slang-shaders/reshade/shaders/LUT/LUT.slang
2017-06-23 20:25:40 -05:00

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Executable file

#version 450
layout(push_constant) uniform Push
{
vec4 SourceSize;
vec4 OriginalSize;
vec4 OutputSize;
uint FrameCount;
float LUT_Size;
} params;
#pragma parameter LUT_Size "LUT Size" 16.0 1.0 64.0 1.0
layout(std140, set = 0, binding = 0) uniform UBO
{
mat4 MVP;
} global;
#pragma stage vertex
layout(location = 0) in vec4 Position;
layout(location = 1) in vec2 TexCoord;
layout(location = 0) out vec2 vTexCoord;
void main()
{
gl_Position = global.MVP * Position;
vTexCoord = TexCoord * 1.0001;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
layout(set = 0, binding = 3) uniform sampler2D SamplerLUT;
// This shouldn't be necessary but it seems some undefined values can
// creep in and each GPU vendor handles that differently. This keeps
// all values within a safe range
vec4 mixfix(vec4 a, vec4 b, float c)
{
return (a.z < 1.0) ? mix(a, b, c) : a;
}
void main()
{
vec4 imgColor = texture(Source, vTexCoord.xy);
float red = ( imgColor.r * (params.LUT_Size - 1.0) + 0.4999 ) / (params.LUT_Size * params.LUT_Size);
float green = ( imgColor.g * (params.LUT_Size - 1.0) + 0.4999 ) / params.LUT_Size;
float blue1 = (floor( imgColor.b * (params.LUT_Size - 1.0) ) / params.LUT_Size) + red;
float blue2 = (ceil( imgColor.b * (params.LUT_Size - 1.0) ) / params.LUT_Size) + red;
float mixer = max((imgColor.b - blue1) / (blue2 - blue1), 0.0);
vec4 color1 = texture( SamplerLUT, vec2( blue1, green ));
vec4 color2 = texture( SamplerLUT, vec2( blue2, green ));
FragColor = mixfix(color1, color2, mixer);
}