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Problem with rotation and forward motion 2D Z-axis up

Discussion in 'Scripting' started by fallingbrickwork, Aug 6, 2014.

  1. fallingbrickwork

    fallingbrickwork

    Joined:
    Mar 16, 2009
    Posts:
    1,072
    Hi all,

    I am currrently working on a top down 2D game where the Z-axis is up. Everything is going great with setting up the grid etc, but I am having a few issues with the AI follow code. The rotation doesn't seem to be working and due to this the forwardDir (see code below which is basically a slightly modified version of the core AIFollow code from the A* Pathfinding Project).
    Code (CSharp):
    1. public void Update () {
    2.        
    3.         if (path == null || pathIndex >= path.Length || pathIndex < 0 || !canMove) {
    4.             return;
    5.         }
    6.        
    7.         //Change target to the next waypoint if the current one is close enough
    8.         Vector3 currentWaypoint = path[pathIndex];
    9.         currentWaypoint.z = tr.position.z;
    10.         while ((currentWaypoint - tr.position).sqrMagnitude < pickNextWaypointDistance*pickNextWaypointDistance) {
    11.             pathIndex++;
    12.             if (pathIndex >= path.Length) {
    13.                 //Use a lower pickNextWaypointDistance for the last point. If it isn't that close, then decrement the pathIndex to the previous value and break the loop
    14.                 if ((currentWaypoint - tr.position).sqrMagnitude < (pickNextWaypointDistance*targetReached)*(pickNextWaypointDistance*targetReached)) {
    15.                     ReachedEndOfPath ();
    16.                     return;
    17.                 } else {
    18.                     pathIndex--;
    19.                     //Break the loop, otherwise it will try to check for the last point in an infinite loop
    20.                     break;
    21.                 }
    22.             }
    23.             currentWaypoint = path[pathIndex];
    24.             currentWaypoint.z = tr.position.z;
    25.         }
    26.  
    27.         Vector3 dir = currentWaypoint - tr.position;
    28.        
    29.         // Rotate towards the target
    30.         tr.rotation = Quaternion.Slerp(tr.rotation, Quaternion.LookRotation(dir), rotationSpeed * Time.deltaTime);
    31.         tr.eulerAngles = new Vector3(0, 0, tr.eulerAngles.z);
    32.  
    33.         //MinusRotatorGO.rotation = Quaternion.identity;
    34.         Vector3 forwardDir = transform.forward;
    35.         forwardDir = forwardDir * speed;
    36.         forwardDir *= Mathf.Clamp01(Vector3.Dot(dir.normalized, tr.forward));
    37.         forwardDir.z = 0;
    38.  
    39.         transform.Translate(forwardDir * Time.deltaTime, Space.World);
    40.  
    41.     }
    I am guessing the problem is within the tr.rotation = Quaternion.Slerp line, but I can't see how to correct it. I have tried amending the Quaternion.LookRotation(dir) part to an Atan2 call which I found elsewhere on the internet but that didn't fix the issue.

    Any pointers on a solution would be greatly received as I'm starting to pull out the hair now (and I don't have too much left as it is!).

    Kindest Regards,
    Matt.
     
  2. fallingbrickwork

    fallingbrickwork

    Joined:
    Mar 16, 2009
    Posts:
    1,072
    Solved, I think.

    I used the second parameter of Quaternion.LookRotation to specify the up direction and check the axis within the scene view to see why the forward axis should now be.
     
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