Emulator

Looks as though the Z buffer doesn't properly get cleared between frames.

Heyyo, the issue isn't just Adreno 506, it's the whole Adreno 5xxx series. Doing some research on it? It's not even just an Android issue. It happens on AMD GPUs for desktop as well.

https://stackoverflow.com/questions/35995198/vulkan-failing-to-clear-depth

https://community.amd.com/thread/205798

I'm no coder but it does seem like the issue should be fixed within Dolphin Emulator Vulkan implementation as I've tried ReteoArch, Vainglory Vulkan Beta, NFS No Limits and Olympus Rising and none of them suffer this bug on my Adreno 530.

Any updates on this?

If no one is gonna work on here, please let me know what function is suspicious.

I've never worked with Vulkan but I guess I could try, given the SO link.

Assuming it's what I was seeing on my Nexus 6P, pretty sure it's a driver issue, although I'm not 100% sure. Basically, clearing the buffer seems to have no effect. I doubt it's a barrier problem, because I've tried even flushing the command buffer and inserting overkill barriers and it still doesn't clear. Perhaps we're the only ones using 32-bit depth buffers, and that's the issue?

Anyway, I have a "fix" here, but it's at the cost of performance, so I never PR'ed it: https://github.com/stenzek/dolphin/commit/9c95b25da4a896c2e6d13244e62cfe2fbee40cbb
I don't have an android environment set up correctly, so if you like, you could try switching the depth buffer format. Should be in Constants.h, but there might be a few other places that need to be changed.

Yeah, changing the depth buffer format did the trick. Although I get "Panic Alert: Unhandled pixel format", it renders fine. I have changed depth buffer to "D16_UNORM", and depth as color buffer to "R16_UINT" (because UNORM was unsupported on my hardware).

It'd be great if someone made the patch for upstream and merge it.

By the way, I changed 'depth as color' only because I wasn't sure if I should change it along. I never tested with other options.

Thanks for testing and confirming the issue.

However, such a change is not going to get merged into master Dolphin. We need the 32-bit depth buffer in order to represent the depth range of the GC/Wii accurately, and having two paths here significantly complicates things. Especially as Dolphin is not at fault here, the driver is advertising support for a format which it cannot handle properly. Furthermore, it would only 'help' a single broken driver, where most devices are not capable of emulating games at full speed anyway.

IMO you would be better off making a small repro case and supplying it to Qualcomm, and hoping they fix their driver. I'm way too busy at the moment to do this, but I could potentially create one at some point as well.