This function can be used to retrieve the follow target of the given camera. The return value can be an object index, an instance ID or -1 if no follow target has been set.
Argument Description camera_id The unique camera ID value returned when you created the camera
Object Index, Instance ID, or -1 if no target is set.
var target =
if target != obj_Player
The above code retrieves the follow target of the camera assigned to view port and then checks this to see if it matches the object index "obj_Player". If it does not then the view camera is set to follow an instance of that object.