code: public void setBackground(Color color) {
  		predraw();
  		GL.glClearColor(color.r, color.g, color.b, color.a);
  		postdraw();
  	}
docs: Set the background colour of the graphics context. This colour
  is used when clearing the context. Note that calling this method
  alone does not cause the context to be cleared.
  
  @param color
  The background color of the graphics context