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EulerAngles aberation with perspective camera in "2D" game.

Discussion in '2D' started by JapanDoudou_fr, Jul 11, 2019.

  1. JapanDoudou_fr


    Jul 11, 2019
    Hello everyone !

    I hope this question where never ask, because I can't find any answere.

    I made a shmup game in 2D with a perspective camera. I'm trying to do an "Aiming Shot" bonus to shoot where you click.

    The "Canon" must rotate around the Player, by Following the mouse. So I create this little script :

    Code (CSharp):
    1. public void FixedUpdate()
    2.     {
    4.         if (playerStatistic.isAimingActive == false)
    5.         {
    6.             isAiming = false;
    7.             return;
    8.         }
    9.         if (playerStatistic.isAimingActive == true)
    10.         {
    12.             //rotation de la souris autour du joueur.
    13.             Vector3 mouseposition = new Vector3(Input.mousePosition.x, Input.mousePosition.y, 50); // avec la camera en perspective, il faut préciser la profondeur, sans quoi les coordonnées sont faussées.
    14.             var newMouseposition = Camera.main.ScreenToWorldPoint(mouseposition);
    15.             Ray ray = new Ray(transform.position, newMouseposition);
    16.             Debug.DrawRay(transform.localPosition, newMouseposition, Color.white);
    17.             Debug.DrawRay(transform.position, newMouseposition, Color.yellow);
    18.             Debug.DrawLine(transform.position, newMouseposition,;
    19.             Debug.DrawLine(transform.localPosition, -newMouseposition,;
    20.             Quaternion rotation = Quaternion.LookRotation(transform.position, -newMouseposition);
    21.             transform.rotation = rotation;
    22.             float angle = transform.localEulerAngles.z - 90;
    23.             transform.eulerAngles = new Vector3(0, 0, angle);
    24.         }
    25.     }
    I Solved many of problèmes with the use of RayCast and the ScreenToWorldPoint. But i have an "aberation". When the player is far of the mouse click, the shoot is … wrong. But when the click is near the player, the precision is good. I Don't understand because i can't find the good raycast or the good solution … and the DrawLine debug tool is wrong too :(

    For more précisions, I use this camera settings :

    And the player is Instantiate at a Z distance of 50. The player move in the scene, the camera can't move.

    Any helps or tips ?

    I'm uploading a WebGL version of the game, I can give you the link later!
    You can "test" the bug by playing my game :p

    Thank You very much !

    Sorry for my English, i'm not used to speak it or write it ...
  2. JapanDoudou_fr


    Jul 11, 2019
    Last edited: Jul 11, 2019
  3. ashapcott


    Apr 4, 2019
    Once you start dealing with a perspective camera you have to start treating these things a lot differently. Here's what I found from a quick search:

    There are also serious problems with your code, most notably here:

    Code (CSharp):
    1. Quaternion rotation = Quaternion.LookRotation(transform.position, -newMouseposition);
    2. transform.rotation = rotation;
    3. float angle = transform.localEulerAngles.z - 90;
    4. transform.eulerAngles = new Vector3(0, 0, angle);
    I'm not sure what the intention is because transform.rotation and transform.eulerAngles are properties that refer to the same underlying value. I'd also avoid assuming a transform's euler angles will be represented in any given fashion.

    If I had to guess you want the angle between those two points and to assign a rotation purely represented on the Z-axis. If that's the case it's trivial to calculate it for yourself:

    Code (CSharp):
    1. Vector3 delta = newMouseposition - transform.position;
    2. float angle = Math.Atan2(delta.y, delta.x) * Mathf.Rad2Deg;
    3. transform.eulerAngles = new Vector3(0, 0, angle);
    JapanDoudou_fr likes this.
  4. JapanDoudou_fr


    Jul 11, 2019
    It works absolutely fine, i'm impressed… I knew the solution was easy , but not so easy. I must read my math book again :(

    Thank you very much … I have a lot of things to learn here !