Tactics Ogre displays some weird tile effects at one point during startup

DaveTCode commented 2 years ago

Only appears for a short while and it's not clear what it means

DaveTCode commented 2 years ago

Mode 2 with all backgrounds enabled and window 0 enabled.

Background 0 is the map
Background 1 is all backdrop
Background 2 is a weird effect and has transforms enabled
Background 3 is the bad effect shown on top of my image and has no transforms enabled but is affine at 128*128

Window 0 is probably the round circle in the middle with effects applied and has WINOUT enabling all but BG2.

So the effect on the center circle is a round window (probably done using hblank effects) which enabled BG2 and alpha blending whereas BG2 is disabled outside the window.

None of that explains why BG3 is showing on my image but on the game properly.

According to me BG3 has priority 1 and BG0 has priority 3 so BG3 should appear over BG0. Maybe this is getting changed during the frame?

DaveTCode commented 2 years ago

I logged out the values of WINOUT, BG3CNT and DISPCNT each time they changed during a frame and got:

DISPCNT updated 3F80 160,157
DISPCNT+1 updated 0080 160,157
BG3CNT updated 2A39 162,1035
BG3CNT+1 updated 2A39 162,1035
WINOUT updated 003B 162,1095
WINOUT+1 updated 003B 162,1095
DISPCNT updated 0041 170,343
DISPCNT+1 updated 3F41 170,343

That is, WINOUT & BG3CNT stay the same the whole time but DISPCNT does get changed twice during VBLANK. From what I see of that it will be 3F41 during the on screen time.

Oh ffs, mode 1 doesn't use background 3 does it! Well that's an easy enough fix I guess

DaveTCode / GBADotnet

Tactics Ogre displays some weird tile effects at one point during startup #27