fixed bug in getting roughness/metallic factors
fixed bug in getting roughness/metallic factors

Kesshi/Babylon.js,BabylonJS/Babylon.js,Hersir88/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,Hersir88/Babylon.js,NicolasBuecher/Babylon.js,RaananW/Babylon.js,Kesshi/Babylon.js,sebavan/Babylon.js,Kesshi/Babylon.js,NicolasBuecher/Babylon.js,jbousquie/Babylon.js,NicolasBuecher/Babylon.js,Hersir88/Babylon.js,RaananW/Babylon.js,sebavan/Babylon.js,BabylonJS/Babylon.js,BabylonJS/Babylon.js,jbousquie/Babylon.js,jbousquie/Babylon.js