minimum hardware to run GZdoom?

[Disciple-X]

Simply put, I want to know if anyone has successfully run GZdoom with a resource intensive wad and if they were able to use a much lower end graphics card and CPU to do so. Playing regular Doom, Doom2, and the Final Doom IWADS with Gzdoom, Riva TNT 64 and a celeron 366mhz CPU seems possible, but even with most features turned off (dynamic lights included, used 640x480/400 res to test), there were hickups at odd points dropping below the Doom standard 35fps. My own wad project, which is very intensive, will run on a celeron 366mhz in software mode, at a constant 35fps, no FPS slowdowns using 320x200 (not even gothic99 runs without hickups on this machine in software mode at 320x200). However, my project using GZdoom on the specs I just listed produced unplayable results.

Obviously anyone who has a super beefy machine are proud of getting ridiculously high FPS thanks to the FPS cap being removed long ago in Zdoom 2.x ports... not to mention that they would have no issue running my current project at 1280x1024 res with all features turned on if their machine can run games like Doom3 or HL2 without performance issues. "cl_capfps 1" is the console command to use if you intend on testing things out after reading this post.

Also, does GZdoom rely on more modern features such as Transform and Lighting or any other form of geometry assisting?

[Graf Zahl]

You forgot to mention 2 very important values: How much RAM does your computer have and how much your GFX card? The GL renderer requires a lot of memory so without these I can't help you.

GZDoom requires one modern feature to render all effects properly: a stencil buffer. But it can run in a limited fashion without it.

[Disciple-X]

sorry for not mentioning sooner...

My ram will differ from 64, 96, 128, and 256 (all SDRAM using 100-133mhz FSB). I acquired celerons and extra ram for test machine purposes. I've used 128mb ram for GZdoom so far. The TNT M64 has a mere 16mb of video ram (this particular card was designed to compete with 3Dfx when they were the top graphics maker way back in the day). Celeron CPUs that will also be used for test purposes include a 400, 500, and a 600mhz celeron, the 600mhz being a small core coppermine chip. Also have an AMD K6-2 500mhz chip with the needed Super Socket 7 platform (has not been tested yet). Again, I'm aiming for a minimum.

Another card I tested my project on was the Intel Extreme Graphics chipset version 1, which works horrible even if you use a Pentium 4 class CPU. What if the card does not have the stencil buffer you speak of? but the wad project does not require any major special effects other than simple dynamic lights or fog? I know the TNT m64 is capable of offering 32bit color depth rendering for games (also a requirement for GZDoom to run), but I did not think that such a card had a stencil buffer, as when I think stencil, I think GeForce 2 cards using such a feature to enable games like Quake 3's "r_shadows 2" option to show off life-like shadows instead of the default blob shadows. Or does a stencil buffer require 32bit rendering only? Vice versa?

[Disciple-X]

One more note. I even tried out the Intel "I740" OpenGL 8mb graphics card (again using 128mb of ram and a celeron 366mhz). I was able to get GZdoom to at least bring up the initialization status in older versions before the new startup environment was applied, but only after I opened the INI file and changed various bit-depth options to 16/8 (cant remember exactly). However, it would immediately crash out upon trying to display the level or main menu. GZdoom would not even start up on such a card with the default INI settings.

The I740 is a very basic OpenGL accelerator, which was originally meant to contend with 3Dfx's Voodoo2 and under series cards. So, I'm guessing a Voodoo4-5 could run GZdoom (Voodoo3's are nothing more than suped upped Voodoo2's), as they allow a stencil buffer and 32bit color rendering. The original GeForce cards before the GeForce 2 series may also run GZdoom happily. The TNT m64 does seem to have a stencil buffer, but it does not have a lot of additional horsepower to run GZdoom, so it acts pretty sluggish.

Also Grahf, anyway to disable stencil use for GZdoom using an INI option? That way I could get GZdoom to treat more modern cards as if they were less featured cards, thus opening up my testing options.

[Graf Zahl]

There's a CVAR called 'gl_vid_compatibility' which forces the engine to start up with lower requirements.Set this to 1 and try again. But in your case the system just appears to be too weak. Unfortunately Doom in OpenGL always needs more power than a real 3D game like Q2 because none of the game data has been prepared with hardware rendering in mind so there's a lot more overhead to draw it.

[Disciple-X]

gl_vid_compatibility seems to make the project almost playable with the Extreme Graphics 1 chipset. It should be noted that the TNT m64 on a 900mhz duron ran things a tad faster than a Extreme Graphics Chipset 1 on a P4 2.66ghz (with gl_vid_compatibility disabled that is). I can only imagine how much more playable the TNT m64 will be once I get back home to try it sometime this week.

Only issue I ran into is that the basic skybox thing does not get used in this compatibility mode. If at all possible, is there a way around that particular issue? or does that have to be hard-coded into GZdoom's gl_vid_compatibility preset? I CERTAINLY need the basic skybox thing to work in this mode, as the project is designed to take full advantage of software rendering and GL rendering.

[Graf Zahl]

gl_vid_compatibility seems to make the project almost playable with the Extreme Graphics 1 chipset. It should be noted that the TNT m64 on a 900mhz duron ran things a tad faster than a Extreme Graphics Chipset 1 on a P4 2.66ghz (with gl_vid_compatibility disabled that is). I can only imagine how much more playable the TNT m64 will be once I get back home to try it sometime this week.

Just shows how extremely bad that chipset is.

As for the skybox, that's one of the things that causes problems. It needs the stencil buffer so if thst is disabled (by gl_vid_compatibility) it won't work. To use GZDoom with full features and at a decent speed you need a more modern graphics card.

[TheDarkArchon]

*hugs his GeForce 8800 GTS*

[Disciple-X]

Well, the good news is that I can work around the lack of stencil and provide simplified sky textures for those who use the CVAR we have discussed. Fog and Dynamic lights still work with that CVAR, and those play a pretty big deal in really showing off the beauty of the levels that I designed. So, my project will have both a minimum and recommended sytem requirements. Minimum will use simple skies, recommended will require a stencil buffer for sky boxes to show in all of their glory.

Using the compatibility option easily allows the maps to yield Doom64 quality graphics (as in Nintendo 64, not the Absolution PC mod).

Lastly, to make things a tad more user friendly, it may be a nice idea to add a startup feature for GZdoom that detects whether or not the graphics hardware on a machine has the modern features needed to run at default settings. If it does not detect the key features, it applies capatibility CVAR. Or does it already do something like that?

[Graf Zahl]

Such a feature is there. But some cards fall between the cracks because their startup information is not precise. In your case it looks like the card reports all features to be present so GZDoom doesn't notice the problem.