## Link to GitHub Issue or related Pull Request, if one exists
n/a
## Description of change
Create three distinct layers for the overlay:
1. Bottommost persistent layer - non-interactable layer that is always
on. This was only for notifications, but now the FPS widget lives here
as well.
2. Overlay windows layer - most interactable windows go here.
3. Topmost main menu - this is reserved for the main menu (escape key)
and this is a modal dialog that occludes the layers below.
Why?
- `toggle overlay` behavior with FPS widget *also* toggling on/off was a
bit confusing (now they're two separate keys)
- FPS widget is popular, but it caused the entire overlay to be active,
which affects how input is handled
- the main menu being a standalone window was a little awkward (now it's
a modal)
## Testing
## Link to GitHub Issue, if one exists
n/a
## Description of change
Update ImGui to `v1.91.4`. We can't update to `v1.91.5` or newer just
yet because impl_spice depends on the old IO model of ImGui which got
removed in `v1.91.5`.
We also can't update the DX9 renderer right now, because at some point
overlay breaks in TDJ (and only in TDJ...)
Enable the new debug logging functionality in ImGui. Add a button in
overlay to toggle debug log window.
Fix some minor bugs spotted by the new ImGui debug log: mismatched API
calls, font loading issues.
## Compiling
👍
## Testing
In progress.
bicarus