processing의 noise() 함수의 자바 소스코드가 궁금하다.
Perlin noise is a random sequence generator producing a more natural
ordered, harmonic succession of numbers compared to the standard
function. It was invented by
in the 1980s and been used
since in graphical applications to produce procedural textures, natural
motion, shapes, terrains etc.
// PERLIN NOISE
// [toxi 040903]
// octaves and amplitude amount per octave are now user controlled
// via the noiseDetail() function.
// [toxi 030902]
// cleaned up code and now using bagel's cosine table to speed up
// [toxi 030901]
// implementation by the german demo group farbrausch
// as used in their demo "art":
http://www.farb-rausch.de/fr010src.zip
static final int PERLIN_YWRAPB = 4;
static final int PERLIN_YWRAP = 1<<PERLIN_YWRAPB;
static final int PERLIN_ZWRAPB = 8;
static final int PERLIN_ZWRAP = 1<<PERLIN_ZWRAPB;
static final int PERLIN_SIZE = 4095;
int perlin_octaves = 4; // default to medium smooth
float perlin_amp_falloff = 0.5f; // 50% reduction/octave
// [toxi 031112]
// new vars needed due to recent change of cos table in PGraphics
int perlin_TWOPI, perlin_PI;
float[] perlin_cosTable;
float[] perlin;
Random perlinRandom;
/**
* Computes the Perlin noise function value at point x.
*/
public float noise(float x) {
// is this legit? it's a dumb way to do it (but repair it later)
return noise(x, 0f, 0f);
}
/**
* Computes the Perlin noise function value at the point x, y.
*/
public float noise(float x, float y) {
return noise(x, y, 0f);
}
/**
* Computes the Perlin noise function value at x, y, z.
*/
public float noise(float x, float y, float z) {
if (perlin == null) {
if (perlinRandom == null) {
perlinRandom = new Random();
}
perlin = new float[PERLIN_SIZE + 1];
for (int i = 0; i < PERLIN_SIZE + 1; i++) {
perlin[i] = perlinRandom.nextFloat(); //(float)Math.random();
}
// [toxi 031112]
// noise broke due to recent change of cos table in PGraphics
// this will take care of it
perlin_cosTable = PGraphics.cosLUT;
perlin_TWOPI = perlin_PI = PGraphics.SINCOS_LENGTH;
perlin_PI >>= 1;
}
if (x<0) x=-x;
if (y<0) y=-y;
if (z<0) z=-z;
int xi=(int)x, yi=(int)y, zi=(int)z;
float xf = (float)(x-xi);
float yf = (float)(y-yi);
float zf = (float)(z-zi);
float rxf, ryf;
float r=0;
float ampl=0.5f;
float n1,n2,n3;
for (int i=0; i<perlin_octaves; i++) {
int of=xi+(yi<<PERLIN_YWRAPB)+(zi<<PERLIN_ZWRAPB);
rxf=noise_fsc(xf);
ryf=noise_fsc(yf);
n1 = perlin[of&PERLIN_SIZE];
n1 += rxf*(perlin[(of+1)&PERLIN_SIZE]-n1);
n2 = perlin[(of+PERLIN_YWRAP)&PERLIN_SIZE];
n2 += rxf*(perlin[(of+PERLIN_YWRAP+1)&PERLIN_SIZE]-n2);
n1 += ryf*(n2-n1);
of += PERLIN_ZWRAP;
n2 = perlin[of&PERLIN_SIZE];
n2 += rxf*(perlin[(of+1)&PERLIN_SIZE]-n2);
n3 = perlin[(of+PERLIN_YWRAP)&PERLIN_SIZE];
n3 += rxf*(perlin[(of+PERLIN_YWRAP+1)&PERLIN_SIZE]-n3);
n2 += ryf*(n3-n2);
n1 += noise_fsc(zf)*(n2-n1);
r += n1*ampl;
ampl *= perlin_amp_falloff;
xi<<=1; xf*=2;
yi<<=1; yf*=2;
zi<<=1; zf*=2;
if (xf>=1.0f) { xi++; xf--; }
if (yf>=1.0f) { yi++; yf--; }
if (zf>=1.0f) { zi++; zf--; }
}
return r;
}
// [toxi 031112]
// now adjusts to the size of the cosLUT used via
// the new variables, defined above
private float noise_fsc(float i) {
// using bagel's cosine table instead
return 0.5f*(1.0f-perlin_cosTable[(int)(i*perlin_PI)%perlin_TWOPI]);
}
// [toxi 040903]
// make perlin noise quality user controlled to allow
// for different levels of detail. lower values will produce
// smoother results as higher octaves are surpressed
public void noiseDetail(int lod) {
if (lod>0) perlin_octaves=lod;
}
public void noiseDetail(int lod, float falloff) {
if (lod>0) perlin_octaves=lod;
if (falloff>0) perlin_amp_falloff=falloff;
}
public void noiseSeed(long what) {
if (perlinRandom == null) perlinRandom = new Random();
perlinRandom.setSeed(what);
// force table reset after changing the random number seed [0122]
perlin = null;
}
