Files
filament/shaders/src/dithering.fs
Romain Guy cabdc255f5 Shader code cleanup
roughness is now called perceptualRoughness and linearRoughness
is now called roughness. It better matches papers, etc.
2019-05-20 14:45:26 -07:00

96 lines
3.5 KiB
GLSL

//------------------------------------------------------------------------------
// Dithering configuration
//------------------------------------------------------------------------------
// Dithering operators
#define DITHERING_NONE 0
#define DITHERING_INTERLEAVED_NOISE 1
#define DITHERING_VLACHOS 2
#define DITHERING_TRIANGLE_NOISE 3
#define DITHERING_TRIANGLE_NOISE_RGB 4
#ifdef TARGET_MOBILE
#define DITHERING_OPERATOR DITHERING_INTERLEAVED_NOISE
#else
#define DITHERING_OPERATOR DITHERING_TRIANGLE_NOISE_RGB
#endif
//------------------------------------------------------------------------------
// Noise
//------------------------------------------------------------------------------
float triangleNoise(highp vec2 n) {
// triangle noise, in [-1.0..1.0[ range
n += vec2(0.07 * fract(postProcessUniforms.time));
n = fract(n * vec2(5.3987, 5.4421));
n += dot(n.yx, n.xy + vec2(21.5351, 14.3137));
highp float xy = n.x * n.y;
// compute in [0..2[ and remap to [-1.0..1.0[
return fract(xy * 95.4307) + fract(xy * 75.04961) - 1.0;
}
float interleavedGradientNoise(const highp vec2 n) {
return fract(52.982919 * fract(dot(vec2(0.06711, 0.00584), n)));
}
//------------------------------------------------------------------------------
// Dithering
//------------------------------------------------------------------------------
vec4 Dither_InterleavedGradientNoise(vec4 rgba) {
// Jimenez 2014, "Next Generation Post-Processing in Call of Duty"
float noise = interleavedGradientNoise(gl_FragCoord.xy + postProcessUniforms.time);
// remap from [0..1[ to [-1..1[
noise = (noise * 2.0) - 1.0;
return vec4(rgba.rgb + noise / 255.0, rgba.a);
}
vec4 Dither_Vlachos(vec4 rgba) {
// Vlachos 2016, "Advanced VR Rendering"
highp vec3 noise = vec3(dot(vec2(171.0, 231.0), gl_FragCoord.xy + postProcessUniforms.time));
noise = fract(noise / vec3(103.0, 71.0, 97.0));
// remap from [0..1[ to [-1..1[
noise = (noise * 2.0) - 1.0;
return vec4(rgba.rgb + (noise / 255.0), rgba.a);
}
vec4 Dither_TriangleNoise(vec4 rgba) {
// Gjøl 2016, "Banding in Games: A Noisy Rant"
return rgba + triangleNoise(gl_FragCoord.xy * frameUniforms.resolution.zw) / 255.0;
}
vec4 Dither_TriangleNoiseRGB(vec4 rgba) {
// Gjøl 2016, "Banding in Games: A Noisy Rant"
vec2 uv = gl_FragCoord.xy * frameUniforms.resolution.zw;
vec3 dither = vec3(
triangleNoise(uv),
triangleNoise(uv + 0.1337),
triangleNoise(uv + 0.3141)) / 255.0;
return vec4(rgba.rgb + dither, rgba.a + dither.x);
}
//------------------------------------------------------------------------------
// Dithering dispatch
//------------------------------------------------------------------------------
/**
* Dithers the specified RGB color based on the current time and fragment
* coordinates the input must be in the final color space (including OECF).
* This dithering function assumes we are dithering to an 8-bit target.
* This function dithers the alpha channel assuming premultiplied output
*/
vec4 dither(vec4 rgba) {
#if DITHERING_OPERATOR == DITHERING_NONE
return rgba;
#elif DITHERING_OPERATOR == DITHERING_INTERLEAVED_NOISE
return Dither_InterleavedGradientNoise(rgba);
#elif DITHERING_OPERATOR == DITHERING_VLACHOS
return Dither_Vlachos(rgba);
#elif DITHERING_OPERATOR == DITHERING_TRIANGLE_NOISE
return Dither_TriangleNoise(rgba);
#elif DITHERING_OPERATOR == DITHERING_TRIANGLE_NOISE_RGB
return Dither_TriangleNoiseRGB(rgba);
#endif
}