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rtlatticenoise.cpp
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#include "rtlatticenoise.h"
#include<cmath>
#include<cstdlib>
inline double
clamp(const double x, const double min, const double max) {
return (x < min ? min : (x > max ? max : x));
}
//kTableSize
const unsigned char RTLatticeNoise::permutation_table[] =
{ 225,155,210,108,175,199,221,144,203,116, 70,213, 69,158, 33,252,
5, 82,173,133,222,139,174, 27, 9, 71, 90,246, 75,130, 91,191,
169,138, 2,151,194,235, 81, 7, 25,113,228,159,205,253,134,142,
248, 65,224,217, 22,121,229, 63, 89,103, 96,104,156, 17,201,129,
36, 8,165,110,237,117,231, 56,132,211,152, 20,181,111,239,218,
170,163, 51,172,157, 47, 80,212,176,250, 87, 49, 99,242,136,189,
162,115, 44, 43,124, 94,150, 16,141,247, 32, 10,198,223,255, 72,
53,131, 84, 57,220,197, 58, 50,208, 11,241, 28, 3,192, 62,202,
18,215,153, 24, 76, 41, 15,179, 39, 46, 55, 6,128,167, 23,188,
106, 34,187,140,164, 73,112,182,244,195,227, 13, 35, 77,196,185,
26,200,226,119, 31,123,168,125,249, 68,183,230,177,135,160,180,
12, 1,243,148,102,166, 38,238,251, 37,240,126, 64, 74,161, 40,
184,149,171,178,101, 66, 29, 59,146, 61,254,107, 42, 86,154, 4,
236,232,120, 21,233,209, 45, 98,193,114, 78, 19,206, 14,118,127,
48, 79,147, 85, 30,207,219, 54, 88,234,190,122, 95, 67,143,109,
137,214,145, 93, 92,100,245, 0,216,186, 60, 83,105, 97,204, 52
/* 151,160,137,91,90,15,
131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
190,6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
88,237,149,56,87,174,20,125,136,171,168,68,175,74,165,71,134,139,48,27,166,
77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208,89,18,169,200,196,
135,130,116,188,159,86,164,100,109,198,173,186,3,64,52,217,226,250,124,123,
5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
23,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167,43,172,9,
129,22,39,253,19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
251,34,242,193,238,210,144,12,191,179,162,241,81,51,145,235,249,14,239,107,
49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127,4,150,254,
138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180*/
};
RTLatticeNoise::RTLatticeNoise()
{
initValueTable();
}
double RTLatticeNoise::linearNoise(RTVector hit) const
{
int x= hit.getX();
int y= hit.getY();
int z= hit.getZ();
/* int X = (int)floor(x) & 255, // FIND UNIT CUBE THAT
Y = (int)floor(y) & 255, // CONTAINS POINT.
Z = (int)floor(z) & 255;
x -= floor(x); // FIND RELATIVE X,Y,Z
y -= floor(y); // OF POINT IN CUBE.
z -= floor(z);
double u = fade(x), // COMPUTE FADE CURVES
v = fade(y), // FOR EACH OF X,Y,Z.
w = fade(z);
int A = value_table[X]+Y, // HASH COORDINATES OF
AA = value_table[A]+Z, // THE 8 CUBE CORNERS,
AB = value_table[A+1]+Z,
B = value_table[X+1]+Y,
BA = value_table[B]+Z,
BB = value_table[B+1]+Z;
return
lerp(w, lerp(v, lerp(u, grad(value_table[AA], x, y, z), // AND ADD
grad(value_table[BA], x-1, y, z)), // BLENDED
lerp(u, grad(value_table[AB], x, y-1, z), // RESULTS
grad(value_table[BB], x-1, y-1, z))), // FROM 8
lerp(v, lerp(u, grad(value_table[AA+1], x, y, z-1), // CORNERS
grad(value_table[BA+1], x-1, y, z-1)),// OF CUBE
lerp(u, grad(value_table[AB+1], x, y-1, z-1 ),
grad(value_table[BB+1], x-1, y-1, z-1 ))));
*/int ix, iy, iz;
double fx, fy, fz;
double xknots[4], yknots[4], zknots[4];
ix = floor(x);
fx = x - ix;
iy = floor(y);
fy = y - iy;
iz = floor(z);
fz = z - iz;
for (int k = -1; k <= 2; k++) {
for (int j = -1; j <= 2; j++) {
for (int i = -1; i <= 2; i++) {
xknots[i+1] = value_table[INDEX(ix + i, iy + j, iz + k)];
}
yknots[j+1] = four_knot_spline(fx, xknots);
}
zknots[k+1] = four_knot_spline(fy, yknots);
}
return (clamp(four_knot_spline(fz, zknots), -1.0, 1.0));
/*int ix, iy, iz;
double fx, fy, fz;
double d[2][2][2];
double x0, x1, x2, x3, y0, y1, z0;
ix = FLOOR(x);
fx = x - ix;
iy = FLOOR(y);
fy = y - iy;
iz = FLOOR(z);
fz = z - iz;
for (int k = 0; k <= 1; k++)
for (int j = 0; j <= 1; j++)
for (int i = 0; i <= 1; i++)
d[k][j][i] = value_table[INDEX(ix + i, iy + j, iz + k)];
x0 = lerp(fx, d[0][0][0], d[0][0][1]);
x1 = lerp(fx, d[0][1][0], d[0][1][1]);
x2 = lerp(fx, d[1][0][0], d[1][0][1]);
x3 = lerp(fx, d[1][1][0], d[1][1][1]);
y0 = lerp(fy, x0, x1);
y1 = lerp(fy, x2, x3);
z0 = lerp(fz, y0, y1);
return z0;*/
}
void RTLatticeNoise::initValueTable()
{
/* for (int i = 0; i < 256; i++) {
value_table[256+i] = value_table[i] = permutation_table[i];
}*/
srand(seed_value);
for (int i = 0; i < kTableSize; i++)
value_table[i] = -1 + static_cast <double> (rand()) /( static_cast <double> (RAND_MAX/(2)));//1.0 - 2.0 * rand();
}
double RTLatticeNoise::fade(double t) const {
return t * t * t * (t * (t * 6 - 15) + 10);
}
double RTLatticeNoise::grad(int hash, double x, double y, double z) const {
int h = hash & 15;
// CONVERT LO 4 BITS OF HASH CODE
double u = h<8||h==12||h==13 ? x : y, // INTO 12 GRADIENT DIRECTIONS.
v = h < 4||h == 12||h == 13 ? y : z;
return ((h & 1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
}
double RTLatticeNoise::lerp(double t, double a, double b) const
{
return (a + t * (b - a));
}
double RTLatticeNoise::four_knot_spline(const double x, const double knots[]) const
{
double c3 = -0.5 * knots[0] + 1.5 * knots[1] - 1.5 * knots[2] + 0.5 * knots[3];
double c2 = knots[0] - 2.5 * knots[1] + 2.0 * knots[2] - 0.5 * knots[3];
double c1 = 0.5 * (-knots[0] + knots [2]);
double c0 = knots[1];
return ((double)((c3*x + c2)*x + c1)*x + c0);
}