15 lines
381 B
Text
15 lines
381 B
Text
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// inefficient cuberoot function
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float cbrt(float x) {
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return pow(x, 1.0/3.0);
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}
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/*
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Alpha Blending a over b after Bruce A. Wallace
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source: https://en.wikipedia.org/wiki/Alpha_compositing
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*/
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vec4 alpha_blend(vec4 b, vec4 a) {
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float alpha = a.a + (b.a * (1.0 - a.a));
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vec3 col = ((a.rgb*a.a) + ((b.rgb*b.a) * (1.0 - a.a)) / alpha);
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return vec4(col.r, col.g, col.b, alpha);
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}
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