Implement the line antialiasing shader, untested as of yet
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@ -48,14 +48,18 @@ const SHADER_URLS: ShaderMap<ShaderProgramURLs> = {
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vertex: "/glsl/gles2/ecaa-edge-detect.vs.glsl",
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fragment: "/glsl/gles2/ecaa-edge-detect.fs.glsl",
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},
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ecaaResolve: {
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vertex: "/glsl/gles2/ecaa-resolve.vs.glsl",
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fragment: "/glsl/gles2/ecaa-resolve.fs.glsl",
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},
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ecaaCover: {
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vertex: "/glsl/gles2/ecaa-cover.vs.glsl",
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fragment: "/glsl/gles2/ecaa-cover.fs.glsl",
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},
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ecaaLine: {
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vertex: "/glsl/gles2/ecaa-line.vs.glsl",
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fragment: "/glsl/gles2/ecaa-line.fs.glsl",
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},
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ecaaResolve: {
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vertex: "/glsl/gles2/ecaa-resolve.vs.glsl",
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fragment: "/glsl/gles2/ecaa-resolve.fs.glsl",
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},
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};
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interface UnlinkedShaderProgram {
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@ -85,8 +89,9 @@ interface ShaderMap<T> {
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directCurve: T;
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directInterior: T;
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ecaaEdgeDetect: T;
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ecaaResolve: T;
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ecaaCover: T;
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ecaaLine: T;
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ecaaResolve: T;
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}
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interface UniformMap {
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@ -9,6 +9,8 @@
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#define MAX_PATHS 65536
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#define EPSILON 0.001
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precision highp float;
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// https://stackoverflow.com/a/36078859
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@ -65,3 +67,11 @@ vec2 packPathID(int pathID) {
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int unpackPathID(vec2 packedPathID) {
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return unpackUInt16(packedPathID);
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}
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bool xor(bool a, bool b) {
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return (a && !b) || (!a && b);
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}
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float det2(vec2 a, vec2 b) {
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return a.x * b.y - b.x * a.y;
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}
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@ -58,7 +58,10 @@ void main() {
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int pathID = fetchUInt16Data(uBVertexPathID, pointIndices.x, uBVertexPathIDDimensions);
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vec2 position = mix(roundedExtents.xy, roundedExtents.zw, (aQuadPosition + 1.0) / 2.0);
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// FIXME(pcwalton): Use a separate VBO for this.
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vec2 quadPosition = (aQuadPosition + 1.0) * 0.5;
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vec2 position = mix(roundedExtents.xy, roundedExtents.zw, quadPosition);
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position = convertScreenToClipSpace(position, uFramebufferSize);
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float depth = convertPathIndexToDepthValue(pathID);
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gl_Position = vec4(position, depth, 1.0);
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@ -0,0 +1,67 @@
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// pathfinder/shaders/gles2/ecaa-line.vs.glsl
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//
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// Copyright (c) 2017 Mozilla Foundation
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precision highp float;
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uniform bool uLowerPart;
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varying vec4 vEndpoints;
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void main() {
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// Unpack.
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vec2 center = gl_FragCoord.xy;
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vec2 p0 = vEndpoints.xy, p1 = vEndpoints.zw;
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bool slopeNegative = p0.y > p1.y;
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// Set up Liang-Barsky clipping.
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vec4 pixelExtents = center.xxyy + vec4(-0.5, 0.5, -0.5, 0.5);
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vec4 p = (p1 - p0).xxyy, q = pixelExtents - p0.xxyy;
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// Use Liang-Barsky to clip to the left and right sides of this pixel.
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vec2 t = clamp(q.xy / p.xy, 0.0, 1.0);
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vec2 spanP0 = p0 + p.yw * t.x, spanP1 = p0 + p.yw * t.y;
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// ...and to the bottom and top.
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if (p.z != 0.0) {
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vec2 tVertical = q.zw / p.zw;
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if (slopeNegative)
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tVertical.xy = tVertical.yx; // FIXME(pcwalton): Can this be removed?
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t = vec2(max(t.x, tVertical.x), min(t.y, tVertical.y));
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}
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// If the line doesn't pass through this pixel, detect that and bail.
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if (t.x >= t.y) {
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bool fill = uLowerPart ? spanP0.y < pixelExtents.z : spanP0.y > pixelExtents.w;
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gl_FragColor = vec4(fill ? spanP1.x - spanP0.x : 0.0);
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return;
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}
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// Calculate A2.x.
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float a2x;
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if (xor(uLowerPart, slopeNegative)) {
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a2x = spanP0.x;
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t.xy = t.yx;
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} else {
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a2x = spanP1.x;
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}
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// Calculate A3.y.
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float a3y = uLowerPart ? pixelExtents.w : pixelExtents.z;
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// Calculate A0-A5.
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vec2 a0 = p0 + p.yw * t.x;
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vec2 a1 = p0 + p.yw * t.y;
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vec2 a2 = vec2(a2x, a1.y);
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vec2 a3 = vec2(a2x, a3y);
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vec2 a4 = vec2(a0.x, a3y);
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// Calculate area with the shoelace formula.
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float area = 0.5 * (det2(a0, a1) + det2(a1, a2) + det2(a2, a3) + det2(a3, a4) + det2(a4, a0));
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if (!slopeNegative)
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area = -area;
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// Done!
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gl_FragColor = vec4(area);
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}
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@ -0,0 +1,56 @@
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// pathfinder/shaders/gles2/ecaa-line.vs.glsl
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//
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// Copyright (c) 2017 Mozilla Foundation
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precision highp float;
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uniform mat4 uTransform;
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uniform ivec2 uFramebufferSize;
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uniform ivec2 uBVertexPositionDimensions;
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uniform ivec2 uBVertexPathIDDimensions;
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uniform sampler2D uBVertexPosition;
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uniform sampler2D uBVertexPathID;
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uniform bool uLowerPart;
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attribute vec2 aQuadPosition;
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attribute vec4 aLineIndices;
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varying vec4 vEndpoints;
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void main() {
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// Fetch B-vertex positions.
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ivec2 pointIndices = ivec2(unpackUInt32Attribute(aLineIndices.xy),
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unpackUInt32Attribute(aLineIndices.zw));
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vec2 leftPosition = fetchFloat2Data(uBVertexPosition,
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pointIndices.x,
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uBVertexPositionDimensions);
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vec2 rightPosition = fetchFloat2Data(uBVertexPosition,
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pointIndices.y,
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uBVertexPositionDimensions);
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vec2 position;
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if (abs(leftPosition.x - rightPosition.x) > EPSILON) {
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leftPosition = transformVertexPosition(leftPosition, uTransform);
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rightPosition = transformVertexPosition(rightPosition, uTransform);
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vec2 verticalExtents = vec2(min(leftPosition.y, rightPosition.y),
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max(leftPosition.y, rightPosition.y));
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vec4 roundedExtents = vec4(floor(vec2(leftPosition.x, verticalExtents.x)),
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ceil(vec2(rightPosition.x, verticalExtents.y)));
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// FIXME(pcwalton): Use a separate VBO for this.
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vec2 quadPosition = (aQuadPosition + 1.0) * 0.5;
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position = mix(roundedExtents.xy, roundedExtents.zw, quadPosition);
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position = convertScreenToClipSpace(position, uFramebufferSize);
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} else {
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position = vec2(0.0);
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}
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int pathID = fetchUInt16Data(uBVertexPathID, pointIndices.x, uBVertexPathIDDimensions);
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float depth = convertPathIndexToDepthValue(pathID);
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gl_Position = vec4(position, depth, 1.0);
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vEndpoints = vec4(leftPosition, rightPosition);
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}
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