mirror of
https://git.code.sf.net/p/quake/quakeforge
synced 2024-11-30 08:00:51 +00:00
110 lines
2.9 KiB
C
110 lines
2.9 KiB
C
#ifdef HAVE_CONFIG_H
|
|
# include "config.h"
|
|
#endif
|
|
|
|
#include <math.h>
|
|
|
|
#include "QF/qtypes.h"
|
|
|
|
#include "noise.h"
|
|
|
|
// returns the 3D noise value for a point in space
|
|
float
|
|
noise3d (vec3_t v, int num)
|
|
{
|
|
int n;
|
|
|
|
n = floor (v[0]) + floor (v[1]) * 57 + floor (v[2]) * 3251;
|
|
n = (n << 13) ^ n;
|
|
n = n * (n * n * 15731 + 789221) + 1376312589;
|
|
return (n & 0x7fffffff) / 2147483648.0;
|
|
}
|
|
|
|
// a variation of Noise3D that takes 3 floats
|
|
float
|
|
noiseXYZ (float x, float y, float z, int num)
|
|
{
|
|
vec3_t v;
|
|
|
|
v[0] = x;
|
|
v[1] = y;
|
|
v[2] = z;
|
|
return noise3d (v, num);
|
|
}
|
|
|
|
// returns a noise value from a scaled up noise pattern
|
|
//
|
|
// Actually created by sampling points on a certain grid
|
|
// and interpolating the inbetween value, making the noise smooth
|
|
float
|
|
noise_scaled (vec3_t v, float s, int num)
|
|
{
|
|
float n = 0;
|
|
vec3_t a, b, c, d;
|
|
|
|
a[0] = floor (v[0] / s) * s;
|
|
b[0] = a[0] + s;
|
|
c[0] = (v[0] - a[0]) / s;
|
|
d[0] = 1 - c[0];
|
|
a[1] = floor (v[1] / s) * s;
|
|
b[1] = a[1] + s;
|
|
c[1] = (v[1] - a[1]) / s;
|
|
d[1] = 1 - c[1];
|
|
a[2] = floor (v[2] / s) * s;
|
|
b[2] = a[2] + s;
|
|
c[2] = (v[2] - a[2]) / s;
|
|
d[2] = 1 - c[2];
|
|
|
|
n += noiseXYZ (a[0], a[1], a[2], num) * d[0] * d[1] * d[2];
|
|
n += noiseXYZ (a[0], a[1], b[2], num) * d[0] * d[1] * c[2];
|
|
n += noiseXYZ (a[0], b[1], a[2], num) * d[0] * c[1] * d[2];
|
|
n += noiseXYZ (a[0], b[1], b[2], num) * d[0] * c[1] * c[2];
|
|
n += noiseXYZ (b[0], a[1], a[2], num) * c[0] * d[1] * d[2];
|
|
n += noiseXYZ (b[0], a[1], b[2], num) * c[0] * d[1] * c[2];
|
|
n += noiseXYZ (b[0], b[1], a[2], num) * c[0] * c[1] * d[2];
|
|
n += noiseXYZ (b[0], b[1], b[2], num) * c[0] * c[1] * c[2];
|
|
|
|
return n;
|
|
}
|
|
|
|
// returns a Perlin noise value for a point in 3D space
|
|
//
|
|
// This noise function combines noise at several different scales
|
|
// which makes it slower than just using one layer of noise
|
|
float
|
|
noise_perlin (vec3_t v, float p, int num)
|
|
{
|
|
float n = 0;
|
|
|
|
n += noise_scaled (v, 1024, num);
|
|
n += 0.5 + (noise_scaled (v, 256, num) - 0.5) * p;
|
|
n += 0.5 + (noise_scaled (v, 64, num) - 0.5) * p * p;
|
|
n += 0.5 + (noise_scaled (v, 16, num) - 0.5) * p * p * p;
|
|
|
|
return n / 2 - 0.5;
|
|
}
|
|
|
|
// Use to create low-res noise patterns without interpolation
|
|
// A good strategy for avoiding seams on terrain and curves
|
|
// when called with a scale value of about 32
|
|
//
|
|
// This is because surfaces have some texture pixels which are
|
|
// actually not in the polygon at all so their edges don't
|
|
// perfectly fit together.
|
|
//
|
|
// Creates a random pattern of light and dark squares on flat
|
|
// axis aligned surfaces, which is usually not what you want
|
|
// but it may have interesting applications
|
|
void
|
|
snap_vector (vec3_t v_old, vec3_t v_new, float scale)
|
|
{
|
|
if (scale <= 0) {
|
|
v_new[0] = v_old[0];
|
|
v_new[1] = v_old[1];
|
|
v_new[2] = v_old[2];
|
|
} else {
|
|
v_new[0] = floor (v_old[0] / scale + 0.5) * scale;
|
|
v_new[1] = floor (v_old[1] / scale + 0.5) * scale;
|
|
v_new[2] = floor (v_old[2] / scale + 0.5) * scale;
|
|
}
|
|
}
|