Emulator Issues #8044

Stair-casing (scaling artefact) since 4.0-4824

Added by fallaha56 almost 7 years ago.

% Done:


Operating system:
Issue type:
Relates to usability:
Relates to performance:
Relates to maintainability:
Regression start:
Fixed in:


Game Name

Game ID

What's the problem? Describe what went wrong in few words.
-scaling artefact has been introduced in D3D backend, whole screen 3D displays stair-casing/steep stepping, very obvious on race track in game on F-Zero

What did you expect to happen instead?
-no stair-casing/stepping

What steps will reproduce the problem?
1. select D3D backend
2. go in game 3D

Dolphin 3.5 and 3.5-367 are old versions of Dolphin that have
known issues and bugs, so don't report issues about them and test the
latest Dolphin version first.
Which versions of Dolphin did you test on?
-all recent builds, problem isolated as below

Does using an older version of Dolphin solve your issue? If yes, which
versions of Dolphin used to work?
-4.0-4824 problem present (stereoscopy update)
-4.0-4811 no problem

What are your PC specifications? (including, but not limited to: Operating
System, CPU and GPU)
-Win7x64, i7 980x, GTX970, latest drivers

Is there any other relevant information? (e.g. logs, screenshots,
configuration files)
-screenshots attached
-scaling options don't seem to help


#1 Updated by Armada almost 7 years ago

  • Status changed from New to Accepted
  • Priority set to Normal
  • Category set to gfx
  • Operating system Windows added

#3 Updated by fallaha56 almost 7 years ago

Hi. Thanks for this but bug still seems present in dirty build 4905 when testing in F-Zero

#4 Updated by fallaha56 almost 7 years ago

Hi Jules I can report that with external frame buffer set to disabled the problem is not present

Is this some kind of blitting bug from the ExtFB to the DX frame buffer?

#5 Updated by Armada almost 7 years ago

I'm not sure yet, it's either a blitting bug from the XFB to the backbuffer or from the EFB to the XFB. Does it also happen when MSAA is off?

Previous testing did indicate that it's likely a sampling bug in the copy shaders.

#6 Updated by fallaha56 almost 7 years ago

Thanks for the insights, have tested with MSAA off and almost certainly the problem is gone (lots of aliasing but the middle of textures look bilinear fine).

Have tested with EFB copies off and with copy to RAM -this doesn't fix the problem.

#7 Updated by ZephyrSurfer almost 7 years ago

Maybe compiling different commits from your PR will pin down this issue.

I could compile them and link to them with dropbox if you'd like.

#8 Updated by Armada almost 7 years ago

The issue is already pretty much pinned down, the problem is that there's no easy fix. Or at least no easy fix without impacting the performance of MSAA.

#9 Updated by fallaha56 almost 7 years ago

If the performance hit for MSAA would be so high anyway just wondering if the solution is just to use x2 internal scaling of the set resolution ie 1080p rendered at 4k and downscale? Or perhaps x1.5/2/3 etc...

I know this is kinda configurable in the .ini (or with DSR) but would be nice to have easy settings in the GUI. Plus most mid/high-end cards can handle 1.5x and upwards pretty well...

Just my 2 cents.

#10 Updated by Armada almost 7 years ago

The solution is to resolve the texture using a fixed-function before applying shaders, but that results in twice as much work. And it's just a workaround, it doesn't solve the underlying issue.

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