Background (skybox, sky and ground)

Use TCastleBackground to define a nice background for 3D games. Just add it to the design by "Add Non-Visual Component → Background" (under any parent) and then set TCastleViewport.Background.

You can provide up to 6 textures that define 6 sides of a skybox. See wikipedia about skyboxes. Set 6 URLs like TCastleBackground.TexturePositiveX for this (our naming follows e.g. X3D and Emil Persson’s conventions.

How to make such skyboxes?
- Sample cubemaps can be found e.g. on OpenGameArt or Emil Persson’s large cubemap collection.
- You can render them in Terragen. We even have helper scripts for rendering skyboxes with Terragen.
- You can render them in Blender.
You can also define a sky gradient using TCastleBackground.SkyTopColor, TCastleBackground.SkyEquatorColor, ground gradient using TCastleBackground.GroundBottomColor, TCastleBackground.GroundEquatorColor, and additional gradient to smooth transition between the sky and ground using TCastleBackground.SmoothEquator.

The sky and ground gradients are visible if you don’t provide the 6 textures for a skybox, or if some of them use alpha for transparency.

Note	If you only want to define a background as a simple color, then leave `TCastleViewport.Background` empty and set `TCastleViewport.BackgroundColor` instead.

Watch the presentation how to use TCastleBackground:

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