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Revision as of 05:30, 20 April 2009 by Capnbishop (Talk | contribs)

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Author: capnbishop


This script will cause an object to rotate towards the mouse cursor along it's y axis.

This action could be good for third person games where objects need to point to the cursor but remain parallel with the ground. For instance, a sentry gun located in the center of the screen that rotates toward the mouse to target oncoming enemies.


Drop this script onto a GameObject to have it look toward the cursor. Change the speed value to alter how quickly the object rotates.

JavaScript - LookAtMouse.js

<javascript> /******

LookAtMouse will cause an object to rotate toward the cursor, along the y axis.

To use, drop on an object that should always look toward the mouse cursor. Change the speed value to alter how quickly the object rotates toward the mouse.

            • /

// speed is the rate at which the object will rotate var speed = 4.0;

function Update () {

   // Generate a plane that intersects the transform's position with an upwards normal.
   var playerPlane = new Plane(Vector3.up, transform.position);
   // Generate a ray from the cursor position
   var ray = Camera.main.ScreenPointToRay (Input.mousePosition);
   // Determine the point where the cursor ray intersects the plane.
   // This will be the point that the object must look towards to be looking at the mouse.
   // Raycasting to a Plane object only gives us a distance, so we'll have to take the distance,
   //   then find the point along that ray that meets that distance.  This will be the point
   //   to look at.
   var hitdist = 0.0;
   // If the ray is parallel to the plane, Raycast will return false.
   if (playerPlane.Raycast (ray, hitdist)) {
       // Get the point along the ray that hits the calculated distance.
       var targetPoint = ray.GetPoint(hitdist);
       // Determine the target rotation.  This is the rotation if the transform looks at the target point.
       var targetRotation = Quaternion.LookRotation(targetPoint - transform.position);
       // Smoothly rotate towards the target point.
       transform.rotation = Quaternion.Slerp(transform.rotation, targetRotation, speed * Time.deltaTime);

} </javascript>

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