[QUOTE=seba182] [QUOTE=ArcadEd] Well the easiest way is on key pressing down, do the spin animation, when the key is released, keep the animation but move sonic forward at a much faster pace.
Is that what you mean? I'm not totally sure what you mean by physics of motion.[/QUOTE]
as changing the angle of the sprite when it rotates 360 degrees for the platform? [/QUOTE]
This isn't a trivial matter as changing the angle of the sprite is the algorithm that gives Sonic games their novelty and is difficult to replicate.This
gives some details on the algorithm. I also recommend looking at Sonic Physics Guide
, which is guide designed for creating Sonic fan games that gives details about the algorithms and variables used to create the classic games.