restructuring for multiple filters

uw8-window/src/gpu/crt.wgsl

@@ -0,0 +1,75 @@
+struct VertexOutput {
+    @builtin(position) clip_position: vec4<f32>,
+    @location(0) tex_coords: vec2<f32>,
+}
+
+struct Uniforms {
+    texture_scale: vec4<f32>,
+}
+
+@group(0) @binding(1) 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>;
+
+fn sample_pixel(coords: vec2<i32>, offset: vec4<f32>) -> vec3<f32> {
+    let is_outside = any(vec2<u32>(coords) >= vec2<u32>(320u, 240u));
+    if(is_outside) {
+        return vec3<f32>(0.0);
+    } else {
+        let f = max(vec4<f32>(0.01) / offset - vec4<f32>(0.003), vec4<f32>(0.0));
+        return textureLoad(screen_texture, coords, 0).rgb * (f.x + f.y + f.z + f.w);
+    }
+}
+
+@fragment
+fn fs_main(in: VertexOutput) -> @location(0) vec4<f32> {
+    let pixel = floor(in.tex_coords);
+    let o = vec2<f32>(0.5) - (in.tex_coords - pixel);
+    let pixel = vec2<i32>(pixel);
+    
+    let offset_x = o.xxxx + vec4<f32>(-0.125, 0.375, 0.125, -0.375) * uniforms.texture_scale.z;
+    let offset_y = o.yyyy + vec4<f32>(-0.375, -0.125, 0.375, 0.125) * uniforms.texture_scale.z;
+    
+    let offset_x0 = max(abs(offset_x + vec4<f32>(-1.0)) - vec4<f32>(0.5), vec4<f32>(0.0));
+    let offset_x1 = max(abs(offset_x) - vec4<f32>(0.5), vec4<f32>(0.0));
+    let offset_x2 = max(abs(offset_x + vec4<f32>(1.0)) - vec4<f32>(0.5), vec4<f32>(0.0));
+    
+    let offset_x0 = offset_x0 * offset_x0;
+    let offset_x1 = offset_x1 * offset_x1;
+    let offset_x2 = offset_x2 * offset_x2;
+    
+    let offset_yr = offset_y + vec4<f32>(-1.0);
+    let offset_yr = vec4<f32>(0.02) + offset_yr * offset_yr;
+    
+    var acc = sample_pixel(pixel + vec2<i32>(-1, -1), offset_x0 + offset_yr);
+    acc = acc + sample_pixel(pixel + vec2<i32>(0, -1), offset_x1 + offset_yr);
+    acc = acc + sample_pixel(pixel + vec2<i32>(1, -1), offset_x2 + offset_yr);
+
+    let offset_yr = vec4<f32>(0.02) + offset_y * offset_y;
+    
+    acc = acc + sample_pixel(pixel + vec2<i32>(-1, 0), offset_x0 + offset_yr);
+    acc = acc + sample_pixel(pixel, offset_x1 + offset_yr);
+    acc = acc + sample_pixel(pixel + vec2<i32>(1, 0), offset_x2 + offset_yr);
+
+    let offset_yr = offset_y + vec4<f32>(1.0);
+    let offset_yr = vec4<f32>(0.02) + offset_yr * offset_yr;
+    
+    acc = acc + sample_pixel(pixel + vec2<i32>(-1, 1), offset_x0 + offset_yr);
+    acc = acc + sample_pixel(pixel + vec2<i32>(0, 1), offset_x1 + offset_yr);
+    acc = acc + sample_pixel(pixel + vec2<i32>(1, 1), offset_x2 + offset_yr);
+
+    return vec4<f32>(acc, 1.0);
+}