cocos2d Book, Chapter 3: Essentials

On July 10, 2010, in Announcements, book, cocos2d, by Steffen Itterheim

Chapter 3 – Essentials

This chapter is a reference about the fundamental classes of cocos2d and how to use them. Nodes, Layers, Scenes, Labels, Sprites, Transitions, Actions, you name it. Also CCDirector, SimpleAudioEngine and other often used singleton classes as well. More advanced concepts will be discussed in a later chapter, Spritesheets for example.

The submission of the first chapter draft is due next Friday, July 16th.

What do you think should be in Chapter 3?

Do you know a cocos2d class or process that you think is essential and should be discussed in this chapter? Let me know!

Summary of working on Chapter 2 – Getting Started

For one I detailed the Hello World sample project and made a simple modification using touch input. At the same time at least some basic level of understanding about cocos2d classes was introduced but the gist of it is done in Chapter 3. In addition, there were a lot of theoretical aspects I wanted to discuss as well, most of all Memory Management and available memory as well as setting expectations on testing on Simulator vs. a device. And of course the devices and their subtle differences. I do hope that those kind of details are appreciated even if they’re not 100% related to cocos2d. I regularly see cocos2d developers struggling with memory issues, with unexpected differences on the device vs the Simulator, or comparing framerates of the Simulator and possibly even Debug builds. That made me want to stray off the beaten path for a moment to hopefully save the readers some misconceptions and the pain associated with them.

I also realized how many steps a new developer has to go through and how much there is to learn in case you’ve never been working with the iPhone SDK before. It starts with registering as iPhone developer and doesn’t end with installing the SDK because you also need the provisioning profiles, a much discussed and troublesome feature. For all of this I refered to existing (and excellent) Apple documentation. Typically the processes change with each new iPhone SDK or may even be under NDA, so discussing how all of this works with iPhone SDK 4 wouldn’t be a good idea since shortly after the book is out iPhone SDK 5 may be coming, introducing changes to the Developer Portal and iTunes Connect with it. It did get me the idea, and I know others have it too, that we need some holding-hands Tutorial which takes one through the steps from registering as iPhone Developer to publishing one’s first App, by referring to the correct official documentation for each step while not forgetting about common pitfalls that are not in the official docs.

I also noticed how easy it can be to overlook how you suddenly introduce a new concept without explaining it first. And then you have to decide how much information is necessary to introduce the concept without straying too far away from what you want to talk about in the first place. It’s especially hard for me because I tend to want to explain everything in detail but some things have to be left for a later discussion. I’m looking forward to editorial feedback now. It has helped tremendeously for the first chapter and I learned a lot from the Apress editorial staff, so I find it exciting that the experts point me to the flaws and make suggestions, I go in to fix them and then see how much better it is. That’s how I like to learn things and it’s going to be one of the core concepts of the book. Show how it’s done, how it shouldn’t be done (if it’s often done wrong) and how it can be done even better if you want to avoid trouble in the long run, while explaining why.

cocos2d Book, Chapter 2: Getting Started

On July 2, 2010, in Announcements, book, cocos2d, by Steffen Itterheim

Chapter 2 – Getting Started

This chapter starts with the usual prerequisites. Download and install iPhone SDK and cocos2d. Installing cocos2d Templates. Creating the first project from a cocos2d project template.

From what I already wrote I estimate that will be about one third of the chapter. I think what would be most interesting in this chapter is to talk about general code structure of cocos2d projects. The basic elements like Scenes, Layers and Nodes. How to transition from one screen to another, to see that we’re actually doing something cool with little effort. For that I think the scheduled selectors should also be introduced to time transitions, and one screen might be a Layer which is waiting for touch input to advance to the next screen.

It might also be a good place to discuss cocos2d memory management, like static autorelease initializers, and making sure dealloc gets called when you switch scenes – otherwise you’re obviously having a memory leak.

The goal is to get the reader into a position where he feels comfortable laying out a screen structure in cocos2d. He knows how to initialize objects and how to add and remove them from the scene. The foundation of working with cocos2d if you so will.

What do you think should be in Chapter 2?

Let me know if you think I’m missing anything important. If you don’t have any suggestions then just think about what you would expect from the chapter by reading this description, that might give you some thoughts.

Also I would welcome any tips and the common pitfalls first-time cocos2d developers might trap themselves into. Expert tips are also welcome, those little nasty things or habits which could bite you later on if you don’t consider them from the beginning.

I’m looking forward to your feedback! The earlier the better. Chapter 2 will be submitted next Friday, July 9th.

What’s planned for the Chapter after this one

Just to put Chapter 2 in context, for Chapter 3 I’m planning to talk about essential cocos2d classes and processes. Sprites, Labels, Menus, Actions, etc. It’ll show you how to work with them using small code snippets. The chapter will probably have a “reference” character with various code samples, so that experienced users feel comfortable skipping ahead while beginners still find it easy and encouraging to pick up the details.

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I’m writing a book for Apress:

Learn iPhone and iPad Cocos2D Game Development: The Leading Framework for Building 2D Graphical and Interactive Applications

I guess someone wanted to be very precise and thorough. 😀

I will blog about the book’s progress here and when it’s published I will add additional materials so readers can continue their journey here. Since this journey is just beginning – I’m submitting the first chapter aptly titled “Introduction” tomorrow – and writing a whole 400 pages book is an entirely new experience to me, I want to let you in on the journey.

Help me help you by providing feedback to the book’s content as I’m writing it!

For the coming weeks, I will announce the current book chapter title and a short description and ask you what you’d like to see in this chapter. I will make these posts every Friday starting tomorrow until the book is complete. In this post you could start by telling me what you’d expect from this book or what you’d like to see in it just given its title? I guess your answer will be “a lot” given the title’s elongated nature. :p

I hope you forgive me if content updates to this website will not be as comprehensive over the coming months, in favor of writing the book and coding sample games. Plus I’m cooking up something special on the side, but all in due time.

Oh, by the way, if you happen to know what kind of fruit that is on the cover I’d like to know. I could just ask my editor but I’d like to see if we can figure it out without the help from Apress. It doesn’t really look like a coconut to me, which would have been fitting given the subject. If you have any ideas what fruit it is, let me know! It sure looks exotic and it’s definetely not a banana nor a lemon. So what is it? The first to post the correct answer in a comment, together with a link to Wikipedia or some other website as proof, gets a copy of the book for free when it’s out (or $40 now)!

And now for something completely different …

As a side note, the Xcode project files from the Xcode Tutorial are now available for download here. I used to ask you to join my Newsletter but I don’t feel too good about hooking you up with my Newsletter using the project as a dangling carrot, so joining the Newsletter will now be a completely voluntary thing. I only send newsletters for substantial updates and important news, at most once or twice per month, so that’s the thing you want if you are already struggling with RSS overflow.

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Prefer Composition over Inheritance

On June 11, 2010, in Programming, Speaking From Experience, by Steffen Itterheim

When the question came up whether to subclass CCSprite or use some model class to build your game entity hierarchy in the cocos2d forum, i stressed that one should try not to use inheritance and keep the inheritance hierarchy to as few levels as possible. I’ve worked with codebases with hundreds of thousands of lines of code, and hundreds of different types of actors in the world. Yet the inheritance hierarchy was 2 super (parent) classes for almost all objects, only very few game objects had 3 or 4 super classes. How can you make complex games this way?

The answer lies in composition, often referred to as Game Components by engines like TorqueX and the PushButton Engine (a Flash game engine from the original Torque developers). This video from the PushButton lead developer Ben Garney explains it very well and also illustrates the problem with inheritance over-use in game engines. Something that most developers new to object-oriented and/or game programming do in fact tend to over-use – i blame that on poorly written books and other introductory OOP sources which emphasize inheritance without discussing its disadvantages.

You can read more about PushButton’s Components system in their documentation. How they implemented Components in TorqueX and what the differences are to XNA Game Components further enhances understanding of the concept.

For further reading and arguments read the Wikipedia article on component based software engineering. As a matter of fact, the Objective-C language was invented to be able to create re-usable software components!

Scott Bilas’ GDC 2002 talk about A Data-Driven Game Object System (PDF) as used by Dungeon Siege contains more pointers on why inheritance fails for game developers and what the advantages (but also some caveats) are with component-based game engines. The talk may be old but it’s still as valid today as it was back then. In fact, in 2002 i started working on SpellForce which already had a component system built into its core, called Aspects, Abilities and Spells. It allowed us to enter all the game data in the database and programmers only needed to write the generic code that dealt with the data, as well as setting certain limits and validity checks (eg. you couldn’t use a damaging spell on yourself but if you wanted to you could target enemies with your heal spell, or have archers shoot buildings … errm).

During GDC 2009 a similar presentation was held by Radical Entertainment’s Marcin Chady. The talk was called Theory and Practice of Game Object Component Architecture (PPT).

Mick West wrote an article Refactoring Game Entities with Components which describes the challenges and benefits of changing the Tony Hawk codebase from an inheritance model to a game component system.

A somewhat more advanced read on component use is a collaborative paper called Dynamic Game Object Component System for Mutable Behavior Characters which talks about components in context of finite state machines and NPC behaviors with a rule-based activation system.

The Game Architect blog calls it an Anatomy of Despair and sums up very good what the cons of inheritance-based class design is and how composition solves them.

No Starterkits for the time being!

On May 30, 2010, in Announcements, cocos2d, by Steffen Itterheim

I will take some time off to carefully consider my options.

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Starterkit: Line-Drawing

On May 27, 2010, in , by Steffen Itterheim

Line-Drawing Game Starterkit

Site License! Unlimited Apps!

Royalty Free! No Attribution!

60 day money-back guarantee!

Made with the popular cocos2d-iphone game engine.
Compatible with cocos2d-iphone v1.1 and v2.0, Xcode 4.6 and iOS 6.
Includes ARC enabled versions of the starterkit!


Sale – only $49 !


All Starterkit project artwork provided by Arezou Ipakchi Design. Promotional images created by Justin from CartoonSmart.

What it is:

Get a head-start for your Line-Drawing game and save days if not weeks of your time! You’ll get gameplay code modelled after the extremely popular Flight Control game. You’ll learn how to draw lines, detect touches on objects, have objects follow a path – and much, much more! Written by a professional game developer and game industry veteran (me) the source code is annotated with lots of comments explaining my rationale and written with readability in mind.

Contains separate iPhone & iPad targets!

The Starterkit includes targets for iPhone and iPad using the same code if you don’t want to create a Universal app, for example to reduce your app’s size or to be able to charge more for the iPad version. If the iPad Target is selected hi-res iPad images will be used. Image selection is done automatically by loading those images whose filenames have the “-ipad” suffix, the same suffix cocos2d uses.

What others are saying:

“Code is quite clearly written and decently documented […] definitely a fine investment.”
From: Commercial cocos2d Code review from Alex Curylo.

“It was an awesome moment when I found the source for a line draw game of this caliber.”
-Franklin Lyons, SpinFall

“Especially the path and movement system is saving me lots of headaches.”
-Martin Hoffmann

Games made with this Starterkit:

Launch Control

Ferries HD

Feature List:

  • cleanly seperated and well-structured GameScene code design with a minimum of dependencies
  • easy to add new objects and extend object parameters
  • touch object & draw a path for it (whether it’s already following a path or not)
  • path drawing ends when path is drawn over appropriate target location (eg airstrip for airplanes, respecting angle of approach)
  • path drawing ends when arbitrary point limit is exceeded (to avoid slowdowns)
  • path is drawn when dragged with thick transparent line style like Harbor Master, without glitches
  • path is split into equal length pieces no matter how quickly user moves finger
  • objects spawn outside screen, locations can be re-defined and extended
  • objects display incoming warning marker at screen border
  • objects display collision warning when any two of them are getting too close
  • objects follow path to end – then fade out and increase score or continue moving
  • objects always rotate in movement direction
  • objects bounce back at screen borders
  • motivational Labels for successful landings, precached
  • Score and HighScore Labels
  • HighScore saved to disk between play sessions
  • supports both Landscape orientations with autorotation
  • loads correct resource files depending on Target (iPhone or iPad)
  • proper Pause handling for incoming calls, SMS
  • many generally useful Math Helper functions included
  • lots of comments explaining rationale and giving tips for improvement
  • assertive coding style to help catch coding errors early on
  • offline and online documentation
  • you can choose between using cocos2d-iphone v1.1 and v2.0
  • you can choose between using ARC or classic manual reference counting
  • compatible with iOS 5.0 and newer, including iOS 6
  • compatible with Xcode 4.6 (the most recent versions also work)
  • easy setup: just unzip, open Xcode project, select build scheme, build and run

Questions? Need Help?

Just send me an email.

Legal Disclaimer

Cocos2D is a registered trademark of Ricardo Quesada. Steffen Itterheim, the Learn & Master Cocos2D website and the Line-Drawing Game Starterkit are neither affiliated with nor endorsed by Zynga or Ricardo Quesada.


Try Before Buy!

Demo App for iPhone
Demo App for iPad

Browse the API Documentation

View a Code Sample


Buy Now!

Site License! Unlimited Apps!

Royalty Free! No Attribution!

60 day money-back guarantee!

Made with the popular cocos2d-iphone game engine.
Compatible with cocos2d-iphone v1.1 and v2.0, Xcode 4.6 and iOS 6.
Includes ARC enabled versions of the starterkit!


Sale – only $49 !



License Agreement

Copyright

Purchase grants you the License to use and modify the source code and assets under the following Terms and Conditions:

You are not allowed to make the source code publicly available. You are not allowed to give or sell the source code to others, modified or not. Licenses are not transferable.

All Licenses are royalty free. You can make as many free or commercial Apps using the source code as you want. You may re-use any existing assets in your App.

If you do contract work and have or want to give the Starterkit source code to your client, your client needs to purchase a Site License as well.

Site License

Each purchase grants you a Site License. The Site license grants you the use of the Starterkit without restrictions at one site.

A site is an office, building or living space rented or owned by the company or individual making the purchase. It allows anyone working on site to use and modify the Starterkit source code.

Large companies operating at several sites need to purchase a site license for each individual location if the Starterkit is to be used at multiple locations. Contact me if you’re such a corporation and you prefer a flat fee license with your own license text to go along with it.

Support

Updates to the Starterkit are done on an as needed basis. I will also keep it up to date and running with the latest stable releases of cocos2d. Updates are distributed via a download link sent to the email address you used for your order. If your email address ever changes please contact me, ideally you should forward me your order confirmation in that case to speed up the change.

Source Code not covered by this License

The licensed Source Code project contains files which are available for free and are governed by different licenses. The Terms & Conditions outlined here do not apply to source code files which do not contain the Copyright notice “Copyright (year) Steffen Itterheim. All rights reserved.”.

Disclaimer

THIS SOFTWARE IS PROVIDED “AS IS” AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Questions? Contact me!

If you have any questions or if you require specific License texts before making a purchase, please contact me.



On May 27th, the whole world saw the future. Because i told you so!


Line-Drawing Game Starterkit –> June 1st!


What’s that you ask?

It is the ideal starting point for your own Line-Drawing game! (like Flight Control and Harbor Master) It is a cocos2d source code project that will be available for sale. But not sight unseen, no. It will appear on the App Store for you to try out. And you get more, the full doxygen-generated source code documentation is available for browsing right now! Just so that you can assess the scope of the project.

What will it cost?

I admit i haven’t decided on that yet.

Show me your license!

Alright, alright. I’ll be fair: Free lifetime upgrades! Unlimited number of developers!

Each license is good for one published game. Additional licenses for follow-up games come at a discount. “Lite” versions do not require an extra license since they are essentially the same game. There will also be a commercial license for developers or studios who make more than $6,000 per month in revenue and can easily afford a higher price.

Why, please tell me why?

Because i can. I like technology and i like programming games. I’m also an enabler and i would love to see others build something unique based on game development technology i provide.

Anything else?

Yes. Today sees the premature end of the best new show of last year. RIP Flash Forward.

If you think your game suffers tremendeously from App Store Piracy, you’re wrong. To put it bluntly: your game has simply failed on the market!

Reports that put the App Store piracy rates at “at least 60%” and developers reporting piracy rates of 80% and even up to 95% are mathematically correct but what they often forget to tell you are actual sales numbers. In the rare cases where Indie developers also mention how many sales they have made, pirates or not, these numbers are always extremely low. For a commercial developer who reports an 80% piracy rate on one of his games it’s simply an attempt to turn terrible sales into a PR story which might give their game a little bit more attention. In fact, i expect the games who report piracy rates of over 30% to have sold no more than 5,000 copies. At $.99 this creates a revenue of $3,500 – maybe a good number for a two-man team but a catastrophe for a commercial developer. This is hardly a problem caused by piracy but a simple failure of the product on the market.

What you have to understand about Software Pirates in general: they use a lot of software. In fact, this is their hobby and favorite passtime, to try out as much software as they can get their hands on. So you will always have a minimum amount of pirated copies of each piece of software, no matter how successful this software is (or not). Of course, with higher success and more sales of the software more pirates are also likely to use it because they, too, value quality software. But given the amount of jailbroken iPhone devices prepared to run pirated software there’s a hard cap of the maximum amount of piracy you will ever see on any title. Just as much as there will be a minimum number of pirates playing every game as soon as it becomes available and regardless of how successful it is on the App Store. If your sales are close or below that minimum number of pirates, you naturally get piracy rates of over 50%. These pirates don’t cut into your revenue however. Ignore them. They never would have bought your App in the first place!


David Rosen from Wolfire reports in his Another View on Piracy article that the highest number of Jailbroken iPhones worldwide is said to be 10%, and in the USA – whose users constitute about two thirds of the iPhone/iPod market – the number of jailbroken devices is just 5%. Assuming a total installed base of 75 Million iPhones (50 Mio. as of April 2010) and iPod touches (20 Mio. as of Sept. 2009) we get at most 7.5 Mio jailbroken devices worldwide, or approximately 2.5 Mio jailbroken devices in the USA. They are not all pirates, however. PinchMedia reports that 38% of jailbroken devices have run at least one pirated App. They also state this number is low. So let’s just take half and we’ll end up with 3.75 Mio. jailbroken devices worldwide which have run at least one pirated App. Still a pretty high number – but it only tells us that they have started one pirated App but not how many or how much of a pirate these users really are. If i had to guess i would say that 10% or just about 400,000 of these users are active pirates who try out a lot of Apps on an almost daily basis. These are the pirates who make the biggest impact in terms of per-App piracy numbers. They are also the users who are least likely to upgrade their pirated copy to a legal one, if they ever do it at all. And trying to fight these pirates is anything but futile – they will never be your customers!

PinchMedia also supports my theory that most Pirates try out as much Software as they can which, of course, leaves less time to use each App intensely: “Pirated applications are used less frequently, less intensely, and for a shorter overall length of time than purchased applications.”

Let’s go back to the gist of it: developers who have a problem with App Store Piracy have, in my opinion, either a problem of perception or they’re making a simple PR statement aimed at getting them more attention, hoping to achieve better sales. The developers who suffer most from App Store Piracy are those who simply are not successful. Their real problem isn’t Piracy, it’s much more likely that they failed either at Marketing, Timing, Quality or finding their Target Audience.

Let me sum this up with a simple chart which i think explains why App Store developers report amazingly high piracy rates, when in fact they are reporting the commercial failure of their App:

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