GLTFExporter: Fix value of emissiveFactor.

[Mugen87]

Related issue: Fixed #21849.

Description

Ensures emissiveFactor is in the correct range [0,1].

[mrdoob]

Thanks!

[WestLangley]

I'd just comment out the existing line for now and add a comment. The glTF spec will likely be changed.

//const emissive = material.emissive.clone().multiplyScalar( material.emissiveIntensity ).toArray();

// note: ignoring `material.emissiveIntensity` for now to accommodate glTF spec. see #21849.
const emissive = material.emissive.toArray();

[Mugen87]

I'm in general no fan of commenting out code. But adding the issue number seems okay to me.

[WestLangley]

This would make me feel better, then :-)

// note: `emissive` is not scaled by `material.emissiveIntensity` for now to accommodate glTF spec. see #21849.
const emissive = material.emissive.toArray();

[mrdoob]

Done!