Updated Event Execution Order

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Revision as of 15:13, 8 August 2009 by Mike (Talk | contribs)

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Author: Michael Garforth


Game loop

The following all happens in a single loop, in the order specified Physics does not necessarily run each time, and can run multiple times

After an instantiation

For objects that were instantiated last game loop iteration:

  • Start

Physics loop

Physics is run in a loop, iterating over the following until physics has caught up to the current frame:

  • FixedUpdate
  • Physics simulation
  • OnCollisionEnter/OnCollisionStay/OnCollisionExit
  • OnTriggerEnter/OnTriggerStay/OnTriggerExit
  • WaitForFixedUpdate (Coroutines which yielded WaitForFixedUpdate will resume execution after the next physics iteration completes)

Update events

The rest of the events are run once per game loop iteration:

  • OnMouseDown/OnMouseUp/OnMouseDrag/OnMouseEnter/OnMouseExit/OnMouseOver
  • Update
  • WaitForSeconds/yield/yield return 0 (Coroutines which yielded one of these will resume execution here, with WaitForSeconds resuming after the defined time)
  • LateUpdate


  • OnPreCull
  • OnBecameVisible/OnBecameInvisible
  • OnWillRenderObject
  • OnPreRender
  • OnRenderObject
  • OnPostRender
  • OnRenderImage (Pro only)

  • OnGUI (Called multiple times. Layout then Repaint events are called first, followed by a Layout and keyboard/mouse event for each input event)
  • OnDrawGizmos (Only when scene is drawn, even if object is inactive)

Before the frame ends

  • WaitForEndOfFrame (Coroutines which yielded WaitForEndOfFrame will resume execution before the next game loop finishes)

First scene load

Repeated once per object:

  • Awake
  • OnEnable (If the object is active)

At the beginning of the next frame, per object:

  • Start

After calling Application.LoadLevel

Before the level loads

Repeated once per active object, after the end of the current frame:

  • OnDisable

Level loads

After level loads

Repeated once per scene object:

  • Awake
  • OnEnable (If the object is active)

Repeated once per active DontDestroyOnLoad object from last level:

  • OnEnable

Repeated once per active object:

  • OnLevelWasLoaded

When quitting

For all active objects:

  • OnApplicationQuit
  • OnDisable

Immediate events

These are all called immediately when certain functions are called (e.g. Instantiate, setting enabled):

  • Awake - called during MonoBehaviour instantiation
  • OnEnable/OnDisable - OnEnable called during MonoBehaviour instantiation
  • Reset - called when the script is reset (Editor Only)
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