fix combinedCamera.copy()

examples/js/cameras/CombinedCamera.js

@@ -111,8 +111,8 @@ THREE.CombinedCamera.prototype.copy = function ( source ) {
 	this.view = source.view === null ? null : Object.assign( {}, source.view );
 	this.aspect = source.aspect;
 
-	this.cameraO = source.cameraO.copy();
-	this.cameraP = source.cameraP.copy();
+	this.cameraO.copy( source.cameraO );
+	this.cameraP.copy( source.cameraP );
 
 	this.inOrthographicMode = source.inOrthographicMode;
 	this.inPerspectiveMode = source.inPerspectiveMode;