Ppsspp: Prince of Persia Revelations graphics bugs.

[blackman91]

What happens?

See those squares with default settings:

What should happen?

Not that

What hardware, operating system, and PPSSPP version? On desktop, GPU matters for graphical issues.

Android 7, latest ppsspp dev, happens in both gl and vulkan.

[marosis]

Is this problem without HW transforming? Is this bug in older builds? If not, can you find build where it started?

[leopard20]

@marosis Actually, It's always been like this! (I remember this since 1.2 or sth) It only goes away if you check "disable slower effects".

If I'm right, those squares are actually some kind of "overlay blending shaders" (I don't know the actual term in computer graphics!). They are blended with the rendered image to produce some kind of post-processing effect (such as shining textures or some kind of pseudo-ambient-occlusion or a simple screen filter). It appears they are not upscaled correctly in this game.

@hrydgard Do you know what the actual name of this technique is?!

[hrydgard]

Not sure exactly what trick they're trying to do in this game, hard to say...

[unknownbrackets]

I'm guessing it's probably some stencil/RGBA mask/logic op issue? I feel like there may be another issue about this... maybe.

-[Unknown]

[Gamemulatorer]

look similar issue #10977 but different games

[leopard20]

Actually, I think it's another manifestation of the same issue!

[weihuoya]

it's like a depal issue. there is a GE_TFMT_CLUT16 format entry to ApplyTextureFramebuffer, gstate.getClutPaletteFormat() return GE_CMODE_16BIT_ABGR4444, and I change it to GE_CMODE_16BIT_BGR5650 in code, then squares disappeared. (or depal failed)

may help for this issue. :pensive:

[leopard20]

@hrydgard This is more or less a duplicate of https://github.com/hrydgard/ppsspp/issues/6423.

[hrydgard]

@weihuoya , that's really interesting, thanks for reporting that.

[hrydgard]

Duplicate of #6423