2017-10-09 17:14:24 -04:00
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// pathfinder/shaders/gles2/xcaa-mono-subpixel-resolve.fs.glsl
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2017-09-07 17:58:41 -04:00
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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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2017-12-30 20:32:51 -05:00
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//! Performs subpixel antialiasing for LCD screens by converting a
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//! 3x-oversampled single-channel color buffer to an RGB framebuffer, applying
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//! the FreeType color defringing filter as necessary.
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precision mediump float;
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2018-01-04 21:07:14 -05:00
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/// The background color of the monochrome path.
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uniform vec4 uBGColor;
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/// The foreground color of the monochrome path.
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uniform vec4 uFGColor;
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/// The alpha coverage texture.
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uniform sampler2D uAAAlpha;
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/// The dimensions of the alpha coverage texture, in texels.
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uniform ivec2 uAAAlphaDimensions;
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uniform vec4 uKernel;
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varying vec2 vTexCoord;
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void main() {
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float onePixel = 1.0 / float(uAAAlphaDimensions.x);
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vec4 shadesL, shadesR;
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float shadeC;
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sample9Tap(shadesL, shadeC, shadesR, uAAAlpha, vTexCoord, onePixel, uKernel);
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vec3 shades = vec3(convolve7Tap(shadesL, vec3(shadeC, shadesR.xy), uKernel),
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convolve7Tap(vec4(shadesL.yzw, shadeC), shadesR.xyz, uKernel),
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convolve7Tap(vec4(shadesL.zw, shadeC, shadesR.x), shadesR.yzw, uKernel));
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vec3 color = mix(uBGColor.rgb, uFGColor.rgb, shades);
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float alpha = any(greaterThan(shades, vec3(0.0))) ? uFGColor.a : uBGColor.a;
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gl_FragColor = alpha * vec4(color, 1.0);
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2017-09-07 17:58:41 -04:00
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}
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