Merge pull request #76 from jprudil/vertex-use-macro

Use vertex_attr_array macro

docs/beginner/tutorial4-buffer/README.md

@@ -123,28 +123,16 @@ For you visually learners, our vertex buffer looks like this.
 
 ![A figure of the VertexBufferDescriptor](./vb_desc.png)
 
-Let's create a static method on `Vertex` that returns this descriptor.
+Let's create a static method on `Vertex` that returns this descriptor. Thankfully, wgpu provides us with a convenient macro for doing this! `vertex_attr_array!` expands into an array of descriptors with automatically calculated offsets.
 
 ```rust
 // main.rs
 impl Vertex {
     fn desc<'a>() -> wgpu::VertexBufferDescriptor<'a> {
-        use std::mem;
         wgpu::VertexBufferDescriptor {
-            stride: mem::size_of::<Vertex>() as wgpu::BufferAddress,
+            stride: std::mem::size_of::<Vertex>() as wgpu::BufferAddress,
             step_mode: wgpu::InputStepMode::Vertex,
-            attributes: &[
-                wgpu::VertexAttributeDescriptor {
-                    offset: 0,
-                    shader_location: 0,
-                    format: wgpu::VertexFormat::Float3,
-                },
-                wgpu::VertexAttributeDescriptor {
-                    offset: mem::size_of::<[f32; 3]>() as wgpu::BufferAddress,
-                    shader_location: 1,
-                    format: wgpu::VertexFormat::Float3,
-                },
-            ]
+            attributes: &wgpu::vertex_attr_array![0 => Float3, 1 => Float3],
         }
     }
 }

docs/beginner/tutorial5-textures/README.md

@@ -247,7 +247,7 @@ let render_pipeline_layout = device.create_pipeline_layout(&wgpu::PipelineLayout
 ```
 
 ## A change to the VERTICES
-There's a few things we need to change about our `Vertex` definition. Up to now we've been using a `color` attribute to dictate the color of our mesh. Now that we're using a texture we want to replace our `color` with `tex_coords`.
+There's a few things we need to change about our `Vertex` definition. Up to now we've been using a `color` attribute to dictate the color of our mesh. Now that we're using a texture we want to replace our `color` with `tex_coords`, which is only two floats instead of three.
 
 ```rust
 #[repr(C)]
@@ -263,25 +263,10 @@ We need to reflect these changes in the `VertexBufferDescriptor`.
 ```rust
 impl Vertex {
     fn desc<'a>() -> wgpu::VertexBufferDescriptor<'a> {
-        use std::mem;
         wgpu::VertexBufferDescriptor {
-            stride: mem::size_of::<Vertex>() as wgpu::BufferAddress,
+            stride: std::mem::size_of::<Vertex>() as wgpu::BufferAddress,
             step_mode: wgpu::InputStepMode::Vertex,
-            attributes: &[
-                wgpu::VertexAttributeDescriptor {
-                    offset: 0,
-                    shader_location: 0,
-                    format: wgpu::VertexFormat::Float3,
-                },
-                wgpu::VertexAttributeDescriptor {
-                    offset: mem::size_of::<[f32; 3]>() as wgpu::BufferAddress,
-                    shader_location: 1,
-                    // We only need to change this to reflect that tex_coords
-                    // is only 2 floats and not 3. It's in the same position
-                    // as color was, so nothing else needs to change
-                    format: wgpu::VertexFormat::Float2,
-                },
-            ]
+            attributes: &wgpu::vertex_attr_array![0 => Float3, 1 => Float2],
         }
     }
 }

docs/beginner/tutorial9-models/README.md

@@ -34,27 +34,14 @@ Let's define our `VertexBufferDescriptor`.
 ```rust
 impl Vertex for ModelVertex {
     fn desc<'a>() -> wgpu::VertexBufferDescriptor<'a> {
-        use std::mem;
         wgpu::VertexBufferDescriptor {
-            stride: mem::size_of::<ModelVertex>() as wgpu::BufferAddress,
+            stride: std::mem::size_of::<ModelVertex>() as wgpu::BufferAddress,
             step_mode: wgpu::InputStepMode::Vertex,
-            attributes: &[
-                wgpu::VertexAttributeDescriptor {
-                    offset: 0,
-                    shader_location: 0,
-                    format: wgpu::VertexFormat::Float3,
-                },
-                wgpu::VertexAttributeDescriptor {
-                    offset: mem::size_of::<[f32; 3]>() as wgpu::BufferAddress,
-                    shader_location: 1,
-                    format: wgpu::VertexFormat::Float2,
-                },
-                wgpu::VertexAttributeDescriptor {
-                    offset: mem::size_of::<[f32; 5]>() as wgpu::BufferAddress,
-                    shader_location: 2,
-                    format: wgpu::VertexFormat::Float3,
-                },
-            ]
+            attributes: &wgpu::vertex_attr_array![
+                0 => Float3,
+                1 => Float2,
+                2 => Float3
+            ],
         }
     }
 }