GSdx software bug: Xenosaga Episode I NTSC Black screen/box covering during a certain grayscale cutscene

[BlackTelomeres]

PCSX2 1.2.1 (r5875)
GSDX32-avx-r5875
Both DirectX9 and DirectX11
Both Hardware Mode and Software Mode but presents slightly differently depending on the resolution you've got the game at in HW mode.

Happens on any plugin configurations I tried and I've heard people mention it before so it probably goes for many/all(?) versions.

When Shion needs to go to sleep in her room to progress the story around an hour or so into the game on the Woglinde (right before the Gnosis come), a "dream" cutscene plays behind a large black box covering either the entire screen or the upper left corner if you increased the resolution sufficiently in HW mode. In SW mode it just covers it all since SW mode uses native resolution.

On the original hardware this cutscene was displayed in grayscale, but in PCSX2's emulation of it, when you see behind the black box by increasing the resolution in HW mode, it is shown in color, which leads me to think it has something to do with an error when trying to apply that grayscale effect.

There are other cutscenes like this in the game so while I haven't gotten to them yet I assume the same issue will probably affect them as well.

The first included image shows what it looks like if you increase the resolution while the cutscene is playing. Obviously if you have it at native resolution there'd be nothing to see--just a black screen, but you can hear things going on in the background so you'll know you're missing something.

The second included image shows what it looks like at the same spot on the original PS2 hardware.

[bositman]

Can you provide a memory card save close to the point of a dream scene?

[BlackTelomeres]

Here you go:

http://www71.zippyshare.com/v/77351189/file.html

Just rest at the bed in the same room the save loads from. There will be a scene with Shion lying down on it and then the screen will black out for the length of the following cutscene. The surest way to see the cutscene with the black box over the top left instead of just a black screen is, if you're in hardware mode and at a resolution higher than native, to hit F9 twice in order to swap into software mode and then back into hardware mode.

[gigaherz]

Sounds like the game may be trying to do the grayscale as post-processing, and then render the result on top (in the black box, but failing to do so. May be wrong though ;P

[bositman]

Confirmed with the NTSC version (SLUS 20469)
My findings are the same, if native resolution or software mode is used, you get a black screen with no way to get an actual display.
If you use some scaling, you still get a black screen, unless you pause/resume emulation or switch from HW to SW mode twice (I guess some framebuffer gets cleared). After you do that, you see the display posted in the first screenshot above.
Tested various GSdx hacks with no effect. ZeroGS also gives a black screen.
Here is a video on how it's supposed to look like: http://youtu.be/IAahuQEyJIo?t=9m31s

[ramapcsx2]

Yea, I looked into this years ago when I ran into it myself :p
The problem is probably texture invalidation or another "popular" GSdx issue.
The fact it also happens in software mode makes it interesting.

[gigaherz]

Hmm I was going to give this a GSDX label but then I thought it could possibly be VU/VIF/GIF so I removed it again ;P

[ramapcsx2]

It can have a GSdx label, just so we check this, should there ever be a GSdx fix ;)

[ramapcsx2]

A forum thread brought this up and thinking about it, this looks like:

• wrong framebuffer used for display
• framebuffer correct but offset wrong (there's many places this could happen)
• far shot, but gsdx could be using the wrong analog output unit (those 2 "CRT" ones)

[bositman]

Still active even with the new software renderer fixes from 42f5159

[gregory38]

I pushed some SW renderer fixes on latest git. Potentially I fix this issue as a side effect :). If not, a gs dump would be nice.

[bositman]

Doesn't seem to fix it. SW is completely black, HW is missing the mist effect and has a black square at the top left, but only after you switch to SW and back to HW again (else it's black as well) :P
Here's a dump: http://bositman.pcsx2.net/dumps/xenosaga_dream_sequence_black.rar

[gregory38]

I think there is something wrong in the merge of 2 display. (note on the HW renderer size is likely wrong). Here a screenshot with the alpha value divided by 2. Could you tell me if the top left corner color is correct or too dark.

[gregory38]

Ok, the game uses the loopback write capability of the GS. Which isn't emulated yet.

By the way, are they any game that also suffer of this kind of corner scaling bug?

[ramapcsx2]

Devil May Cry:
http://i.imgur.com/19RAfP0.png

[FlatOutPS2]

Devil May Cry:

Here's the related issue:
#694

[gregory38]

So yeah, the game just do a color => luminance conversion. I will implement it on openGL first. SW won't be too difficult (but SSE/AVX is slower to code)

[bositman]

It's supposed to be black and white as seen here: http://youtu.be/IAahuQEyJIo?t=9m31s

[gregory38]

@bositman thank for the confirmation. It will be fixed before Monday ;)

[bositman]

Wow I remember the time when we were like "omg this might get fixed one day if we find what's wrong and the planets align" :P You've reached guru level on GSdx ;)

[gregory38]

I need to double check the math, but I think I'm close of the result (a bit too light)

I will try to spot the upscaling bug first.

[gregory38]

Branch for the HW renderer:
https://github.com/PCSX2/pcsx2/tree/greg/feedback-write

I will give a look at SW renderer before the PR. But it is more complex than expected (and will suck the perf). So maybe I won't do it.

[gregory38]

See PR #1614 and right on time :p

[jcdenton2k]

Small thing. Would it be possible to make this an option in the UI?

Like 'render grayscale as either grayscale or color'? Just a thought.

Also related issue:
http://wiki.pcsx2.net/index.php/Blood_Will_Tell

That game has a similar grayscale (and later sepia) post-processing effect during specific sequences. On original hardware it even pops up a tutorial explicitly telling the player the game is in grayscale because of the story and not to adjust their TV. Thought it was a nice touch ;)

If this issue gets 'fixed' I'll rip my ISO from the disc again (gotta dig it out) and test it if needed.

[gregory38]

You must be kidding right.

Blood will tell uses a channel shuffle effect to remove the color (done with special texturing). Whereas Xenosage does a YUV conversion with the display converter.

Those games use those effect to improve the immersion why do you want to remove it. We already have enough option.

[jcdenton2k]

I just thought it would be interesting. An enhancement, if you will. Like how we upscale games to make them look better than on original hardware.
It was just a suggestion. The important thing is to implement the correct 'accurate' behavior so that the game plays as intended.

[gregory38]

@jcdenton2k
I prefer the game is grayscale so no.

[Delliser]

Hello,

Not-really-tech-savvy-person here. I understand, reading the conversation, this bug's resolved. Nonetheless, downloading a new pcsx2 build from the official website does not work (i assume the bugfix isn't in the public release yet.
Downloading the last developer version nets me a "savestate corrupted" error, while trying to load the savestate I made during the cutscene.
What I'm doing wrong, and how can I fix it?

Sincerest apologies for asking this here. I understand this would be better asked by pm, but I can't seem to find a PM function on this site.

[FlatOutPS2]

@Delliser This hasn't been fixed for the Direct3D Hardware renderers. You might need to change renderer.
Savestates made in older PCSX2 versions are not always compatible with new versions. So you'll need to use regular memory card savegames.

[Delliser]

@FlatOutPS2 Thanks for your prompt response. I've tried both direct3d and opengl, hardware and software, to no avail. Maybe I just overlooked one of them, I'll try again. Unfortunately this game suffers from a problem which boots you to bios when using some specific save points, so I haven't got a memory card save near the bug occurrance point. I'll retry later, in the next part of the game where a dream sequence comes up, with both dev pcsx2 and regular one, so as to see if it works for me or I need to do something more.

[Delliser]

I confirm the fix. Played with the dev version, the second dream cutscene (which I assume uses the same graphical functionality) works correctly. Do not remember if I've used OpenGL hardware or software, but it worked.

[trostboot]

@gregory38 Is this intended to still be broken on the D3D software renderers? It works on OGL HW and SW, but why is there a difference in SW renderers between D3D and OGL?

[gregory38]

It is not intended but it is expected. SW renderer doesn't do all the rendering on the CPU. The basic present/merge/interlace/post-processing drawing are done on the GPU. The improvement were done on the merge part hence only in openGL.