Changed gradient idx table to match previous implementation, removed seeds from public API

stb_perlin.h

@@ -1,4 +1,4 @@
-// stb_perlin.h - v0.4 - perlin noise
+// stb_perlin.h - v0.3 - perlin noise
 // public domain single-file C implementation by Sean Barrett
 //
 // LICENSE
@@ -71,10 +71,10 @@
 #ifdef __cplusplus
 extern "C" {
 #endif
-extern float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap, unsigned char seed);
-extern float stb_perlin_ridge_noise3(float x, float y, float z, float lacunarity, float gain, float offset, int octaves, unsigned char seed);
-extern float stb_perlin_fbm_noise3(float x, float y, float z, float lacunarity, float gain, int octaves, unsigned char seed);
-extern float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity, float gain, int octaves, unsigned char seed);
+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);
+extern float stb_perlin_fbm_noise3(float x, float y, float z, float lacunarity, float gain, int octaves);
+extern float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity, float gain, int octaves);
 #ifdef __cplusplus
 }
 #endif
@@ -126,45 +126,46 @@ static unsigned char stb__perlin_randtab[512] =
 
 // 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 21/256ths and 22/256ths
+// to 5/64ths and 6/64ths
 
-// same as array above but with value % 12
-static unsigned char stb__perlin_randtab_mod12[512] =
+// this array is designed to match the previous implementation
+// of gradient hash: indices[stb__perlin_randtab[i]&63]
+static unsigned char stb__perlin_randtab_grad_idx[512] =
 {
-    11, 5, 5, 4, 7, 9, 10, 1, 7, 5, 11, 1, 4, 6, 8, 3,
-    8, 10, 1, 9, 3, 6, 1, 10, 0, 4, 4, 1, 9, 6, 11, 0,
-    7, 3, 5, 6, 1, 4, 0, 3, 1, 8, 3, 6, 9, 8, 6, 0,
-    8, 2, 0, 1, 1, 6, 5, 11, 9, 1, 3, 6, 2, 6, 11, 9,
-    9, 4, 10, 1, 0, 2, 5, 0, 7, 6, 1, 0, 8, 2, 7, 5,
-    10, 8, 4, 9, 2, 11, 9, 3, 3, 10, 10, 10, 11, 8, 6, 4,
-    9, 2, 7, 6, 10, 11, 2, 10, 1, 7, 4, 10, 7, 2, 1, 3,
-    5, 7, 10, 8, 1, 8, 7, 8, 8, 3, 4, 8, 4, 4, 7, 2,
-    2, 8, 9, 7, 11, 9, 7, 4, 2, 5, 2, 3, 4, 6, 4, 4,
-    10, 11, 0, 11, 8, 0, 6, 10, 0, 2, 3, 7, 3, 8, 4, 6,
-    0, 0, 11, 0, 0, 6, 2, 1, 10, 2, 0, 1, 2, 4, 5, 3,
-    7, 1, 5, 1, 1, 6, 5, 0, 7, 4, 5, 8, 9, 10, 9, 3,
-    2, 11, 5, 6, 1, 9, 5, 11, 7, 8, 6, 2, 11, 10, 10, 5,
-    11, 11, 7, 3, 6, 9, 11, 3, 0, 8, 5, 10, 9, 0, 2, 2,
-    3, 3, 0, 2, 11, 8, 2, 0, 7, 9, 7, 5, 3, 9, 4, 3,
-    1, 4, 11, 9, 6, 7, 10, 3, 5, 9, 11, 5, 0, 8, 10, 5,
+    7, 9, 5, 0, 11, 1, 6, 9, 3, 9, 11, 1, 8, 10, 4, 7,
+    8, 6, 1, 5, 3, 10, 9, 10, 0, 8, 4, 1, 5, 2, 7, 8,
+    7, 11, 9, 10, 1, 0, 4, 7, 5, 0, 11, 6, 1, 4, 2, 8,
+    8, 10, 4, 9, 9, 2, 5, 7, 9, 1, 7, 2, 2, 6, 11, 5,
+    5, 4, 6, 9, 0, 1, 1, 0, 7, 6, 9, 8, 4, 10, 3, 1,
+    2, 8, 8, 9, 10, 11, 5, 11, 11, 2, 6, 10, 3, 4, 2, 4,
+    9, 10, 3, 2, 6, 3, 6, 10, 5, 3, 4, 10, 11, 2, 9, 11,
+    1, 11, 10, 4, 9, 4, 11, 0, 4, 11, 4, 0, 0, 0, 7, 6,
+    10, 4, 1, 3, 11, 5, 3, 4, 2, 9, 1, 3, 0, 1, 8, 0,
+    6, 7, 8, 7, 0, 4, 6, 10, 8, 2, 3, 11, 11, 8, 0, 2,
+    4, 8, 3, 0, 0, 10, 6, 1, 2, 2, 4, 5, 6, 0, 1, 3,
+    11, 9, 5, 5, 9, 6, 9, 8, 3, 8, 1, 8, 9, 6, 9, 11,
+    10, 7, 5, 6, 5, 9, 1, 3, 7, 0, 2, 10, 11, 2, 6, 1,
+    3, 11, 7, 7, 2, 1, 7, 3, 0, 8, 1, 1, 5, 0, 6, 10,
+    11, 11, 0, 2, 7, 0, 10, 8, 3, 5, 7, 1, 11, 1, 0, 7,
+    9, 0, 11, 5, 10, 3, 2, 3, 5, 9, 7, 9, 8, 4, 6, 5,
 
     // and a second copy so we don't need an extra mask or static initializer
-    11, 5, 5, 4, 7, 9, 10, 1, 7, 5, 11, 1, 4, 6, 8, 3,
-    8, 10, 1, 9, 3, 6, 1, 10, 0, 4, 4, 1, 9, 6, 11, 0,
-    7, 3, 5, 6, 1, 4, 0, 3, 1, 8, 3, 6, 9, 8, 6, 0,
-    8, 2, 0, 1, 1, 6, 5, 11, 9, 1, 3, 6, 2, 6, 11, 9,
-    9, 4, 10, 1, 0, 2, 5, 0, 7, 6, 1, 0, 8, 2, 7, 5,
-    10, 8, 4, 9, 2, 11, 9, 3, 3, 10, 10, 10, 11, 8, 6, 4,
-    9, 2, 7, 6, 10, 11, 2, 10, 1, 7, 4, 10, 7, 2, 1, 3,
-    5, 7, 10, 8, 1, 8, 7, 8, 8, 3, 4, 8, 4, 4, 7, 2,
-    2, 8, 9, 7, 11, 9, 7, 4, 2, 5, 2, 3, 4, 6, 4, 4,
-    10, 11, 0, 11, 8, 0, 6, 10, 0, 2, 3, 7, 3, 8, 4, 6,
-    0, 0, 11, 0, 0, 6, 2, 1, 10, 2, 0, 1, 2, 4, 5, 3,
-    7, 1, 5, 1, 1, 6, 5, 0, 7, 4, 5, 8, 9, 10, 9, 3,
-    2, 11, 5, 6, 1, 9, 5, 11, 7, 8, 6, 2, 11, 10, 10, 5,
-    11, 11, 7, 3, 6, 9, 11, 3, 0, 8, 5, 10, 9, 0, 2, 2,
-    3, 3, 0, 2, 11, 8, 2, 0, 7, 9, 7, 5, 3, 9, 4, 3,
-    1, 4, 11, 9, 6, 7, 10, 3, 5, 9, 11, 5, 0, 8, 10, 5,
+    7, 9, 5, 0, 11, 1, 6, 9, 3, 9, 11, 1, 8, 10, 4, 7,
+    8, 6, 1, 5, 3, 10, 9, 10, 0, 8, 4, 1, 5, 2, 7, 8,
+    7, 11, 9, 10, 1, 0, 4, 7, 5, 0, 11, 6, 1, 4, 2, 8,
+    8, 10, 4, 9, 9, 2, 5, 7, 9, 1, 7, 2, 2, 6, 11, 5,
+    5, 4, 6, 9, 0, 1, 1, 0, 7, 6, 9, 8, 4, 10, 3, 1,
+    2, 8, 8, 9, 10, 11, 5, 11, 11, 2, 6, 10, 3, 4, 2, 4,
+    9, 10, 3, 2, 6, 3, 6, 10, 5, 3, 4, 10, 11, 2, 9, 11,
+    1, 11, 10, 4, 9, 4, 11, 0, 4, 11, 4, 0, 0, 0, 7, 6,
+    10, 4, 1, 3, 11, 5, 3, 4, 2, 9, 1, 3, 0, 1, 8, 0,
+    6, 7, 8, 7, 0, 4, 6, 10, 8, 2, 3, 11, 11, 8, 0, 2,
+    4, 8, 3, 0, 0, 10, 6, 1, 2, 2, 4, 5, 6, 0, 1, 3,
+    11, 9, 5, 5, 9, 6, 9, 8, 3, 8, 1, 8, 9, 6, 9, 11,
+    10, 7, 5, 6, 5, 9, 1, 3, 7, 0, 2, 10, 11, 2, 6, 1,
+    3, 11, 7, 7, 2, 1, 7, 3, 0, 8, 1, 1, 5, 0, 6, 10,
+    11, 11, 0, 2, 7, 0, 10, 8, 3, 5, 7, 1, 11, 1, 0, 7,
+    9, 0, 11, 5, 10, 3, 2, 3, 5, 9, 7, 9, 8, 4, 6, 5,
 };
 
 static float stb__perlin_lerp(float a, float b, float t)
@@ -201,7 +202,7 @@ static float stb__perlin_grad(int grad_idx, float x, float y, float z)
    return grad[0]*x + grad[1]*y + grad[2]*z;
 }
 
-float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap, unsigned char seed)
+float stb_perlin_noise3_internal(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap, unsigned char seed)
 {
    float u,v,w;
    float n000,n001,n010,n011,n100,n101,n110,n111;
@@ -233,14 +234,14 @@ float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z
    r10 = stb__perlin_randtab[r1+y0];
    r11 = stb__perlin_randtab[r1+y1];
 
-   n000 = stb__perlin_grad(stb__perlin_randtab_mod12[r00+z0], x  , y  , z   );
-   n001 = stb__perlin_grad(stb__perlin_randtab_mod12[r00+z1], x  , y  , z-1 );
-   n010 = stb__perlin_grad(stb__perlin_randtab_mod12[r01+z0], x  , y-1, z   );
-   n011 = stb__perlin_grad(stb__perlin_randtab_mod12[r01+z1], x  , y-1, z-1 );
-   n100 = stb__perlin_grad(stb__perlin_randtab_mod12[r10+z0], x-1, y  , z   );
-   n101 = stb__perlin_grad(stb__perlin_randtab_mod12[r10+z1], x-1, y  , z-1 );
-   n110 = stb__perlin_grad(stb__perlin_randtab_mod12[r11+z0], x-1, y-1, z   );
-   n111 = stb__perlin_grad(stb__perlin_randtab_mod12[r11+z1], x-1, y-1, z-1 );
+   n000 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r00+z0], x  , y  , z   );
+   n001 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r00+z1], x  , y  , z-1 );
+   n010 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r01+z0], x  , y-1, z   );
+   n011 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r01+z1], x  , y-1, z-1 );
+   n100 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r10+z0], x-1, y  , z   );
+   n101 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r10+z1], x-1, y  , z-1 );
+   n110 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r11+z0], x-1, y-1, z   );
+   n111 = stb__perlin_grad(stb__perlin_randtab_grad_idx[r11+z1], x-1, y-1, z-1 );
 
    n00 = stb__perlin_lerp(n000,n001,w);
    n01 = stb__perlin_lerp(n010,n011,w);
@@ -253,7 +254,12 @@ 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, unsigned char seed)
+float stb_perlin_noise3(float x, float y, float z, int x_wrap, int y_wrap, int z_wrap)
+{
+    return stb_perlin_noise3_internal(x,y,z,x_wrap,y_wrap,z_wrap,0);
+}
+
+float stb_perlin_ridge_noise3(float x, float y, float z, float lacunarity, float gain, float offset, int octaves)
 {
    int i;
    float frequency = 1.0f;
@@ -262,19 +268,18 @@ float stb_perlin_ridge_noise3(float x, float y, float z, float lacunarity, float
    float sum = 0.0f;
 
    for (i = 0; i < octaves; i++) {
-      float r = stb_perlin_noise3(x*frequency,y*frequency,z*frequency,0,0,0,seed);
+      float r = stb_perlin_noise3_internal(x*frequency,y*frequency,z*frequency,0,0,0,(unsigned char)i);
       r = offset - fabs(r);
       r = r*r;
       sum += r*amplitude*prev;
       prev = r;
       frequency *= lacunarity;
       amplitude *= gain;
-      seed++;
    }
    return sum;
 }
 
-float stb_perlin_fbm_noise3(float x, float y, float z, float lacunarity, float gain, int octaves, unsigned char seed)
+float stb_perlin_fbm_noise3(float x, float y, float z, float lacunarity, float gain, int octaves)
 {
    int i;
    float frequency = 1.0f;
@@ -282,15 +287,14 @@ float stb_perlin_fbm_noise3(float x, float y, float z, float lacunarity, float g
    float sum = 0.0f;
    
    for (i = 0; i < octaves; i++) {
-      sum += stb_perlin_noise3(x*frequency,y*frequency,z*frequency,0,0,0,seed)*amplitude;
+      sum += stb_perlin_noise3_internal(x*frequency,y*frequency,z*frequency,0,0,0,(unsigned char)i)*amplitude;
       frequency *= lacunarity;
       amplitude *= gain;
-      seed++;
    }
    return sum;
 }
 
-float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity, float gain, int octaves, unsigned char seed)
+float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity, float gain, int octaves)
 {
    int i;
    float frequency = 1.0f;
@@ -298,11 +302,10 @@ float stb_perlin_turbulence_noise3(float x, float y, float z, float lacunarity,
    float sum = 0.0f;
    
    for (i = 0; i < octaves; i++) {
-      float r = stb_perlin_noise3(x*frequency,y*frequency,z*frequency,0,0,0,seed)*amplitude;
+      float r = stb_perlin_noise3_internal(x*frequency,y*frequency,z*frequency,0,0,0,(unsigned char)i)*amplitude;
       sum += fabs(r);
       frequency *= lacunarity;
       amplitude *= gain;
-      seed++;
    }
    return sum;
 }