Spectrum Computing

I’m a bit of an emulator noob, so I was hoping for some help on how snapshots work.

I have Fuse for MacOS on my MacMini with an M1 chip. I want to practice a particular level of R-Type. I play up to that stage, and just before it starts, I save a snapshot. When I load the snapshot, sure enough the level starts where I left off but my joystick input is no longer read. I checked the settings, but they are fine. This happens every single time. I restart the game from the beginning, and my joystick suddenly works again! It’s frustrating.

Is this a bug, or am I doing something wrong?

Also, I have read of some people using “rollbacks”. I researched this from past posts in this forum, but it seems this feature isn’t in Fuse for MacOS. Can someone confirm this or please help me to utilize this function? As the other post says, it’s not obvious where this feature is to be found.

Finally, can anyone please point me to an emulator that does have this rollback feature?

Thanks!

What format do you save the snapshots in? Some snapshot types also save particular hardware config settings.

Out of the supported formats by Fuse (sna, z80, szx) the latter is the newest format, and I would expect that to work best.
Otherwise try snapshots in z80 format.

Rollback is not supported in Fuse. AFAIK there is no Spectrum emulator on macOS that supports this feature.

GRC7800 wrote: ↑Tue Feb 27, 2024 5:30 am When I load the snapshot, sure enough the level starts where I left off but my joystick input is no longer read.

FUSE's configuration is quite complex, but most likely you are looking for "--joystick-prompt" also available via Options -> General... -> Snap joystick prompt. This is necessary because unless FUSE's configuration matches exactly what snapshot was configured for, FUSE will silently skip joystick setup. Note: not all details of the FUSE's config are persisted even in SZX files. However, even z80 + --joystick-prompt should be enough to re-connect everything properly in most cases. But, as PQR mentioned already, SZX is much better for "internal" use, when you only plan on loading snapshot in exactly the same emulator.

"Rollbacks" are part of the RZX recording. When RZX recording is going on (and you have "Always embed snapshot" enabled, which is the default), you should be able to use File -> Recording -> Rollback. I doubt it's completely missing on MacOS. Perhaps just quite hard to figure out.

Thanks, @PQR and @jamesh !

I'll give these tips a go. I appreciate the help!

Sadly, these weren’t the solutions. Turns out that .szx files are default. As are the joystick settings for snapshots. I’ll keep fiddling with it, but in case anyone else has some suggestions, I’m all ears.

Interesting, I do not think there is any Mac-specific code involved. Just tried it yesterday on Linux. For me it is enough to start snapshot with Or explicitly connect the joystick with Of course, the same can be configured using Options -> Joysticks -> Joystick 1... and choosing Kempston there.

GRC7800 wrote: ↑Tue Feb 27, 2024 10:41 pm Sadly, these weren’t the solutions. Turns out that .szx files are default. As are the joystick settings for snapshots. I’ll keep fiddling with it, but in case anyone else has some suggestions, I’m all ears.

I believe this was fixed in the new v1.6.0 version as it has this in the release note

Fix activation of joystick and IF2 peripherals when loading a snapshot

The Mac port by Fredrick Meunier is still on the older v1.5.6 so you are going to have to compile from source to get this to work. I've done this and it works fine and in fact I find it better as you can do some things which aren't possible on Fredrick's port like view memory while in the debugger. You can get the source here https://fuse-emulator.sourceforge.net/#Source

PM if you need help compiling it.

TomD

Oh, that explains everything. 1.5.6 is not even the latest in the 1.5.x series.

TomD wrote: ↑Wed Feb 28, 2024 10:30 am I believe this was fixed in the new v1.6.0 version as it has this in the release note



The Mac port by Fredrick Meunier is still on the older v1.5.6 so you are going to have to compile from source to get this to work. I've done this and it works fine and in fact I find it better as you can do some things which aren't possible on Fredrick's port like view memory while in the debugger. You can get the source here https://fuse-emulator.sourceforge.net/#Source

PM if you need help compiling it.

TomD

This does look to be it! Thanks for clearing it up! I'll give it a go tonight, but I might take you up on help with the compilation process.