Question by OutRage_Studios · Jan 26, 2012 at 12:59 AM · 2d vector3 angle projectile fire

Firing a projectile in 2D

I am attempting to make a 2D catapult that fires at a certain angle depending on where the user drags the mouse cursor to from a starting position.

I have managed to get it semi working with the code below but it provides qute unusual behaviour (the projectile never fires on the correct dragged angle). Any ideas?

var ClickDown : Vector3;

var ClickUp : Vector3;

var point : Vector3;

var pooPrefab : Transform;

var multiplier : float;

function OnMousedown(){

var ray : Ray = Camera.main.ScreenPointToRay (Input.mousePosition);

var hit : RaycastHit;

   if (collider.Raycast (ray, hit, 100.0)) {

       ClickDown = hit.point;

   }

}

function OnMouseUp(){

 var ray : Ray = Camera.main.ScreenPointToRay (Input.mousePosition);

 var hit : RaycastHit;

     if (collider.Raycast (ray, hit, 100.0)) {

          ClickUp = hit.point;

     }

 FirePoo();

}

function FirePoo () {

   var projectile = Instantiate (pooPrefab, ClickUp, Quaternion.identity);

   var shootVector = ClickDown - ClickUp;

   projectile.rigidbody.velocity = shootVector * multiplier;

}

Add comment · Show 4

kevork · Jan 26, 2012 at 01:08 AM 0

Depending on the objects in your scene, you aren't necessarily firing in 2D. Are your ClickUp & ClickDown vectors what you expect them to be?

OutRage_Studios · Jan 26, 2012 at 01:16 AM 0

Yeh the object fires on the X/Y axis, the problem is that on mouse up the ball fires correctly from the end position, however it does not fire in the dragged angle if that makes sense. Imagine an angry birds style catapult the fires in a random direction (its not meant to though)

kevork · Jan 26, 2012 at 01:38 AM 0

Since you are using Physics to drive the motion there are a myriad of settings that could cause your motion to be not as expected. Here's a random list of things to try or check.

If you want the object to be constrained to the X,Y plane you can constrain the Z position & rotation.
You can attempt to use http://unity3d.com/support/documentation/ScriptReference/Rigidbody.AddForce.html ins$$anonymous$$d of setting the velocity directly.
Ensure both the drag and angular drag settings are what you intend.
Ensure your gravity is going the direction you intend.