float angle;
void setup() {
  size(800, 400, P3D);
  fill(255);
  noStroke();
}
float d = 32;
void draw() {
  float camZ = (height/2) / tan(PI*60/360);
  camera(mouseX, mouseY, camZ, width/2, height, 0, 0, 1, 0);
  translate(width/2, height/2, 0);
  rotateY(mouseX*PI/width);
  //rotateY(angle);
  
  lights();
  //ambientLight(102, 102, 102);
  //directionalLight(102, 102, 102, 1, 1, 0);
  //pointLight(255, 255, 255, 500*cos(angle), 0, 500*sin(angle));
  spotLight(0, 255, 0,
  500*cos(angle), 500*cos(angle), 500*sin(angle),
  1, 1, 1, PI, 2);
  background(0);
  for (int i = -height/2; i < height/2; i+=d*1.2) {
    for (int j = -height/2; j < height/2; j+=d*1.2) {
      pushMatrix();
      translate(i,j,-j);
      box(d, d, d);
      popMatrix();
    }
  }
  angle+=0.04;
  if (angle>2*PI) angle=0;
}