4846ccd86d
Nothing wrong with EOCF/OECF but the "T" version is more common and readers will therefore be more likely to be more familiar with it.
113 lines
4.0 KiB
GLSL
113 lines
4.0 KiB
GLSL
//------------------------------------------------------------------------------
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// Dithering configuration
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//------------------------------------------------------------------------------
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// Dithering operators
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#define DITHERING_NONE 0
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#define DITHERING_INTERLEAVED_NOISE 1
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#define DITHERING_VLACHOS 2
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#define DITHERING_TRIANGLE_NOISE 3
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#define DITHERING_TRIANGLE_NOISE_RGB 4
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#define DITHERING_OPERATOR DITHERING_TRIANGLE_NOISE
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//------------------------------------------------------------------------------
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// Noise
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//------------------------------------------------------------------------------
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// n must be normalized in [0..1] (e.g. texture coordinates)
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float triangleNoise(highp vec2 n) {
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// triangle noise, in [-1.0..1.0[ range
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n = fract(n * vec2(5.3987, 5.4421));
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n += dot(n.yx, n.xy + vec2(21.5351, 14.3137));
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highp float xy = n.x * n.y;
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// compute in [0..2[ and remap to [-1.0..1.0[
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return fract(xy * 95.4307) + fract(xy * 75.04961) - 1.0;
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}
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// n must not be normalized (e.g. window coordinates)
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float interleavedGradientNoise(highp vec2 n) {
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return fract(52.982919 * fract(dot(vec2(0.06711, 0.00584), n)));
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}
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//------------------------------------------------------------------------------
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// Dithering
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//------------------------------------------------------------------------------
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vec4 Dither_InterleavedGradientNoise(vec4 rgba, const highp float temporalNoise01) {
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// Jimenez 2014, "Next Generation Post-Processing in Call of Duty"
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highp vec2 uv = gl_FragCoord.xy + temporalNoise01;
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// The noise variable must be highp to workaround Adreno bug #1096.
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highp float noise = interleavedGradientNoise(uv);
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// remap from [0..1[ to [-0.5..0.5[
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noise -= 0.5;
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return rgba + vec4(noise / 255.0);
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}
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vec4 Dither_TriangleNoise(vec4 rgba, const highp float temporalNoise01) {
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// Gjøl 2016, "Banding in Games: A Noisy Rant"
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highp vec2 uv = gl_FragCoord.xy * frameUniforms.resolution.zw;
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uv += vec2(0.07 * temporalNoise01);
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// The noise variable must be highp to workaround Adreno bug #1096.
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highp float noise = triangleNoise(uv);
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// noise is in [-1..1[
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return rgba + vec4(noise / 255.0);
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}
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vec4 Dither_Vlachos(vec4 rgba, const highp float temporalNoise01) {
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// Vlachos 2016, "Advanced VR Rendering"
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float noise = dot(vec2(171.0, 231.0), gl_FragCoord.xy + temporalNoise01);
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vec3 noiseRGB = fract(vec3(noise) / vec3(103.0, 71.0, 97.0));
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// remap from [0..1[ to [-0.5..0.5[
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noiseRGB -= 0.5;
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return vec4(rgba.rgb + (noiseRGB / 255.0), rgba.a);
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}
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vec4 Dither_TriangleNoiseRGB(vec4 rgba, const highp float temporalNoise01) {
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// Gjøl 2016, "Banding in Games: A Noisy Rant"
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highp vec2 uv = gl_FragCoord.xy * frameUniforms.resolution.zw;
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uv += vec2(0.07 * temporalNoise01);
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vec3 noiseRGB = vec3(
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triangleNoise(uv),
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triangleNoise(uv + 0.1337),
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triangleNoise(uv + 0.3141));
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// noise is in [-1..1[
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return rgba + noiseRGB.xyzx / 255.0;
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}
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//------------------------------------------------------------------------------
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// Dithering dispatch
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//------------------------------------------------------------------------------
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/**
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* Dithers the specified RGBA color based on the current time and fragment
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* coordinates the input must be in the final color space (including OETF).
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* This dithering function assumes we are dithering to an 8-bit target.
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* This function dithers the alpha channel assuming premultiplied output
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*/
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vec4 dither(vec4 rgba, const highp float temporalNoise01) {
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#if DITHERING_OPERATOR == DITHERING_NONE
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return rgba;
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#elif DITHERING_OPERATOR == DITHERING_INTERLEAVED_NOISE
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return Dither_InterleavedGradientNoise(rgba, temporalNoise01);
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#elif DITHERING_OPERATOR == DITHERING_VLACHOS
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return Dither_Vlachos(rgba, temporalNoise01);
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#elif DITHERING_OPERATOR == DITHERING_TRIANGLE_NOISE
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return Dither_TriangleNoise(rgba, temporalNoise01);
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#elif DITHERING_OPERATOR == DITHERING_TRIANGLE_NOISE_RGB
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return Dither_TriangleNoiseRGB(rgba, temporalNoise01);
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#endif
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}
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