CrepuscularRays.pde

float zoff = 0;

void setup(){
  //fullScreen();
  //size(1000, 1000);
  size(500, 500);
  blendMode(ADD);
}

void draw(){
  background(0);
  strokeWeight(5);
  PVector o = new PVector(mouseX, 0);
  int h = height/5*3;
  for(int i=width/5*2; i<width/5*3; i++){
    PVector pos = new PVector(i, height/5);
    stroke(noise(float(i)/100, zoff)*300-125);
    PVector diff = new PVector(pos.x-o.x, pos.y-o.y);
    line(pos.x, pos.y, pos.x+diff.x/diff.y*h, pos.y+h);
  }
  zoff+=0.01;
}