bsnes-libretro/shaders/Retro.shader/gamma.fs

32 lines
673 B
GLSL

// Gamma Adjustment Shader
// Written by Themaister - based on byuu's bsnes gamma ramp code
#version 150
uniform sampler2D source[];
in Vertex {
vec2 texCoord;
};
out vec4 fragColor;
const float saturation = 1.0;
const float gamma = 1.0;
const float luminance = 1.2;
vec3 grayscale(vec3 col)
{
// Non-conventional way to do grayscale,
// but bSNES uses this as grayscale value.
return vec3(dot(col, vec3(0.3333)));
}
void main() {
vec3 res = texture(source[0], texCoord).xyz;
res = mix(grayscale(res), res, saturation); // Apply saturation
res = pow(res, vec3(gamma)); // Apply gamma
fragColor = vec4(clamp(res * luminance, 0.0, 1.0), 1.0);
}