Very large object animating.

[zabnat]

I have an object that takes about the half the pixels of my 640x480 sized background, but the rectangual area of the object is the whole background (640x480). I want to animate that object and then merge it into the background. So the animation occurs only once in the game. Right now I have done this so that I just animate the object and the merge it to the background.
I was wondering if there was a better way to do this performance-wise?
Would using transparency on the object make it slower or faster?

[monkey0506]

From what I understand large transparent objects are drawn the same way as large solid objects, only slightly more intensive than a solid object since it then has to render the transparent areas transparent. So AFAIK an object with a large transparent area would be less efficient than the same object cropped to the smallest possible size. (I could be wrong though... :)