bsnes/snesfilter/nall/interpolation.hpp

60 lines
1.7 KiB
C++
Executable File

#ifndef NALL_INTERPOLATION_HPP
#define NALL_INTERPOLATION_HPP
namespace nall {
struct Interpolation {
static inline double Nearest(double mu, double a, double b, double c, double d) {
return (mu < 0.5 ? c : d);
}
static inline double Sublinear(double mu, double a, double b, double c, double d) {
mu = ((mu - 0.5) * 2.0) + 0.5;
if(mu < 0) mu = 0;
if(mu > 1) mu = 1;
return c * (1.0 - mu) + d * mu;
}
static inline double Linear(double mu, double a, double b, double c, double d) {
return c * (1.0 - mu) + d * mu;
}
static inline double Cosine(double mu, double a, double b, double c, double d) {
mu = (1.0 - cos(mu * 3.14159265)) / 2.0;
return c * (1.0 - mu) + d * mu;
}
static inline double Cubic(double mu, double a, double b, double c, double d) {
double A = d - c - a + b;
double B = a - b - A;
double C = c - a;
double D = b;
return A * (mu * mu * mu) + B * (mu * mu) + C * mu + D;
}
static inline double Hermite(double mu1, double a, double b, double c, double d) {
const double tension = 0.0; //-1 = low, 0 = normal, +1 = high
const double bias = 0.0; //-1 = left, 0 = even, +1 = right
double mu2, mu3, m0, m1, a0, a1, a2, a3;
mu2 = mu1 * mu1;
mu3 = mu2 * mu1;
m0 = (b - a) * (1.0 + bias) * (1.0 - tension) / 2.0;
m0 += (c - b) * (1.0 - bias) * (1.0 - tension) / 2.0;
m1 = (c - b) * (1.0 + bias) * (1.0 - tension) / 2.0;
m1 += (d - c) * (1.0 - bias) * (1.0 - tension) / 2.0;
a0 = +2 * mu3 - 3 * mu2 + 1;
a1 = mu3 - 2 * mu2 + mu1;
a2 = mu3 - mu2;
a3 = -2 * mu3 + 3 * mu2;
return (a0 * b) + (a1 * m0) + (a2 * m1) + (a3 * c);
}
};
}
#endif