PShape cube;

void setup() {
  size(400, 400, P3D);
  smooth();

  cube = createShape(BOX, 100);
}

void draw() {
  background(120);
    
  lights();
    
  translate(mouseX, mouseY);
  rotateX(frameCount * 0.01f);
  rotateY(frameCount * 0.01f);
    
  shape(cube);    
}

void keyPressed() {
  // Changing the smooth configuration restarts the OpenGL surface. 
  // Automatically recreates all the current GL resources.
  noSmooth();
}