@script RequireComponent(CharacterController)

// Movement variables.
var jumpSpeed : float = 0.4;
var gravity : float = 1;

//Init movement variables.
private var movement = Vector3.zero;
private var grounded : boolean = true;
private var jumping : boolean = false;

//Init controller variables.
private var controller : CharacterController;
private var collisionFlags : CollisionFlags;

function Update() {

	var controller : CharacterController = GetComponent(CharacterController);

	// Make jump when jump button is pressed and we're on the ground.
	// Jump button is spacebar.
	if ((Input.GetButtonDown("Jump")) && IsGrounded()) {
		// Check we're not already jumping...
		// ...we don't want to let you jump in mid-air.
		if (!jumping) {
			jumping = true;
			grounded = false;
			movement.y = jumpSpeed;
		}
	}

	//Are we jumping?
	if (jumping) {
		// Are we moving up and have hit our head on something?
		// Then stop moving up.
		if ((IsHitAbove()) && (movement.y > 0)) {
			movement.y = 0;
		}
		// Are we moving down and have landed on something?
		// Then set us as grounded and not jumping.
		if ((IsGrounded()) && (movement.y < 0)) {
			jumping = false;
			grounded = true;
		}
	}
	
	//Are we standing on something and not jumping?
	//Then zero down speed - needed for correct gravity if you fall off something...
	//...otherwise gravity keeps building up and you fall to the ground instantly.
	if ((IsGrounded()) && (grounded)) {
		movement.y = 0;
	}
		
	// Apply gravity.
	movement.y -= gravity * Time.deltaTime;
	
	// Move the character.
	collisionFlags = controller.Move(movement);
}

// Func to check if we've hit anything below us.
function IsGrounded() {
	return (collisionFlags & CollisionFlags.CollidedBelow) != 0;
}

// Func to check if we've hit anything above us.
function IsHitAbove() {
	return (collisionFlags & CollisionFlags.CollidedAbove) != 0;
}