Just a quick note about colorspace — the three.js renderer works in linear colorspace, and so for color-correct output to the screen it's best to set renderer.gammaOutput=true on the WebGLRenderer. Because this viewer doesn't do that, you'll see that colors are noticeably darker than they should be:

http://gltf-viewer.donmccurdy.com/	http://sandbox.babylonjs.com/	https://tojacob.github.io/gltf-viewer/build/

In particular I would use:

this.renderer.gammaOutput = true;
this.renderer.gammaFactor = 2.2;