Use vertex_attr_array

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
+            ],
         }
     }
 }