Look At Mouse

var transformList:Transform[];
var mousePlane:GameObject;
var cam:Camera;
var planeOffset:float = -1f;
var mouseLocationIndicator:Transform;

function Start() {
	if (!cam) {
		if (!Camera.main) {
			Debug.LogError("No Main Camera found. Please either assign a camera, or tag an existing camera as 'Main Camera'.");
			Destroy(this); //Remove the script since it will only cause errors if it continues to run with no camera assigned.
			return;
		}
		cam = Camera.main;
	}

	//host the mousePlane to the camera's transform, so they move and rotate together
	mousePlane.transform.parent = cam.transform;

	//Hide the plane so it doesn't show up in the scene.
	mousePlane.renderer.enabled = false;

	//offset the plane some distance from the camera to make the objects (eg, eyes) turn more or less to look at the mouse.
	if (planeOffset<0f) {planeOffset=cam.nearClipPlane*2f;}
	mousePlane.transform.position = cam.transform.position + cam.transform.forward * planeOffset;

	//rotate the plane so its normal points directly towards the camera (so rays cast from the camera will intersect with it)
	mousePlane.transform.up = -cam.transform.forward;
}

function Update () {

	//The point underneath the mouse on the screen covers a line in 3D. So we use a Ray
	//(a kind of straight line) intersected with a plane to find the point we want the
	//object(s) to look at.
	var ray:Ray = cam.ScreenPointToRay(Input.mousePosition);

	//Find the point of intersection between the ray and the plane.
	var hitinfo:RaycastHit;
	if (Physics.Raycast(ray,hitinfo)) {

		//If there is a point of intersection, make all the objects look at it...
		for (var i:int=0; i<transformList.Length; i++) {
			transformList[i].LookAt(hitinfo.point);
		}

		//... and optionally place the mouseLocationIndicator at the point of intersection.
		if (mouseLocationIndicator){
			mouseLocationIndicator.position = hitinfo.point;
		}
	}
}