2D- Scale&rotate Object between two points - calling math wizards

[boulderkock]

Hi Guys,

Basically i need a characters tongue to shoot out towards a point on the screen the player clicks. After the click an object will shoot towards that point and on arrival, immediately move back towards the player. I have a sprite that is the graphics of the tongue and i need it to scale and rotate to the tongue shoot object as the object moves the screen point.

I’m having issues coding the scale and the rotation of the tongue sprite object, particularly the rotation.

Here’s the code i have so far:

function Update () {

	var pos1 = GameObject.Find ("Player").transform.position;
	var pos2 = GameObject.Find ("TongueHitBox").transform.position;
	
	var angle = Mathf.Atan2(pos2.y , pos2.x ) * Mathf.Rad2Deg;
	transform.position = pos1;
	
	if (pos2 != pos1) {

	     var v3 = pos2 - pos1;
         transform.position = pos1;
         transform.localScale.x = v3.magnitude/3.0f;
         transform.rotation = Quaternion.Euler (new Vector3 (0, 0, angle));
	}
	
}

At the moment the object scales sort of correctly, a little bit too long but I think I can fix that… It’s more the rotation. When I shoot the tongue it spins around to a different direction depending on how long it is.

I’ve pretty much formed this entire script from snippets of other answers. I’m no math wizard, and having experimented with different values I was left no choice but to seek help!

Any help would be much appreciated!

Regards,
Genaza

[robertbu]

I’m imaging the tongue of a frog shooting towards a fly. Typically I want to do the setup so that the code is as simple as possible. So you need to do the following:

• Setup the sprite so that the front of the tongue points right in the sprite when the rotation is (0,0,0).
• Set the pivot for the sprite to be ‘Left’.
• Figure out the real-world width of the sprite when the scale is (1,1,1). You can do that first select the texture for the sprite and recording the ‘Pixels To Units’ setting. Next record the pixel width of the sprite. Use both pieces to get the real-world width (I’m calling it objectWidth).

Then to rotate and scale, you can do:

 var dir = target - transform.position;
 var angle = Mathf.Atan2(dir.y, dir.x) * Mathf.Rad2Deg;
 transform.rotation = Quaternion.AngleAxis(angle, Vector3.forward);
 transform.localScale.x = dir.magnitude / objectWidth;

Where ‘target’ is a Vector3 of the position you want the tongue to hit.