notify earlier, avoid disposing rendertargettexture
notify earlier, avoid disposing rendertargettexture

BabylonJS/Babylon.js,RaananW/Babylon.js,RaananW/Babylon.js,BabylonJS/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,sebavan/Babylon.js,BabylonJS/Babylon.js,sebavan/Babylon.js