Sprites are pre loaded to vram.
The cool thing is that animation frames are cycled just changing R#25. Sprite Base Address Register. It acts as a "sprite page".
I don't update the SPRATR table. Is is fixed.
The method I use, which I explained above, can be considered kind of "cheating" as it cannot be used for a game, but for this particular use I feel it is a very elegant solution.
There are 8 sprites "pages" on VRAM. They are selected by R#25 register.
Each of them is a 256x256 pixel area.
I use only the first 4 pages. The animation uses 4 frames. Each frame of both characters is loaded at one page.
Earthquake (the big guy at right) is using the first 256x128 area, starting at 0,0
The other character uses the second 256x128 area below, starting at 0,128 coordinate.
This way the pattern numbers on SPRATR are always the same.
Just changing R#25 is enough for the sprites pointed by SPRATR be all new ones, a new frame of animation.
I hope my explanation would be good. But in case of any doubt don't hesitate to ask.
