* Start converting SDL2 backend to SDL3.
Game starts, but a lot of stuff is broken. Oh well.
* Fix text input
SDL3 changed the API somewhat, for the better. Changes all over UI/Clyde/SDL3 layer.
* Fix mouse buttons being broken
* Remove records from SDL3 WSI
The fact that this shaved 2-3% off Robust.Client.dll is mindboggling. Records are so bad.
* Set Windows/X11 native window properties
* Fix window resize events getting wrong size
oops
* Remove "using static" from SDL3 WSI
Seriously seems to hurt IDE performance, oh well.
* Apparently I never called CheckThreadApartment().
* Add STAThreadAttribute to sandbox
Necessary for content start
* Set window title on creation properly.
* Load window icons
* Fix GLFW NoTitleBar style handling
Yeah this PR is supposed to be about SDL3, so what?
* Implement more window creation settings in SDL3
Mostly the ones that need a lot of platform-specific stuff to work.
* Make fullscreen work properly in SDL3.
* File dialogs with SDL3
Removes need for swnfd.
* Fix some TODOs
* Fix WebView build
Fixed being able to position the cursor vertically if placeholder text was visible and multi-line. This is because the code was using line break info for the place holder. On top of not being correct behavior, this caused further exceptions since the cursor would get outside the editable text rope.
Fixed index exception if you try to move left in an empty text edit.
Has regression tests.
Fixes#4957, fixes#4953
