Bootcamp Multiplayer Demo

Prediction

Events arrive delayed because of network latency and maybe also because of processing delays due to low frame rate or high server load. To minimize a position synchronization delay we predict where the remote players might have moved to when we receive a new movement update. For our prediction algorithm we assume that the remote player kept moving with the same speed into the same direction. Rotation is excluded from our prediction.

/// From file: PlayerRemote.cs
    
    /// updates a (remote player's) position. directly gets the new position from the received event
   internal void SetPosition(Hashtable evData)
   {

	Vector3 p = GetPosition((float[])evData[Constants.STATUS_PLAYER_POS]);
	Quaternion r = GetRotation((float[])evData[Constants.STATUS_PLAYER_ROT]);
	float diff =  UnityEngine.Time.time - this.lastUpdateTime;
	if (diff > 0.2f)
	{
          /// old info, walk to newest available (skip prediction)
	   this.pos = p;	
	}
	else 
	{
          /// predict that he continues to walk into same direction with same speed
    	   this.pos = p + p - realPos;				
	}


	this.rot = r;	
	this.realPos = p;
	this.lastUpdateTime = UnityEngine.Time.time;

	targetpos = GetPosition((float[])evData[Constants.STATUS_TARGET_POS]);
	SendMessage("SetTargetPos", targetpos);			
   }

    
  void Update()
  {
       if (this.lastUpdateTime > 1f)
	{
		/// move to real pos in case we have not received anything for a second
		this.pos = this.realPos;
		this.lastUpdateTime = UnityEngine.Time.time;
	}

  }