56 lines
1.7 KiB
C++
56 lines
1.7 KiB
C++
#pragma once
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namespace nall {
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struct Interpolation {
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static inline auto Nearest(double mu, double a, double b, double c, double d) -> double {
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return (mu <= 0.5 ? b : c);
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}
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static inline auto Sublinear(double mu, double a, double b, double c, double d) -> double {
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mu = ((mu - 0.5) * 2.0) + 0.5;
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if(mu < 0) mu = 0;
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if(mu > 1) mu = 1;
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return b * (1.0 - mu) + c * mu;
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}
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static inline auto Linear(double mu, double a, double b, double c, double d) -> double {
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return b * (1.0 - mu) + c * mu;
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}
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static inline auto Cosine(double mu, double a, double b, double c, double d) -> double {
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mu = (1.0 - cos(mu * Math::Pi)) / 2.0;
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return b * (1.0 - mu) + c * mu;
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}
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static inline auto Cubic(double mu, double a, double b, double c, double d) -> double {
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double A = d - c - a + b;
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double B = a - b - A;
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double C = c - a;
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double D = b;
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return A * (mu * mu * mu) + B * (mu * mu) + C * mu + D;
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}
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static inline auto Hermite(double mu1, double a, double b, double c, double d) -> double {
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const double tension = 0.0; //-1 = low, 0 = normal, +1 = high
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const double bias = 0.0; //-1 = left, 0 = even, +1 = right
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double mu2, mu3, m0, m1, a0, a1, a2, a3;
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mu2 = mu1 * mu1;
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mu3 = mu2 * mu1;
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m0 = (b - a) * (1.0 + bias) * (1.0 - tension) / 2.0;
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m0 += (c - b) * (1.0 - bias) * (1.0 - tension) / 2.0;
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m1 = (c - b) * (1.0 + bias) * (1.0 - tension) / 2.0;
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m1 += (d - c) * (1.0 - bias) * (1.0 - tension) / 2.0;
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a0 = +2 * mu3 - 3 * mu2 + 1;
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a1 = mu3 - 2 * mu2 + mu1;
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a2 = mu3 - mu2;
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a3 = -2 * mu3 + 3 * mu2;
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return (a0 * b) + (a1 * m0) + (a2 * m1) + (a3 * c);
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}
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};
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}
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