1// Shader model 4.0 twin of translucent.wgsl: the frame, blended in linear light, premultiplied
2// again in sRGB for a window server that composites that way.
3Texture2D frame : register(t0);
4
5float4 vertex(uint index : SV_VertexID) : SV_Position {
6 float2 corner = float2((index << 1) & 2, index & 2);
7 return float4(corner * 2.0 - 1.0, 0.0, 1.0);
8}
9
10float3 encode(float3 linear_light) {
11 return linear_light <= 0.0031308 ? linear_light * 12.92
12 : 1.055 * pow(linear_light, 1.0 / 2.4) - 0.055;
13}
14
15float4 fragment(float4 at : SV_Position) : SV_Target {
16 float4 pixel = frame.Load(int3(at.xy, 0));
17 if (pixel.a == 0.0) {
18 return 0.0;
19 }
20 return float4(encode(pixel.rgb / pixel.a) * pixel.a, pixel.a);
21}