Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
08287 Graphics Major Always Apr 7, 2022, 03:44 Sep 23, 2022, 23:25
Tester Yonah View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10/11 (64-bit)
Status [?] Acknowledged Driver
Version 0.242 Fixed in Version Build 64-bit
Fixed in Git Commit Github Pull Request #
Summary MESS-specific 08287: a2600: Frames are being blended together
Description Every frame appears to be blended with the previous frame, similar to the effect of using motion blur. HLSL is not enabled. See included animation taken from E.T.
Steps To Reproduce Use SHIFT+P to observe frame by frame.
Additional Information
Github Commit
Regression Version
Affected Sets / Systems a2600
Attached Files
gif file icon a2600-Frames.gif (38,221 bytes) Apr 7, 2022, 03:44 Uploaded by Yonah
There are no relationship linked to this issue.
User avatar
Apr 7, 2022, 07:38
edited on: Apr 7, 2022, 07:41
A VCS2600 is intrinsically flickery. Some games have sprites flashing up only every 2nd or 3rd frame (often varying by visible sprite count on screen), other use homemade interlace tricks (drawing sprites every 2nd scanline either alternatingly or omitting always even or odd scanlines) etc. Not even the framerates are stable because it has no framebuffer and everything is very software-defined (bitbanging/cycle counting without IRQ), so screen output is almost as flexible as a vector display. I.e. playing at reduced framerate (showing only every 2nd or 3rd frame) may make certain sprites sporadically invisible, which would disturb gameplay very much. Also digitizing the stuff for youtube often makes such trouble.

Therefore the blur was likely added to mitigate such nuisance, but it definitely needs an option to turn it off.
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Apr 7, 2022, 18:17
Shouldn't this stuff be handled by the shaders? Or did the original hardware not display any of that flickering?
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Apr 15, 2022, 18:45
I'm pretty sure it was implemented to be this way always.
Should it be changed or can it be easily adjusted? Hard to say.
I'll acknowledge for now.
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Sep 23, 2022, 18:43
Just wanted to point out that this also happens in 2600p (its PAL clone) and in 2600_pop (which is not listed as a clone).

I couldn't find any other driver that does this additional blur, which is now redundant with the phosphor decay options in the current shaders (and collides with them since it can't be turned off).
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Senior Tester
Sep 23, 2022, 23:25
The Game Gear driver does similar, but yeah, it should really just be post-process at this point.