Examples: Issues with webgl_materials_nodes

[Mugen87]

Describe the bug

It seems there are two issue with webgl_materials_nodes:

1. The following warning is logged in the browser console:

THREE.WebGLProgram: Unsupported encoding: undefined

2. The preset basic / physical has a broken shader.

> ERROR: 0:924: 'clearcoatNormal' : undeclared identifier

To Reproduce

Steps to reproduce the behavior:

1. https://threejs.org/examples/webgl_materials_nodes
2. Open the browser console.

Platform:

• Device: [Desktop, Mobile]
• OS: [Windows, MacOS, Linux, Android, iOS]
• Browser: [Chrome, Firefox, Safari, Edge]
• Three.js version: [dev, r121]

[Mugen87]

THREE.WebGLProgram: Unsupported encoding: undefined

It seems this warning has no effect on a node material since the encoding logic is implemented directly in the node material system. Hence, the material does not rely on the code injection of WebGLRenderer. Nevertheless, it would be good to find a way to avoid the warning.

The actual root cause of the issue is the fact that e.g. MeshStandardNodeMaterial has a map property but it's not assigned with a texture but a node like ColorAdjustmentNode. This node has no encoding property which makes getTexelDecodingFunction() fail.