update for button down
update for button up
returns button down state duration in hnsecs (1/10000 of second).
mouse button flags when down event occured
Clock.currStdTime() for down event of this button (0 if button is up).
x coordinates of down event
y coordinates of down event
Clock.currStdTime() for up event of this button (0 if button is still down).
mouse button state details