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20 lines
396 B
Plaintext
20 lines
396 B
Plaintext
/*
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* simulate scanlines by darkening every other line.
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*
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*/
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kernel vec4 scanline(sampler image, float opacity)
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{
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vec2 coord = samplerCoord(image);
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vec4 pixel = sample(image, coord);
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float isOdd = mod(floor(coord.y), 2.0);
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// isOdd == 0 --> return pixel
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// isOdd == 1 --> return pixel * opacity
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float multiplier = compare(isOdd - 1.0, 1.0, opacity);
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return pixel * multiplier;
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}
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