Issue 8317 - Messed up bloom

[TheComet]

Hey guys


A while ago I opened a bug concerning a broken bloom effect in the game "Spyro - A Hero's Tail". The game runs fine safe for this issue.

I recently decided to try and see if I could fix the bug myself. I'm a fairly experienced programmer but the project is overwhelming to take in.

Can someone take a look at this and tell me where I should be looking in the code? If you can give me some hints or theories as to what's causing this that would also help a lot.

FIFO Log

(extension is actually dff.tar.xz, I had to add .bmp so the forums could accept)
(unzip with 7zip or if you're on a *nix based system, tar --xz -xf <file>)


  spyro-a-heros-tail-swamp.dff.tar.xz.bmp (Size: 428.91 KB / Downloads: 207)

Bug Report

The filed bug can be found here: https://bugs.dolphin-emu.org/issues/8317

Video

Here is a video of the bug in action:

https://www.youtube.com/watch?v=spBwTw5AyuA

Screenshots

Here's a screenshot of the issue, notice the smear on the fairy's wings:



apitrace of fifo log replay

I ran an apitrace of the game (using the GL backend) and found some interesting results. The scene I traced can be seen here:



The bug appears during the second downsampling pass of the "glow mask" (these images were scaled up with GIMP):

Initial mask (texture size: 160x122)


First pass (texture size: 80x56)


Second pass (texture size: 40x28)


(If anyone wants the .trace file I can upload it.)

See the result from the second pass? It's all smeared. This should not be happening and this is the cause of the smears seen in the video.

Any ideas what's causing this and where I should be looking?