Unity: A boilerplate 2D controller for use with Unity 3D

Unity 2DController

#pragma strict

/***********************************************************************
 * Notes
 ***********************************************************************/

/*
 * This is a boilerplate controller for a 2D or 2.5D platform game.
 * To that end, this controller allows for movement along the X and Y
 * axes only. There is built-in support for jumping, double jumping,
 * rotating in 3D (as opposed to 2D), setting a spawn point, etc.
 * This script was influenced by Unity's 2D Gameplay Tutorial:
 * http://unity3d.com/support/resources/tutorials/2d-gameplay-tutorial.
 */

/***********************************************************************
 * Requires
 ***********************************************************************/

// Require a character controller to be attached to the same game object
@script RequireComponent(CharacterController)

/***********************************************************************
 * Variables
 ***********************************************************************/

var spawnPoint : Transform; // The character will spawn here
var movement : Movement;

private var controller : CharacterController;

/***********************************************************************
 * Classes
 ***********************************************************************/

class Movement {

    /*******************************
     * Public (Inspector) variables
     *******************************/

    var enabled : boolean = true; // Is the character controller enabled?
    var gravity : float = 20;
    var jumpHeight : float = 8;
    var walkSpeed : float = 3;
    var rotate : boolean = false; // Should the character rotate?
    var rotateIn3D : boolean = false; // Should the character be rotated in 3D?
    var rotationSmoothing : float = 10; // Rotation Smoothing speed (for "Rotate In 3D")

    /*******************************
     * NonSerialized variables
     *******************************/

    // The character's current horizontal direction
    @System.NonSerialized
    var horizontalDirection : int;

    // The character's current direction (on all planes)
    @System.NonSerialized
    var direction : Vector3;

    // The character's current movement offset
    @System.NonSerialized
    var offset : Vector3;

    /*******************************
     * Jumping
     *******************************/

    // Did the user press the jump input button while midair?
    @System.NonSerialized
    var usedExtraJump : boolean = false;
}

/***********************************************************************
 * Unity Functions
 ***********************************************************************/

function Awake() {
    controller = GetComponent(CharacterController);
    Spawn();
}

function FixedUpdate() {
    // Make sure the character stays in the 2D plane
    transform.position.z = 0;
}

function Update() {
    // GetAxisRaw("Horizontal") will return either -1 or 1 while the left or right input is depressed
    // Otherwise, GetAxisRaw("Horizontal") returns 0 for no input
    movement.horizontalDirection = (movement.enabled) ? Input.GetAxisRaw("Horizontal") : 0;
    if (movement.horizontalDirection != 0) movement.direction = Vector3(movement.horizontalDirection, 0, 0);
    MoveCharacter();
}

/***********************************************************************
 * Custom Functions
 ***********************************************************************/

function Spawn() {
    transform.position = spawnPoint.position;
}

// Move the character using Unity's CharacterController.Move function
// http://docs.unity3d.com/Documentation/ScriptReference/CharacterController.Move.html
function MoveCharacter() {
    ApplyMovement();
    ApplyGravity();
    // Move the character (with deltaTime to ensure frame rate independence)
    controller.Move(movement.offset * Time.deltaTime);
}

function ApplyMovement() {
    switch (controller.isGrounded) {
        // The character is on the ground
        case true:
            movement.usedExtraJump = false;
            if (movement.enabled) {
                movement.offset = Vector3(Input.GetAxis("Horizontal"), 0, 0) * movement.walkSpeed;
                if (Input.GetButtonDown("Jump")) ApplyJump();
            } else {
                movement.offset = Vector3.zero;
            }
        break;

        // The character is midair
        case false:
            if (movement.enabled) {
                movement.offset.x = Input.GetAxis("Horizontal") * movement.walkSpeed;
                // Apply an extra jump if the jump input button is pressed a second time
                // The final jump height will be greatest at the apex of the first jump
                if (Input.GetButtonDown("Jump") && ! movement.usedExtraJump) {
                    movement.usedExtraJump = true;
                    ApplyJump();
                }
            }
        break;
    }

    if (movement.rotate) ApplyRotation();
}

function ApplyJump () {
    movement.offset.y = movement.jumpHeight;
}

function ApplyRotation() {
    if (movement.direction.x != 0) {
        if (movement.rotateIn3D) {
            // http://docs.unity3d.com/Documentation/ScriptReference/Transform-rotation.html
            transform.rotation = Quaternion.Slerp(transform.rotation, Quaternion.LookRotation(movement.direction), Time.deltaTime * movement.rotationSmoothing);
        } else {
            // http://docs.unity3d.com/Documentation/ScriptReference/Quaternion.LookRotation.html
            transform.rotation = Quaternion.LookRotation(movement.direction);
        }
    }
}

function ApplyGravity () {
    movement.offset.y -= movement.gravity * Time.deltaTime;
}

This is new!