I need to make a sprite that will be loaded as a bitmap and it can then be moved around and rotated by the user. It will also be drawn with transparent regions.
At the moment I'm doing this by creating a rotated bitmap of the original loaded bitmap and drawing it to the screen every time the sprite is moved. Because It has transparent regions it also has to create a mask bitmap every time it's drawn too - using scanlines to check if each pixel is the transparent colour. This is very slow.
I can't create preloaded bitmaps of each rotation angle because there are too many possible angles.
So has anyone got a good way of doing it. Flash seems to do it very fast. I could load the pixels into an array when the bitmap is loaded, which might speed up the rotation algorithm but then drawing it on the screen would be slow.

Thanks

Peter