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-rw-r--r--src/noise.cpp84
-rw-r--r--src/noise.h5
2 files changed, 82 insertions, 7 deletions
diff --git a/src/noise.cpp b/src/noise.cpp
index a98dd5886..7b651dbb3 100644
--- a/src/noise.cpp
+++ b/src/noise.cpp
@@ -23,6 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#define NOISE_MAGIC_X 1619
#define NOISE_MAGIC_Y 31337
+#define NOISE_MAGIC_Z 52591
#define NOISE_MAGIC_SEED 1013
double cos_lookup[16] = {
@@ -50,6 +51,29 @@ double biLinearInterpolation(double x0y0, double x1y0, double x0y1, double x1y1,
return linearInterpolation(u,v,ty);
}
+double triLinearInterpolation(
+ double v000, double v100, double v010, double v110,
+ double v001, double v101, double v011, double v111,
+ double x, double y, double z)
+{
+ /*double tx = easeCurve(x);
+ double ty = easeCurve(y);
+ double tz = easeCurve(z);*/
+ double tx = x;
+ double ty = y;
+ double tz = z;
+ return(
+ v000*(1-tx)*(1-ty)*(1-tz) +
+ v100*tx*(1-ty)*(1-tz) +
+ v010*(1-tx)*ty*(1-tz) +
+ v110*tx*ty*(1-tz) +
+ v001*(1-tx)*(1-ty)*tz +
+ v101*tx*(1-ty)*tz +
+ v011*(1-tx)*ty*tz +
+ v111*tx*ty*tz
+ );
+}
+
double noise2d(int x, int y, int seed)
{
int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y
@@ -59,30 +83,61 @@ double noise2d(int x, int y, int seed)
return 1.0 - (double)n/1073741824;
}
+double noise3d(int x, int y, int z, int seed)
+{
+ int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_Z * z
+ + NOISE_MAGIC_SEED * seed) & 0x7fffffff;
+ n = (n>>13)^n;
+ n = (n * (n*n*60493+19990303) + 1376312589) & 0x7fffffff;
+ return 1.0 - (double)n/1073741824;
+}
+
double noise2d_gradient(double x, double y, int seed)
{
+ // Calculate the integer coordinates
int x0 = (x > 0.0 ? (int)x : (int)x - 1);
int y0 = (y > 0.0 ? (int)y : (int)y - 1);
+ // Calculate the remaining part of the coordinates
double xl = x - (double)x0;
double yl = y - (double)y0;
+ // Calculate random cosine lookup table indices for the integer corners.
+ // They are looked up as unit vector gradients from the lookup table.
int n00 = (int)((noise2d(x0, y0, seed)+1)*8);
int n10 = (int)((noise2d(x0+1, y0, seed)+1)*8);
int n01 = (int)((noise2d(x0, y0+1, seed)+1)*8);
int n11 = (int)((noise2d(x0+1, y0+1, seed)+1)*8);
- /* In this format, these fail to work on MSVC8 if n00 < 4
- double s = dotProduct(cos_lookup[n00], cos_lookup[(n00-4)%16], xl, yl);
- double u = dotProduct(-cos_lookup[n10], cos_lookup[(n10-4)%16], 1.-xl, yl);
- double v = dotProduct(cos_lookup[n01], -cos_lookup[(n01-4)%16], xl, 1.-yl);
- double w = dotProduct(-cos_lookup[n11], -cos_lookup[(n11-4)%16], 1.-xl, 1.-yl);*/
+ // Make a dot product for the gradients and the positions, to get the values
double s = dotProduct(cos_lookup[n00], cos_lookup[(n00+12)%16], xl, yl);
double u = dotProduct(-cos_lookup[n10], cos_lookup[(n10+12)%16], 1.-xl, yl);
double v = dotProduct(cos_lookup[n01], -cos_lookup[(n01+12)%16], xl, 1.-yl);
double w = dotProduct(-cos_lookup[n11], -cos_lookup[(n11+12)%16], 1.-xl, 1.-yl);
- /*std::cout<<"x="<<x<<" y="<<y<<" x0="<<x0<<" y0="<<y0<<" xl="<<xl<<" yl="<<yl<<" n00="<<n00<<" n10="<<n01<<" s="<<s<<std::endl;
- std::cout<<"cos_lookup[n00]="<<(cos_lookup[n00])<<" cos_lookup[(n00-4)%16]="<<(cos_lookup[(n00-4)%16])<<std::endl;*/
+ // Interpolate between the values
return biLinearInterpolation(s,u,v,w,xl,yl);
}
+double noise3d_gradient(double x, double y, double z, int seed)
+{
+ // Calculate the integer coordinates
+ int x0 = (x > 0.0 ? (int)x : (int)x - 1);
+ int y0 = (y > 0.0 ? (int)y : (int)y - 1);
+ int z0 = (z > 0.0 ? (int)z : (int)z - 1);
+ // Calculate the remaining part of the coordinates
+ double xl = x - (double)x0;
+ double yl = y - (double)y0;
+ double zl = y - (double)z0;
+ // Get values for corners of cube
+ double v000 = noise3d(x0, y0, z0, seed);
+ double v100 = noise3d(x0+1, y0, z0, seed);
+ double v010 = noise3d(x0, y0+1, z0, seed);
+ double v110 = noise3d(x0+1, y0+1, z0, seed);
+ double v001 = noise3d(x0, y0, z0+1, seed);
+ double v101 = noise3d(x0+1, y0, z0+1, seed);
+ double v011 = noise3d(x0, y0+1, z0+1, seed);
+ double v111 = noise3d(x0+1, y0+1, z0+1, seed);
+ // Interpolate
+ return triLinearInterpolation(v000,v100,v010,v110,v001,v101,v011,v111,xl,yl,zl);
+}
+
double noise2d_perlin(double x, double y, int seed,
int octaves, double persistence)
{
@@ -98,3 +153,18 @@ double noise2d_perlin(double x, double y, int seed,
return a;
}
+double noise3d_perlin(double x, double y, double z, int seed,
+ int octaves, double persistence)
+{
+ double a = 0;
+ double f = 1.0;
+ double g = 1.0;
+ for(int i=0; i<octaves; i++)
+ {
+ a += g * noise3d_gradient(x*f, y*f, z*f, seed+i);
+ f *= 2.0;
+ g *= persistence;
+ }
+ return a;
+}
+
diff --git a/src/noise.h b/src/noise.h
index c069046c3..63974e86a 100644
--- a/src/noise.h
+++ b/src/noise.h
@@ -24,11 +24,16 @@ double easeCurve(double t);
// Return value: -1 ... 1
double noise2d(int x, int y, int seed);
+double noise3d(int x, int y, int z, int seed);
double noise2d_gradient(double x, double y, int seed);
+double noise3d_gradient(double x, double y, double z, int seed);
double noise2d_perlin(double x, double y, int seed,
int octaves, double persistence);
+double noise3d_perlin(double x, double y, double z, int seed,
+ int octaves, double persistence);
+
#endif