Material defines won't be set in constructor options

[alexpineda]

I ran into this issue while attempting to add the built in vUv varyings to a customized MeshBasicMaterial.

new MeshBasicMaterial({
                defines: {
                    USE_UV: "",
                },
                onBeforeCompile: (shader: Shader) => {
                    ...
                    );
                },
            })

In this case it will not work since the defines is not defined in the material. This would work in something like MeshStandardMaterial (albeit it would override STANDARD unless merged or also included).

Expected behavior

It should always set defines (eg. defaulted in Material), or maybe even merge defines on constructor.

Platform:

• Three.js version: 145

[WestLangley]

Does the defines pattern in #10764 (comment) solve your issue?

[alexpineda]

Yes of course. Just making note as the api seems inconsistent (depending on which material is used). I'm happy to move on.

[Mugen87]

Defines are not something that the user is supposed to set when creating built-in materials (I'm not referring to custom materials via ShaderMaterial). I understand that defines might be relevant when using onBeforeCompile() but apart from that there should be no need to work with them.

Hence, the approach outlined in #24771 (comment) is more appropriate.