Some testing with Mesa3D and the 3.5 legacy build

[drfrag]

I've done some testing with Mesa3D for windows 18.1.5 and the 3.5.0 legacy build, it's relatively fast on my 2.4 GHz Core2 Duo.
https://fdossena.com/?p=mesa/index.frag

That thing is a GL 3.3 software driver and i guess it requires a dual core cpu for decent performance.
I need to disable render buffers (+gl_renderbuffers 0) and run in legacy mode (with -glversion 2). Without legacy mode it's very slow.
I get 50 fps @1024 with software 8 bit and nearly 30 with truecolor and the GL hardware renderer (MAP01).
Of course LZDoom will be a better alternative for those stuck with GL 1.x when running the software renderer. BTW porting the "fix" for the speed regression in the software renderer (yes it's in the legacy build as well) to the old GLWSFB seems to pay off for Mesa, however that port has still D3D and even DDRAW.

Also i've done some testing with the old GL renderer (1.9.2 in ZDoom32) and it's almost as fast as the legacy renderer but with shaders. That means i can use the software sector light mode and that thing makes a huge difference. I get 50 fps @640 and i could even use 320 on my laptop since intel GPUs support that resolution natively. However out of curiosity the driver is detected as GL 3.1 there.

[drfrag]

More testing on a pentium dual core @1.67 (cut down core2) with intel graphics.
It's pretty much the same, i get 85 fps @640 for paletted software and close to 60 for both truecolor and "hardware" OpenGL with the Mesa driver.
The intel hardware driver gives more than double the performance but wait there's a surpise, in software truecolor with the intel driver i actually get half the performance (only 30 fps).
I've also found that decreasing gamma in the intel control panel Doom (and everything) looks much better (too bright before).
Edit: i forgot to mention that this software driver crashes when changing video modes.

[Rachael]

From my own testing (I did this exclusively in Linux, sorry) I looked at it and it seems like the systems that would actually benefit from it, unfortunately, are not fast enough to handle it, even for strictly software rendering. AFAIR I was not able to get past 10-15 FPS on my laptop (which is one of the older processors).

I think software Mesa3D may possibly be one of those things that benefits a lot from 64-bit due to expanded register usage.

This is the laptop that benchmarked (and killed) ZDoom's ASM drawers. I don't remember if I have the 715 or 725 in mine, but it doesn't really matter. It's single core, 32-bit, crappy GPU (does it even have one?!). If any computer needed a fast software OpenGL implementation, it's definitely that one, and that one can't run it well.

[drfrag]

Well it's the llvmpipe driver of course and that's included in modern linux distributions. SSE2 is required (and a dual core cpu too for decent performance).
I remember your old laptop, SSE2 performance was low on the pentium m.
That guy's builds are supposed to be fast, 64 bit builds will be faster but AFAIK they can be used only with 64 bit apps.
This guy has 64 bit builds: https://github.com/pal1000/mesa-dist-win/releases
Also _mental_ has a bit older compiled windows versions.
There are dual core intel laptops with only GL 1.x support if i remember right.

Anyway i've done more testing and on my intel laptop i get 90 fps @320 with ZDoom32 (1.9.2 GL renderer) and software light mode. It doesn't look that bad this is Doom after all. There are pauses when loading textures, may be precaching and compressed textures could help.
Out of curiosity on my trident laptop (p4 @2.8) with _mental_ mesa 11.2 driver i get 50 fps for the 3.5 legacy buid @320 with 8 bit paletted software. Higher resolutions run like shit as expected.
For ZDoom32 i get 30 fps @320 again using software light mode, driver is identified as GL 3.0 compliant.