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perlin noise function pull request by Jack Mott but deleted before I could pull it

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Sean Barrett ago%!(EXTRA string=8 years)
parent 03611a369e
commit a2bc1eabec
1 changed files with 106 additions and 12 deletions
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  1. 118
      stb_perlin.h

118
stb_perlin.h
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@ -1,4 +1,4 @@
// stb_perlin.h - v0.2 - perlin noise
// stb_perlin.h - v0.3 - perlin noise
// public domain single-file C implementation by Sean Barrett
//
// LICENSE
@ -9,8 +9,8 @@
// to create the implementation,
// #define STB_PERLIN_IMPLEMENTATION
// in *one* C/CPP file that includes this file.
//
//
// Documentation:
//
// float stb_perlin_noise3( float x,
@ -31,22 +31,55 @@
// 0 to mean "don't care". (The noise always wraps every 256 due
// details of the implementation, even if you ask for larger or no
// wrapping.)
//
// Fractal Noise:
//
// Three common fractal noise functions are included, which produce
// a wide variety of nice effects depending on the parameters
// provided. Note that each function will call stb_perlin_noise3
// 'octaves' times, so this parameter will affect runtime.
//
// float stb_perlin_ridge_noise3(float x, float y, float z,
// float lacunarity, float gain, float offset, int octaves,
// int x_wrap, int y_wrap, int z_wrap);
//
// float stb_perlin_fbm_noise3(float x, float y, float z,
// float lacunarity, float gain, int octaves,
// int x_wrap, int y_wrap, int z_wrap);
//
// float stb_perlin_turbulence_noise3(float x, float y, float z,
// float lacunarity, float gain,int octaves,
// int x_wrap, int y_wrap, int z_wrap);
//
// Typical values to start playing with:
// octaves = 6 -- number of "octaves" of noise3() to sum
// lacunarity = ~ 2.0 -- spacing between successive octaves (use exactly 2.0 for wrapping output)
// gain = 0.5 -- relative weighting applied to each successive octave
// offset = 1.0? -- used to invert the ridges, may need to be larger, not sure
//
//
// Contributors:
// Jack Mott - additional noise functions
//
#ifdef __cplusplus
extern "C" float stb_perlin_noise3(float x, float y, float z, int x_wrap=0, int y_wrap=0, int z_wrap=0);
#else
extern "C" {
#endif
extern float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap);
extern float stb_perlin_ridge_noise3(float x, float y, float z,float lacunarity, float gain, float offset, int octaves,int x_wrap, int y_wrap, int z_wrap);
extern float stb_perlin_fbm_noise3(float x, float y, float z,float lacunarity, float gain, int octaves,int x_wrap, int y_wrap, int z_wrap);
extern float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity, float gain, int octaves,int x_wrap, int y_wrap, int z_wrap);
#ifdef __cplusplus
}
#endif
#ifdef STB_PERLIN_IMPLEMENTATION
#include <math.h> // floor()
// 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 int stb__perlin_randtab[512] =
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,
@ -89,6 +122,12 @@ 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)
{
@ -110,7 +149,7 @@ static float stb__perlin_grad(int hash, float x, float y, float z)
// 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 5/16ths and 6/16ths, and the same 4 cases get the extra weight.
// 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,
@ -122,6 +161,7 @@ static float stb__perlin_grad(int hash, float x, float y, float z)
};
// 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;
}
@ -136,9 +176,9 @@ float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z
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 = (int) floor(x);
int py = (int) floor(y);
int pz = (int) floor(z);
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;
@ -177,6 +217,60 @@ float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z
return stb__perlin_lerp(n0,n1,u);
}
float stb_perlin_ridge_noise3(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)(stb_perlin_noise3(x*frequency,y*frequency,z*frequency,x_wrap,y_wrap,z_wrap));
r = r<0 ? -r : r; // fabs()
r = offset - r;
r = r*r;
sum += r*amplitude*prev;
prev = r;
frequency *= lacunarity;
amplitude *= gain;
}
return sum;
}
float stb_perlin_fbm_noise3(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 += stb_perlin_noise3(x*frequency,y*frequency,z*frequency,x_wrap,y_wrap,z_wrap)*amplitude;
frequency *= lacunarity;
amplitude *= gain;
}
return sum;
}
float stb_perlin_turbulence_noise3(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 = stb_perlin_noise3(x*frequency,y*frequency,z*frequency,x_wrap,y_wrap,z_wrap)*amplitude;
r = r<0 ? -r : r; // fabs()
sum += r;
frequency *= lacunarity;
amplitude *= gain;
}
return sum;
}
#endif // STB_PERLIN_IMPLEMENTATION
/*

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