envMaps = refraction not working in r131 for PBR materials

Describe the bug

Since release 131 it’s not possible to change the mapping of the envMap to RefractionMapping for PBR materials.

r130	r131

Probably it is related to the following adjustment:

The envMap property of MeshStandardMaterial and MeshPhysicalMaterial is now internally converted to a PMREM.

See also:

• Migration-Guide: https://github.com/mrdoob/three.js/wiki/Migration-Guide#130--131
• PR: https://github.com/mrdoob/three.js/pull/22178

To Reproduce

Steps to reproduce the behavior:

1. Checkout tag r130 or r131
2. Run three.js/docs/scenes/material-browser.html#MeshStandardMaterial
3. Change parameter (roughness: 0, metalness: 1, color: ffffff, envMaps: refraction

(or run material-browser: https://threejs.org/docs/scenes/material-browser.html#MeshStandardMaterial directly)

[Mugen87]

This means that mapping type refraction has no longer an effect for PBR materials?

When CubeUVRefractionMapping is removed, yes. The automatic PMREM conversion does already support only reflection.

I have not achieved a comparable effect with PBR materials and transmission properties.

The effect of CubeUVRefractionMapping is physically not correct so using refraction based on transmission will look different.

And is the parameter refractionRatio for PBR materials still relevant?

When CubeUVRefractionMapping is removed, then no.

As I understand it, all other mappings (CubeRefractionMapping, EquirectangularRefractionMapping) are also affected (for PBR materials) when refraction is no longer supported?

PBR materials only supports the cubeUV format. Meaning CubeRefractionMapping, CubeReflectionMapping as well as EquirectangularRefractionMapping and EquirectangularReflectionMapping are no valid mappings.

[mrdoob]

Oh wait, I guess you mean removing it only from the PBR materials but still keep the code for the other materials?