This script will pull the physics object on the server, collect the position rotation and velocities into an array and sync that to the client.
the client will receive the array and update its local physics object in reverse, extracting from the array and placing it on to the physics server object.
extends MultiplayerSynchronizer
class_name PhysicsSynchronizer
@export var sync_bstate_array : Array = \
[0, Vector3.ZERO, Quaternion.IDENTITY, Vector3.ZERO, Vector3.ZERO]
@onready var sync_object : RigidBody3D = get_node(root_path)
@onready var body_state : PhysicsDirectBodyState3D = \
PhysicsServer3D.body_get_direct_state( sync_object.get_rid() )
var frame : int = 0
var last_frame : int = 0
enum {
FRAME,
ORIGIN,
QUAT, # the quaternion is used for an optimized rotation state
LIN_VEL,
ANG_VEL,
}
#copy state to array
func get_state( state, array ):
array[ORIGIN] = state.transform.origin
array[QUAT] = state.transform.basis.get_rotation_quaternion()
array[LIN_VEL] = state.linear_velocity
array[ANG_VEL] = state.angular_velocity
#copy array to state
func set_state( array, state ):
state.transform.origin = array[ORIGIN]
state.transform.basis = Basis( array[QUAT] )
state.linear_velocity = array[LIN_VEL]
state.angular_velocity = array[ANG_VEL]
func get_physics_body_info():
# server copy for sync
get_state( body_state, sync_bstate_array )
func set_physics_body_info():
# client rpc set from server
set_state( sync_bstate_array, body_state )
func _physics_process(_delta):
if is_multiplayer_authority() and sync_object.visible:
frame += 1
sync_bstate_array[FRAME] = frame
get_physics_body_info()
# make sure to wire the "synchronized" signal to this function
func _on_synchronized():
correct_error()
# is this necessary?
if is_previouse_frame():
return
set_physics_body_info()
# very basic network jitter reduction
func correct_error():
var diff :Vector3= body_state.transform.origin - sync_bstate_array[ORIGIN]
# print(name,": diff origin ", diff.length())
# correct minor error, but snap to incoming state if too far from reality
if diff.length() < 3.0:
sync_bstate_array[ORIGIN] = body_state.transform.origin.lerp(sync_bstate_array[ORIGIN],0.05)
func is_previouse_frame() -> bool:
if sync_bstate_array[FRAME] <= last_frame:
return true
else:
last_frame = sync_bstate_array[FRAME]
return false
it requires one property to sync
and one signal connected to itself
