dithering.glsl (894B)
1 /* This Source Code Form is subject to the terms of the Mozilla Public 2 * License, v. 2.0. If a copy of the MPL was not distributed with this 3 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ 4 5 #ifdef WR_FRAGMENT_SHADER 6 7 #ifdef WR_FEATURE_DITHERING 8 9 // A 8x8 texture producing values in the range [0, 64/255]. 10 uniform sampler2D sDither; 11 12 vec4 dither(vec4 color) { 13 const int matrix_mask = 7; 14 15 ivec2 pos = ivec2(gl_FragCoord.xy) & ivec2(matrix_mask); 16 float noise_normalized = texelFetch(sDither, pos, 0).r * 255.0 / 64.0; 17 // Center the range around zero and scale it down by some amount to 18 // avoid hardware-specific rounding differences. 19 float noise = (noise_normalized - 0.5) / 256.0 * 0.87; 20 21 return color + vec4(noise, noise, noise, 0); 22 } 23 24 #else 25 26 vec4 dither(vec4 color) { 27 return color; 28 } 29 30 #endif //WR_FEATURE_DITHERING 31 32 #endif //WR_FRAGMENT_SHADER