Load DEM texture

src/app/dem_renderer.rs

@@ -1,7 +1,7 @@
 use super::raster::Dem;
 use {
     bytemuck::{Pod, Zeroable},
-    std::{borrow::Cow, rc::Rc},
+    std::{borrow::Cow, num::NonZero, rc::Rc},
     wgpu::util::DeviceExt,
 };
 
@@ -12,7 +12,8 @@ pub struct DemRenderer {
     vertex_buffer: wgpu::Buffer,
     index_buffer: wgpu::Buffer,
     index_count: usize,
-    uniforms: Uniforms,
+    camera: Camera,
+    uniforms: UniformBufferManager,
     animation_start: std::time::Instant,
 }
 
@@ -30,32 +31,27 @@ impl Vertex {
     }
 }
 
-struct Uniforms {
+struct Camera {
     projection_matrix: glam::Mat4,
     view_matrix: glam::Mat4,
-    buffer: wgpu::Buffer,
 }
 
-impl Uniforms {
+impl Camera {
-    fn new(device: &wgpu::Device, aspect_ratio: f32) -> Self {
+    fn new(device: &wgpu::Device, viewport_aspect_ratio: f32) -> Self {
-        let projection_matrix =
+        let projection_matrix = glam::Mat4::perspective_rh(
-            glam::Mat4::perspective_rh(std::f32::consts::FRAC_PI_4, aspect_ratio, 1.0, 10000.0);
+            std::f32::consts::FRAC_PI_4,
+            viewport_aspect_ratio,
+            1.0,
+            10000.0,
+        );
         let view_matrix = glam::Mat4::look_at_rh(glam::Vec3::ZERO, glam::Vec3::ZERO, glam::Vec3::Z);
-        let camera_matrix = projection_matrix * view_matrix;
-        let camera_matrix_ref: &[f32; 16] = camera_matrix.as_ref();
-        let buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
-            label: Some("Uniform Buffer"),
-            contents: bytemuck::cast_slice(camera_matrix_ref),
-            usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
-        });
         Self {
             projection_matrix,
             view_matrix,
-            buffer,
         }
     }
 
-    fn set_camera_position(&mut self, camera_position: glam::Vec3, camera_look_at: glam::Vec3) {
+    fn set_position(&mut self, camera_position: glam::Vec3, camera_look_at: glam::Vec3) {
         self.view_matrix = glam::Mat4::look_at_rh(camera_position, camera_look_at, glam::Vec3::Z);
     }
 
@@ -64,14 +60,63 @@ impl Uniforms {
             glam::Mat4::perspective_rh(std::f32::consts::FRAC_PI_4, ratio, 1.0, 10.0);
     }
 
-    fn update_buffer(&self, queue: &wgpu::Queue) {
+    fn get_matrix(&self) -> glam::Mat4 {
-        let camera_matrix = self.projection_matrix * self.view_matrix;
+        self.projection_matrix * self.view_matrix
-        let camera_matrix_ref: &[f32; 16] = camera_matrix.as_ref();
+    }
-        queue.write_buffer(&self.buffer, 0, bytemuck::cast_slice(camera_matrix_ref))
+}
+
+#[repr(C)]
+#[derive(Clone, Copy, Pod, Zeroable)]
+struct UniformBufferContents {
+    camera_matrix: [f32; 16],
+    dem_texture_size: [u32; 2],
+}
+// This struct is 72 bytes but WGSL expects the buffer size to be be a multiple
+// of the alignment of the member with the largest alignment. The mat4x4<f32>
+// type has a 16-byte alignment, so we round up to 16 * 5 = 80.
+const UNIFORM_BUFFER_SIZE: u64 = 80;
+
+struct UniformBufferManager {
+    cpu_buffer: UniformBufferContents,
+    gpu_buffer: wgpu::Buffer,
+}
+
+impl UniformBufferManager {
+    fn new(device: &wgpu::Device) -> Self {
+        let cpu_buffer = UniformBufferContents::zeroed();
+        let gpu_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+            label: Some("Uniform Buffer"),
+            contents: &[0u8; UNIFORM_BUFFER_SIZE as usize],
+            usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+        });
+        Self {
+            cpu_buffer,
+            gpu_buffer,
+        }
     }
 
-    fn binding(&self) -> wgpu::BindingResource<'_> {
+    fn set_camera_matrix(&mut self, camera_matrix: glam::Mat4) {
-        self.buffer.as_entire_binding()
+        self.cpu_buffer
+            .camera_matrix
+            .clone_from_slice(&camera_matrix.to_cols_array())
+    }
+
+    fn set_dem_texture_size(&mut self, dem_texture_size: glam::UVec2) {
+        self.cpu_buffer
+            .dem_texture_size
+            .clone_from_slice(&dem_texture_size.to_array());
+    }
+
+    fn get_binding(&self) -> wgpu::BindingResource<'_> {
+        wgpu::BindingResource::Buffer(wgpu::BufferBinding {
+            buffer: &self.gpu_buffer,
+            offset: 0,
+            size: NonZero::new(UNIFORM_BUFFER_SIZE),
+        })
+    }
+
+    fn update_buffer(&self, queue: &wgpu::Queue) {
+        queue.write_buffer(&self.gpu_buffer, 0, bytemuck::bytes_of(&self.cpu_buffer));
     }
 }
 
@@ -80,6 +125,7 @@ impl DemRenderer {
         source: Rc<Dem>,
         device: &wgpu::Device,
         surface_config: &wgpu::SurfaceConfiguration,
+        queue: &wgpu::Queue,
     ) -> Self {
         let (vertex_data, index_data) = create_vertices(&source);
 
@@ -97,25 +143,67 @@ impl DemRenderer {
 
         let index_count = index_data.len();
 
-        let uniforms = Uniforms::new(
+        let (dem_texture_view, dem_texture_size) = {
+            let texture_size = wgpu::Extent3d {
+                width: source.num_cells_x,
+                height: source.num_cells_y,
+                depth_or_array_layers: 1,
+            };
+            let texture = device.create_texture(&wgpu::TextureDescriptor {
+                label: Some("Dem Texture"),
+                size: texture_size,
+                mip_level_count: 1,
+                sample_count: 1,
+                dimension: wgpu::TextureDimension::D2,
+                format: wgpu::TextureFormat::R16Uint,
+                usage: wgpu::TextureUsages::TEXTURE_BINDING | wgpu::TextureUsages::COPY_DST,
+                view_formats: &[],
+            });
+
+            queue.write_texture(
+                wgpu::ImageCopyTexture {
+                    texture: &texture,
+                    mip_level: 0,
+                    origin: wgpu::Origin3d::ZERO,
+                    aspect: wgpu::TextureAspect::All,
+                },
+                bytemuck::cast_slice(&source.grid[..]),
+                wgpu::ImageDataLayout {
+                    offset: 0,
+                    bytes_per_row: Some(std::mem::size_of::<u16>() as u32 * source.num_cells_x),
+                    rows_per_image: Some(source.num_cells_y),
+                },
+                texture_size,
+            );
+
+            (
+                texture.create_view(&wgpu::TextureViewDescriptor::default()),
+                glam::UVec2::new(source.num_cells_x, source.num_cells_y),
+            )
+        };
+
+        let camera = Camera::new(
             device,
             surface_config.width as f32 / surface_config.height as f32,
         );
 
+        let mut uniforms = UniformBufferManager::new(device);
+        uniforms.set_dem_texture_size(dem_texture_size);
+
         let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
             label: None,
             entries: &[
                 wgpu::BindGroupLayoutEntry {
                     binding: 0,
-                    visibility: wgpu::ShaderStages::VERTEX,
+                    visibility: wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
                     ty: wgpu::BindingType::Buffer {
                         ty: wgpu::BufferBindingType::Uniform,
                         has_dynamic_offset: false,
-                        min_binding_size: wgpu::BufferSize::new(64),
+                        min_binding_size: wgpu::BufferSize::new(UNIFORM_BUFFER_SIZE),
                     },
                     count: None,
                 },
-                /*wgpu::BindGroupLayoutEntry {
+                wgpu::BindGroupLayoutEntry {
                     binding: 1,
                     visibility: wgpu::ShaderStages::FRAGMENT,
                     ty: wgpu::BindingType::Texture {
@@ -124,16 +212,22 @@ impl DemRenderer {
                         view_dimension: wgpu::TextureViewDimension::D2,
                     },
                     count: None,
-                },*/
+                },
             ],
         });
 
         let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
             layout: &bind_group_layout,
-            entries: &[wgpu::BindGroupEntry {
+            entries: &[
+                wgpu::BindGroupEntry {
                     binding: 0,
-                resource: uniforms.binding(),
+                    resource: uniforms.get_binding(),
-            }],
+                },
+                wgpu::BindGroupEntry {
+                    binding: 1,
+                    resource: wgpu::BindingResource::TextureView(&dem_texture_view),
+                },
+            ],
             label: Some("DemRendererBindGroup"),
         });
 
@@ -190,6 +284,7 @@ impl DemRenderer {
             index_buffer,
             index_count,
             animation_start: std::time::Instant::now(),
+            camera,
             uniforms,
         }
     }
@@ -198,13 +293,14 @@ impl DemRenderer {
         let mut encoder = device.create_command_encoder(&wgpu::CommandEncoderDescriptor {
             label: Some("DemRendererCommandEncoder"),
         });
-        self.uniforms.set_camera_position(
+        self.camera.set_position(
             get_animated_camera_position(
                 self.animation_start.elapsed(),
                 self.get_max_dem_dimension(),
             ),
             self.get_dem_centre(),
         );
+        self.uniforms.set_camera_matrix(self.camera.get_matrix());
         self.uniforms.update_buffer(queue);
         {
             let mut rpass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {

src/app/dem_renderer.wgsl

@@ -1,21 +1,34 @@
 struct VertexOutput {
+    @location(0) test: vec2<f32>,
     @builtin(position) position: vec4<f32>,
 };
 
-@group(0)
+struct Uniforms {
-@binding(0)
+    transform: mat4x4<f32>,
-var<uniform> transform: mat4x4<f32>;
+    dem_texture_size: vec2<u32>
+}
+
+@group(0) @binding(0)
+var<uniform> uniforms: Uniforms;
+
+@group(0) @binding(1)
+var dem_texture: texture_2d<u32>;
+
 
 @vertex
 fn vs_main(
     @location(0) position: vec4<f32>,
 ) -> VertexOutput {
     var result: VertexOutput;
-    result.position = transform * position;
+    result.position = uniforms.transform * position;
+    result.test = position.xy;
     return result;
 }
 
 @fragment
 fn fs_solid(vertex: VertexOutput) -> @location(0) vec4<f32> {
-    return vec4<f32>(1.0, 1.0, 1.0, 1.0);
+    let texture_index = vec2<i32>(fract(abs(vertex.test)/500.0)*vec2<f32>(uniforms.dem_texture_size));
+    let v_i = textureLoad(dem_texture, texture_index, 0).r;
+    let v = f32(v_i) / 65535.0;
+    return vec4<f32>(v, v, 1.0, 1.0);
 }

src/app/mod.rs

@@ -153,6 +153,7 @@ impl MvuApp<Model> for App {
                         dem.clone(),
                         &context.device,
                         &context.config,
+                        &context.queue,
                     ))
                 }
             }