Emulator

Could we get a 3 frame fifolog of this?

https://dolphin-emu.org/docs/guides/fifo-player-documentation-testers-and-developers/

phire wrote:

Looks like it happens on all video backends including video software.

I did just about as much testing as I could with my one computer, trying out all kinds of settings, and nothing that I've tried has worked. Your confirmation just rules out the possibility of it being a GPU/CPU-specific issue (unless you have same/similar specs).

So, while drawing the Wiimote, the game sets the alpha equation to essentially:

(texture[1].a * konst[3].b) + prev.a

Texture[1] is the diffuse color of the wiimote and has a constant alpha across it. konst[3].b is 0.333 and prev.a is.... undefined.

prev wasn't written to by an earlier tev stage, so it will default to the constant color[0] which the game never sets (despite religiously setting every other constant register several hundred times a frame). System menu also doesn't set the constant color[0] to anything either so the value of this register is undefined.

Dolphin defaults all the constants to zero, so it ends up with a constant 0.333 alpha across the entire wiimote. Somehow the wii is managing to get a value that results in the wiimote not being transparent (any value between 170 and 1023 would work).

Hardware tests are needed.

Note: we aren't even 100% sure that color[0] gets transferred to prev at the start of every pixel, it's theoretically possible that it's getting the result of the previous pixel, which in the case of the wiimote would be the hand (which has an alpha of 1)

I wonder if it's an issue with my ISO. If we can contact someone else, maybe we can rule out that possibility.

It's not, just tested it on console and dolphin; both booted from the system menu.

Versions of dolphin before 4.0-9135 render the wiimote more or less correctly on the video software backend.

phire wrote:

Versions of dolphin before 4.0-9135 render the wiimote more or less correctly on the video software backend.

I found the bug on 4.0-9109...

EDIT: Oops, I thought I had tested Software Renderer, but apparently I hadn't.

Since we obviously don't want to force Software Renderer in game INI, what else might fix the problem?

Nothing. It's kind of an impossible problem for the hardware backends. Any fix would be a hack.

Confirmed via hardware test, if prev isn't set it simply takes the color of the previous pixel that was rendered.

Dolphin:

Actual Wii:

Basically impossible to emulate correctly on the hardware backends, though we can probably get it working correctly on video software.