o2 dithering in opengl (quake)

stormy

Active member
Jun 23, 2019
179
69
28
Hi all,

I haven't seen this discussed anywhere before. It might be the fact that I grew up playing all the Quake games on my 3dfx and TNT cards over the years, I have quite the attention to detail for these things... I noticed on my o2 Quake 1/2 (and possibly 3, I haven't checked) have some serious low quality dithering going on. It's far more obvious when running the game full screen on the actual hardware than it is on screenshots, but it's like having a cross-hatch effect overlaying the screen at all times.

I've taken some screenshots to try and show it off, they do demonstrate it but like I say, it looks far worse in-game on the monitor itself. I've taken two screenshots in Q1 and Q2, and zoomed two sections of them. Anywhere where there is contrast, dark-light areas, it's everywhere if you look carefully.

I'm wondering why this is the case, it's the kind of dithering you'd expect in software mode in 8bpp quality, not in 24bit OpenGL? What are your thoughts. And just FYI, this is definitely not the case on any PC hardware, even of the 1990's variety.

quake1a.png
quake1a_zoom.png

quake1b.png
quake1b_zoomed.png

quake2a.png
quake2a_zoom.png
 
Last edited:
And here are some photographs I took directly from the monitor. It's very easy to see in Q1 with the menu up, the darkened background shows off the crosshatch effect.

PXL_20240421_144637569.MP.jpg PXL_20240421_144642716.jpg PXL_20240421_144647389.jpg
 
Thanks to drmadison, he recommended that I change to 32x32 in the bottom left corner of the display screen. This fixes the graphics and now everything looks great! Anyone else with an o2, make sure you have this on 32x32!


o2settings.png
 

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