PShape cube;

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

    cube = createShape(BOX, 100);
  }

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

  public void keyPressed() {
    // Restarts the OpenGL surface. Automatically 
    // recreates all the current GL resources.
    ((PGraphicsOpenGL)g).restartPGL();
  }