Add HDR output support.

[allenwp]

Changes:

• Tonemap mode: ACES -> AgX with 1.53 contrast.
• HDR 2D: off -> on
• Request HDR output: off -> on
• Windows rendering device driver: vulkan -> d3d12

I've chosen 1.53 as an AgX contrast, but this can be different if preferred by anyone.

[Calinou]

I wonder if we should add a HDR toggle in the game options, so you can play with HDR off even if HDR is enabled on the display. Are there any use cases for this in 2026?

[allenwp]

Yeah, this demo project is packed full of lots of in-game player settings that often wouldn't be exposed in a real game, presumably for the purpose of demonstrating Godot engine features. So I think that expanding the player settings to include this sort of thing is entirely in-line with the spirit of this project.

You could even go so far as exposing player settings similar to the ones I have in my demo project that include max luminance and HDR brightness controls. But maybe best to wait until the dust settles and we know for sure which platforms will support changing which of these.

(You're welcome to supersede this PR with your own! To be completely open and honest, I half made this PR as a joke to show how easy adding HDR output to an existing project is. In reality, this project probably should add in some more menu options, even though this is not strictly required.)

[allenwp]

This PR should also set the Linux display server to Wayland. I’ll update it at some point.

[iuymatiao]

As an aside,

I would also like to see the debug screen (that shows FPS and V-Sync) to be updated to provide more debug info, including related to HDR. I’m thinking of adding:

1. Renderer (Compatibility, Mobile, Forward+)
2. Driver (d3d12, metal, vulkan)
3. Input Resolution (ex: “1920x1080” if running FSR 2.2 in 4K Performance preset)
4. Output Resolution (ex: “3840x2160” using the previous example)
5. HDR Output (Enabled/Disabled)
6. Reference Luminance (ex: 200 nits)
7. Maximum Luminance (ex: 1000 nits)