Cocos2D action that makes a node move towards a specific point at a set speed

FollowAction.h

//
//  FollowAction.h
//  Battle Pong
//
//  Created by Hugo Wetterberg on 2009-11-29.
//  Copyright 2009 Good Old. All rights reserved.
//

#import <Foundation/Foundation.h>
#import "cocos2d.h"

@interface FollowAction : Action {
	float speed;
	CGPoint goal;
}

@property (assign) float speed;
@property (assign) CGPoint goal;

- (id)initWithSpeed:(float)distancePerSecond goal:(CGPoint)aGoal;

@end

FollowAction.m

//
//  FollowAction.m
//  Battle Pong
//
//  Created by Hugo Wetterberg on 2009-11-29.
//  Copyright 2009 Good Old. All rights reserved.
//

#import "FollowAction.h"

@implementation FollowAction

@synthesize speed, goal;

- (id)initWithSpeed:(float)distancePerSecond goal:(CGPoint)aGoal {
	if ((self = [super init])) {
		goal = aGoal;
		speed = distancePerSecond;
	}
	return self;
}

-(void) dealloc {
	[super dealloc];
}

-(BOOL) isDone {
	return NO;
}

-(void) step:(ccTime)dt {
	CocosNode *t = (CocosNode *)self.target;
	
	// Check so that we don't move too fast
	float dy = goal.y - t.position.y;
	float dx = goal.x - t.position.x;
	
	if (dx != 0 || dy != 0) {
		float d = sqrt((dy*dy)+(dx*dx));
		float f = speed * dt / d;
		if (f < 1) {
			dy = dy * f;
			dx = dx * f;
		}
		t.position = ccp(t.position.x + dx, t.position.y + dy);
	}
}

@end