35 lines
1.1 KiB
GLSL
35 lines
1.1 KiB
GLSL
// pathfinder/shaders/gles2/xcaa-multi-edge-mask-line.vs.glsl
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//
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// Copyright (c) 2017 The Pathfinder Project Developers.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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precision highp float;
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varying vec4 vEndpoints;
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varying float vWinding;
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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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// 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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vec2 dp = p1 - p0;
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vec4 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 / dp.xx, 0.0, 1.0);
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vec2 spanP0 = p0 + dp * t.x, spanP1 = p0 + dp * t.y;
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// Discard if not edge.
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if (!isPartiallyCovered(p0, dp, center, vWinding))
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discard;
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gl_FragColor = vec4(1.0);
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}
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