GLES3: Models flicker between textured and black when per pixel lighting is enabled on materials (Intel driver bug)

[TheRektafire]

My Drive

Godot version: 3.2.3 Stable

OS/device including version: Device: HP BS212WM (intel celeron n4000, 4gb ram, intel hd 600), Windows 10 64 bit, latest gpu drivers

Issue description:

Many models that I import into godot (both my own and models from other devs/games too) seem to flicker between being textured and fully black, but also seemingly only when per pixel lighting is enabled in the material. When I enabled the "Vertex Lighting" option in the SpatialMaterial in the imported mesh the issue seems to go away. This issue doesnt seem to effect GLES2, only GLES3. Also this issue seems to be more severe in 3.1 but it still exists in 3.2.3

Steps to reproduce:

Import a model into godot and leave per pixel lighting enabled in the material settings

Minimal reproduction project:

ayylmao1.zip

[Calinou]

I can't reproduce this on 3.2.4beta2 (Linux, GeForce GTX 1080, NVIDIA 455.45):

Peek 2020-11-26 18-03

[clayjohn]

Can you provide a GPUInfo report?

Download tool here https://opengl.gpuinfo.org/download.php

Please run the tool, submit the report, and then link the report to us here.

It is very likely that this issue is driver/hardware related. So having complete information will help us.

Please also test out the assets in other engines if possible, e.g. try them in Blender and other game engines.

[TheRektafire]

Here is the GPU report https://opengl.gpuinfo.org/displayreport.php?id=5653 I made that model in that project in blender myself so i would have noticed if it happened there but it doesn't. I have had unrelated opengl issues with other programs though in the past so a driver issue is likely. For example ultimate doom builder used to have lots of issues with intel uhd cards (as you can see in the issues on the github) but I helped the devs come up with a fix that seems to have worked, for me at least

[TheRektafire]

So ive done a bit more testing and found some odd things, it seems like it will render correctly sometimes but only at specific camera angles. For example here when looking up it looks correct

whereas here its wrong

In this screenshot i set the scales material to use vertex lighting and now it works t any angle

Also when i press alt tab the textures consistently flicker on and off for a few frames even when looking at a bad angle

[Calinou]

https://github.com/godotengine/godot-proposals/issues/1609 confirmed this on the same Intel GPU generation (Intel HD 605). These are old and low-end IGPs with a very limited power budget, so forcing GLES2 on them may not be a bad idea to get playable framerates.

It'd be interesting to test 4.0.beta3 on those IGPs to see how its Vulkan Mobile and OpenGL renderer behave. (Vulkan Clustered is probably not a good idea due to its higher-end requirements.)

[TheRektafire]

Vulkan actually seems to work pretty well on it so far, performance isn't amazing obviously but that can be overcome by just lowering the resolution :) It certainly seems to work better than some other vulkan based engines I've tried like FTEQW where the vulkan backend just crashes, whereas in beta 4 I haven't had any crash issues related to vulkan yet, even when using more advanced features like SDFGI (but then the FPS really suffers with that stuff enabled...) but I haven't actually done much testing to see if this particular bug persists in the new renderer, I'll need to check with a godot 4 version of the above test scene to see. I did notice that when importing

godotengine/godot-proposals#1609 confirmed this on the same Intel GPU generation (Intel HD 605). These are old and low-end IGPs with a very limited power budget, so forcing GLES2 on them may not be a bad idea to get playable framerates.

It'd be interesting to test 4.0.beta3 on those IGPs to see how its Vulkan Mobile and OpenGL renderer behave. (Vulkan Clustered is probably not a good idea due to its higher-end requirements.)

[TheRektafire]

@Calinou so after making a similar test scene in beta 3 (I apparently don't have beta 4 downloaded rn I guess) using the Forward+ renderer I don't seem to be having the same issues, I tried with both a PhysicalSkyMaterial and ProceduralSkyMaterial both with and without sunlight and didn't see anything particularly strange this time, the physical sky without sunlight test gave me a completely black scene but I guess that's to be expected? 😂 I also added a noise texture in the "cover" slot in the procedural sky to see if that would screw things up at all and aside from the noise texture looking stretched at the top of the sky nothing bad happened so maybe the bug technically got fixed in godot 4, at least for Intel UHD 600 lol. Then again I did try importing Dam from goldeneye 64 the other day and had similar issues as to what someone else referenced in proposal 1609 with sky contribution not applying to the mesh under certain circumstances but maybe that's just an issue with the model or something since it did go through a multi program trip between the game editor to Blender (to convert to GLTF since the game editor exports the map as fbx) then to godot so maybe something got messed up along the way there because a custom made map I made in blender didn't have the same issue even when it was in the same scene, I'll need to do some more testing to figure it out...