50 lines
1.4 KiB
GLSL
50 lines
1.4 KiB
GLSL
// pathfinder/shaders/gles2/common.inc.glsl
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//
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// Copyright (c) 2017 Mozilla Foundation
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#version 100
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#extension GL_EXT_draw_buffers : require
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#extension GL_EXT_frag_depth : require
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#define MAX_PATHS 65536
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precision highp float;
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// https://stackoverflow.com/a/36078859
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int imod(int ia, int ib) {
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float a = float(ia), b = float(ib);
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float m = a - floor((a + 0.5) / b) * b;
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return int(floor(m + 0.5));
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}
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vec2 transformVertexPosition(vec2 position, mat4 transform) {
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return (transform * vec4(position, 0.0, 1.0)).xy;
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}
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vec2 convertScreenToClipSpace(vec2 position, ivec2 framebufferSize) {
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return position / vec2(framebufferSize) * 2.0 - 1.0;
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}
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float convertPathIndexToDepthValue(int pathIndex) {
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return mix(-1.0, 1.0, float(pathIndex) / float(MAX_PATHS));
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}
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vec4 fetchFloat4Data(sampler2D dataTexture, int index, ivec2 dimensions) {
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ivec2 pixelCoord = ivec2(imod(index, dimensions.x), index / dimensions.x);
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return texture2D(dataTexture, (vec2(pixelCoord) + 0.5) / vec2(dimensions));
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}
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vec4 fetchFloat4NormIndexedData(sampler2D dataTexture, float normIndex, ivec2 dimensions) {
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return fetchFloat4Data(dataTexture, int(normIndex * float(dimensions.x)), dimensions);
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}
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vec2 packPathID(int pathID) {
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return vec2(imod(pathID, 256), pathID / 256) / 255.0;
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}
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int unpackPathID(vec2 packedPathID) {
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ivec2 pathIDBytes = ivec2(floor(packedPathID * 255.0));
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return pathIDBytes.y * 256 + pathIDBytes.x;
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}
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