Question

I am using Unity3D to create a shopping based game. In my game I have my objects go along a conveyer belt which they then have to pick up and throw using the mouse into a shopping trolley. So far I can get the mouse to pick the items up but how would I go about letting them throw it a particular direction. I also need to make it so the mouse cannot drag an object outside of the boundaries of the room the game is in.

The code I have so far is:

#pragma strict

var screenPoint:Vector3;
var offset:Vector3;

private var oldMouse:Vector3;
private var mouseSpeed:Vector3;

function Start(){
    oldMouse = Vector3.zero;
}

function Update(){
 mouseSpeed = oldMouse - Input.mousePosition;
 oldMouse = Input.mousePosition;
}

function OnMouseDown()
{
    screenPoint = Camera.main.WorldToScreenPoint(gameObject.transform.position);
    offset = gameObject.transform.position - Camera.main.ScreenToWorldPoint(new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z));
}


function OnMouseDrag()
{
    var curScreenPoint:Vector3 = new Vector3(Input.mousePosition.x, Input.mousePosition.y, screenPoint.z);
    var curPosition:Vector3 = Camera.main.ScreenToWorldPoint(curScreenPoint) + offset;
    transform.position = curPosition;
}

function OnMouseUp(){
rigidbody.AddForce(mouseSpeed*Time.deltaTime, ForceMode.Force);
}

James

Answer 1

Try setting the position with rigidbody.MovePosition(). This should detect collisions with the world.

I haven’t tested your code yet, but I think it could be more appropriate to set the rigidbody’s velocity in OnMouseUp(), rather than adding a force.

Keep in mind both of these should be performed in FixedUpdate(), so perhaps you should set flags in the event methods.