Nodes: Add CubeMapNode.

[Mugen87]

Related issue: -

Description

WebGPURenderer must be able to automatically convert equirectangular textures into the cube map format. This is now done by a new utility class CubeMapNode. Similar to PMREMNode, this class is intended to setup the environment map for materials and later the background (see #28827).

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
685.1 kB (169.6 kB)	685.1 kB (169.6 kB)	+0 B

🌳 Bundle size after tree-shaking

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

Filesize dev	Filesize PR	Diff
462 kB (111.5 kB)	462 kB (111.5 kB)	+0 B

[Mugen87]

@sunag This module should be for internal use only so it is not exported in Nodes.js. Still, I'm a bit unsure about the name CubeMapNode since its quite similar to CubeTextureNode.

CubeMapNode should be in some sense the non-PBR version of PMREMNode. Meaning it encapsulate different inputs to provide a single environment map format for the material.

[sunag]

I'm not sure if we need this, wouldn't just manipulating the UV be enough since we don't need to pre-filter for non-PBR?

import { texture, equirectUV, reflectVector, refractVector } from 'three/ts';

const coord = reflectVector; // refractVector 
const env = texture( textureEquirec, equirectUV( coord ) );

[Mugen87]

The problem with using equirectangular uvs are the artifacts that result at the poles which do not occur with the cube map format. They were previously reported as bugs which was one reason for not directly supporting equirectangular textures in the shader.

I'm afraid users will complain when the artifacts appear again when migrating from WebGLRenderer.

[sunag]

Interesting, if so let's merge the PR, it seems good to me.