Function VisualServerSingleton.lightmapCaptureCreate
Creates a lightmap capture and adds it to the VisualServer. It can be accessed with the RID that is returned. This RID will be used in all lightmap_capture_*
VisualServer functions.
Once finished with your RID, you will want to free the RID using the VisualServer's freeRid
static method.
To place in a scene, attach this lightmap capture to an instance using instanceSetBase
using the returned RID.