What is Kobold2D?
It’s the Ultimate Cocos2D Project, of course. Or more precisely, the official name for it. Right now, the website www.kobold2.com is only a “coming soon” page while development is under way.
What’s in a name?
Calling it “The Ultimate Cocos2D Project” all the time would have become tedious rather quickly. I wanted a name that is reminiscent of Cocos2D yet completely different. As luck would have it, I’ve recently watched a lot of Battlestar Galactica episodes. You might remember that in this show humanity’s home planet is called Kobol. I couldn’t help but think of COBOL all the time. 
From there it was a small step to Kobold, which in germany is widely associated with a famous cartoon Kobold called Pumuckl. As a kid, I was a big fan of Pumuckl, so picking Kobold2D as the name was a no brainer. Even more so since it has the same ring to it than Cocos2D.
Why create a new brand name?
For one, giving the project a name of its own clearly makes it more attractive. It expresses a certain dedication to the project. It should also signal that it’s no longer just about Cocos2D. With all those extra libraries and additional glue code, plus an experimental project I’m working on, I’m tempted to call it a Game Development Kit (GDK). That’s the long term vision for Kobold2D: more power, easier – for everyone!
Speaking of long term, that’s another reason to give it its own brand name. The visionary thought being that ultimately, something like Kobold2D could be implemented for other game engines as well, with the same core values: give the developers more power, greater flexibility but at the same time make it easier for them to get started.
The Kobold Team
I’m not the only developer who is aching for a more professional work environment. Kobold2D is a joint-venture with another senior software developer and a couple helping hands who help out wherever and whenever they can. We agreed to share the development burden on a voluntary basis. We all have different stakes and interests in the development of Kobold2D.
For me personally the most important aspect is my ambition to develop a project for its users, both professional and casual. I know I can build professional systems that are easy to use, well documented and thus get the job done painlessly. This basically sums up what I’ve been doing for the past 10 years.
What we’re not doing …
There’s one issue I think i going to come up, which might confuse some people, so I want to be clear about this: we are not creating a branch of Cocos2D. We have no intention to do so. We use the library as is, and we stick to the stable builds. The same goes for all other libraries of course.
At the same time, we don’t push each and every line of our additional code back or even contribute to the development of the libraries in Kobold2D. That’s not what we set out to do, and we simply don’t want to spend too much time consulting with and compromising on changes with others when our code is already there and working for us. Our code uses the MIT License, so it’s there for the taking.
In very few cases we can’t get around to modify library code. We only do this where necessary, for example if it breaks our build and the fix is rather simple. Other than that, if a library doesn’t work to our satisfaction, we try to add our fixes and improvements on top, either by subclassing or by making use of Objective-C categories. So far this has been working very well and allows us to keep updating the underlying libraries with far fewer hassles.
Next steps
One big task that I set myself out to complete before continuing with Kobold2D is figuring out the Xcode 4 template format for File Templates and Project Templates. I almost have everything together after spending practically the whole week on it. I’m also documenting all my findings and I’m going to publish the Xcode 4 Template Tutorial / Reference / Documentation / Manual (not sure about the name yet) by the end of the month.
The goal for Kobold2D is to have various project templates, which is why I’m doing extensive research on the new Xcode 4 template format. Unfortunately at the moment it seems that it will not work satisfactory with cross-referenced Xcode projects, but I remain positive that I can find a solution.
Kobold2D private beta!
There will also be a private beta test for Kobold2D starting in a couple weeks (couple == definitely more than 2 weeks). Reply to the private beta sign-up thread if you want a chance to be picked for the private beta test.
In my book I explained how to create collision shapes for physic engines using the freely available version of VertexHelper Pro. Granted, it works, but as soon as you need to update your shapes frequently or you have many different shapes to edit it’s going to be a lot of manual work and error-prone copy & paste between VertexHelper’s code generator and your source code.
VertexHelper, meet your replacement: PhysicsEditor
PhysicsEditor was written by Andreas Löw, the author of the very popular TexturePacker tool. He has proved again that he can create powerful yet easy to use tools for game developers.
The greatest part about PhysicsEditor: it can automatically trace your shapes to generate collision shapes and it works flawlessly! You can even tweak the amount of vertices (and a lot of other things) as needed, for example if your physics engine has a limitation on how many vertices can be used for a collision shape (Box2D default: 8 vertices).
But it doesn’t just create the collision shapes, it also allows you to edit physics properties of a shape that often go along with it. Density, friction, “bouncyness”, and other parameters can be tweaked in the GUI.
As they say, an image speaks louder than words, so I suppose a video speaks in a thousand images:
Not just Cocos2D
PhysicsEditor currently exports to Cocos2D + Box2D (Chipmunk/SpaceManager support is forthcoming and should be available soon) and also to Sparrow Framework + Chipmunk and of course Corona SDK.
And it works on Windows, too! Which makes sense given that Corona supports Android development under Windows.
I also found this post about PhysicsEditor with a working Flash example (at the bottom). It seems that even exporting respectively using PhysicsEditor with Flash + Box2D seems to work well. Wow!
Brace for impact!
Check out the PhysicsEditor Features page to learn more about what this great tool can do for you! You can get PhysicsEditor alone for $17.94 but you can also grab a bundle deal which includes TexturePacker for $29.99, or almost 20% off.
The Ultimate Cocos2D Project is: Kobold2D!
Put simply: Kobold2D is designed to make Cocos2D developers more productive.
Original Post
Time for a weekly update. This time about startup code and configuration. One of the things that I frequently encountered following the development of Cocos2D and working with it, is how any change to the startup code – the main function, the App delegate and the root ViewController – caused issues and headscratching among developers.
I decided it doesn’t need to be this way.
The main() function
A code snippets speaks more than words:
{
return KKMain(argc, argv, NULL);
}
That’s right, all of the startup code is now part of the project’s source code. You can still do whatever you need to do before and after the call to KKMain (probably nothing, except maybe anti-piracy code). And the third parameter (NULL) to KKMain is reserved for future use, to pass in any configuration parameters if the need arises.
Let’s see what KKMain does:
{
SMainParameters parameters;
initMainParameters(¶meters, userParameters);
#ifdef __IPHONE_OS_VERSION_MAX_ALLOWED
NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
#else
// Mac OS X specific startup code
[MacGLView load_];
#endif
// This makes the CCDirector class known to wax:
[CCDirector class];
// wax setup is sufficient for all intents and purposes
wax_setup();
[KKLua doString:kLuaInitScript];
[KKLua doString:kLuaInitScriptPlatformSpecific];
[KKLua doString:kLuaInitScriptForWax];
// This loads the config.lua file
[KKConfig loadConfigLua];
// run the app with the provided general-purpose AppDelegate which handles a lot of tedious stuff for you
#ifdef __IPHONE_OS_VERSION_MAX_ALLOWED
int retVal = UIApplicationMain(argc, argv, nil, parameters.appDelegateClassName);
[pool release];
#else
int retVal = NSApplicationMain(argc, (const char**)argv);
#endif
return retVal;
}
The usual, really, except that it also initializes Wax and thus Lua for your App as well as providing the necessary startup code for both supported platforms: iOS and Mac OS X. The KKLua class is an Objective-C wrapper around the most imortant Lua functions, most notably it has the doString and doFile methods which allow you to run any Lua code or file containing Lua code.
KKConfig is a class that loads a Lua table and stores it in a NSDictionary for fast access to Lua parameters at runtime. I’ll discuss it in detail another time. The main purpose of KKConfig is to loadConfigLua, which loads the config.lua script returning a table containing startup parameters and making those parameters available to Objective-C.
Config.lua in detail
Let’s have a quick look at an excerpt of the config.lua file. It contains all of the startup parameters a developer using Cocos2D would ever want to tweak in a conveniently editable Lua script:
{
KKStartupConfig =
{
-- load first scene from a class with this name, or from a Lua script with this name with .lua appended
FirstSceneClassName = "GameScene",
-- set the director type, and the fallback in case the first isn't available
DirectorType = DirectorType.DisplayLink,
DirectorTypeFallback = DirectorType.NSTimer,
MaxFrameRate = 60,
DisplayFPS = YES,
DisplayFPSInAdHocBuilds = NO,
-- Render settings
DefaultTexturePixelFormat = TexturePixelFormat.RGB565,
GLViewColorFormat = GLViewColorFormat.RGB565,
GLViewDepthFormat = GLViewDepthFormat.DepthNone,
GLViewPreserveBackBuffer = NO,
GLViewMultiSampling = NO,
GLViewNumberOfSamples = 0,
Enable2DProjection = NO,
EnableRetinaDisplaySupport = YES,
-- ... and many more settings!
},
}
return config
Since you don’t want to guess what those settings mean, I’ve documented them for you:
Config.lua Parameter Documentation (PDF)
This should also illustrate the kind of documentation I’m striving for. Documentation will be available online. It’s created in a Confluence Wiki with the help of ScreenSteps for more visual, step-by-step documentation.
App Delegate & Root ViewController
You may be wondering how you can modify and tweak the App Delegate and Root ViewController if they’re both part of the distribution, rather than copied into each project? That’s actually very simple: both are regular Objective-C classes, so they can be subclassed and methods overridden as needed.
Both KKAppDelegate and KKRootViewController provide a default implementation which you can tweak with the config.lua parameters. If that shouldn’t be enough, for example if you have to plug in some 3rd party code into the App Delegate, each project will have a subclass of KKAppDelegate and KKRootViewController in which you can override any of the UIApplicationDelegate and UIViewController protocol methods. Usually you would first call the super implementation, unless you want to entirely replace the default behavior.
The KKAppDelegate method calls one specific method called initializationComplete at the end of the delegate method applicationDidFinishLaunching. This allows you to run any custom code right before the first scene is shown. You can use that to call the CCDirector runWithScene method manually, in case you have more than one scene which might be run as first scene depending on certain conditions.
If you set the FirstSceneClassName config.lua setting, the project will first check if there’s a classname.lua file. If so, it will run this Lua script, assuming it contains the implementation of the first scene (more on that some other time). Otherwise it checks if there’s an existing Objective-C class derived from CCScene with that name, and if so allocates and initializes this scene and calls runWithScene for you.
In essence
From your point of view, the execution of the App now starts with the first scene, before that there’s no code that you’ll have to concern yourself with. Any startup configuration tweaks that you need to do can be done comfortably via the config.lua file, and the only setting you’ll need to change is the name of the first scene’s class name or Lua script. In addition you’ll get access to some features out of the box, for example adding iAd banners is now a simple on/off switch.
Moreover, any time there’s a change in Cocos2D’s startup code, or the startup code in any other library (most notably Wax), I can just make those changes for you and release a new version. This isn’t something you need to concern yourself with anymore, and makes upgrading existing projects to new versions of Cocos2D and other libraries even easier.
The Ultimate Cocos2D Project is: Kobold2D!
Put simply: Kobold2D is designed to make Cocos2D developers more productive.
Original Post
Last week I wrote that I’m Building The Ultimate Cocos2D Xcode Project. In today’s weekly update I wanted to give you some more details on the use of libraries in that project.
Cocos3D included
So there happens to be a Cocos3D now. Rather than being part of the Cocos2D distribution, it’s an extension project. Guess what that means? Right, installing Cocos3D means fumbling with the dreaded install-templates.sh script (see this Cocos3D tutorial). Of course the first user reactions were: how do I install it? Installation failed, what am I doing wrong? And so on …
The Ultimate Cocos2D Project wouldn’t be ultimate if it didn’t include Cocos3D out of the box. And unmodified of course, as with all included libraries I want to make it as simple as possible to replace one library version with another. Once you get to half a dozen of included libraries, maintaining them all can become a hassle, so the very least I can do is to make it easy for everyone to upgrade specific libraries.
Obviously: Cocos2D included
Of course Cocos2D is also included as a static library as opposed to cluttering your project with all of its source files. Xcode project references make it very convenient to add external code and keeping it seperate. I’ve described the process in detail in my Cocos2D Xcode Project tutorial but since then I’ve learned a couple more things about how to make this even better.
For example, I no longer include cocos2d-iphone directly, instead there’s a seperate Xcode project in between so that I have full control over build settings (using XCConfig files) and make it possible to build both iOS and Mac OS targets in the same Xcode project. I will also include the current version of Cocos2D in the download because my goal is to make everything work out of the box.
No fumbling with install scripts, no additional downloads necessary, no need to modify any Xcode build settings – including developer certificates and header search paths. Build configurations for Ad Hoc and App Store release builds are also included, which will create .IPA and .ZIP files for you ready for Ad Hoc distribution respectively upload on iTunes Connect.
Popular libraries included
Now let’s get to the juicy part. Early on I realized that Cocos2D users often needed (or wanted) to include other libraries. Some of them have become so popular among the Cocos2D crowd that they could as well be part of the official distribution. Alas, they’re not. That’s a service I want to provide.
Often those libraries require special and non-obvious steps to successfully add them to an existing project. All too often those steps are either undocumented, untested, hard to follow, refer to outdated versions of Xcode, iOS SDK, etc. and generally require technical expertise of project configuration and compiler settings.
This is all taken care of for you. Here’s the list of libraries that are already included in the Ultimate Cocos2D Xcode Project:
- Cocos2D (iOS & Mac OS in the same project)
- Cocos3D (ready to use of course)
- Wax & Lua (Wax is enabled and setup, essential Lua functions have an ObjC interface)
- ObjectAL – “iOS Audio, minus the headache” (has excellent documentation!)
- iSimulate – lib included with permission, requires separate iSimulate Lite App or full version
- Cocos2D Gems: GameKitHelper, ClippingNode, Multiple Update Selectors, FrameOrFile, more…
- iAd (already setup in RootViewController, just enable it)
- Chipmunk SpaceManager (ObjC interface for Chipmunk physics)
- SneakyInput (or alternative Joypad library if there is one)
- Objective-C Optimized Singleton Macro (gets rid of @synchronized to improve speed)
- LOG_EXPR (logs any statement, no format strings needed: LOG_EXPR([self contentSize]) )
- … did I miss an essential library? Please leave a comment!
That is quite a list. All you need to do to use these libraries is to either enable them in code or merely include the header file and start using them. If you worry that all these libraries will bloat your App, rest assured that Xcode is very clever: if you don’t actually make use of a static library (eg don’t include any of its header files), it will not be linked with your App and not waste any space or performance. I verified that.
Update policy
These are a lot of libraries to keep up to date. I plan to make about 4-8 point releases each year, usually triggered by a major (speak: non-beta) release of Cocos2D. If updating other libraries justifies an update depends on the library’s importance and the significance of the update.
Your libraries
Adding your own libraries to the project will be easy and the process will be documented. This will encourage code-sharing because your library will just work with other user’s project, it only needs to follow a few simple guidelines to become plugin-capable. This opens the door for better and tighter integration of 3rd party code into your projects. Even if you don’t intend to share your code, you’ll still benefit because your code will be easier to re-use and maintain.
Also, if you like you can make a request for a specific library or additional source code that should be included in the project, please leave a comment. I’ll see what I can do. 
I have a seemingly simple requirement for my project: each node should have preUpdate and postUpdate methods in addition to the regular update method. Preprocessing and postprocessing before and after all entities have run their “update” logic is a common requirement in game development. Sometimes called the setup stage before processing all entities in the world, and the finalize stage to complete the current game step and possibly resolve collisions or check any win, lose or achievements conditions.
Of course there are alternative and some may argue “better” implementations, after all an experienced game dev might argue that using pre and post update methods are merely signs of a badly designed game update loop (the jury is out on that one). However beginning game developers definitely understand this concept much better and every game-making tool I know implements pre and post updates, so it has its validity. Plus I find it more convenient than “outsourcing” some logic to a central game loop.
On the other hand it’s also bad practice to rely on one node’s update method to be called before or after all others. Especially once you get to prioritizing update method calls among various groups of nodes it’s just going to get you into trouble. If you set the priority wrong just once you can introduce very subtle issues that’ll be hard to track down. Think of some objects not colliding with the player, or some monsters crashing when you shoot at them with a specific weapon. Scheduled methods should never rely on the order they are called for various entities.
Not so easy …
It turns out the system in Cocos2D only allows one update method per node. That means for each node you can only have one update selector, and via the priority parameter you can only control when its update method is called relative to all other nodes’ update method. In that way you can at least ensure that the player’s update method is always called first, or last, depending on your requirements. But it’s bad programming practice to do so.
I thought, why not just schedule a “regular” selector with CCScheduler? Well, they don’t have a priority, and they are always called after any update method, so you could never schedule a “before update” method this way. And those scheduled selectors aren’t meant to be used for selectors that are called every frame due to the additional processing overhead (eg allocating, updating and releasing the CCTimer object, and comparing & updating time elapsed every frame).
So I had to write a class called ScheduleMultiUpdate which creates proxy instances, registers them with CCScheduler to receive an update message of their own, and then they forward that message to the actual node implementing the special update selector. By using the priority you can define if the selector is called before or after the regular update by using a negative (before) respectively a positive priority (after, must be 1 or greater).
Example Code
Here’s an example usage scheduling the beforeUpdate and afterUpdate selectors to be called before and after the regular update method.
KKScheduleMultiUpdate* multiUpdate;
// in implementation (.m)
-(void) scheduleUpdateMethods
{
multiUpdate = [[KKScheduleMultiUpdate alloc] initWithNode:self];
[multiUpdate scheduleUpdateSelector:@selector(beforeUpdate:) priority:-1];
[self scheduleUpdateWithPriority:priority];
[multiUpdate scheduleUpdateSelector:@selector(afterUpdate:) priority:1];
}
// this has to be cleanup because CCScheduler retains scheduled targets
// we have to give KKScheduleMultiUpdate a chance to unschedule its selectors or it won't be deallocated
-(void) cleanup
{
[multiUpdate release];
multiUpdate = nil;
[super cleanup];
}
-(void) beforeUpdate:(ccTime)delta
{
}
-(void) update:(ccTime)delta
{
}
-(void) afterUpdate:(ccTime)delta
{
}
Here’s the actual implementation of KKScheduleMultiUpdate and its proxy class. Notice how the KKScheduleMultiUpdate simply retains a list of proxies and creates new ones, while the proxy class registers itself with CCScheduler to schedule its own update method based on the given priority, and then forwards the message to the baseNode. There’s currently no way to unschedule an update selector, but it should be fairly easy to add if you ever need to unschedule an update method while the game is running (I’d rather just use a bool and skip update).
@interface
/** Allows you to schedule multiple update methods per node. */
@interface KKScheduleMultiUpdate : NSObject
{
CCNode* baseNode;
CCArray* updateProxies;
}
-(id) initWithNode:(CCNode*)node;
-(void) scheduleUpdateSelector:(SEL)selector priority:(int)priority;
@end
/** Since there can be only one update selector scheduled per instance, this proxy will implement
that update method and forward the message to the desired selector. */
@interface KKScheduleMultiUpdateProxy : NSObject
{
id target;
SEL selector;
TICK_IMP impMethod;
}
-(id) initWithTarget:(id)target selector:(SEL)selector priority:(int)priority;
@end
@implementation
@implementation KKScheduleMultiUpdate
-(id) initWithNode:(CCNode*)node
{
if ((self = [super init]))
{
NSAssert(node != nil, @"%@ %@ - node is nil!", NSStringFromClass([self class]), NSStringFromSelector(_cmd));
baseNode = [node retain];
updateProxies = [[CCArray alloc] initWithCapacity:1];
}
return self;
}
-(void) dealloc
{
CCLOG(@"%@ %@", NSStringFromSelector(_cmd), self);
[baseNode release];
baseNode = nil;
// must do a cleanup to unschedule CCSelector, this is because CCScheduler retains scheduled targets
[updateProxies makeObjectsPerformSelector:@selector(cleanup)];
[updateProxies release];
updateProxies = nil;
NSAssert([self retainCount] == 1, @"%@ %@ - retainCount on cleanup should be 1 but is %i", NSStringFromClass([self class]), NSStringFromSelector(_cmd), [self retainCount]);
[super dealloc];
}
-(void) scheduleUpdateSelector:(SEL)selector priority:(int)priority
{
NSAssert([baseNode respondsToSelector:selector], @"%@ %@ - node %@ does not respond to selector", NSStringFromClass([self class]), NSStringFromSelector(_cmd), baseNode);
// TODO: might want to check here if the selector happens to be already scheduled
KKScheduleMultiUpdateProxy* proxy = [[KKScheduleMultiUpdateProxy alloc] initWithTarget:baseNode selector:selector priority:priority];
[updateProxies addObject:proxy];
[proxy release];
}
@end
@implementation KKScheduleMultiUpdateProxy
-(id) initWithTarget:(id)target_ selector:(SEL)selector_ priority:(int)priority
{
if ((self = [super init]))
{
NSAssert(target_ != nil, @"target is nil");
NSAssert(selector_ != nil, @"selector is nil");
target = target_; // weak ref
selector = selector_; // weak ref
impMethod = (TICK_IMP)[target methodForSelector:selector];
NSAssert(impMethod != nil, @"selector is not an instance method of target %@", target);
[[CCScheduler sharedScheduler] scheduleUpdateForTarget:self priority:priority paused:NO];
}
return self;
}
-(void) cleanup
{
CCLOG(@"%@ %@", NSStringFromSelector(_cmd), self);
[[CCScheduler sharedScheduler] unscheduleUpdateForTarget:self];
impMethod = nil;
NSAssert([self retainCount] == 1, @"%@ %@ - retainCount after cleanup should be 1 but is %i", NSStringFromClass([self class]), NSStringFromSelector(_cmd), [self retainCount]);
}
-(void) dealloc
{
CCLOG(@"%@ %@", NSStringFromSelector(_cmd), self);
[super dealloc];
}
-(void) update:(ccTime)delta
{
impMethod(target, selector, delta);
}
@end
As always, you’re free to use this code. I release it under the MIT License. You do not need to include a copyright notice, but I’d appreciate any mention or backlink to this website.
I’m now hosting an unofficial Cocos2D (for iOS & Mac OS) API Reference, accessible via the Knowledge Base tab.
What’s so “unofficial” about it?
My version of the API reference includes previously undocumented classes, some are documented but just not in the official documentation, others are completely undocumented but at least now you know they’re there. Currently, there is no additional documentation added other than what’s in the official cocos2d source code files, and as far as I can tell nothing is missing. If there is, please let me know.
Since at least the release of v0.99.5 about a month ago important classes like CCLayer, CCArray and CCDirectorIOS have been missing from the official API reference. Did anyone even take notice, or was it just me? I hope it will be fixed soon and the missing classes added back to the official API reference.
I’d like to call it “unofficial” just to make sure everyone gets the idea that I’m not involved in the development of Cocos2D in any way, and my version of the API reference may contain crucial omissions or mistakes as well.
Angry Birds Tutorial causes slowdown
Current and well-deserved cause of the cocos2d-iphone.org slowdown is the SpaceManager Game Tutorial with source code by the mobile bros. LLC. The tutorial shows you how to make an Angry Birds style of game.
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