Add 3D panoramic skybox feature with 4 different skies.

[jacke9708]

Adds a manual "3D Skybox" configuration section with a dropdown selector. Uses a single equirectangular 2D texture projection.

Video.Project.1.mp4

This is my first contribution, so any feedback on style or code adjustments is welcome.

Changes

• SkyboxTheme: Created enum to track selections and resource paths.
• HdPluginConfig: Added configuration section and dropdown item.
• EnvironmentManager: Exposed isOverworld().
• ZoneRenderer: Added shader pass, camera tracking math, and overworld environment gating to disable rendering in caves/dungeons.
• Texture Management: Cleans up old texture IDs via glDeleteTextures during real-time dropdown hot-swaps.
• Assets: Added four CC0 4K panoramic textures from Polyhaven.

[cypher112]

sick work dude

[3-X]

Skyboxes look really nice! Unfortunately plugins have a size limit of 10mb currently and the plugin is already about 9mb, that being said we are starting to look at possible solutions to be able to start to allow us to use larger images/textures! That may be a little while off though for full transparency

In the meantime if you'd like to pursue other ways of implementing nicer skyboxes using shaders, that would get you around the size limitation! I actually ran into the same thing when working on this pr #655 and pursued it through shaders if youd like to take a look and play around with it!

That pr should be hopefully getting merged in the somewhat near future so skyboxes are getting some love in the meantime as well while a solution is worked on for these larger files