OniLinkPlus,
Flipping has to copy to and from both bitmaps, seems like that
would take longer than just a simple one way copy.
If it flips and there was a sprite move I have to completely
rewrite the off-screen buffer.
With a simple copy I only need to move the sprite, the pixels
behind the old sprite position are automatically restored, and
then just copy to the on-screen buffer.
Jerryd
Unless I'm misunderstanding, you seem to think that double buffering copies the contents of the buffers to each other? This is completely false. All that happens is that a pointer is swapped. One frame, the graphics card reads from one buffer. The next frame, it reads from the other. There is no copying involved.
If a sprite "just moves," you have to completely redraw the buffer anyways, or you'll have a "ghosting" effect where the sprite appears in both its old position and its new position. You could redraw both where the sprite was and where the sprite is now to be rid of the ghosting, but determining what sprites will have to be redrawn and then redrawing them only in those spots would be needlessly complex and time consuming for the graphics cards, especially if you have multiple sprites moving, which you almost definitely will. In fact, it's far more efficient in general to just redraw everything each frame.