Using CubeTexture in Three.js TSL

Based on your code, there are a few issues with how you're trying to access the cube texture in TSL (Three.js Shader Language).

Issues in Your Current Implementation

1. You're not returning anything from your TSL function
2. The rayVec you're using is just zeros, which won't sample the cubemap correctly
3. You need to make sure this.textureCube is actually a valid CubeTexture object

Corrected Implementation

Here's how you should modify your code:

TYPESCRIPTCopied
this.materialParams = {
    cubeTex: this.textureCube, // Make sure this is a valid CubeTexture
};

const customShaderNode = tslFn((input) => {
    // Use the normalized position or reflection vector for proper cubemap sampling
    // For example, using the normalized position:
    const rayVec = normalize(positionLocal).toVar();
    
    // Or using reflection:
    // const rayVec = reflect(normalize(positionWorld.sub(cameraPosition)), normalWorld).toVar();
    
    // Sample the cubemap
    const col = vec4(cubeTexture(input.cubeTex, rayVec), 1.0).toVar();
    
    // Return the color
    return col;
});

let material = new MeshBasicNodeMaterial();
material.colorNode = customShaderNode(this.materialParams);

Loading a CubeTexture

Make sure you're properly loading the cube texture before using it:

TYPESCRIPTCopied
// Load the cubemap using CubeTextureLoader
const loader = new THREE.CubeTextureLoader();
loader.setPath('path/to/cubemap/');

// Load the 6 sides of the cubemap
this.textureCube = loader.load([
    'px.jpg', 'nx.jpg',
    'py.jpg', 'ny.jpg',
    'pz.jpg', 'nz.jpg'
]);

Key Points

1. When sampling a cubemap, you need to use a direction vector (typically normalized)
2. For environment reflections, use the reflection vector
3. Make sure to return the sampled color from your TSL function
4. Verify that your cubemap is loaded correctly before passing it to the shader

This should help you correctly sample the cubemap in your Three.js TSL implementation.