Textures Flickering

Mon Dec 31, 2018 11:16 pm

Hi Devs, I just tried GZdoom 3.7.0 and while I am overall liking the improvements and enhanced performance, I have noticed that in some cases I see texture flickering. I noticed this initially in Extermination Day's Map-13, but it is not limited to extermination day. I also noticed this bug to a lesser extent in Hexen Deathkings. This flicker stops after a 1-2 seconds and doesn't happen again in that area though it can happen again when in a new area of the map.

I am using a laptop with both a dedicated GPU (Radeon 530) and a integrated GPU (intel UHD 620). Texture flickering only happens when using integrated GPU (However i don't want to use AMD dedicated GPU because I get much worse performance with it).

My Specs:
- Dell Inspiron 5570
- Win 10 64-bit (build 17134)
- BIOS 1.0.4
- 4GB ram
- Intel core i5-8250U
- Intel UHD 620 (integrated GPU)
- AMD Radeon 530 (dedicated GPU)

Re: Textures Flickering

Tue Jan 01, 2019 1:08 am

This sounds more like a driver bug, if it only happens on the Intel GPU? Have you updated to the latest driver version?

Re: Textures Flickering

Tue Jan 01, 2019 3:33 am

It does seem like a intel GPU driver bug. I'll see if there are updates for the driver and then try. I will inform soon

Re: Textures Flickering

Tue Jan 01, 2019 4:53 am

OK, so it seems like I could be trouble. I went here:
https://www.dell.com/support/home/pk/en ... op/drivers

And found out the latest version of Intel HD drivers supported by Inspiron 5570 is (23.20.16.4973 ,A05) which is already installed in my comp. I hope I am not out of luck here, am I?

And BTW how is Vulkan support coming up (Vulkan would mean I could finally use my AMD card).

Re: Textures Flickering

Tue Jan 01, 2019 5:33 am

ReaperAA wrote:And BTW how is Vulkan support coming up (Vulkan would mean I could finally use my AMD card).



Not much progress so far. The main problem is that before this becomes an option an alternative render path needs to be created that performs a lot less commands that need to be placed into the command buffer. With how things work currently it'd just be too slow.

Why can't you use OpenGL on your AMD anyway? If it supports Vulkan, OpenGL should be fine, and normally faster than the Intel.

Re: Textures Flickering

Tue Jan 01, 2019 6:14 am

Graf Zahl wrote:Why can't you use OpenGL on your AMD anyway? If it supports Vulkan, OpenGL should be fine, and normally faster than the Intel.


One would assume that the dedicated GPU would always perform better than the integrated GPU, but this is not my case. The AMD card performs better on DirectX/Vulkan games but when it comes to OpenGL, its performance is usually worse than the iGPU.

Its not just GZdoom that performs worse, I also get worse performance with Quakespasm, UT99's OpenGL renderer, EDGE, Yamagi Quake 2 etc.

Re: Textures Flickering

Tue Jan 01, 2019 6:21 am

That's a bit puzzling. I always assumed that AMD's drivers would be better than Intel's...

Re: Textures Flickering

Tue Jan 01, 2019 8:28 am

It once was that way.

To be fair, though, the GPU's themselves (sans drivers) are still faster, and not by any short mile either.

Re: Textures Flickering

Tue Jan 01, 2019 9:34 am

Rachael wrote:To be fair, though, the GPU's themselves (sans drivers) are still faster, and not by any short mile either.


This. I should've just gone with a laptop with a Nvidia GPU (their opengl drivers are far better than AMD's crap drivers)

Re: Textures Flickering

Sun Jan 27, 2019 7:59 pm

I'm getting this too on my Dell tablet I primarily use to play doom on. Thought the shader cache had something to do with this but thankfully not.
Noticed all the flickering straight away after I upgraded from v3.6.0 to v3.7.2 and launched into BTSX map01 w/ LegenDoom/DRPG (excluding DRPG didn't fix it, hah).

Tested appveyor builds from each commit made after v3.6.0 and found the changes made to hw_lightbuffer.h in this commit: https://github.com/coelckers/gzdoom/com ... bfda75960a is causing the issue.
Downloaded v3.7.2 source and compiled me a build with the changes to hw_lightbuffer.h reverted and found the flickering fixed.

Interestingly the issue did not occur when I loaded BTSX with no mods.
I wondered if perhaps the mods shaders required changes but then I rememebered this doesn't happen on my NVIDIA PC, so, hmm.

My tablet specs:
Dell Latitude 7175
Core m5 6y57
4 GB RAM
HD Graphics 515 (OpenGL 4.5, driver 25.20.100.6519)

Re: Textures Flickering

Mon Jan 28, 2019 12:17 am

Reverting that change just hides the real problem. I thought it was fixed.