implement square filter

uw8-window/src/gpu/mod.rs

@@ -17,8 +17,10 @@ use winit::platform::unix::EventLoopExtUnix;
 use winit::platform::windows::EventLoopExtWindows;
 
 mod crt;
+mod square;
 
 use crt::CrtFilter;
+use square::SquareFilter;
 
 pub struct Window {
     event_loop: EventLoop<()>,
@@ -95,7 +97,7 @@ impl Window {
             present_mode: wgpu::PresentMode::AutoNoVsync,
         };
 
-        let filter: Box<dyn Filter> = Box::new(CrtFilter::new(
+        let mut filter: Box<dyn Filter> = Box::new(CrtFilter::new(
             &device,
             &palette_screen_mode.screen_view,
             window.inner_size(),
@@ -144,6 +146,22 @@ impl Window {
                                     });
                                 }
                                 Some(VirtualKeyCode::R) => reset = true,
+                                Some(VirtualKeyCode::Key1) => {
+                                    filter = Box::new(SquareFilter::new(
+                                        &device,
+                                        &palette_screen_mode.screen_view,
+                                        window.inner_size(),
+                                        surface_config.format,
+                                    ))
+                                }
+                                Some(VirtualKeyCode::Key2) => {
+                                    filter = Box::new(CrtFilter::new(
+                                        &device,
+                                        &palette_screen_mode.screen_view,
+                                        window.inner_size(),
+                                        surface_config.format,
+                                    ))
+                                }
                                 _ => (),
                             }
 

uw8-window/src/gpu/square.rs

@@ -0,0 +1,157 @@
+use wgpu::util::DeviceExt;
+use winit::dpi::PhysicalSize;
+
+use super::Filter;
+
+pub struct SquareFilter {
+    uniform_buffer: wgpu::Buffer,
+    bind_group: wgpu::BindGroup,
+    pipeline: wgpu::RenderPipeline,
+}
+
+impl SquareFilter {
+    pub fn new(
+        device: &wgpu::Device,
+        screen: &wgpu::TextureView,
+        resolution: PhysicalSize<u32>,
+        surface_format: wgpu::TextureFormat,
+    ) -> SquareFilter {
+        let uniforms = Uniforms {
+            texture_scale: texture_scale_from_resolution(resolution),
+        };
+
+        let uniform_buffer = device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
+            label: None,
+            contents: bytemuck::cast_slice(&[uniforms]),
+            usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+        });
+
+        let bind_group_layout = device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
+            entries: &[
+                wgpu::BindGroupLayoutEntry {
+                    binding: 0,
+                    visibility: wgpu::ShaderStages::FRAGMENT,
+                    ty: wgpu::BindingType::Texture {
+                        multisampled: false,
+                        view_dimension: wgpu::TextureViewDimension::D2,
+                        sample_type: wgpu::TextureSampleType::Float { filterable: true },
+                    },
+                    count: None,
+                },
+                wgpu::BindGroupLayoutEntry {
+                    binding: 1,
+                    visibility: wgpu::ShaderStages::FRAGMENT,
+                    ty: wgpu::BindingType::Sampler(wgpu::SamplerBindingType::Filtering),
+                    count: None,
+                },
+                wgpu::BindGroupLayoutEntry {
+                    binding: 2,
+                    visibility: wgpu::ShaderStages::VERTEX_FRAGMENT,
+                    ty: wgpu::BindingType::Buffer {
+                        ty: wgpu::BufferBindingType::Uniform,
+                        has_dynamic_offset: false,
+                        min_binding_size: None,
+                    },
+                    count: None,
+                },
+            ],
+            label: None,
+        });
+
+        let sampler = device.create_sampler(&wgpu::SamplerDescriptor {
+            mag_filter: wgpu::FilterMode::Linear,
+            ..Default::default()
+        });
+
+        let bind_group = device.create_bind_group(&wgpu::BindGroupDescriptor {
+            layout: &bind_group_layout,
+            entries: &[
+                wgpu::BindGroupEntry {
+                    binding: 0,
+                    resource: wgpu::BindingResource::TextureView(&screen),
+                },
+                wgpu::BindGroupEntry {
+                    binding: 1,
+                    resource: wgpu::BindingResource::Sampler(&sampler),
+                },
+                wgpu::BindGroupEntry {
+                    binding: 2,
+                    resource: uniform_buffer.as_entire_binding(),
+                },
+            ],
+            label: None,
+        });
+
+        let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: None,
+            source: wgpu::ShaderSource::Wgsl(include_str!("square.wgsl").into()),
+        });
+
+        let render_pipeline_layout =
+            device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+                label: None,
+                bind_group_layouts: &[&bind_group_layout],
+                push_constant_ranges: &[],
+            });
+
+        let render_pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            label: None,
+            layout: Some(&render_pipeline_layout),
+            vertex: wgpu::VertexState {
+                module: &shader,
+                entry_point: "vs_main",
+                buffers: &[],
+            },
+            fragment: Some(wgpu::FragmentState {
+                module: &shader,
+                entry_point: "fs_main",
+                targets: &[Some(wgpu::ColorTargetState {
+                    format: surface_format,
+                    blend: None,
+                    write_mask: wgpu::ColorWrites::ALL,
+                })],
+            }),
+            primitive: Default::default(),
+            depth_stencil: None,
+            multisample: Default::default(),
+            multiview: None,
+        });
+
+        SquareFilter {
+            uniform_buffer,
+            bind_group,
+            pipeline: render_pipeline,
+        }
+    }
+}
+
+impl Filter for SquareFilter {
+    fn resize(&self, queue: &wgpu::Queue, new_size: PhysicalSize<u32>) {
+        let uniforms = Uniforms {
+            texture_scale: texture_scale_from_resolution(new_size),
+        };
+        queue.write_buffer(&self.uniform_buffer, 0, bytemuck::cast_slice(&[uniforms]));
+    }
+
+    fn render<'a>(&'a self, render_pass: &mut wgpu::RenderPass<'a>) {
+        render_pass.set_pipeline(&self.pipeline);
+        render_pass.set_bind_group(0, &self.bind_group, &[]);
+        render_pass.draw(0..6, 0..1);
+    }
+}
+
+fn texture_scale_from_resolution(res: PhysicalSize<u32>) -> [f32; 4] {
+    let scale = ((res.width as f32) / 160.0).min((res.height as f32) / 120.0);
+    [
+        scale / res.width as f32,
+        scale / res.height as f32,
+        2.0 / scale,
+        0.0,
+    ]
+}
+
+#[repr(C)]
+#[derive(Debug, Copy, Clone, bytemuck::Pod, bytemuck::Zeroable)]
+struct Uniforms {
+    texture_scale: [f32; 4],
+}

uw8-window/src/gpu/square.wgsl

@@ -0,0 +1,44 @@
+struct VertexOutput {
+    @builtin(position) clip_position: vec4<f32>,
+    @location(0) tex_coords: vec2<f32>,
+}
+
+struct Uniforms {
+    texture_scale: vec4<f32>,
+}
+
+@group(0) @binding(2) var<uniform> uniforms: Uniforms;
+
+@vertex
+fn vs_main(
+    @builtin(vertex_index) in_vertex_index: u32,
+) -> VertexOutput {
+    var out: VertexOutput;
+    let i = in_vertex_index / 3u + in_vertex_index % 3u;
+    let x = -1.0 + f32(i % 2u) * 322.0;
+    let y = -1.0 + f32(i / 2u) * 242.0;
+    out.clip_position = vec4<f32>((vec2<f32>(x, y) - vec2<f32>(160.0, 120.0)) * uniforms.texture_scale.xy, 0.0, 1.0);
+    out.tex_coords = vec2<f32>(x, y);
+    return out;
+}
+
+@group(0) @binding(0) var screen_texture: texture_2d<f32>;
+@group(0) @binding(1) var linear_sampler: sampler;
+
+fn aa_tex_coord(c: f32) -> f32 {
+    let low = c - uniforms.texture_scale.z * 0.5;
+    let high = c + uniforms.texture_scale.z * 0.5;
+    let base = floor(low);
+    let center = base + 0.5;
+    let next = base + 1.0;
+    if high > next {
+        return center + (high - next) / (high - base);
+    } else {
+        return center;
+    }
+}
+
+@fragment
+fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
+    return textureSample(screen_texture, linear_sampler, vec2<f32>(aa_tex_coord(in.tex_coords.x), aa_tex_coord(in.tex_coords.y)) / vec2<f32>(320.0, 240.0));
+}