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Last active October 15, 2019 09:55
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Gaussian Free Field
int gffSize = 30; // field density
int rays = 150;
float rsteps = TWO_PI / rays;
float[][] gff;
void setup() {
size(800,800);
smooth(8);
noStroke();
fill(235);
background(21,20,19);
colorMode(HSB,360,100,100,100);
// initialize field
gff = new float[gffSize][gffSize];
for(int x=0;x<gffSize;x++) {
for(int y=0;y<gffSize;y++) {
gff[x][y] = randomGaussian();
}
}
}
void draw() {
fill(0,0,10,200);
rect(0,0,width,height);
float kappa = frameCount * 0.0031;
float hf = sqrt(8.0 * (kappa / PI)) / (4.0 - kappa);
for(int t=0; t<rays; t++) {
float theta = t * rsteps;
float x = width * 0.5;
float y = height * 0.5;
fill(degrees(theta),90,100,95);
for(int i=0; i<350;i++) {
float v = hf * getFieldValue(x,y);
// uncomment below to use Perlin noise instead of Gaussian field
//float v = hf * 2.0 * (noise(x/(float)gffSize,y/(float)gffSize)-0.5);
float sx = sin(v + theta);
float sy = cos(v + theta);
rect(x,y,0.8,0.8);
x+=sx;
y+=sy;
}
}
}
// bilinear interpolation
float getFieldValue(float x, float y) {
float px = map(x,0,width,0,gffSize);
float py = map(y,0,height,0,gffSize);
int ix = floor(px);
int iy = floor(py);
float rx = px - ix;
float ry = py - iy;
ix = ix % gffSize;
iy = iy % gffSize;
int ixp = (ix+1) % gffSize;
int iyp = (iy+1) % gffSize;
float vy1 = lerp(gff[ix][iy], gff[ixp][iy], rx);
float vy2 = lerp(gff[ix][iyp], gff[ixp][iyp], rx);
return lerp(vy1,vy2,ry);
}
void keyPressed() {
if(keyCode==32) {
saveFrame("######.jpg");
}
}
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