Epic: Support controller screens on the Traktor S4 MK3

[ywwg]

Feature Description

This is an epic bug to track work for supporting external screens on controllers, with an initial implementation for the Traktor S4 MK3

Task List:

• QML: Add scrolling waveforms #3967
• Allow controller mapping to discard polling #12558
• Ability for controller to share data at runtime #12199
• feat: controller screen renderer #11407
• Add PlayerProxy missing current track when created after loading #12559
• [Traktor S4 Mk3] Screen support #12557
• Support for bulk devices on Windows and Mac #13008
• Register WinUSB as device driver for USB Bulk devices under Windows (e.g. by using https://github.com/pbatard/libwdi)
• Refactor Bulk integration to perform endpoint capability detection (see Allow controller mapping to discard polling #12558)
• fix: allow missing COs on QML component #13011 (required for testing, fixing tests)

Working branch at https://github.com/acolombier/mixxx/tree/traktor-s4-mk3

[ywwg]

@acolombier

[acolombier]

/assign

[ywwg]

I'll keep myself assigned because mixxx helped pay for the controller I'm using to do the testing and work

[ywwg]

@acolombier can you write an update here about what we have included now, and what is left to do? I believe the big issue right now is the controller data sharing which needs design work. (I am so happy with how quickly this is coming together, I assumed screen support would be a year of work!)

[acolombier]

I believe the big issue right now is the controller data sharing which needs design work

Yes, that's correct. I think we are waiting for a formal design proposal on how to make that doable with the current engine, without closing any doors for the future of controllers.

As it stands, if you merge both branches from #12199 and #12557, everything appears to be working just fine.

I assumed screen support would be a year of work!

Technically, I've been working on that feature since march 2023, but I know what you mean. I'm also glad we managed to get that fat PR out of the way in a fairly short time.