Change default mappings between retropad and Genesis-Plus-GX core

[fekir]

As far as I've understood, the core itself is responsible for the default mappings between retropad ad the core, if not, sorry

To the best of my knowledge, the mapping between retropad and a Sega 3 buttons controller looks like

|===
|Retropad (input) |Sega 3 buttons controller (game)
|A                |C
|B                |B
|X                |
|Y                |A
|L                |
|R                |
|Start            |Start
|Select           |
|D-Pad            |D-Pad
|Retroarch Menu   |
|===

I would like to add a new default mapping between retropad button A and Sega 3 buttons controller button A.

The main motivation is that it makes playing with a horizontal wiimote, which has a really similar layout, more practical, as all buttons (except start) are placed at the same position.

The new mapping (with an additional column for the wiimote) would look like the following

|===
|Wiimote (input)  |Retropad (input) |Sega 3 buttons controller (output)
|2                |A                |C
|1                |B                |B
|A                |X                |A (new mapping)
|B                |Y                |A
|                 |L                |
|                 |R                |
|+                |Start            |Start
|-                |Select           |
|D-Pad            |D-Pad            |D-Pad (8 directions instead of 4)
|HOME             |Retroarch Menu   |
|===

Since it adds a new mapping, it should not break any existing configuration.

On the other hand, changing the mappings between the wiimote and retropad (like swapping the wiimote A/B buttons and retropad X/Y buttons) would be a breaking change.

[hizzlekizzle]

This sort of thing is typically handled by input remapping in the frontend. It's not sustainable to add different input configurations into cores to suit every physical input device.

[fekir]

Hi @hizzlekizzle, thank you for the feedback.

I thought the cores interacted with the retropad, and decided individually how to handle it.

Where should be the right place for suggesting the mentioned change (and also the one suggested in libretro/mgba#310)

[hizzlekizzle]

No, you're right about the retropad interaction, and an example of what you're wanting to do would be FBNeo's "arcade stick (classic)" device vs "arcade stick (modern)," which sets up the mappings differently since Street Fighter games (and, accordingly, fight sticks) switched their typical layouts around the PS2 era. There are still quite a few sticks that use the old layout floating around, so having another input device makes it easier to switch between the two.

That said, sideways Wiimote strikes me as a pretty uncommon (and highly limited) input device to get that far into the weeds to accommodate.

In RetroArch, at least, you can change which core functions are mapped to any given retropad input and save a core remap so that it always takes effect when the core is loaded. If you're using some other libretro frontend that doesn't have this sort of capability, though, you'd have a bigger problem, of course.

[fekir]

No, you're right about the retropad interaction [...]

Ok, then this is the right place?

and an example of what you're wanting to do would be FBNeo's "arcade stick (classic)" device vs "arcade stick (modern)," which sets up the mappings differently since Street Fighter games (and, accordingly, fight sticks) switched their typical layouts around the PS2 era. There are still quite a few sticks that use the old layout floating around, so having another input device makes it easier to switch between the two.

I'm not sure what you are trying to tell me, sorry, I'm not proposing to add a different input device for supporting the wiimote.

That said, sideways Wiimote strikes me as a pretty uncommon (and highly limited) input device to get that far into the weeds to accommodate.

I'm not sure what you mean by uncommon.

Sideways wiimote is how the wiimote is mapped by default in retroarch and works relatively well, so how the wiimote itself is configured is not uncommon.

If you mean that not many people are using it as input device... I do not know, I can only talk about my experience.
Which is that wiimotes are cheap (second hand), robust, small/portable, wireless, relatively easy to find, and work well for multiple retro platforms or games that do not use all buttons on their native platform.

It's not sustainable to add different input configurations into cores to suit every physical input device.

But that's the point.
I'm not proposing to add a different input configuration, but to change a default mapping of the existing input configuration between retropad and Genesis-Plus-GX, which, to the best of my knowledge (and please correct me if I'm wrong) does not break any other configuration.
Genesis-Plus-GX does not need to know anything about the wiimote.

[hizzlekizzle]

This is where you would change the core-function-to-retropad mapping, yes.

If you're not proposing a new input device, that does change the discussion a bit, insofar as it's no longer a matter of cost:benefit of added complexity to benefit a single button on a single hardware device, but rather that this core doesn't appear to have different sets of assignments for 3-button and 6-button pads.

So, to duplicate one of the button functions on just the 3-button pad, I believe you'd need to separate those mappings out and then add the duplicated button to just the 3-button input device. I still don't love the idea vs just remapping on the user's end but it's not the worst thing in the world, either.

[fekir]

OK, now I get your point.

I was making an argument both for mgba and Genesis-Plus-GX

Yes; if the same mapping is used both for the 3 button and the 6 button layout, then it is not "simply" changing a default value.

This should not be the case for libretro/mgba#310 though.