Need help with Stella and the DPC+ Jitter issue

[+SpiceWare]

We're trying to get a handle on the screen jitter issue that can occur in some DPC+ games if the Fractional Data Fetcher Increments are not reset on every frame.  There's a number of versions of the DPC+ driver floating around, some of them exhibit jitter while some of them do not.  Stella also selectively emulates the jitter issue, but is not aware of all the versions of the driver so whether a given ROM jitters or not in Stella may not match what's seen on real hardware.

 

To that end I've written a script file that'll find all the unique DPC+ driver versions when provided a set of ROMs.  So far I've found 4 DPC+ driver versions. What I need now is more DPC+ games to see if I can find any other versions so we can make Stella emulate them correctly.  Please add ROMs or links to DPC+ games in this topic.

 

 

 

 

If you're curious about this issue you can run these versions of Doom Patrol that have been merged with the 4 DPC+ drivers I've found so far. The hexadecimal numbers in the filenames are the MD5 value of the DPC+ driver used in that ROM.  If you'd like more info about this check my recent blog entry (and the comments) DPC+ Jitter.

 

This one jitters on real hardware, and in Stella

DP_17884ec14f9b1d06fe8d617a1fbdcf47.bin

 

 

This one is stable on real hardware, incorrectly jitters in Stella.

DP_5f80b5a5adbe483addc3f6e6f1b472f8.bin

 

 

This one is stable on real hardware, and in Stella.

This DPC+ driver is also NOT compatible with the Harmony Encore, the other 3 are.

DP_8dd73b44fd11c488326ce507cbeb19d1.bin

 

 

This one jitters on real hardware, and in Stella.

DP_b328dbdf787400c0f0e2b88b425872a5.bin

[Omegamatrix]

Honestly, I'm surprised you found four versions. The first two must have been from the real early days of development?

[+SpiceWare]

Most likely.  Hope to eventually narrow down dates for each version I find.