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stella-emu / stella

A multi-platform Atari 2600 Emulator
https://stella-emu.github.io
GNU General Public License v2.0
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Emulate that HMOVE during VSYNC breaks VSYNC #980

Closed thrust26 closed 1 year ago

thrust26 commented 1 year ago

The game "Laserface" flickers (during boss fight and lava scene) on the ZPH stream (and other real hardware?), but not in Stella, even with all developer settings enabled.

Note: It does HMOVE during VSYNC, which IIRC shouldn't work (another issue?). But that shouldn't cause the problem.

https://forums.atariage.com/topic/352788-new-games-laserface-island-completed-and-laserface-planet-wip/ Laserface.zip

thrust26 commented 1 year ago

I found no VSYNC timing issues in the broken ROM. But the fixed ROM (also) moved HMOVE out of the VSYNC area, so I figure this must be the culprit. @DirtyHairy We should try to emulate that a HMOVE during VSYNC breaks the VSYNC. Laserface.zip

thrust26 commented 1 year ago

After some testing, I cannot reproduce the screen rolls on my hardware. I figure that James (ZPH) setup is extremely sensitive to varying VSYNC times. And using HMOVE during VSYNC was not the culprit.