pakt10

See /f0blog/pact-februari/

//pakt10

int index, n;
float rows, cols;
float rowMod, colMod;
float magic;
PGraphics grad;

void setup() {
  size(640, 480, JAVA2D);
  frameRate(60);
  smooth();
  index= 0;
  n= 1200;
  rows= 11;
  cols= 12;
  rowMod= 2.0;
  colMod= 3.0;
  magic= 0.0;
  grad= createGraphics(width, height, JAVA2D);
  grad.beginDraw();
  grad.background(0);
  createGradient(grad, width*0.5, height*0.5, width*2.0, color(0.2*255, 0.2*255, 0.5*255), color(0, 0, 0));
  grad.endDraw();

  stroke(255.0, 255.0, 0.2*255.0, 0.85*255.0);
}
void draw() {
  float r= rows+(sin(index*0.013)*rowMod)+(sin(index*0.00133)*rowMod*0.56);
  float c= cols+(cos(index*0.022)*colMod)+(cos(index*0.00122)*colMod*0.45);

  image(grad, 0, 0);

  for (int i= 0; i<n; i++) {
    float px= (r+i)%width;
    float py= ((c+i)*(i%(magic+1.01)))%height;
    line(px, py, px+(10.0+sin((index+i)*0.02)), py+(10.0*cos((index+i)*0.03)));
  }
  rows= rows+(sin(index*0.0004));
  cols= cols+(sin(index*0.0005));
  index++;
  magic= (magic+0.00002)%15.0;
}
void createGradient(PGraphics ctx, float x, float y, float radius, color c1, color c2) {
  ctx.noStroke();
  for (float r= radius; r>=0.0; r--) {
    color col= lerpColor(c1, c2, r/radius);
    ctx.fill(col);
    ctx.ellipse(x, y, r, r);
  }
}