Emulator Issues #6630
closed
Real XFB (and efb2ram?) distortion on OpenGL and DX11 backends.
0%
Description
Easiest to explain this defect with some screenshots (from the opengl backend)
Open both of these in separate tabs and switch between them.
No XFB: http://i.imgur.com/xyYboBK.png
Real XFB: http://i.imgur.com/QPjK0Pj.png
Apart from Real XFB looking just looking worse in general, you should see that the contents of the bottom right triangle are offset to the left by a pixel or so.
DirectX 11 has similar problems, but they aren't as bad as OpenGL (possibly only 0.5 pixels off)
We had a discussion on IRC and both neoBrain and degasus have noticed this, yet have been too lazy to file a bug report, so I've CCed them. According to degasus, efb2ram is affected too.
Looks like this problem is a regression since 3.5, oh and DX9 works fine.
Updated by phire about 11 years ago
I'm guessing either the UV coordinates or XV coordinates of the rectangle are broken.
Updated by nigel.harris.uk about 11 years ago
Its the same issue as I found and documented here?
https://forums.dolphin-emu.org/Thread-d3d11-ogl-video-backend-iq-comparisons
Updated by phire about 11 years ago
@nigel
It's possible this bug is causing the differences between (A) and (B), but hard to tell as that screenshot is less than ideal. This bug shows up best on screenshots of text and other sharp lines.
Updated by phire about 11 years ago
Ok, I've bisected this down to revision addd3926d91d but that should only affect the opengl backend. The DX11 bug must be someone where else.
Not sure why Triangle Strips would be any different to Triangle Fans.
Degaus, it's your commit; Do you want to fix it?
Updated by degasus about 11 years ago
PhireN: If this commit change anything, then I have to fix it. Can you please upload a fifo log which is affected by this commit?
Updated by phire about 11 years ago
Sorry, dff files don't work with real xfb.
It's super easy to replicate, just open any game, choose Real XFB and flick it on and off. Screens with text or other gui elements with straight lines work the best.
The error is easiest to notice along the diagonal between the top right and bottom left corners.
Updated by phire about 11 years ago
Considering the change from Triangle Fans to Triangle strips shouldn't make a difference, it might be a driver bug.
Could someone try replicating this on Intel and AMD gpus?
I've only tested this on my Nvidia gtx 260, on both linux and windows.
Updated by skidau about 11 years ago
For me, OGL started getting this problem again as of r0255e1391244 (on a ATI HD4870). I have not seen this issue in D3D recently.
Updated by phire almost 11 years ago
- Status changed from New to Fixed
This is Fixed as of r994426b3dc0e98c0bfdec727bcb3acbef90c95ef