libretro core graphical glitches with OpenGL driver

[ner00]

Game or games this happens in

ULUS-10277 - Castlevania - The Dracula X Chronicles
ULES-00910 - SEGA Rally
ULUS-10246 - Virtua Tennis 3

What area of the game / PPSSPP

Just in-game, generally, when using gl or glcore drivers - D3D11 works fine.

A few screenshots demonstrating the issue:

What should happen

Not have graphical glitches or crash.

Logs

No response

Platform

libretro / Retroarch

Mobile phone model or graphics card

Intel UHD Graphics 630

PPSSPP version affected

v1.13.3-80-g59f3d4b

Last working version

74f08be

Graphics backend (3D API)

OpenGL / GLES

Checklist

• Test in the latest git build in case it's already fixed.
• Search for other reports of the same issue.
• Try resetting settings or older versions and include if the issue is related.
• Try without any cheats and without loading any save states.
• Include logs or screenshots of issue.

[BParks21]

The same thing happens in the standalone ppsspp with opengl. Just tested it. Not exclusive to libretro. Happens with Vulkan as well in standalone. D3D11 is fine.

[unknownbrackets]

A bunch of games being broken in almost all backends since April (74f08be) and including in the latest stable release (v1.12.3) seems a bit surprising, especially because I haven't seen such widespread issues. Is the a more recent working commit?

Could you try exporting a GE frame dump? These help a lot. Just make sure to export it when you see the issue - it's almost like a screenshot. If you make it while the issue isn't happening, it won't help.

See here for instructions - it's not hard and works on Android too:
https://github.com/hrydgard/ppsspp/wiki/How-to-create-a-frame-dump

You can zip that and then drag and drop it into a reply here.

-[Unknown]

[BParks21]

Here ya go. Hope I did it correctly. In the process of doing this I discovered that these graphical bugs are only occurring when I go Fullscreen. They go away when I enter windowed mode.
Edit: Ok actually the graphical bugs are reduced not eliminated in windowed mode.
recording.zip
.

[unknownbrackets]

Alright, so I can reproduce at least this Castlevania issue, but only in OpenGL.

Here's a PSP rendering:

Here's our software rendering, pretty close but it's calculating something brighter and there's a black line at the bottom:

Here's Vulkan on an Intel UHD Graphics 630 (no black space on right because this is a screenshot):

However, GLES indeed looks wrong:

That said, this problem at least is not since April or anything, but is only since #14833. There was some expectation that there might be issues after that merge, although we'll need to check more. I've personally see some issues that seem like NVIDIA driver glitches in one other game, but need to update my driver one step.

I think it's unlikely that culling would cause the issue in the Virtua Tennis screenshot, so that needs its own GE frame dump.

-[Unknown]

[BParks21]

Well this is definitely effecting opengl and vulkan for me. The graphical glitches look identical with both. I'm using an Nvidia 1080ti. They also look like the screenshots the original poster provided.

[unknownbrackets]

Here's another frame dump from a game I'm seeing an NVIDIA driver glitch with:
https://cdn.discordapp.com/attachments/478294170662862852/900898289443033158/14833_ULUS10144_loh5_guardband.ppdmp

Other people on discord with the latest NVIDIA driver reported not seeing any issues with the dump (for me, it's very obvious, there are black missing triangles in the sky.)

This issue seems to be behaving the same way. Just stepping through the frame is enough to prevent the issue and it depends how far into the frame I step (no matter whether things are flushing to the GPU or not), which may imply it's fixed by having the GE debugger preview GL instance state.

Do you see the same glitch in that frame dump? You just have to open the file in PPSSPP, as if it were a game.

-[Unknown]

[BParks21]

It looks exactly the same when I open the frame dump. If I take a screenshot with Windows key and Prtsc key it looks normal. This is what I'm seeing, except it's flickering. Took this one with f12

[unknownbrackets]

Sorry I meant the other frame dump I linked to, which is from Legend of Heroes: Cagesong of the Ocean.

https://cdn.discordapp.com/attachments/478294170662862852/900898289443033158/14833_ULUS10144_loh5_guardband.ppdmp

Interesting also that your missing things are different from my missing things on NVIDIA GL.

-[Unknown]

[BParks21]

The first one is with vulkan the second is with opengl.

[BParks21]

They look normal in windowed mode.

[ner00]

That said, this problem at least is not since April or anything, but is only since #14833.

The previous working version of PPSSPP that I had was from April, I had no other backup in-between, and I was under the assumption that this was an exclusive libretro issue, otherwise I would have downloaded an older version from the site.

On that last note, I was unable to get any kind of graphical glitch with any of the 3 games mentioned when running standalone PPSSPP v1.12.3, under Win10 x64, Intel UHD 630 - not even with OpenGL so I'm very confused at this point why I'm not experiencing the issue with the standalone as you are.

[unknownbrackets]

I think it's a driver glitch, so the specifics of when you do and don't experience it aren't so simple. For example, I found if I increase the render resolution to 8x AND fast forward, I can reproduce on Vulkan. It's very strange.

Not everyone is experiencing this on NVIDIA, apparently, which is stranger still.

-[Unknown]

[BParks21]

I'm like 1 or 2 drivers behind on the Nvidia side. I haven't updated because the Yuzu team reported that the latest driver is causing graphics issues for them. So I can't win if I hop onto the latest lol.

[hrydgard]

#15058 might have fixed this, uninitialized values could end up in cull distance.

[hrydgard]

Turns out #15058 indeed fixed this problem on Vulkan but on Discord there was an OpenGL crash reported still existing on Intel Xe:

 stuken: xbrz texture scaling is breaking it
 stuken: thinking that its not the cull changes, but the texture one just before
 stuken: yup happening on build 97

[unknownbrackets]

Is that specific to libretro or is that proper PPSSPP?

-[Unknown]

[hrydgard]

Sounded libretro-specific, not sure why. Haven't tested myself yet

[BParks21]

Seems fixed in standalone and libretro for me. Not sure about crashes.

[unknownbrackets]

#15109 improved texture scaling on Mali, is it possible it fixed this issue too?

It seems like there haven't been many reports of issues like this recently.

-[Unknown]

[unknownbrackets]

There haven't been any new reports of the OpenGL crash or any comments since my last comment, so I'm going to close this. The primary issue was definitely fixed.

If you have more information or can confirm it still happens in the latest git builds, please reply to this issue and it'll be reopened. If you have a new issue with the same game, just create a new issue instead.

-[Unknown]