JoltPhysics/TestFramework/Math/Perlin.cpp

#include <TestFramework.h>

#include <Math/Perlin.h>

// not same permutation table as Perlin's reference to avoid copyright issues;
// Perlin's table can be found at http://mrl.nyu.edu/~perlin/noise/
// @OPTIMIZE: should this be unsigned char instead of int for cache?
static unsigned char stb_perlin_randtab[512] =
{
   23, 125, 161, 52, 103, 117, 70, 37, 247, 101, 203, 169, 124, 126, 44, 123,
   152, 238, 145, 45, 171, 114, 253, 10, 192, 136, 4, 157, 249, 30, 35, 72,
   175, 63, 77, 90, 181, 16, 96, 111, 133, 104, 75, 162, 93, 56, 66, 240,
   8, 50, 84, 229, 49, 210, 173, 239, 141, 1, 87, 18, 2, 198, 143, 57,
   225, 160, 58, 217, 168, 206, 245, 204, 199, 6, 73, 60, 20, 230, 211, 233,
   94, 200, 88, 9, 74, 155, 33, 15, 219, 130, 226, 202, 83, 236, 42, 172,
   165, 218, 55, 222, 46, 107, 98, 154, 109, 67, 196, 178, 127, 158, 13, 243,
   65, 79, 166, 248, 25, 224, 115, 80, 68, 51, 184, 128, 232, 208, 151, 122,
   26, 212, 105, 43, 179, 213, 235, 148, 146, 89, 14, 195, 28, 78, 112, 76,
   250, 47, 24, 251, 140, 108, 186, 190, 228, 170, 183, 139, 39, 188, 244, 246,
   132, 48, 119, 144, 180, 138, 134, 193, 82, 182, 120, 121, 86, 220, 209, 3,
   91, 241, 149, 85, 205, 150, 113, 216, 31, 100, 41, 164, 177, 214, 153, 231,
   38, 71, 185, 174, 97, 201, 29, 95, 7, 92, 54, 254, 191, 118, 34, 221,
   131, 11, 163, 99, 234, 81, 227, 147, 156, 176, 17, 142, 69, 12, 110, 62,
   27, 255, 0, 194, 59, 116, 242, 252, 19, 21, 187, 53, 207, 129, 64, 135,
   61, 40, 167, 237, 102, 223, 106, 159, 197, 189, 215, 137, 36, 32, 22, 5,

   // and a second copy so we don't need an extra mask or static initializer
   23, 125, 161, 52, 103, 117, 70, 37, 247, 101, 203, 169, 124, 126, 44, 123,
   152, 238, 145, 45, 171, 114, 253, 10, 192, 136, 4, 157, 249, 30, 35, 72,
   175, 63, 77, 90, 181, 16, 96, 111, 133, 104, 75, 162, 93, 56, 66, 240,
   8, 50, 84, 229, 49, 210, 173, 239, 141, 1, 87, 18, 2, 198, 143, 57,
   225, 160, 58, 217, 168, 206, 245, 204, 199, 6, 73, 60, 20, 230, 211, 233,
   94, 200, 88, 9, 74, 155, 33, 15, 219, 130, 226, 202, 83, 236, 42, 172,
   165, 218, 55, 222, 46, 107, 98, 154, 109, 67, 196, 178, 127, 158, 13, 243,
   65, 79, 166, 248, 25, 224, 115, 80, 68, 51, 184, 128, 232, 208, 151, 122,
   26, 212, 105, 43, 179, 213, 235, 148, 146, 89, 14, 195, 28, 78, 112, 76,
   250, 47, 24, 251, 140, 108, 186, 190, 228, 170, 183, 139, 39, 188, 244, 246,
   132, 48, 119, 144, 180, 138, 134, 193, 82, 182, 120, 121, 86, 220, 209, 3,
   91, 241, 149, 85, 205, 150, 113, 216, 31, 100, 41, 164, 177, 214, 153, 231,
   38, 71, 185, 174, 97, 201, 29, 95, 7, 92, 54, 254, 191, 118, 34, 221,
   131, 11, 163, 99, 234, 81, 227, 147, 156, 176, 17, 142, 69, 12, 110, 62,
   27, 255, 0, 194, 59, 116, 242, 252, 19, 21, 187, 53, 207, 129, 64, 135,
   61, 40, 167, 237, 102, 223, 106, 159, 197, 189, 215, 137, 36, 32, 22, 5,
};

static float stb_perlin_lerp(float a, float b, float t)
{
   return a + (b-a) * t;
}

static int stb_perlin_fastfloor(float a)
{
	int ai = (int) a;
	return (a < ai) ? ai-1 : ai;
}

// different grad function from Perlin's, but easy to modify to match reference
static float stb_perlin_grad(int hash, float x, float y, float z)
{
   static float basis[12][4] =
   {
      {  1, 1, 0 },
      { -1, 1, 0 },
      {  1,-1, 0 },
      { -1,-1, 0 },
      {  1, 0, 1 },
      { -1, 0, 1 },
      {  1, 0,-1 },
      { -1, 0,-1 },
      {  0, 1, 1 },
      {  0,-1, 1 },
      {  0, 1,-1 },
      {  0,-1,-1 },
   };

   // perlin's gradient has 12 cases so some get used 1/16th of the time
   // and some 2/16ths. We reduce bias by changing those fractions
   // to 5/64ths and 6/64ths, and the same 4 cases get the extra weight.
   static unsigned char indices[64] =
   {
      0,1,2,3,4,5,6,7,8,9,10,11,
      0,9,1,11,
      0,1,2,3,4,5,6,7,8,9,10,11,
      0,1,2,3,4,5,6,7,8,9,10,11,
      0,1,2,3,4,5,6,7,8,9,10,11,
      0,1,2,3,4,5,6,7,8,9,10,11,
   };

   // if you use reference permutation table, change 63 below to 15 to match reference
   // (this is why the ordering of the table above is funky)
   float *grad = basis[indices[hash & 63]];
   return grad[0]*x + grad[1]*y + grad[2]*z;
}

float PerlinNoise3(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap)
{
   float u,v,w;
   float n000,n001,n010,n011,n100,n101,n110,n111;
   float n00,n01,n10,n11;
   float n0,n1;

   unsigned int x_mask = (x_wrap-1) & 255;
   unsigned int y_mask = (y_wrap-1) & 255;
   unsigned int z_mask = (z_wrap-1) & 255;
   int px = stb_perlin_fastfloor(x);
   int py = stb_perlin_fastfloor(y);
   int pz = stb_perlin_fastfloor(z);
   int x0 = px & x_mask, x1 = (px+1) & x_mask;
   int y0 = py & y_mask, y1 = (py+1) & y_mask;
   int z0 = pz & z_mask, z1 = (pz+1) & z_mask;
   int r0,r1, r00,r01,r10,r11;

   #define stb_perlin_ease(a)   (((a*6-15)*a + 10) * a * a * a)

   x -= px; u = stb_perlin_ease(x);
   y -= py; v = stb_perlin_ease(y);
   z -= pz; w = stb_perlin_ease(z);

   r0 = stb_perlin_randtab[x0];
   r1 = stb_perlin_randtab[x1];

   r00 = stb_perlin_randtab[r0+y0];
   r01 = stb_perlin_randtab[r0+y1];
   r10 = stb_perlin_randtab[r1+y0];
   r11 = stb_perlin_randtab[r1+y1];

   n000 = stb_perlin_grad(stb_perlin_randtab[r00+z0], x  , y  , z   );
   n001 = stb_perlin_grad(stb_perlin_randtab[r00+z1], x  , y  , z-1 );
   n010 = stb_perlin_grad(stb_perlin_randtab[r01+z0], x  , y-1, z   );
   n011 = stb_perlin_grad(stb_perlin_randtab[r01+z1], x  , y-1, z-1 );
   n100 = stb_perlin_grad(stb_perlin_randtab[r10+z0], x-1, y  , z   );
   n101 = stb_perlin_grad(stb_perlin_randtab[r10+z1], x-1, y  , z-1 );
   n110 = stb_perlin_grad(stb_perlin_randtab[r11+z0], x-1, y-1, z   );
   n111 = stb_perlin_grad(stb_perlin_randtab[r11+z1], x-1, y-1, z-1 );

   n00 = stb_perlin_lerp(n000,n001,w);
   n01 = stb_perlin_lerp(n010,n011,w);
   n10 = stb_perlin_lerp(n100,n101,w);
   n11 = stb_perlin_lerp(n110,n111,w);

   n0 = stb_perlin_lerp(n00,n01,v);
   n1 = stb_perlin_lerp(n10,n11,v);

   return stb_perlin_lerp(n0,n1,u);
}

float PerlinRidgeNoise3(float x, float y, float z, float lacunarity, float gain, float offset, int octaves, int x_wrap, int y_wrap, int z_wrap)
{
   int i;
   float frequency = 1.0f;
   float prev = 1.0f;
   float amplitude = 0.5f;
   float sum = 0.0f;

   for (i = 0; i < octaves; i++) {
      float r = (float)(PerlinNoise3(x*frequency,y*frequency,z*frequency,x_wrap,y_wrap,z_wrap));
      r = r<0 ? -r : r; // abs()
      r = offset - r;
      r = r*r;
      sum += r*amplitude*prev;
      prev = r;
      frequency *= lacunarity;
      amplitude *= gain;
   }
   return sum;
}

float PerlinFBMNoise3(float x, float y, float z, float lacunarity, float gain, int octaves, int x_wrap, int y_wrap, int z_wrap)
{
   int i;
   float frequency = 1.0f;
   float amplitude = 1.0f;
   float sum = 0.0f;

   for (i = 0; i < octaves; i++) {
      sum += PerlinNoise3(x*frequency,y*frequency,z*frequency,x_wrap,y_wrap,z_wrap)*amplitude;
      frequency *= lacunarity;
      amplitude *= gain;
   }
   return sum;
}

float PerlinTurbulenceNoise3(float x, float y, float z, float lacunarity, float gain, int octaves, int x_wrap, int y_wrap, int z_wrap)
{
   int i;
   float frequency = 1.0f;
   float amplitude = 1.0f;
   float sum = 0.0f;

   for (i = 0; i < octaves; i++) {
      float r = PerlinNoise3(x*frequency,y*frequency,z*frequency,x_wrap,y_wrap,z_wrap)*amplitude;
      r = r<0 ? -r : r; // abs()
      sum += r;
      frequency *= lacunarity;
      amplitude *= gain;
   }
   return sum;
}

/*
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This software is available under 2 licenses -- choose whichever you prefer.
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SOFTWARE.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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