17 Replies Latest reply on Feb 4, 2015 8:48 AM by cgrant78@netzero.com

    AMD, OpenGL and id tech 4 / 5 engines

    motorsep

      I filed a bug report a long while ago, about Doom 3 BFG not working on WinXP. It was never answered, but that no longer matters since WinXP is now obsolete. I am hoping that AMD still supports OpenGL and is interested in fixing the driver so that indie devs who use open source engine from iD Software would deliver games to AMD users too, not only to Nvidia and Intel users.

       

      We are using modified Doom 3 BFG engine (id Tech 4 with threading and renderer from id Tech 5) to power our upcoming game. Currently the engine works like a clock using Nvidia and Intel GPUs, but has severe performance issues on AMD.

       

      Particularly it runs at ~60 fps on GeForce 670 GTX installed on AMD Phenom x3 2.2Ghz under Windows 7, but on the same scene it runs at ~20fps on AMD HD7850 installed on AMD Phenom x4 2.4Ghz under Windows 8.1.

       

      Is there any specific person I can get a hold of to discuss whether it's possible for AMD to look into the issue and resolve it (it's strange that it hasn't been resolved, since RAGE has been out for loooong time and since then none of the id Tech 5 based games perform well on AMD GPUs) or if we should give up on AMD OpenGL driver and either add DirectX renderer (which is least likely to happen) or simply not support AMD GPUs (which of course doesn't matter to AMD, but matters to us since AMD has a larger user base than Nvidia and Intel, based on Steam hardware stats) ?

       

      Thank you for your time.

        • Re: AMD, OpenGL and id tech 4 / 5 engines
          cgrant78@netzero.com

          One thing to note also is that a performance issue is not always related to a driver bug. Each OpenGL implementation has it quirks and certain use case may actually take the slow path through the implementation ( resulting in decrease performance ). Could you elaborate on how you are collecting your performance data ? FPS is not really a valid performance metric when it comes to development so it would be nice to see that actual GPU and CPU times for each subsystem or draw calls to help narrow down the culprit.

          • Re: AMD, OpenGL and id tech 4 / 5 engines
            motorsep

            It's definitely driver's issue. I asked someone with GeForce 560 GTX to test the same case, and his RB/GPU/fps values were lower than mine. So the question is how is it older Nvidia outperforms newer Nvidia GPU ? Easy - he was using older driver. So I downgraded my driver to exactly the same version as the test guy was using and bam!, GPU timer went down from 21.7ms to 12.7ms (which is still higher than it was on 560GTX test case, which was ~8ms).

             

            So while Nvidia engineers got with me on the subject promptly, I am still wondering what I need to do to get attention of AMD engineers :/

            • Re: AMD, OpenGL and id tech 4 / 5 engines
              motorsep

              It's been a while since I posted this, but either AMD has bad customer service (specifically for OpenGL devs), or terribly short handed, or don't care for PCs and OpenGL any longer after monopolizing consoles market. On the contrary, Nvidia not only cooperates with developers of various caliber and helps to resolve issues, but also sends free hardware (some times) to expedite debugging on the spot.

              • Re: AMD, OpenGL and id tech 4 / 5 engines

                I checked with the support engineers for this forum. We're not aware of any issues with Doom BFG but will be happy to look at your game. I'll be in touch directly.

                  • Re: AMD, OpenGL and id tech 4 / 5 engines
                    motorsep

                    What project is it for? Is it for a commercial game? Something else?

                     

                    I am registered dev and I've been in touch with Nvidia devs since Steam on Linux went to live testing phase. So I do get respond via e-mail. I don't expect driver devs to hang out on the forums. Forums are for discussions between other devs, and for someone like Jim to notice critical issue and communicate it to the driver engineers. Perhaps your issue was fixed in the driver update (like mine was), and they expected you to update driver. It doesn't seem you were persistent enough on the forums, thus it might have been assumed that driver update fixed the issue ?

                    • Re: AMD, OpenGL and id tech 4 / 5 engines

                      No one is perfect, not even nVidia.   There are plenty of  stones we could cast at any major company.  I am quite sure that if we dug through the AMD forum we'd find more than one potential bug report with no or sub-optimal resolution. My goal is to minimize that happening to AMD developers as long as I'm here. We won't be perfect, but we should be better.

                       

                      Let's keep this focused on the technical issues. I won't let this devolve into a comparative analysis of companies and/or nVidia bashing or praising. 

                       

                      I've been discussing this one privately with Alex, and the simple truth is I don't think we're going to be able to help him.   There are only so many customer-focused engineers to go around, I had one who was going to look into this, and higher priority work got in the way as we ramp up for GDC. I'm sure this kind of non-maskable interrupt happens where you work.

                        • Re: AMD, OpenGL and id tech 4 / 5 engines
                          cgrant78@netzero.com

                          I agree with jtrudeau..there is no need for fan-boyism or bashing in dev forums. I'm intimately familiar with both dev forums and the same thing happen on both, no exceptions. I can understand the opt frustration since I have posted issues on these forums and have received little or nor response, but development/life goes on...find a work around and proceed until the issue is addressed. If it can't be addressed by a workaround, then there is no need for name calling, the sad fact of the matter is that you may have to mark the platform as not supported or have some caveat in place to say that the end-user should expect perf issues on the platform.