&quot; a subset of a few files in the engine contains some code from other open source libraries&quot;<p>The code that is ThreeJS derived includes most of the 3D engine classes including:<p>The main Renderer class (!).  As well as the Texture, Camera, RenderTarget, ShaderLib, ShaderBuilder, EventTarget classes.  Also the majority of the stuff in the &#x2F;math, &#x2F;lights, &#x2F;pass directories.<p>GooEngine&#x27;s renderer (not game engine) was clearly forked from ThreeJS some time ago and diverged (significantly in some places and for the better) but the lineage is clear.