On Jul 16, 2011, at 12:46 AM, Nadeem Abdul Hamid wrote: > Ah, right. How about you keep the picture separate, and functions like > 'move', 'rotate', etc. add to a list in the sprite structure; when the sprite > structure is passed to the draw handler, the draw handler updates the picture > based on those new segments or whatever, and then clears them from the > sprite's list.
Wait: so now instead of "move" mutating the picture, "draw" is mutating the sprite? Out of the frying pan into the fire.... > This way you don't have to conflate the sprite with the picture, nor do you > have to worry about efficiency w.r.t. redrawing the entire history of the > sprite movement every draw update. Tests for the 'tick' handler can be > written in a functional style since only the sprite structure is involved. ? Not if the draw handler is mutating them behind the scenes. I could have two sprites that look identical to me, but since one of them has been drawn more recently than the other, they're not really equal. Stephen Bloch [email protected] _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
