Skip to main content
genetransfer
Up and Coming
February 4, 2015

Direct Mode Min Clip Distance Issue???

Hi, I have been using direct mode for last week or so in my custom engine (dx11). I have been boggled as to why I am getting such dismal frame rates on the simplest of geometry (In this case basically an unfurnished room and 4 point lights).

after much trial an error I found setting my Minimum clip distance to just greater than 1.0f (1.1f for example) seemed to stop the drop in frame rate (37 fps) and stays at 75fps.

in extended mode everything is good with a minimum clip distance of 0.005f, actually this drop doesn't seem to happen, but in extended mode directx11 actually goes into full screen mode on launch so not sure if that has anything to do with it.

in my test vsync is on, both in engine and OVR_SDK lib.

So any reason as to why the minimum clip distance is causeing an issue in direct mode? (mainly when approching walls it seems but does happen sometimes when not near walls)

thank you for any help in this issue, as I just want to make sure it's not just something I'm doing wrong.

side note: One cool thing I've found with the dx11 ovr is black smear seems to be gone, so a +1 for that, just wish I could understand why this issue is happening. also Is direct mode supposed to launch in fullscreen mode (i.e. device fullscreen) or it doesn't matter?

    7 replies

    cybereality
    Inspiring
    February 5, 2015
    When you have VSync enabled, you will either hit 75fps, or it will drop to 37.5fps if you are just a fraction of a second off. So it may be that you are right on the performance cut-off (say 74fps) and changing the clip distance is enough to give you that one extra frame.
    AMD Ryzen 7 1800X | MSI X370 Titanium | G.Skill 16GB DDR4 3200 | EVGA SuperNOVA 1000 | Corsair Hydro H110i Gigabyte RX Vega 64 x2 | Samsung 960 Evo M.2 500GB | Seagate FireCuda SSHD 2TB | Phanteks ENTHOO EVOLV
    genetransferAuthor
    Up and Coming
    February 5, 2015
    Thanks Cybereality, just wondering why extended does not have this issue, which with min clip of 0.005f (or any setting) maintains 75fps not dropping (I moved around the whole room watching the fps counter). we are talking about a relatively low poly room also even though normal mapped and lit with 4 lights.

    having vsync off isn't an option because of tearing, it just looks so distracting.

    will direct mode eventually get the performance/stability of extended mode or is something we are just going to have to live with? I hope extended mode stays as an "option" because of things like this, unless of coarse direct mode becomes magic leaving extended completely pointless.

    Is there any news for us indies on that front as far as extended mode remaining an option on cv1 release, it will help plan the games we work on, like recently finding out dx9 was dumped saved me countless hours (and fury lol), just need to know what we are working with to plan for these things.
    cybereality
    Inspiring
    February 5, 2015
    First of all, can you turn V-Sync "Off" and tell me the fps you get in both Direct and Extended Mode?

    Also, please list you OS version, system specs, and GPU driver version.

    In terms of future updates, I can't really speak about that right now. But I can tell you that the engineering team is definitely aware of the issues developers are having, and we are actively looking into solutions.
    AMD Ryzen 7 1800X | MSI X370 Titanium | G.Skill 16GB DDR4 3200 | EVGA SuperNOVA 1000 | Corsair Hydro H110i Gigabyte RX Vega 64 x2 | Samsung 960 Evo M.2 500GB | Seagate FireCuda SSHD 2TB | Phanteks ENTHOO EVOLV
    genetransferAuthor
    Up and Coming
    February 5, 2015
    Thank again Cybereality.

    both direct and extended run at 107 fps with vsync off, tested with both min clip distance above and below 1.0f (1 meter).
    I'll keep looking for things my side that could cause this but if it was just an engine issue I'd assume it would happen for both modes not just direct.

    Windows 7 Home Premium 64-bit (SP1)
    Intel(R) Core(TM) i5-4590 CPU @ 3.30GHz (4 CPUs), ~3.3Ghz (3.7GHz Turbo)
    MSI B85-G43 Gaming Motherboard
    PSU - Be Quiet! L8 600W
    G.Skill Ripjaws (2x4GB) DDR3
    Geforce GTX 650 1024 MB GDDR5 (drivers 344.75).
    DirectX 11

    I understand you can't confirm anything until the right time, but hopefully extended will remain if needed, better have a gun and not need it then need it and not have it as the saying goes. Thanks again.
    genetransferAuthor
    Up and Coming
    February 7, 2015
    well I think I got to the bottom of it. In the nvidia control panel I switched Anti-aliasing mode from application controlled to off and seemed to fix it. I don't use AA in the engine as I have an FXAA Shader to do that if needed. not sure why application controlled AA setting causes this, any ideas? is there a d3d11 setting to state it as off other than DXGI_SAMPLE_DESC (count 1, quality 0)? at least frame rate is staying at 75 now in direct mode.

    I still have to test alpha and compute shader particles to see if this helps there, as my initial tests showed better performance in extended mode with those, but will see if this has effected anything now.
    genetransferAuthor
    Up and Coming
    February 7, 2015
    just confirming, compute shader particles and alpha seem to be working well now as well, yay. Edit: so will just have to figure out why "application controlled" AA is an issue in nvidia control panel for direct mode with my engine. for the swap chain I was setting the count and I thought quality but it may have not been the case, so I set it individually and manually with...
    scd.SampleDesc.Count = 1;
    scd.SampleDesc.Quality = 0;
    and when I switched back to application controlled AA in nvidia control panel it seemed to now be ok. well that's a load off, just putting this info here in case anyone finds it useful. was so worried I would get this nailed down.
    anyway thanks again for the help.
    genetransferAuthor
    Up and Coming
    February 10, 2015
    just installed the latest nvidia drivers and judder (framerate drop) came back. rolled back to 344.75 but judder remained when near walls so went back to the latest 347.25. everything is fine in extended mode. I don't think there is anything else I can do ??? anyway just letting you guys know.
    Terms & ConditionsAccessibility statement