I wanted to see if anyone can help me. I am making an organ application using processing which will play different notes/pipes when different stops (buttons) are pressed. I have the coding written for the basic functionality, but I would like to know if I can somehow make it look like the buttons are being either pushed in or pulled out when the user clicks on them. I know this might be possible using local illumination, so can someone give me a clue as to what the code would look like?

Thanking you in advance.

PS I'm using PImages assigned to coordinates as my buttons as it stands.