Explicitly set VideoTexture#colorSpace to SRGBColorSpace

[ycw]

Related: #31416, Discussion: #31533

Due to inherent design constraints in WebGPURenderer, VideoTexture#colorSpace must be explicitly set to SRGBColorSpace. Assigning alternative values may result in perceptible color inaccuracies, including luminance shifts and hue distortion. This outcome is a direct consequence of the renderer's internal texture handling mechanisms (i.e. copyExternalImageToTexture with destination.colorSpace:'srgb') and is entirely independent of the color space employed by the browser during video decoding.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.82 79.08	338.82 79.08	+0 B +0 B
WebGPU	566.16 156.5	566.16 156.5	+0 B +0 B
WebGPU Nodes	564.77 156.26	564.77 156.26	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	470.25 113.78	470.25 113.78	+0 B +0 B
WebGPU	637.38 172.47	637.38 172.47	+0 B +0 B
WebGPU Nodes	592.02 161.71	592.02 161.71	+0 B +0 B

[mrdoob]

Due to inherent design constraints in WebGPURenderer, VideoTexture#colorSpace must be explicitly set to SRGBColorSpace.

@sunag @Mugen87 If that's the case, shouldn't the renderer set this automatically? Maybe warning the user once that colorSpace was changed?

[Mugen87]

Yes, a warning that informs about an invalid color space is surely helpful.

[Mugen87]

@ycw Are you interested in giving this a try? A possible place for a check is below when the texture is initialized for the first time:

three.js/src/renderers/common/Textures.js

Lines 320 to 323 in 54ac263

	if ( textureData.initialized !== true ) {
	textureData.initialized = true;
	textureData.generation = texture.version;

Although @sunag might recommend an alternative place.

[sunag]

Although @sunag might recommend an alternative place.

If the idea is to align with both backends it would be a good place.