Crash: Mind over Mutant missing visible circle in digging

[Panderner]

When I digging a hole using spinning in Crash: Mind over Mutant the visible circle is missing for Vulkan but not OpenGL.

OpenGL:

Vulkan:

GE dump:
ULUS10377_0001.ppdmp.zip

[UbiSergei]

Somewhere In Main Windiw UI:

Pixel 127..

[ghost]

PPSSSPP latest development build
Redmi Note 9 Vulkan

[ghost]

@Panderner no feedback!?

[Panderner]

Still occur in latest build. I'm using POCO M3

[ghost]

So this is adreno gpu vulkan issue only

[Panderner]

And yes it does not occur for my PC using Vulkan:

[Panderner]

This must be Adreno GPU specific

[hrydgard]

Probably yet another minor stencil/blending bug in the driver, sigh. Not sure we can do much about it.

[unknownbrackets]

The circle is drawn at 35/100 (as 90 verts for 30 TRIANGLES.) It uses:

• Depth test (ALWAYS)
• Stencil test (ALWAYS REPLACE 4C)
• Depth write disable
• Depth clamp
• No texture
• RGB masked

In other words, it should directly write 4C to stencil, and do nothing else. After that it does smaller circles that are the same: stencil=99, then stencil=e5.

After that, it uses alphablending with dst.a vs 1.0 - dst.a to draw only in the masked areas with bevel.

The Adreno bug we knew about was not being able to discard stencil when there's no depth. This bug seems different - it seems like alpha is failing to be written (maybe.) I'm also able to reproduce this issue on a Google Pixel that has the previous bug patched.

-[Unknown]

[hrydgard]

s/directly write 4C to depth/directly write 4C to stencil right? (and yeah thus also to alpha, because of how we try to keep those in sync).

A lot of bugs in this area for sure... Seems they get a little aggressive with their optimizer when they see ALWAYS ?

It should be possible to make a test for this in the GPU testing thing in developer settings...

[unknownbrackets]

Oops, yes. I agree. Luckily, this is a fairly simple frame dump and a simple draw.

-[Unknown]

[unknownbrackets]

Just an update: this is also an issue on an Adreno 620 with the latest Android updates.

-[Unknown]

[unknownbrackets]

This was also coming from the #10421 workaround, and works with the changes in #16379 (at least the frame dump.)

-[Unknown]