Hello, I need to do something very similar. My use case: I want to draw a sprite to RAM, apply some transformation to the memory zone and then draw the memory back to the screen. I think that I have it it in mind, I will use memcpy and some tricks. Once I got something usable I will post it here, it might be useful to you. The goal is to perform one oldschool demoscene effect: bitmap distortion. So the distortion will be applied not only to a sprite, but also to the pixel that are on the left and on the right.