Controller support within GUI

[eruvanos]

Vision:

GUI should support controller input without or just a little effort.

Tasks:

• General focus traversal
• Pass controller events as UIEvents
• provide first example
• Make all interactable widgets usable:
  • UITexturedButton
  • UIFlatButton
  • UISlider
  • UIDropdown
• Handle different views
• Interoperability with ActionsInput
• Global switch to toggle focus handling
• UIWidgets have to show focus themselves

Task from Feedback

Discord

• If a controller connects multiple times, it crashes because of .open, which can be simply catched with a try except ( I did it on my machine)
• UIDropdown overlay widgets cant be focused, because they are not re-detected on show
• can only click on UISlider, and if so, it will set it to the middle value
• Currently i have an issue with UIGridLayout and UIScrollbar not working together. The focus is in the wrong place. Image attached.
• UIFlatButtons and UITextureButtons dont count focus as hover, which i think would be a nice addition

PR: #2566

Details

• An adapter handles connected controllers and passes on_ controller callbacks to the UIManager as UIEvents
• A UIFocusMixin can be used to make Layouts handle controller input
• to support UIScrollArea, UIFocusGroup or UIFocusMixin has to be inside of it

Further notes

It might be a good idea to provide some ControllerWindow or something which passes controller events to the window, so the UIManager enable/disable flow could just work.

[pushfoo]

It might be a good idea to provide some ControllerWindow

We might be near the point where we should start looking into the pyglet event -> class adapter design. I have the following questions:

1. Do you want someone with a controller to help test this on Linux?
2. Are we assuming that each OOP event handler method takes only the following? 1. self
   2. the event object

[eruvanos]

1. that would be great :)
2. at least for GUI that is how the event handler look like, they only get the event (and self)