Object Callbacks

scene.new_obj_callback is called whenever there is a new object that has been created in the scene, one that the user does not have a reference to. Use this to make references to any new objects that may appear during a programs lifetime. Also a good way to find camera ID’s.

scene.delete_obj_callback is called whenever there is an object has been deleted in the scene. arena-py will look for all “action” = “delete” messages and call this callback. Use this to delete references and to be notified when an object is removed by another user or program.

The following source code was mirrored from the arena-py object_callbacks.py example.

from arena import *

scene = Scene(host="arenaxr.org", scene="example")

# [scene] is the Scene that called the callback
# [obj] will be an Object instance
# [msg] is the raw JSON message as a dict
def new_obj_callback(scene, obj, msg):
    # do stuff with obj here
    print("new", obj, obj.object_id, obj.data.position.x)
    # etc.
    # could also do obj["object_id"] or msg["object_id"]

scene.new_obj_callback = new_obj_callback

# [scene] is the Scene that called the callback
# [obj] will be an Object instance
# [msg] is the raw JSON message as a dict
def delete_obj_callback(scene, obj, msg):
    # do stuff with obj here
    print("delete", obj, obj.object_id, obj.data.position.x)
    # etc.
    # could also do obj["object_id"] or msg["object_id"]

scene.delete_obj_callback = delete_obj_callback