Star Ocean: Second Evolution: map errors with Vulkan

[leoxxx]

Game or games this happens in

ULJM-05325 Star Ocean: Second Evolution

What area of the game / PPSSPP

As shown in the picture, map error in battle and world map with Vulkan in v1.15. I'm not sure if there are other map errors.

It's O.K in v1.14.

What should happen

It's O.K. with OpenGL.

Logs

No response

Platform

Android

Mobile phone model or graphics card

Helio X20 (MT6797+Mali-T880 MP4) Android Tablet

PPSSPP version affected

v1.15

Last working version

v1.14

Graphics backend (3D API)

Vulkan

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.

[hrydgard]

Interesting! Can you get a GE frame capture ?

[leoxxx]

Interesting! Can you get a GE frame capture ?

I will try it later. Now the tablet is charging.

[leoxxx]

@hrydgard
Here is the new map error dump, it's in world map.
1569474716.zip

Here is the battle map error dump.
1034509260.zip

[hrydgard]

Thank you @leoxxx, will have a look.

[hrydgard]

Both render OK on PC, gonna have to test on some phones..

Both also render fine on Mali G71 (Galaxy S8). Will try on more Malis.

[hrydgard]

Both render fine on:

• Mali G71 (Galaxy S8).
• Mali G78 (Galaxy S21).

T880 is a fairly old Mali GPU and the drivers are likely not very up to date, so I'm guessing we're hitting some depth-related driver bug. I don't think I'll be able to fix this for 1.15.1 as I might need to get a device, so re-tagging to the potential 1.15.2.

Though, there's one remaining chance to figure it out: Try various builds from https://buildbot.orphis.net/ppsspp/index.php?m=fulllist and see what change broke it. If you start by large steps and go narrower and narrower, you should be able to find what change broke it within 10-11 tries (bisection).

[leoxxx]

v1.14.4-188-g350cb55c6 It's last working version.

v1.14.4-191-g8d3a3285d No bird. Only a shadow.

v1.14.4-197-g30586be75 Map error is the same as v1.15.

v1.14.4-772-gdc7f461b—v1.14.4-790-g938230e7d All game crash when start.

And I found OpenGL also have map error.

No shadow under the bird.

Have shadow with Vulkan.

[hrydgard]

Thanks, that's useful. Can you explain what you mean by "map error"? I don't see something specifically wrong with the map, what did it look like before?

[hrydgard]

Alright, so this is definitely a case of an old GPU driver not handling even pretty simple shader code correctly, these bugs have later been fixed obviously since on newer phones this works correctly.

The two changes are:

• 191 Vertex shaders: On platforms with uniform buffers, use indexing and loop over the lights. #16787
• 197 Lighting code cleanup and optimization #16791

The first one we've previously seen similar problems with in Raspberry Pi drivers. Might try to apply the same workaround.

The second one I'm surprised makes a difference.

Can you go into Settings/Tools/System Information and check the exact Vulkan driver version and device name (take a screenshot where it's visible)?

[leoxxx]

O.K.

I marked the picture.
No shadow with OpenGL.
Have shadow with Vulkan.

[hrydgard]

Oh right, I thought you meant by "map" the overlay map on the bottom right:

Didn't see anything wrong with that. Now, I need a picture of the driver version and stuff on the System Information screen.

[leoxxx]

Alright, so this is definitely a case of an old GPU driver not handling even pretty simple shader code correctly, these bugs have later been fixed obviously since on newer phones this works correctly.

The two changes are:

• 191 Vertex shaders: On platforms with uniform buffers, use indexing and loop over the lights. #16787
• 197 Lighting code cleanup and optimization #16791

The first one we've previously seen similar problems with in Raspberry Pi drivers. Might try to apply the same workaround.

The second one I'm surprised makes a difference.

Can you go into Settings/Tools/System Information and check the exact Vulkan driver version and device name (take a screenshot where it's visible)?

#15526 (comment)
You can see them in this issue.

[hrydgard]

perfect, thanks for the link.

[hrydgard]

Alright, there should be a new build up in maybe half an hour on the buildbot with the above workaround, please test when available.

[leoxxx]

v1.15-42-gec10c73a8 It's O.K.
But still no shadow with OpenGL.

[hrydgard]

Cool, thanks for testing!

We can look into OpenGL later. Can you post your system information page the way it looks if you switch to OpenGL? (The information strings are different than in Vulkan).

[leoxxx]

[leoxxx]

@hrydgard
So, need I open a new issue?

[hrydgard]

Thanks!

Yeah, I guess that would make sense. I'm not likely to work on it for a while though.