Hey, Gmlb.

Seems like I spoke too soon.

I managed to install your hacked OVL driver and gave the game another go. I dialed the FSB down to 100 and 133 and the game works a treat. My specs are the ones on my second cpu-z verification sig.

I have yet to see a fatal crash with this driver. It will also launch successfully from both DOS and Windows, although any environmental variables to set SST_SWAPINTERVAL to 0 or SST_SCREENREFRESH to 85 will get ignored under the latter. No big deal, just a matter of switching to DOS mode and loading a cdrom driver. Thank you so much for your work.

If it is of any use to you, I can still upload the LOG.txt file from my rig.

I'm wondering why and how this driver even works.
Is the voodoo 2 simply a reissue of the voodoo graphics with higher clocks, more ram and a driver with the ability to delegate to a second tmu?

Spark wrote on 2023-03-13, 23:14:

I'm wondering why and how this driver even works.
Is the voodoo 2 simply a reissue of the voodoo graphics with higher clocks, more ram and a driver with the ability to delegate to a second tmu?

Architecture-wise, the Voodoo2 is a superset of the Voodoo Graphics (SST-1) card. Having the same memory mapped address space and the registers being fully compatible despite enhancements to handle hardware triangle setup, SLI and the second TMU.

Spark wrote on 2023-03-13, 23:14:

I'm wondering why and how this driver even works.
Is the voodoo 2 simply a reissue of the voodoo graphics with higher clocks, more ram and a driver with the ability to delegate to a second tmu?

wait till you hear about voodoo3 :-] 3dfx kept reheating same hardware for 3 generations with 16bit framebuffer and 256x256 texture limits 😀

Could this diver also work for a Banshee, if modified with the correct hardware Id, or is the architecture of that card too different?

The architecture of 3dfx hardware since the Voodoo Banshee is different despite what people say. Haven't seen any success with them running older Glide games (DOS executables with the API integrated or Windows ones using GLIDE.DLL + SST1INIT.DLL) that doesn't check the PCI device ID.

Bit of an update, just to confirm that FX_GLIDE_SWAPINTERVAL=2 works much better than fiddling with the clock speed with Screamer 2/Rally to smooth out the framerate. So thanks for the tip there.

If i use this voodoo graphics driver, turn 1 tmu off, knock back the tmu memory to 2mb and set the clock to 50mhz, would my voodoo2 bench the same as a voodoo graphics? Presumably this driver can't make use of the v2 triangle setup hardware? It would be quite handy to make a v2 behave like a v1 in this way.
Unfortunately I don't have a voodoo 1 anymore to test it myself.

Spark wrote on 2023-07-03, 21:35:

Bit of an update, just to confirm that FX_GLIDE_SWAPINTERVAL=2 works much better than fiddling with the clock speed with Screamer 2/Rally to smooth out the framerate. So thanks for the tip there.

You're welcome!

If i use this voodoo graphics driver, turn 1 tmu off, knock back the tmu memory to 2mb and set the clock to 50mhz, would my voodoo2 bench the same as a voodoo graphics? Presumably this driver can't make use of the v2 triangle setup hardware? It would be quite handy to make a v2 behave like a v1 in this way.
Unfortunately I don't have a voodoo 1 anymore to test it myself.

I believe that the performance will be closer to the Voodoo Graphics card, but I don't have time to do the testing for confirmation.

Tested the modded files on a VIA C3 Nehemiah CPU and the best results that I got was by setting the FSB to 100 MHz, changing the multiplier to 10.5x and disabling the branch predictor.

P.S. VIA C3 CPUs does have P6-style MTRRs, but Glide will automatically enable write combining for speedup in certain scenarios on the Voodoo Graphics and Voodoo2 cards when active only on Intel CPUs based on the P6 microarchitecture and later.

Odd....I was curious to read about peoples discussion here since I was already running V2 and Banshee under DOS games since some years.
Just go the respective glide2x.ovl from the driver package and switch the one used.
Not sure what is the new thing here?

P.S. I don't remember if I did that with V3, but for V2 and Banshee I remember this for a fact!

demonized999 wrote on 2023-10-16, 13:20:

Odd....I was curious to read about peoples discussion here since I was already running V2 and Banshee under DOS games since some […]
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Odd....I was curious to read about peoples discussion here since I was already running V2 and Banshee under DOS games since some years.
Just go the respective glide2x.ovl from the driver package and switch the one used.
Not sure what is the new thing here?

P.S. I don't remember if I did that with V3, but for V2 and Banshee I remember this for a fact!

This mod allows the Voodoo2 card to run several DOS Glide games that required GLIDE2X.OVL but couldn't by normal means. The Voodoo2 architecture (unlike the other Voodoo cards) being fully backwards compatible with the Voodoo Graphics makes it possible.

Tested Dreams to Reality, Prost Grand Prix, and Tie Break Tennis 98 in pure dos on a Voodoo2. They all work with this driver and a Pentium 4 2.8ghz on a 100mhz fsb. I use the "Cpuspd O4" command to dial the cpu back just enough to get the Voodoo2 card to work. I also clock the Voodoo2 card at 75 instead of 90 as a preventative measure. Tie Break Tennis has some major frame rate issue, but it does the same thing in software mode.

Excellent!

I have updated the notes to add a way to limit framerates and to mention ODCM throttling. vetz should also update the Voodoo2 DOS compatibility matrix as well.

Maybe someone with a slower CPU can test Tie Break Tennis. I tried using ODCM, throttle, and disabling the cache, but it's still broken. Unfortunately, my fsb doesn't go lower than 100mhz. But as I mentioned, it has the same frame rate issue even when using software rendering. So I'm guessing they didn't implement a frame limiter in the code and the game just goes bananas on a p4. Dreams and Prost run correctly. Regardless, it's very interesting that you've figured out a solution to getting these three problematic games to run on a Voodoo2. Great work.