I want to create a stronger perception of depth in my sketch by having objects in the distance appear fainter. I've tried drawing a rect every -500 pixels in the z axis, but I'm having some confusing results with the way alpha is handled. When I draw them with an alpha value of 50, they absorb a general colour of what is behind them, but are still completely opaque. Does processing handle alpha differently in OPENGL mode? I'm using version 2.0a4.