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Top and bottom border sprites were trivial. A single poke turned off those borders.

Side border sprites were trickier as you had to catch the raster and, to prevent flickering, time your code with a few “nop” instructions.

Then there’s the full screen scrolling trick. Not the 8 pixel shift. I mean full screen scrolling. It used a “bug” in the VIC.

Mayhem In Monsterland been an actual real world use: https://youtu.be/ldo2ewLBt3Y



Yeah VSP. Although you could scroll the entire screen with $d016 by splitting up the fullscreen byte shift in the 7 frames before the shift :)


Doesn't it support scrolling officially?


It supports scrolling up to 7 pixels but after that you have to actually move the memory backing the screen, and the cpu is slow enough that it’s pretty hard to do.




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