Nodes: Triplanar Texture Mapping

[sunag]

Related issue: #15048, #24674

Description

Added Triplanar Texture Mapping for new Node Material System, it works in WebGL and WebGPU backends.

Example:

import { texture, triplanarTexture } from 'three/nodes';

...
material = new Nodes.MeshBasicNodeMaterial();

material.colorNode = triplanarTexture( texture( diffuseMap ) );
// or
material.colorNode = triplanarTextures( texture( diffuseMap ), texture( diffuseMap ), texture( diffuseMap ) );

This contribution is funded by Google