How do I show sprites in the border on C64?

Question

I\'ve seen cool C64 demos showing sprites in the border area of the screen. It shouldn\'t be possible; I think they managed to fool the graphics chip somehow. How exactly di

Answer 1

For a good tutorial on the topic of opening the borders on the C64, check out Pasi Ojala's excellent article in C=Hacking Issue 6.

Without getting too technical, the trick uses a feature of the VIC chip to let you switch between 25/24 rows and 40/38 columns of text/graphics, and involves making this switch at the exact right moment to fool the VIC into thinking it has already switched the borders on when in fact it hasn't. Check out the above article for a more thorough explanation with code examples.