See:
https://bugzilla.icculus.org/show_bug.cgi?id=2795
Basically, my nVidia card is in 16bpp mode in X, and so none of the bpc modes have 8 bits. When the line resetting sdlcolorbits to 4 /in each run of the detection loop/ was removed, it forces it to 8 on every test after the first. Oops. It's a one-line fix, and it makes Tremulous launch properly on my machine; I'm operating under the assumption (possibly erroneous) that the fix should go upstream as well.
Feel free to disregard this if it doesn't apply to ioq3, but I feel like it probably does.
Created attachment 984[details]
One-line fix against trunk to help find the proper GL settings.
Here is the aforementioned patch. It's a one-liner. As stated above, it fixes problems with Tremulous; I'm assuming it won't hurt ioq3 either.
Further exploration shows that this is definitely a bug in ioq3. (The patch is essentially a revert of r713.) Timbo said that he'd wait for the fix upstream instead of merging it separately.
Setting a QA contact on all ioquake3 bugs, even resolved ones. Sorry if you get a flood of email from this, it should only happen once. Apologies for the incovenience.
--ryan.
Created attachment 984 [details] One-line fix against trunk to help find the proper GL settings. Here is the aforementioned patch. It's a one-liner. As stated above, it fixes problems with Tremulous; I'm assuming it won't hurt ioq3 either.