]</span>
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<span class="token key property">image</span> <span class="token punctuation">=</span> <span class="token string">"0.23"</span>
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<span class="token key property">shaderc</span> <span class="token punctuation">=</span> <span class="token string">"0.7"</span>
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<span class="token key property">wgpu</span> <span class="token punctuation">=</span> <span class="token punctuation">{</span> <span class="token key property">version</span> <span class="token punctuation">=</span> <span class="token string">"0.18"</span><span class="token punctuation">,</span> <span class="token key property">features</span> <span class="token punctuation">=</span> <span class="token punctuation">[</span><span class="token string">"spirv"</span><span class="token punctuation">]</span> <span class="token punctuation">}</span>
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<span class="token key property">pollster</span> <span class="token punctuation">=</span> <span class="token string">"0.3"</span>
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</code></pre></div><p>Using that we'll create a simple <code>RenderPipeline</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> vs_src <span class="token operator">=</span> <span class="token macro property">include_str!</span><span class="token punctuation">(</span><span class="token string">"shader.vert"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> fs_src <span class="token operator">=</span> <span class="token macro property">include_str!</span><span class="token punctuation">(</span><span class="token string">"shader.frag"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> <span class="token keyword">mut</span> compiler <span class="token operator">=</span> <span class="token namespace">shaderc<span class="token punctuation">::</span></span><span class="token class-name">Compiler</span><span class="token punctuation">::</span><span class="token function">new</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">unwrap</span><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> vs_spirv <span class="token operator">=</span> compiler
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<span class="token punctuation">.</span><span class="token function">compile_into_spirv</span><span class="token punctuation">(</span>
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vs_src<span class="token punctuation">,</span>
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<span class="token namespace">shaderc<span class="token punctuation">::</span></span><span class="token class-name">ShaderKind</span><span class="token punctuation">::</span><span class="token class-name">Vertex</span><span class="token punctuation">,</span>
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<span class="token string">"shader.vert"</span><span class="token punctuation">,</span>
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<span class="token string">"main"</span><span class="token punctuation">,</span>
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<span class="token class-name">None</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 function">unwrap</span><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> fs_spirv <span class="token operator">=</span> compiler
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<span class="token punctuation">.</span><span class="token function">compile_into_spirv</span><span class="token punctuation">(</span>
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fs_src<span class="token punctuation">,</span>
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<span class="token namespace">shaderc<span class="token punctuation">::</span></span><span class="token class-name">ShaderKind</span><span class="token punctuation">::</span><span class="token class-name">Fragment</span><span class="token punctuation">,</span>
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<span class="token string">"shader.frag"</span><span class="token punctuation">,</span>
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<span class="token string">"main"</span><span class="token punctuation">,</span>
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<span class="token class-name">None</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 function">unwrap</span><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> vs_data <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 function">make_spirv</span><span class="token punctuation">(</span>vs_spirv<span class="token punctuation">.</span><span class="token function">as_binary_u8</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">let</span> fs_data <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 function">make_spirv</span><span class="token punctuation">(</span>fs_spirv<span class="token punctuation">.</span><span class="token function">as_binary_u8</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">let</span> vs_module <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_shader_module</span><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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label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Vertex Shader"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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source<span class="token punctuation">:</span> vs_data<span class="token punctuation">,</span>
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flags<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderFlags</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>
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<span class="token keyword">let</span> fs_module <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_shader_module</span><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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label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Fragment Shader"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
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source<span class="token punctuation">:</span> fs_data<span class="token punctuation">,</span>
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flags<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ShaderFlags</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>
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<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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|
label<span class="token punctuation">:</span> <span class="token class-name">Some</span><span class="token punctuation">(</span><span class="token string">"Render 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 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> render_pipeline <span class="token operator">=</span> 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>
|
|
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><span class="token operator">&</span>render_pipeline_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>vs_module<span class="token punctuation">,</span>
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entry_point<span class="token punctuation">:</span> <span class="token string">"main"</span><span class="token punctuation">,</span>
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buffers<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>
|
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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>fs_module<span class="token punctuation">,</span>
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entry_point<span class="token punctuation">:</span> <span class="token string">"main"</span><span class="token punctuation">,</span>
|
|
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> texture_desc<span class="token punctuation">.</span>format<span class="token punctuation">,</span>
|
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alpha_blend<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><span class="token constant">REPLACE</span><span class="token punctuation">,</span>
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color_blend<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><span class="token constant">REPLACE</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>
|
|
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>
|
|
<span class="token comment">// Setting this to anything other than Fill requires Features::NON_FILL_POLYGON_MODE</span>
|
|
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>
|
|
<span class="token punctuation">}</span><span class="token punctuation">,</span>
|
|
depth_stencil<span class="token punctuation">:</span> <span class="token class-name">None</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>
|
|
count<span class="token punctuation">:</span> <span class="token number">1</span><span class="token punctuation">,</span>
|
|
mask<span class="token punctuation">:</span> <span class="token operator">!</span><span class="token number">0</span><span class="token punctuation">,</span>
|
|
alpha_to_coverage_enabled<span class="token punctuation">:</span> <span class="token boolean">false</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><span class="token punctuation">;</span>
|
|
</code></pre></div><p>We're going to need an encoder, so let's do that.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">let</span> <span class="token keyword">mut</span> encoder <span class="token operator">=</span> device<span class="token punctuation">.</span><span class="token function">create_command_encoder</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">CommandEncoderDescriptor</span> <span class="token punctuation">{</span>
|
|
label<span class="token punctuation">:</span> <span class="token class-name">None</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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|
</code></pre></div><p>The <code>RenderPass</code> is where things get interesting. A render pass requires at least one color attachment. A color attachment requires a <code>TextureView</code> to attach to. We used to use a texture from <code>SwapChain</code> for this, but any <code>TextureView</code> will do, including our <code>texture_view</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token punctuation">{</span>
|
|
<span class="token keyword">let</span> render_pass_desc <span class="token operator">=</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">RenderPassDescriptor</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 Pass"</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
|
color_attachments<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">RenderPassColorAttachment</span> <span class="token punctuation">{</span>
|
|
view<span class="token punctuation">:</span> <span class="token operator">&</span>texture_view<span class="token punctuation">,</span>
|
|
resolve_target<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
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|
ops<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Operations</span> <span class="token punctuation">{</span>
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load<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">LoadOp</span><span class="token punctuation">::</span><span class="token class-name">Clear</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Color</span> <span class="token punctuation">{</span>
|
|
r<span class="token punctuation">:</span> <span class="token number">0.1</span><span class="token punctuation">,</span>
|
|
g<span class="token punctuation">:</span> <span class="token number">0.2</span><span class="token punctuation">,</span>
|
|
b<span class="token punctuation">:</span> <span class="token number">0.3</span><span class="token punctuation">,</span>
|
|
a<span class="token punctuation">:</span> <span class="token number">1.0</span><span class="token punctuation">,</span>
|
|
<span class="token punctuation">}</span><span class="token punctuation">)</span><span class="token punctuation">,</span>
|
|
store<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">StoreOp</span><span class="token punctuation">::</span><span class="token class-name">Store</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><span class="token punctuation">,</span>
|
|
depth_stencil_attachment<span class="token punctuation">:</span> <span class="token class-name">None</span><span class="token punctuation">,</span>
|
|
<span class="token punctuation">}</span><span class="token punctuation">;</span>
|
|
<span class="token keyword">let</span> <span class="token keyword">mut</span> render_pass <span class="token operator">=</span> encoder<span class="token punctuation">.</span><span class="token function">begin_render_pass</span><span class="token punctuation">(</span><span class="token operator">&</span>render_pass_desc<span class="token punctuation">)</span><span class="token punctuation">;</span>
|
|
|
|
render_pass<span class="token punctuation">.</span><span class="token function">set_pipeline</span><span class="token punctuation">(</span><span class="token operator">&</span>render_pipeline<span class="token punctuation">)</span><span class="token punctuation">;</span>
|
|
render_pass<span class="token punctuation">.</span><span class="token function">draw</span><span class="token punctuation">(</span><span class="token number">0</span><span class="token punctuation">..</span><span class="token number">3</span><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><span class="token punctuation">;</span>
|
|
<span class="token punctuation">}</span>
|
|
</code></pre></div><p>There's not much we can do with the data when it's stuck in a <code>Texture</code>, so let's copy it into our <code>output_buffer</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code>encoder<span class="token punctuation">.</span><span class="token function">copy_texture_to_buffer</span><span class="token punctuation">(</span>
|
|
<span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ImageCopyTexture</span> <span class="token punctuation">{</span>
|
|
aspect<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">TextureAspect</span><span class="token punctuation">::</span><span class="token class-name">All</span><span class="token punctuation">,</span>
|
|
texture<span class="token punctuation">:</span> <span class="token operator">&</span>texture<span class="token punctuation">,</span>
|
|
mip_level<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
|
|
origin<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Origin3d</span><span class="token punctuation">::</span><span class="token constant">ZERO</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">ImageCopyBuffer</span> <span class="token punctuation">{</span>
|
|
buffer<span class="token punctuation">:</span> <span class="token operator">&</span>output_buffer<span class="token punctuation">,</span>
|
|
layout<span class="token punctuation">:</span> <span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">ImageDataLayout</span> <span class="token punctuation">{</span>
|
|
offset<span class="token punctuation">:</span> <span class="token number">0</span><span class="token punctuation">,</span>
|
|
bytes_per_row<span class="token punctuation">:</span> u32_size <span class="token operator">*</span> texture_size<span class="token punctuation">,</span>
|
|
rows_per_image<span class="token punctuation">:</span> texture_size<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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texture_desc<span class="token punctuation">.</span>size<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>Now that we've made all our commands, let's submit them to the gpu.</p> <div class="language-rust extra-class"><pre class="language-rust"><code>queue<span class="token punctuation">.</span><span class="token function">submit</span><span class="token punctuation">(</span><span class="token class-name">Some</span><span class="token punctuation">(</span>encoder<span class="token punctuation">.</span><span class="token function">finish</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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</code></pre></div><h2 id="getting-data-out-of-a-buffer"><a href="#getting-data-out-of-a-buffer" class="header-anchor">#</a> Getting data out of a buffer</h2> <p>In order to get the data out of the buffer, we need to first map it, then we can get a <code>BufferView</code> that we can treat like a <code>&[u8]</code>.</p> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token comment">// We need to scope the mapping variables so that we can</span>
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<span class="token comment">// unmap the buffer</span>
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<span class="token punctuation">{</span>
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<span class="token keyword">let</span> buffer_slice <span class="token operator">=</span> output_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>
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<span class="token comment">// NOTE: We have to create the mapping THEN device.poll() before await</span>
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<span class="token comment">// the future. Otherwise the application will freeze.</span>
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<span class="token keyword">let</span> <span class="token punctuation">(</span>tx<span class="token punctuation">,</span> rx<span class="token punctuation">)</span> <span class="token operator">=</span> <span class="token namespace">futures_intrusive<span class="token punctuation">::</span>channel<span class="token punctuation">::</span>shared<span class="token punctuation">::</span></span><span class="token function">oneshot_channel</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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buffer_slice<span class="token punctuation">.</span><span class="token function">map_async</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">MapMode</span><span class="token punctuation">::</span><span class="token class-name">Read</span><span class="token punctuation">,</span> <span class="token keyword">move</span> <span class="token closure-params"><span class="token closure-punctuation punctuation">|</span>result<span class="token closure-punctuation punctuation">|</span></span> <span class="token punctuation">{</span>
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tx<span class="token punctuation">.</span><span class="token function">send</span><span class="token punctuation">(</span>result<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">unwrap</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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device<span class="token punctuation">.</span><span class="token function">poll</span><span class="token punctuation">(</span><span class="token namespace">wgpu<span class="token punctuation">::</span></span><span class="token class-name">Maintain</span><span class="token punctuation">::</span><span class="token class-name">Wait</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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rx<span class="token punctuation">.</span><span class="token function">receive</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token keyword">await</span><span class="token punctuation">.</span><span class="token function">unwrap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">unwrap</span><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> data <span class="token operator">=</span> buffer_slice<span class="token punctuation">.</span><span class="token function">get_mapped_range</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 namespace">image<span class="token punctuation">::</span></span><span class="token punctuation">{</span><span class="token class-name">ImageBuffer</span><span class="token punctuation">,</span> <span class="token class-name">Rgba</span><span class="token punctuation">}</span><span class="token punctuation">;</span>
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<span class="token keyword">let</span> buffer <span class="token operator">=</span>
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<span class="token class-name">ImageBuffer</span><span class="token punctuation">::</span><span class="token operator"><</span><span class="token class-name">Rgba</span><span class="token operator"><</span><span class="token keyword">u8</span><span class="token operator">></span><span class="token punctuation">,</span> _<span class="token operator">></span><span class="token punctuation">::</span><span class="token function">from_raw</span><span class="token punctuation">(</span>texture_size<span class="token punctuation">,</span> texture_size<span class="token punctuation">,</span> data<span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">unwrap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
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buffer<span class="token punctuation">.</span><span class="token function">save</span><span class="token punctuation">(</span><span class="token string">"image.png"</span><span class="token punctuation">)</span><span class="token punctuation">.</span><span class="token function">unwrap</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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output_buffer<span class="token punctuation">.</span><span class="token function">unmap</span><span class="token punctuation">(</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
|
|
</code></pre></div><div class="note"><p>I used <a href="https://docs.rs/futures-intrusive" target="_blank" rel="noopener noreferrer">futures-intrusive<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> as that's the crate they use in the <a href="https://github.com/gfx-rs/wgpu/tree/master/wgpu/examples/capture" target="_blank" rel="noopener noreferrer">exampls on the wgpu repo<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> <h2 id="main-is-not-asyncable"><a href="#main-is-not-asyncable" class="header-anchor">#</a> Main is not asyncable</h2> <p>The <code>main()</code> method can't return a future, so we can't use the <code>async</code> keyword. We'll get around this by putting our code into a different function so that we can block it in <code>main()</code>. You'll need to use a crate that can poll futures such as the <a href="https://docs.rs/pollster" target="_blank" rel="noopener noreferrer">pollster crate<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 class="note"><p>There are crates such as <a href="https://docs.rs/async-std" target="_blank" rel="noopener noreferrer">async-std<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>, and <a href="https://docs.rs/tokio" target="_blank" rel="noopener noreferrer">tokio<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> that you can use to annotate <code>main()</code> so it can be async. I opted not to do that as both those crates are a little more hefty for this project. You're welcome to use whatever async setup you like 🙂</p></div> <div class="language-rust extra-class"><pre class="language-rust"><code><span class="token keyword">async</span> <span class="token keyword">fn</span> <span class="token function-definition function">run</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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<span class="token comment">// Windowless drawing code...</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">main</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
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|
<span class="token namespace">pollster<span class="token punctuation">::</span></span><span class="token function">block_on</span><span class="token punctuation">(</span><span class="token function">run</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>
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</code></pre></div><p>With all that you should have an image like this.</p> <p><img src="data:image/png;base64,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" alt="a brown triangle"></p> <div class="auto-github-link"><a href="https://github.com/sotrh/learn-wgpu/tree/master/code/showcase/windowless/" 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">12/1/2023, 2:10:48 AM</span></div></footer> <div class="page-nav"><p class="inner"><span class="prev">
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