Finished depth buffer

src/lib.rs

@@ -7,9 +7,69 @@ use winit::{
     keyboard::{KeyCode, PhysicalKey},
     window::{Window, WindowBuilder},
 };
+use cgmath::prelude::*;
+use crate::texture::Texture;
 
 mod texture;
 
+struct Instance {
+    position: cgmath::Vector3<f32>,
+    rotation: cgmath::Quaternion<f32>,
+}
+
+impl InstanceRaw {
+    fn desc() -> wgpu::VertexBufferLayout<'static> {
+        use std::mem;
+        wgpu::VertexBufferLayout {
+            array_stride: mem::size_of::<InstanceRaw>() as wgpu::BufferAddress,
+            // We need to switch from using a step mode of Vertex to Instance
+            // This means that our shaders will only change to use the next
+            // instance when the shader starts processing a new instance
+            step_mode: wgpu::VertexStepMode::Instance,
+            attributes: &[
+                // A mat4 takes up 4 vertex slots as it is technically 4 vec4s. We need to define a slot
+                // for each vec4. We'll have to reassemble the mat4 in the shader.
+                wgpu::VertexAttribute {
+                    offset: 0,
+                    // While our vertex shader only uses locations 0, and 1 now, in later tutorials, we'll
+                    // be using 2, 3, and 4, for Vertex. We'll start at slot 5, not conflict with them later
+                    shader_location: 5,
+                    format: wgpu::VertexFormat::Float32x4,
+                },
+                wgpu::VertexAttribute {
+                    offset: mem::size_of::<[f32; 4]>() as wgpu::BufferAddress,
+                    shader_location: 6,
+                    format: wgpu::VertexFormat::Float32x4,
+                },
+                wgpu::VertexAttribute {
+                    offset: mem::size_of::<[f32; 8]>() as wgpu::BufferAddress,
+                    shader_location: 7,
+                    format: wgpu::VertexFormat::Float32x4,
+                },
+                wgpu::VertexAttribute {
+                    offset: mem::size_of::<[f32; 12]>() as wgpu::BufferAddress,
+                    shader_location: 8,
+                    format: wgpu::VertexFormat::Float32x4,
+                },
+            ],
+        }
+    }
+}
+
+impl Instance {
+    fn to_raw(&self) -> InstanceRaw {
+        InstanceRaw {
+            model: (cgmath::Matrix4::from_translation(self.position) * cgmath::Matrix4::from(self.rotation)).into(),
+        }
+    }
+}
+
+#[repr(C)]
+#[derive(Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+struct InstanceRaw {
+    model: [[f32; 4]; 4],
+}
+
 #[repr(C)]
 #[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
 struct Vertex {
@@ -222,15 +282,20 @@ struct State<'a> {
     #[allow(dead_code)]
     diffuse_texture: texture::Texture,
     diffuse_bind_group: wgpu::BindGroup,
-    // NEW!
     camera: Camera,
     camera_controller: CameraController,
     camera_uniform: CameraUniform,
     camera_buffer: wgpu::Buffer,
     camera_bind_group: wgpu::BindGroup,
     window: &'a Window,
+    instances: Vec<Instance>,
+    instance_buffer: wgpu::Buffer,
+    depth_texture: Texture,
 }
 
+const NUM_INSTANCES_PER_ROW: u32 = 10;
+const INSTANCE_DISPLACEMENT: cgmath::Vector3<f32> = cgmath::Vector3::new(NUM_INSTANCES_PER_ROW as f32 * 0.5, 0.0, NUM_INSTANCES_PER_ROW as f32 * 0.5);
+
 impl<'a> State<'a> {
     async fn new(window: &'a Window) -> State<'a> {
         let size = window.inner_size();
@@ -288,6 +353,8 @@ impl<'a> State<'a> {
             desired_maximum_frame_latency: 2,
         };
 
+        let depth_texture = texture::Texture::create_depth_texture(&device, &config, "depth_texture");
+
         let diffuse_bytes = include_bytes!("happy-tree.png");
         let diffuse_texture =
             texture::Texture::from_bytes(&device, &queue, diffuse_bytes, "happy-tree.png").unwrap();
@@ -392,7 +459,7 @@ impl<'a> State<'a> {
             vertex: wgpu::VertexState {
                 module: &shader,
                 entry_point: "vs_main",
-                buffers: &[Vertex::desc()],
+                buffers: &[Vertex::desc(), InstanceRaw::desc()],
                 compilation_options: Default::default(),
             },
             fragment: Some(wgpu::FragmentState {
@@ -421,7 +488,13 @@ impl<'a> State<'a> {
                 // Requires Features::CONSERVATIVE_RASTERIZATION
                 conservative: false,
             },
-            depth_stencil: None,
+            depth_stencil: Some(wgpu::DepthStencilState {
+                format: texture::Texture::DEPTH_FORMAT,
+                depth_write_enabled: true,
+                depth_compare: wgpu::CompareFunction::Less,
+                stencil: wgpu::StencilState::default(),
+                bias: wgpu::DepthBiasState::default(),
+            }),
             multisample: wgpu::MultisampleState {
                 count: 1,
                 mask: !0,
@@ -446,6 +519,33 @@ impl<'a> State<'a> {
         });
         let num_indices = INDICES.len() as u32;
 
+        let instances = (0..NUM_INSTANCES_PER_ROW).flat_map(|z| {
+            (0..NUM_INSTANCES_PER_ROW).map(move |x| {
+                let position = cgmath::Vector3 { x: x as f32, y: 0.0, z: z as f32 } - INSTANCE_DISPLACEMENT;
+
+                let rotation = if position.is_zero() {
+                    // this is needed so an object at (0, 0, 0) won't get scaled to zero
+                    // as Quaternions can affect scale if they're not created correctly
+                    cgmath::Quaternion::from_axis_angle(cgmath::Vector3::unit_z(), cgmath::Deg(0.0))
+                } else {
+                    cgmath::Quaternion::from_axis_angle(position.normalize(), cgmath::Deg(45.0))
+                };
+
+                Instance {
+                    position, rotation,
+                }
+            })
+        }).collect::<Vec<_>>();
+
+        let instance_data = instances.iter().map(Instance::to_raw).collect::<Vec<_>>();
+        let instance_buffer = device.create_buffer_init(
+            &wgpu::util::BufferInitDescriptor {
+                label: Some("Instance Buffer"),
+                contents: bytemuck::cast_slice(&instance_data),
+                usage: wgpu::BufferUsages::VERTEX,
+            }
+        );
+
         Self {
             surface,
             device,
@@ -464,6 +564,9 @@ impl<'a> State<'a> {
             camera_bind_group,
             camera_uniform,
             window,
+            instances,
+            instance_buffer,
+            depth_texture,
         }
     }
 
@@ -478,6 +581,8 @@ impl<'a> State<'a> {
             self.config.height = new_size.height;
             self.surface.configure(&self.device, &self.config);
 
+            self.depth_texture = Texture::create_depth_texture(&self.device, &self.config, "depth_texture");
+
             self.camera.aspect = self.config.width as f32 / self.config.height as f32;
         }
     }
@@ -524,7 +629,14 @@ impl<'a> State<'a> {
                         store: wgpu::StoreOp::Store,
                     },
                 })],
-                depth_stencil_attachment: None,
+                depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
+                    view: &self.depth_texture.view,
+                    depth_ops: Some(wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(1.0),
+                        store: wgpu::StoreOp::Store,
+                    }),
+                    stencil_ops: None,
+                }),
                 occlusion_query_set: None,
                 timestamp_writes: None,
             });
@@ -533,8 +645,9 @@ impl<'a> State<'a> {
             render_pass.set_bind_group(0, &self.diffuse_bind_group, &[]);
             render_pass.set_bind_group(1, &self.camera_bind_group, &[]);
             render_pass.set_vertex_buffer(0, self.vertex_buffer.slice(..));
+            render_pass.set_vertex_buffer(1, self.instance_buffer.slice(..));
             render_pass.set_index_buffer(self.index_buffer.slice(..), wgpu::IndexFormat::Uint16);
-            render_pass.draw_indexed(0..self.num_indices, 0, 0..1);
+            render_pass.draw_indexed(0..self.num_indices, 0, 0..self.instances.len() as _);
         }
 
         self.queue.submit(iter::once(encoder.finish()));

src/model.rs

@@ -0,0 +1,44 @@
+pub trait Vertex {
+    fn desc() -> wgpu::VertexBufferLayout<'static>;
+}
+
+#[repr(C)]
+#[derive(Copy, Clone, Debug, bytemuck::Pod, bytemuck::Zeroable)]
+pub struct ModelVertex {
+    pub position: [f32; 3],
+    pub tex_coords: [f32; 2],
+    pub normal: [f32; 3],
+}
+
+impl Vertex for ModelVertex {
+    fn desc() -> wgpu::VertexBufferLayout<'static> {
+        todo!();
+    }
+}
+
+impl Vertex for ModelVertex {
+    fn desc() -> wgpu::VertexBufferLayout<'static> {
+        use std::mem;
+        wgpu::VertexBufferLayout {
+            array_stride: mem::size_of::<ModelVertex>() as wgpu::BufferAddress,
+            step_mode: wgpu::VertexStepMode::Vertex,
+            attributes: &[
+                wgpu::VertexAttribute {
+                    offset: 0,
+                    shader_location: 0,
+                    format: wgpu::VertexFormat::Float32x3,
+                },
+                wgpu::VertexAttribute {
+                    offset: mem::size_of::<[f32; 3]>() as wgpu::BufferAddress,
+                    shader_location: 1,
+                    format: wgpu::VertexFormat::Float32x2,
+                },
+                wgpu::VertexAttribute {
+                    offset: mem::size_of::<[f32; 5]>() as wgpu::BufferAddress,
+                    shader_location: 2,
+                    format: wgpu::VertexFormat::Float32x3,
+                },
+            ],
+        }
+    }
+}

src/shader.wgsl

@@ -1,3 +1,11 @@
+struct InstanceInput {
+    @location(5) model_matrix_0: vec4<f32>,
+    @location(6) model_matrix_1: vec4<f32>,
+    @location(7) model_matrix_2: vec4<f32>,
+    @location(8) model_matrix_3: vec4<f32>,
+};
+
+
 // Vertex shader
 struct CameraUniform {
     view_proj: mat4x4<f32>,
@@ -18,10 +26,17 @@ struct VertexOutput {
 @vertex
 fn vs_main(
     model: VertexInput,
+    instance: InstanceInput,
 ) -> VertexOutput {
+    let model_matrix = mat4x4<f32>(
+        instance.model_matrix_0,
+        instance.model_matrix_1,
+        instance.model_matrix_2,
+        instance.model_matrix_3,
+    );
     var out: VertexOutput;
     out.tex_coords = model.tex_coords;
-    out.clip_position = camera.view_proj * vec4<f32>(model.position, 1.0); // 2.
+    out.clip_position = camera.view_proj * model_matrix * vec4<f32>(model.position, 1.0);
     return out;
 }
 

src/texture.rs

@@ -78,3 +78,45 @@ impl Texture {
         Ok(Self { texture, view, sampler })
     }
 }
+
+impl Texture {
+    pub const DEPTH_FORMAT: wgpu::TextureFormat = wgpu::TextureFormat::Depth32Float;
+
+    pub fn create_depth_texture(device: &wgpu::Device, config: &wgpu::SurfaceConfiguration, label: &str) -> Self {
+        let size = wgpu::Extent3d {
+            width: config.width.max(1),
+            height: config.height.max(1),
+            depth_or_array_layers: 1,
+        };
+        let desc = wgpu::TextureDescriptor {
+            label: Some(label),
+            size,
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: Self::DEPTH_FORMAT,
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT
+                | wgpu::TextureUsages::TEXTURE_BINDING,
+            view_formats: &[],
+        };
+        let texture = device.create_texture(&desc);
+
+        let view = texture.create_view(&wgpu::TextureViewDescriptor::default());
+        let sampler = device.create_sampler(
+            &wgpu::SamplerDescriptor {
+                address_mode_u: wgpu::AddressMode::ClampToEdge,
+                address_mode_v: wgpu::AddressMode::ClampToEdge,
+                address_mode_w: wgpu::AddressMode::ClampToEdge,
+                mag_filter: wgpu::FilterMode::Linear,
+                min_filter: wgpu::FilterMode::Linear,
+                mipmap_filter: wgpu::FilterMode::Nearest,
+                compare: Some(wgpu::CompareFunction::LessEqual),
+                lod_min_clamp: 0.0,
+                lod_max_clamp: 100.0,
+                ..Default::default()
+            }
+        );
+
+        Self { texture, view, sampler }
+    }
+}