3 ms·

This looks like a pretty nutty technique, essentially exploiting an undocumented state (or bug?) in the VIC chip. The Atari 2600's TIA had lots of sharp corner

by sehugg 10y ago

This looks like a pretty nutty technique, essentially exploiting an undocumented state (or bug?) in the VIC chip. The Atari 2600's TIA had lots of sharp corners caused by the reliance on polynomial counters, which saved silicon but made for lots of seemingly-random edge cases (after all, polynomial counters are also used to generate pseudo-random noise!)

vidarh 10y ago
> essentially exploiting an undocumented state (or bug?) in the VIC chip. You just described most of the new effects in C64 demos over the last 30+ years... But, yes, this is one of the nuttier. When I was a kid and trying to do demos, the "simple" stuff like tricking the VIC to keep the borders open was still amongst the more exciting things you could do (opening the top and bottom border is trivial once you know how; opening the left/right border was harder - especially if moving sprites in the Y-direction as it affects the number of bus cycles available to the CPU). That was quite literally childs play compared to this one.