55 lines
1.1 KiB
C++
55 lines
1.1 KiB
C++
#include <psemek/pcg/blur.hpp>
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#include <cmath>
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#include <vector>
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namespace psemek::pcg
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{
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static std::vector<float> gauss_coeffs(int size, float sigma)
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{
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std::vector<float> res(2 * size + 1);
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float sum = 0.f;
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for (int i = -size; i <= size; ++i)
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{
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float x = (i / sigma);
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res[i + size] = std::exp(- x * x);
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sum += res[i + size];
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}
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for (auto & c : res)
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c /= sum;
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return res;
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}
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gfx::basic_pixmap<float> blur(gfx::basic_pixmap<float> const & p, int size, float sigma, seamless_tag)
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{
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gfx::basic_pixmap<float> res({p.width(), p.height()}, 0.f);
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auto c = gauss_coeffs(size, sigma);
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for (int y = 0; y < p.height(); ++y)
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{
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for (int x = 0; x < p.width(); ++x)
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{
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for (int j = - size; j <= size; ++j)
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{
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for (int i = - size; i <= size; ++i)
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{
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int ix = (x + i);
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while (ix < 0) ix += p.width();
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if (ix >= p.width()) ix = ix % p.width();
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int iy = (y + j);
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while (iy < 0) iy += p.height();
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if (iy >= p.height()) iy = iy % p.height();
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res(x, y) += p(ix, iy) * c[i + size] * c[j + size];
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}
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}
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}
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}
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return res;
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}
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}
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