ShaderMaterial: Added loop unroll control

[Mugen87]

Solves #12312

[mrdoob]

I wonder if this is something that we could "hide" in material.defines for the time being without having to touch the API that much...

[Mugen87]

Do you mean something like this? 56da730

[blaze33]

Hi ! Could it be considered to reopen the PR ? I had the same issue with a ShaderMaterial where I was trying to add three.js shader chunks to compute shadows and it took me hours to debug it with only 0:102(109): error: sampler arrays indexed with non-constant expressions are forbidden in GLSL 1.30 and later as an error message. Thanks :)

[blaze33]

Actually I got it working with :

material.isShaderMaterial = false
material.isMeshStandardMaterial = true
material.isMeshPhysicalMaterial = true

Then I could include lights_template.glsl in my shader material and have the loops unrolled :)

[Mugen87]

Implemented via #13140