bitwise.pde

int freq = 49;
int num = 128; // column and row count
int darkColor = 36;
int litColor = 200;

void setup() {
  fullScreen(P2D);
  noStroke();
  // set sane default input
  mouseX = width/2;
  mouseY = height/2;
}

void draw() {
  // read mouse input
  freq = floor(map(mouseX, 0, width, 0, 60));
  // w means cell size
  float w = width / (float) num; 
  float t = radians(frameCount);
  
  // draw the grid
  background(darkColor);
  translate(0, height/2-width/2);
  for (int xi = 0; xi < num; xi++) {
    for (int yi = 0; yi < num; yi++) {
      float x = xi*w;
      float y = yi*w;
      if(isLit(xi,yi,num/2, num/2, t)){
        fill(litColor);
        rect(x, y, w, w);
      }
    }
  }
}

boolean isLit(int xi, int yi, float centerX, float centerY, float t) {
  return ((xi ^ yi) % freq) == 1
       || (yi ^ xi) % (freq/2) == 0;
}