Flickering floors glitch (Intel Iris)

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Flickering floors glitch (Intel Iris)

Postby bLUEbYTE » Fri Nov 15, 2019 4:52 am

Hi,
I have GZDoom set up and running nice and smoothly, almost perfect except for one issue which occurs intermittently and tends to be very disruptive during gameplay.

It seems as tough textures or surfaces are flickering temporarily, when a 'new' area is viewed. Parts of the map blink and turn transparent and the skybox can be seen. Everthing turns normal after 2-3 seconds. Looks like something is being loaded in the gfx hardware. This doesn't occur very often, perhaps in one or two areas in some maps.

I captured a short video of it happening right at the start of MAP24 in cchest2: https://www.mediafire.com/file/g1a1c3pz ... h.MOV/file
gzdoom-A.ini


I'll also add my gzdoom config and detailed graphics info below.

GZDoom 4.2.4 x64 on Win10 x64
Intel 8259u CPU, Intel Iris Plus 655
I am running the latest stable gfx drivers, and this issue has been happening in previous driver versions too...

The issue doesn't happen if I enable Vulkan, but then I get micro freezes during gameplay, so I'd like to keep it running in OpenGL...

This appears to be the same issue as in viewtopic.php?f=57&t=63094

Any help would be appreciated!
Last edited by bLUEbYTE on Sun Nov 17, 2019 3:02 am, edited 2 times in total.
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Joined: 15 Nov 2019
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Graphics Processor: Intel with Vulkan Support

Re: Flickering floors glitch

Postby bLUEbYTE » Fri Nov 15, 2019 4:57 am

attached gzdoom config & graphics info

new config pastebin https://pastebin.com/jnsXq3em
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Last edited by bLUEbYTE on Wed Nov 20, 2019 5:17 am, edited 1 time in total.
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Re: Flickering floors glitch

Postby Graf Zahl » Fri Nov 15, 2019 5:04 am

Unfortunately, OpenGL and AMD/Intal are a very sad story. They always had driver issues. So obviously the bigger issue here is why you get micro freezes with Vulkan.
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Re: Flickering floors glitch

Postby bLUEbYTE » Fri Nov 15, 2019 5:08 am

Graf Zahl wrote:Unfortunately, OpenGL and AMD/Intal are a very sad story. They always had driver issues. So obviously the bigger issue here is why you get micro freezes with Vulkan.


Any ideas on how we can get to the bottom of that? Happy to investigate this and provide more files if applicable. Thanks.
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Graphics Processor: Intel with Vulkan Support

Re: Flickering floors glitch

Postby Graf Zahl » Fri Nov 15, 2019 5:21 am

Nopt right now. dpJudas may be able to give more help about all things Vulkan.
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Re: Flickering floors glitch

Postby dpJudas » Fri Nov 15, 2019 7:10 am

I have no idea why he might be getting microstutters. For most people I've heard from they said the vulkan backend produced fewer of those compared to OpenGL.
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Re: Flickering floors glitch

Postby _mental_ » Fri Nov 15, 2019 7:35 am

I don't think that 6x texture scaling is a good idea on this hardware. Depending on overall system load, 16 GB of RAM shared between CPU and GPU can be a problem.
Also, we have no idea how well Intel drivers share memory between system and graphics.
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Re: Flickering floors glitch

Postby bLUEbYTE » Fri Nov 15, 2019 7:56 am

_mental_ wrote:I don't think that 6x texture scaling is a good idea on this hardware. Depending on overall system load, 16 GB of RAM shared between CPU and GPU can be a problem.
Also, we have no idea how well Intel drivers share memory between system and graphics.


I thought GL texture precaching would cancel any ill effects of it...

I'll try disabling it and run a few maps in Vulkan tomorrow and report back.
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Joined: 15 Nov 2019
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Graphics Processor: Intel with Vulkan Support

Re: Flickering floors glitch

Postby Graf Zahl » Fri Nov 15, 2019 8:05 am

Texture precaching will cancel all effects of the texture upload. What it cannot do is cancel all effects of the GPU accessing the texture data. If high texture load leads to problems with memory throughput and impacts CPU cache performance all the precaching in the world wouldn't be able to cancel it. The quality difference between 4x and 6x is marginal anyway, but 4x will use less than half the memory as 6x.
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Re: Flickering floors glitch

Postby bLUEbYTE » Fri Nov 15, 2019 5:58 pm

I tested with texture resizing off, Vulkan enabled.

Unfortunately the brief freezes still occur :evil: They don't happen in intense moments during combat specifically but seem to occur randomly even within simple & empty places in the map... They are about 1/2 seconds long. I did not have anything else running in the background, and OpenGL mode never exhibits this. I'm going to write this off as yet another flaw in driver implementation.

Thanks all for your input.
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Re: Flickering floors glitch (Intel Iris)

Postby bLUEbYTE » Sun Nov 17, 2019 3:10 am

I tried a several recent driver versions, all had the micro-freeze issue with Vulkan. Then as a last resort, I uninstalled the Intel Graphics Command Center thingy and also the drivers, restarted, and let Windows auto update download the driver. The driver version that it downloaded was quite old, and wasn't even available from Intel's site, but to my surprise, the micro-freezes were gone!

The good one in my case is Driver Version: 24.20.100.6345. Hopefully this will continue being available from WU and fellow Intel users won't hit that issue. I am quite happy with this, as vulkan is significantly faster than OpenGL, too!

I attached some annotated benchmark results from demonastery.wad's start location.

Now, gentlemen, I'm off to cut some demon arse.
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Re: Flickering floors glitch (Intel Iris)

Postby Graf Zahl » Sun Nov 17, 2019 3:26 am

I don't really believe it was the driver causing this but something interfering with the driver, that just got uninstalled along with it. That Intel Command Center maybe?
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Re: Flickering floors glitch (Intel Iris)

Postby bLUEbYTE » Sun Nov 17, 2019 3:44 am

Command Center only got installed when I updated to the latest generic .74xx driver yesterday - it is the new incarnation of Graphics Control Panel, which is no longer available. Both apps were the 'companions' to the drivers, but separate from them, as part of this new 'DCH drivers movement'. All the .6xxx series drivers except this one (.6345) installed that previous app. This older version did not install either, but had the old-style Graphics Properties application built-in inside the driver.

Really glad that I lucked into this driver version. It supports Vulkan 1.1.83, a bit older than the others, obviously - the .74xx one supported 1.1.125. I think it supports less Vulkan extensions, and I realise it is not exactly future-proof, but hey, nothing beats a butter smooth GZDoom gameplay.
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Re: Flickering floors glitch (Intel Iris)

Postby bLUEbYTE » Sun Nov 17, 2019 3:46 am

Also, big props to you guys for the Vulkan implementation, it is already performing very stable on my system. There is about 40% performance boost compared to OpenGL on my system judging by those benchmark results.
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Re: Flickering floors glitch (Intel Iris)

Postby bLUEbYTE » Fri Dec 06, 2019 3:23 am

The OpenGL benchmarks were wrong, as it turns out that I had forgotten vsync on while benchmarking that backend. I found the perfect configuration though, with that older driver version .6345 installed by Windows 10 update. GL mode crashed GZDoom 4.2.4, so I tried -glversion 3. Did not crash, and no more graphical glitches! What's more, OpenGL is actually performing better than Vulkan. At the start location of MAP13 of Doom II, at 1920x1080 resolution I got:
- 72 FPS in Vulkan
- 91 FPS in OpenGL

Perfection, at last!

edit: Added demonstery.wad benchmark results:
Code: Select allExpand view
Map MAP01: "Demonastery", vulkan, 1920x1080
x = 2944.0000, y = -2240.0000, z = -111.0000, angle = 135.0000, pitch = 0.0000
Walls: 4681 (0 splits, 242 t-splits, 8840 vertices)
Flats: 599 (602 primitives, 37383 vertices)
Sprites: 818, Decals=0, Portals: 1, Command buffers: 5
BSP = 0.464, Clip=1.134
W: Render=1.270, Setup=1.134
F: Render=0.277, Setup=0.093
S: Render=0.519, Setup=0.299
2D: 0.290 Finish3D: 0.003
Main thread total=2.066, Main thread waiting=0.467 Worker thread total=1.972, Worker thread waiting=0.446
All=13.282, Render=2.183, Setup=2.107, Portal=0.024, Drawcalls=0.690, Postprocess=0.020, Finish=8.726
DLight - Walls: 427 processed, 384 rendered - Flats: 290 processed, 169 rendered
67 fps

Map MAP01: "Demonastery", OpenGL, 1920x1080
x = 2944.0000, y = -2240.0000, z = -111.0000, angle = 135.0000, pitch = 0.0000
Walls: 4681 (0 splits, 242 t-splits, 8840 vertices)
Flats: 599 (602 primitives, 37383 vertices)
Sprites: 818, Decals=0, Portals: 1, Command buffers: 0
BSP = 0.451, Clip=1.078
W: Render=0.877, Setup=1.424
F: Render=0.226, Setup=0.122
S: Render=0.447, Setup=0.374
2D: 0.213 Finish3D: 0.292
Main thread total=2.462, Main thread waiting=0.933 Worker thread total=2.392, Worker thread waiting=0.473
All=11.096, Render=3.807, Setup=2.589, Portal=0.114, Drawcalls=0.162, Postprocess=0.890, Finish=3.589
DLight - Walls: 427 processed, 380 rendered - Flats: 290 processed, 169 rendered
74 fps
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Joined: 15 Nov 2019
Location: Australia
Graphics Processor: Intel with Vulkan Support


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