зеркало из https://github.com/mozilla/gecko-dev.git
41 строка
1.5 KiB
GLSL
41 строка
1.5 KiB
GLSL
#line 1
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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// TODO(gw): Write a fast path blur that handles smaller blur radii
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// with a offset / weight uniform table and a constant
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// loop iteration count!
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// TODO(gw): Make use of the bilinear sampling trick to reduce
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// the number of texture fetches needed for a gaussian blur.
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float gauss(float x, float sigma) {
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return (1.0 / sqrt(6.283185307179586 * sigma * sigma)) * exp(-(x * x) / (2.0 * sigma * sigma));
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}
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void main(void) {
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vec4 cache_sample = texture(sCacheRGBA8, vUv);
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vec4 color = vec4(cache_sample.rgb, 1.0) * (cache_sample.a * gauss(0.0, vSigma));
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for (int i=1 ; i < vBlurRadius ; ++i) {
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vec2 offset = vec2(float(i)) * vOffsetScale;
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vec2 st0 = clamp(vUv.xy + offset, vUvRect.xy, vUvRect.zw);
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vec4 color0 = texture(sCacheRGBA8, vec3(st0, vUv.z));
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vec2 st1 = clamp(vUv.xy - offset, vUvRect.xy, vUvRect.zw);
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vec4 color1 = texture(sCacheRGBA8, vec3(st1, vUv.z));
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// Alpha must be premultiplied in order to properly blur the alpha channel.
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float weight = gauss(float(i), vSigma);
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color += vec4(color0.rgb * color0.a, color0.a) * weight;
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color += vec4(color1.rgb * color1.a, color1.a) * weight;
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}
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// Unpremultiply the alpha.
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color.rgb /= color.a;
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oFragColor = dither(color);
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}
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