98 lines
2.7 KiB
C++
98 lines
2.7 KiB
C++
#ifndef PERLIN_H
|
|
#define PERLIN_H
|
|
|
|
#include "rayTracer.h"
|
|
|
|
class perlin {
|
|
public:
|
|
perlin() {
|
|
randVector = new vec3[pointCount];
|
|
for (int i = 0; i < pointCount; i++) {
|
|
randVector[i] = unitVector(vec3::random(-1, 1));
|
|
}
|
|
|
|
permX = perlinGeneratePerm();
|
|
permY = perlinGeneratePerm();
|
|
permZ = perlinGeneratePerm();
|
|
}
|
|
|
|
~perlin() {
|
|
delete[] randVector;
|
|
delete[] permX;
|
|
delete[] permY;
|
|
delete[] permZ;
|
|
}
|
|
|
|
double noise(const point3& p) const {
|
|
auto u = p.x() - floor(p.x());
|
|
auto v = p.y() - floor(p.y());
|
|
auto w = p.z() - floor(p.z());
|
|
|
|
auto i = int(floor(p.x()));
|
|
auto j = int(floor(p.y()));
|
|
auto k = int(floor(p.z()));
|
|
vec3 c[2][2][2];
|
|
|
|
for (int di = 0; di < 2; di++) {
|
|
for (int dj = 0; dj < 2; dj++) {
|
|
for (int dk = 0; dk < 2; dk++) {
|
|
c[di][dj][dk] = randVector[
|
|
permX[(i+di) & 255] ^
|
|
permY[(j+dj) & 255] ^
|
|
permZ[(k+dk) & 255]
|
|
];
|
|
}
|
|
}
|
|
}
|
|
return perlinInterpolation(c, u, v, w);
|
|
}
|
|
|
|
private:
|
|
static const int pointCount = 256;
|
|
vec3* randVector;
|
|
int* permX;
|
|
int* permY;
|
|
int* permZ;
|
|
|
|
static int* perlinGeneratePerm(void) {
|
|
auto p = new int[pointCount];
|
|
|
|
for (int i = 0; i < pointCount; i++) {
|
|
p[i] = i;
|
|
}
|
|
|
|
permute(p, pointCount);
|
|
|
|
return p;
|
|
}
|
|
|
|
static void permute(int* p, int n) {
|
|
for (int i = n - 1; i > 0; i--) {
|
|
int target = randomInt(0, i);
|
|
int tmp = p[i];
|
|
p[i] = p[target];
|
|
p[target] = tmp;
|
|
}
|
|
}
|
|
|
|
static double perlinInterpolation(const vec3 c[2][2][2], double u, double v, double w) {
|
|
auto uu = u * u * (3 - 2 * u);
|
|
auto vv = v * v * (3 - 2 * v);
|
|
auto ww = w * w * (3 - 2 * w);
|
|
auto accum = 0.0;
|
|
|
|
for (int i = 0; i < 2; i++)
|
|
for (int j = 0; j < 2; j++)
|
|
for (int k = 0; k < 2; k++) {
|
|
vec3 weightV(u - i, v - j, w - k);
|
|
accum += (i * uu + (1 - i)*(1 - uu))
|
|
* (j * vv + (1 - j) * (1 - vv))
|
|
* (k * ww + (1 - k) * (1 - ww))
|
|
* dot(c[i][j][k], weightV);
|
|
}
|
|
|
|
return accum;
|
|
}
|
|
};
|
|
|
|
#endif |