73 lines
3.9 KiB
C++
73 lines
3.9 KiB
C++
#include "util/random/perlin.h"
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#include <math.h>
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// This should go in the const section of the binary.
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static const int p[512] = {
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151,160,137,91,90,15,
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131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
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190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
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88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
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77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
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102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
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135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
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5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
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223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
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129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
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251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
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49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
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138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
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151,160,137,91,90,15,
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131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
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190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
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88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
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77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
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102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
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135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
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5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
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223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
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129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
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251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
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49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
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138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180,
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};
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inline float fade(float t) {
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return t * t * t * (t * (t * 6 - 15) + 10);
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}
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inline float lerp(float t, float a, float b) {
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return a + t * (b - a);
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}
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inline float grad(int hash, float x, float y, float z) {
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int h = hash & 15; // CONVERT LO 4 BITS OF HASH CODE
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float u = h < 8 ? x : y; // INTO 12 GRADIENT DIRECTIONS.
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float v = h < 4 ? y : (h == 12 || h == 14 ? x : z);
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return ((h & 1) == 0 ? u : -u) + ((h & 2) == 0 ? v : -v);
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}
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float Noise(double iz, double iy, double ix) {
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double fx = floor(ix), fy = floor(iy), fz = floor(iz);
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int X = (int)fx & 255, // FIND UNIT CUBE THAT
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Y = (int)fy & 255, // CONTAINS POINT.
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Z = (int)fz & 255;
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float x = (float)(ix - fx); // FIND RELATIVE X,Y,Z
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float y = (float)(iy - fy); // OF POINT IN CUBE.
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float z = (float)(iz - fz);
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float u = fade(x); // COMPUTE FADE CURVES
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float v = fade(y); // FOR EACH OF X,Y,Z.
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float w = fade(z);
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int A = p[X ]+Y, B = p[X+1]+Y;
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int AA = p[A]+Z, AB = p[A+1]+Z; // HASH COORDINATES OF
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int BA = p[B]+Z, BB = p[B+1]+Z; // THE 8 CUBE CORNERS,
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return lerp(w, lerp(v, lerp(u, grad(p[AA ], x , y , z ), // AND ADD
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grad(p[BA ], x-1, y , z )), // BLENDED
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lerp(u, grad(p[AB ], x , y-1, z ), // RESULTS
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grad(p[BB ], x-1, y-1, z ))), // FROM 8
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lerp(v, lerp(u, grad(p[AA+1], x , y , z-1 ), // CORNERS
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grad(p[BA+1], x-1, y , z-1 )), // OF CUBE
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lerp(u, grad(p[AB+1], x , y-1, z-1 ),
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grad(p[BB+1], x-1, y-1, z-1 ))));
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}
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