Potential texture bug in new engine

[Bart]

This is not critical or anything -- I don't want to interrupt from the awesome work Ian and Harry are doing on fixing up the lighting model -- but I'm putting this here for future reference.

Fighting Vipers 2 may be exhibiting a texture mapping bug in the new engine. Textures are screwed up in both engines during the attract mode intro sequence due to timing issues but in-game, they ought to be fine. I noticed that the wristwatch on Emi's arm has a scrolling texture that looks different in the legacy and new engines. I'm not actually sure which is correct but the legacy engine looks more reasonable. I've uploaded a save state to: http://supermodel3.com/tmp/fvipers2.st0

At the beginning of the round, in the new engine, there is Japanese text whereas in the old engine, it's an English message. But more noticeably, there is a small portion that is black in my engine but has a perpendicular scroll in the new engine. I can't really be sure which is correct because nothing about this game's aesthetic makes any rational sense

fv2_tex_bug.jpg (363.13 KiB) Viewed 7422 times

I've drawn ugly red arrows to indicate where the glitch is.

[Ian]

Bug reports make the engine better
It's probably an issue with texture offsets or something. Arcade footage just to compare would help

[HarryTuttle]

I've just checked. In this https://youtu.be/HzpdYm6aY4Q?t=71 video (from Dreamcast) there's Japanese text. Btw I think that depends on the country set in Test menu.

In my personal build I've left "PowerPCFrequency" for all the games to 66 (my PC is not fast enough) and, just for testing, I modified in <Model3.cpp> the timings for "fvipers2" and "swtrilgya" to be like this:

Code: Select all

statusCycles = (unsigned)((float)frameCycles * 67.5f/100.0f)


This gives correct speed in both games and correct texture uploading in the intro of fvipers2, but at this point I think also affect some texture during gaming, because my wristwatch text is also in English.

UPDATE:
Another one captured from an ancient videotape from the 90s https://youtu.be/yQF5ESkj8aE?t=960, that guy has also few others videos. That's the best material I've found till now.

UPDATE #2:
The wristwatch alternates Japanese and English text, maybe that's how is intended to be.

[HarryTuttle]

English:

fv1.jpeg (248.61 KiB) Viewed 7379 times

Japanese:

fv2.jpeg (246.23 KiB) Viewed 7379 times

[Ian]

I had a quick look at this issue. I thought it could have been something like a texture offset issue, since this game uses texture offsets in the culling nodes.
However it's something even more fundamental .. just a basic texture wrap/repeat issue



The legacy one is displaying say the bottom half of the texture, and mine the top half. Not sure which is correct ...

New3D


Legacy3D

[Bart]

Note the black square that is displayed in my engine. In the new engine, there is text scrolling there as well but in the perpendicular direction.

[Ian]

Yeah i noticed the black square ..
but the first part to understanding this potential bug is to see why different parts of the texture are being used in the diff engines.
I can't imagine the scrolling texture on the top part being a bug .. that would be quite strange.