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22 lines
714 B
C++
22 lines
714 B
C++
/*
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Gauss-4tap v1.0 by fishku
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Copyright (C) 2023
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Public domain license (CC0)
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Simple two-pass Gaussian blur filter which does two taps per pass.
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Idea based on:
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https://www.rastergrid.com/blog/2010/09/efficient-gaussian-blur-with-linear-sampling/
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Changelog:
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v1.0: Initial release.
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*/
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// Finds the offset so that two samples drawn with linear filtering at that
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// offset from a central pixel, multiplied with 1/2 each, sum up to a 3-sample
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// approximation of the Gaussian sampled at pixel centers.
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float get_offset(float sigma) {
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// Weight at x = 0 evaluates to 1 for all values of sigma.
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const float w = exp(-1.0 / (sigma * sigma));
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return 2.0 * w / (2.0 * w + 1.0);
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}
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