C64 games that take advantage of VSP will crash when starting - Githubissues

TASEmulators / BizHawk

BizHawk is a multi-system emulator written in C#. BizHawk provides nice features for casual gamers such as full screen, and joypad support in addition to full rerecording and debugging tools for all system cores.

http://tasvideos.org/BizHawk.html

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C64 games that take advantage of VSP will crash when starting #1571

Closed switchhacks closed 5 years ago

switchhacks commented 5 years ago

Any game that uses VSP to scroll the screen crash on startup, and cannot be played. This is especially annoying because BizHawk is the only Commodore emulator that has movie recording and playback for TAS.

hegyak commented 5 years ago

Can you tell us what game(s) have issues?

SaxxonPike commented 5 years ago

VSP support is definitely lacking. It's not something that is explicitly supported, rather it is a function of how the VIC counts its internal addresses while you juggle the Y-position bits mid-raster.

I did a bit of research and found some small yet potentially helpful VSP resources that showed up a few months ago: https://github.com/chris73it/C64_Scrolling_PAL

These are simple enough that verifying working VSP should be a bit more straightforward than attempting to do so with a fully featured demo. It is a feature that was not very understood way back when, and not really used except for modern demos and homebrew. So, the impact of this should be relatively small.

SaxxonPike commented 5 years ago

Oh, I'll take this one. Forgot to mention that.

SaxxonPike commented 5 years ago

This intro from JCB is the simplest demonstration of the effect. I've extracted it from the source T64 (as we don't support that format currently) vsp-ik.zip

SaxxonPike commented 5 years ago

These updates should resolve much of the VSP problems, once they're more fully vetted.

https://github.com/TASVideos/BizHawk/pull/1607

SaxxonPike commented 5 years ago

VSP effects all seem to be working with that commit, including the examples in that Github repo. I'm closing this as fixed.