CubeTextureLoader: Return sRGB textures by default.

[Mugen87]

Related issue: #23614

Description

When working at the sRGB migration, I've noticed that the examples use CubeTextureLoader to load always sRGB textures. Compared to TextureLoader, you usually do not use CubeTextureLoader to load non-color data like normal, roughness or ao maps. Even for HDR textures three.js offers specific loaders.

Because of this and because sRGB output is the default since r152, I think it's safe to change the color space of the loaded cube texture to SRGBColorSpace.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
642.7 kB (159.1 kB)	642.8 kB (159.1 kB)	+22 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
432.9 kB (104.8 kB)	432.9 kB (104.8 kB)	+0 B

[sunag]

I made these changes in the WebGPU version as well here #26152
( I had the same problem )

[donmccurdy]

Agreed!