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TomHarte / CLK

A latency-hating emulator of: the Acorn Electron and Archimedes, Amstrad CPC, Apple II/II+/IIe and early Macintosh, Atari 2600 and ST, ColecoVision, Enterprise 64/128, Commodore Vic-20 and Amiga, MSX 1/2, Oric 1/Atmos, early PC compatibles, Sega Master System, Sinclair ZX80/81 and ZX Spectrum.
MIT License
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Stable rasters on the VIC-20 #1383

Closed polluks closed 1 month ago

polluks commented 1 month ago

What about the left border? See http://www.sleepingelephant.com/ipw-web/bulletin/bb/viewtopic.php?p=121320#p121320

TomHarte commented 1 month ago

If I'm going to look at the VIC again then there's definitely also a long-standing issue with background colour changes not being delayed for the proper number of pixels — so e.g. in the [semi-]recent port of Pitfall the background, which appears to be entirely a result of palette changes, appears shifted a few pixels to the left, making judgment of holes, etc, problematic.

Sadly I forgot to make a detailed note to myself on exactly how far delayed that's meant to be. So mild additional research also required.

TomHarte commented 1 month ago

Also, trivially confirmed that something there seems to be amiss. I don't have a good offhand guess as to what, sadly.

TomHarte commented 1 month ago

The problem turns out not to have been with the VIC itself at all (technically*), but to be in the way video data is streamed by the emulator. So: fixed. But not the other other VIC issues. I'll need to refresh my memory on the whole topic, I think.

Vic raster

* in that, technically, my VIC starts outputting the border level a little too close to the end of sync, and if it didn't then it wouldn't have triggered the issue, but the actual issue was an inadvertent completely incorrect response to that situation.