Question about Clamping Mode and Round Mode

[karasuhebi]

Hey there! I was wondering if someone could tell me exactly what the different options for Clamping Mode and Round Mode in EE/IOP and VU mean and what they do. The reason I ask is because I'm very curious as to how people figured out that by playing with those settings they could fix issues in certain games. This knowledge could possibly help me with issues I may run into with other games in the future.

Also, what kind of problems could changing Clamping Mode options cause? For example, I know that changing the EE/IOP clamping to 'Full' and the VU clamping to 'Extra + Preserve Sign' fixes the 'characters are turned the wrong way in battle' problem in Final Fantasy X. Could I leave these settings like that for all my games? Or would I run into problems?

Same question goes for the Round Mode options. What kind of problems could that cause? I read on Alexander's guide (http://forums.pcsx2.net/Thread-Alexander...or-Windows) that I could change the Round Mode to 'Negative' on both EE/IOP and VU to fix the FFX issue, so if changing Clamping Mode options could mess with my games, I'd be inclined to trying this instead.


Also if I'm allowed a bonus question, why does PCSX2 create a cheats_ws folder? If PCSX2 can run the widescreen hacks from the included cheats_ws.zip, why make a cheats_ws folder?

Thank you so much!

P.S. The 'characters are turned the wrong way in battle' problem is not listed under "Known Issues" in the wiki page for Final Fantasy X. Should I add it on there along with the suggested fixes? Or is it not really a widespread problem?

______________EDIT______________
I did some more testing on FFX (made a save state seconds before the battle with Geosgaeno starts) and it turns out that you don't need to mess with Clamping Mode or Round Mode for the VUs. That doesn't actually do anything at all to fix the issue. All you need to mess with is the Clamping Mode or Round Mode for EE/IOP. Hope this helps narrow down this bug!

The forum won't let me attach the save state (it's 15MB) so here's a Dropbox link to it:
https://dl.dropboxusercontent.com/u/6425...%29.00.p2s
This is for SLUS-20312, AKA the NTSC-U FFX.
________________________________

[Blyss Sarania]

Questions:

Rounding and clamping have to do with the way PCSX2 converts PS2 style floating point numbers to PC style floating point numbers. There was a good explanation made by one of the devs, but I can't seem to find it at the moment. As for problems, they should be left at default unless they are needed to fix something. However, when I played FFX international, there were 0 issues caused by the alternate settings and I left them on about 75% of the game.

Wiki: Add it if you like.

Cheats_WS: Because a user might have got some patches from somewhere else, or created their own.

As for fixing the problem in FFX: http://forums.pcsx2.net/Thread-About-the...eindex-dbf

[Nobbs66]

here is the article on clamping written by cottonvibes.
http://pcsx2.net/developer-blog/209-what...ed-it.html

[Blyss Sarania]

That's the article I couldn't find. Thanks. +1

[Nobbs66]

You know that's the second time I've gotten a rep from you for posting that article.

[Blyss Sarania]

Haha, I didn't notice. Still it's an excellent article, and I looked for it to link in my post but couldn't find. I seriously had this thought in my head "Well, Nobbs is on, so he will post it, and then I will give him a rep."

[Nobbs66]

Yeah, I just had to look in my first page of reps.

[karasuhebi]

Thanks for the info and the links guys, much appreciated!

@Blyss Sarania: I already knew how to fix the issue (set Round Mode to 'Negative' or set the Clamping Mode to 'Full' on the EE) but it's nice to see that you're lobbying to get the fix included in gameindex.dbf. Do you think that this issue is maybe worth looking into by the dev team if the workaround doesn't get implemented into gameindex.dbf? Also, what kind of issues should I be on the lookout for if I mess with Clamping Mode and Round Mode? (My apologies if that gets explained on the blog post linked above by Nobbs66, I'm working on catching up on forum posts before jumping onto that massive read lol.)

[Blyss Sarania]

As I said, I didn't notice any issues. But possible issues are basically the same issues they fix.

And as far as my other post, we continued the discussion in IRC. Rama decided instead of using the gameindex.dbf, he wanted to try to find the root of the problem and fix it. I sent him a memory card with my save and he was able to reproduce the issue. From there, I don't know if any progress has been made or not.

[Nobbs66]

Setting clamping to none messes up the walk animation on Ratchet and Clank. Some glitches can be minor and some break the game like the example I just gave.