Function VisualServerSingleton.canvasOccluderPolygonCreate
Creates a new light occluder polygon and adds it to the VisualServer. It can be accessed with the RID that is returned. This RID will be used in all canvas_occluder_polygon_*
VisualServer functions.
Once finished with your RID, you will want to free the RID using the VisualServer's freeRid
static method.