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OpenGL flicker bug

Posted: Mon Feb 11, 2019 4:57 pm
by Duion
With OpenGL rendering there is a flicker bug, that sometimes appears, I don't know exactly when, but it happens when displaying the NavMesh and in some scenes with heavy load I think.

Here is the NavMesh flicker example video, first normal scene, then switching on NavMesh render, flicker appears, then disabled NavMesh view and everything is normal:

https://duion.com/files/temp/bugs/openG ... avmesh.mp4

And here a flicker happening in a normal ingame scene, it happens on very few levels, this is a very big scene with lots of forest and groundCover elements, the flicker only happens sometimes, so sometimes you can launch the game and play the level fine, another time it has heavy flickering. When I decreased mesh render quality in graphic settings I could make it stop through that, my mesh render quality settings reduce the number of groundcover objects, maybe that is a hint, that it happens when there are too many objects or polygons to render, like the NavMesh that adds a lot of overhead:

https://duion.com/files/temp/bugs/openGL-flickerbug.mp4

Also you may notice the recordings in OpenGL are somehow upside down and mirrored in some way and I have no idea why, they were recorded with OBS and it normally works fine, but this only happens in OpenGL as well, maybe another bug.

I would suggest to replicate it with the NavMesh method, which is pretty reliable, the other thing happens very rarely. The issue exists for quite a while now and with multiple versions, but I ignored it so far, since I thought it was just something with the NavMesh display and maybe it is, but maybe those issues are related.

Re: OpenGL flicker bug

Posted: Fri Feb 15, 2019 6:29 am
by Jason Campbell
The navmesh has always looked like that for me also, plus I cant create a navmesh over 256x256. Always fails.

Re: OpenGL flicker bug

Posted: Sun Feb 17, 2019 2:02 am
by JeffR
I did some testing on this, and while I wasn't able to get it to completely explode, I did get a few frames of poly-explosions when I had a lot of stuff on screen and built a large navmesh(or deleted a lot of objects with a large navmesh)

Mango in discord suspected that the massive changes in vertex buffers are causing hangups in the drivers, and I'd suspect something similar. We'll have to keep testing stuff to figure out exactly where it's wigging out, because it definitely stems out of the rendering of navmesh, but beyond that it gets fuzzy.