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it's probably the same problem as Super Ghouls and Ghost


EDIT: my first guess about Mode 7 was wrong. however, I'll see tomorrow if I can update MESS to use newer findings by Anomie. Good night.

It is the same problem of Super Ghouls 'n Ghosts, a.k.a. wrong HIRQ timing that doesn't enable the HDMA in time.

Umihara: fixed.

Mystic Quest: lines fixed. Text still wrong (in battle, damage to player is incorrect)

Madara 2: the break in the text isn't gone, just "so low it shows up much less"

Strike Gunner: additional bug when the first boss flies past you. The shadow looks "just plain awful", and it definitely shouldn't.

The Flintstones - Treasure of the Sierra Madrock shows a sprite glitch in the attract sequence. (also demonstrates two other MESS issues: it doesn't start identically in fast forward mode, and if it locks up because of fast forward, a reset will not fix it!)

Super Bases Loaded 2 does not start (226 partial updates??)

Ys 3 also suffers from Mode 7 having too many bits of precision in the formula.

Super Robot Wars EX locks up in combat. Snes9x had this issue and it amounts to "improper TIMEUP emulation"

Top Gear 2 cannot get in game, which makes me depressed. (However, the music works!)

EDIT: ok, I can't follow the draw code at all, but is Mode 4 even using offset-per-tile? If you use the standard variation used by 2 and 6, it won't work (can only scroll in one direction per tile in Mode 4), but that would "definitely" break Puzzle Bobble.

you asked for it, you got it: Mode 7 correct math implemented




more comparison shots here: http://mamedev.emulab.it/etabeta/?p=102

I'd like to review a bit more the whole mode 7 routines, and then I'll commit the fix


EDIT: there is no offset-per-tile implementation so far... I'm looking into it, but it could take some time.

Then Puzzle Bobble is screwed for cause.
Let me see if my screen-at-a-time renderer has an exact implementation.

The one quirk I can point out for sure is that it's not instantaneous, so the first opt offsets apply to the SECOND tile of the line. The reason is that the tilemap fetches are understood to occur consecutively during caching, allowing too little time for the offsets to be applied.

anyway, Mode 4 is a single 16-bit value. $8000 is the H/V flag (believe set is V). (aside from Mode 7, all PPU accesses are 16-bit, if that helps).

And sweet work to Kale and etabeta78. You guys are making a couple hours spent reviewing old emulator change logs looking for familiar bugs a very worthwhile undertaking!

thanks for info. they coincide with both anomie's docs and byuu's code.

the main problem is to exactly understand exactly how offsets are used to determine tiles in MESS (last night I was not able to get the logic behind them, but I was really tired... I hope I overlooked something obvious)

It alters where you fetch the (BG1?) tilemap data from. Essentially, it's added like a scroll value, iirc.

Unfortunately, my sources aren't complete enough to just glance at and tell exactly what I expect (and it has seriously shoddy interrupt logic because I can't find byuu's definitive interrupt specifications)

F1 Roc 2 - Race of Champions doesn't allow the player to write to the nvram (?)
F1 Grand Prix Part 3 has heavy video artifacts on the course presentation screens, it is bugged on zsnes and snes9x too, my guess is that it does a pretty fancy thing with color window effects and the h/v beam positions.
(Gameplay is broken too, but I guess that etabeta fixes will fix that?)

how annoying is mode 7 precision... we gained the road on the title screen of SCHQ and we lost the red car in the "game start" screen...

I'm trying to find which exact bit caused the regression. if I cannot find it soon, I will commit the changes as they are and we will investigate the disappeared car later

EDIT: added changes to svn. next thing I'll try: MOSAIC (at least for Mode 7 )

EDIT2: it seems that I actually screwed out Super Chase HQ (ingame road is broken). later tonight I'll go back to fix it. sorry for the inconvenience....

Road gfxs are also still broken in F-1 Grand Prix Part 3...

Anyway...

r5374 /src/mame/machine/snes.c: SNES: Make the unsupported reads on i/o open bus, fixes (at least) a layer enable in Super Kick Boxing







Technical explaination: uses mode 2, one layer and sprites only and it reads from the TM (bg enable) register. Since it's actually an open bus register that isn't very good for business.