Tuesday, 22 November 2011

Things learned from "iLabyrinth"

Was reading the code of iLabyrinth game by UD7 Studios and learned quite a few things worth written down even though only looked at a few files:

1)The way they handle the loading of different sprite/map files according to different device/resolution:

2) The "isDeviceIPad()" is a macro defined as below for detecting if the device is an iPad, very handy.

static BOOL isDeviceIPad(){
    if ( UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad ) {
        return YES;
    return NO;

3) The "hightRes()" part (shouldn't it be "highRes()" :-) ?) also worth a look, probably to differentiate between devices like iPhone 4 which has higher resolution from previous devices.

+ (BOOL)hightRes {
    if( [[CCDirector sharedDirector] contentScaleFactor] > 1 ){
        return YES;
    return isDeviceIPad();

4) In my older projects, I always use lots of "#define" to define different game states, later learned to use "typedef enum" to just list out all of them and saved a lot of typing. Noticed as below they also assign each item a value using bit shift operation, which means may be these items can also be used for calculation/operation if required, which is quite cool.

typedef enum {
WalkPathWalk = 0,
WalkPathToTop   = 1 << 1,
WalkPathToRight = 1 << 2,
WalkPathToBottom= 1 << 3,
WalkPathToLeft  = 1 << 4,
WalkPathEntrance= 1 << 5,
WalkPathExit = 1 << 6,
WalkPathNoPath = 1 << 7,
} WalkPath;

typedef enum {
    ZeroPathToBottom= 1 << 7,
    ZeroPathToLeft  = 1 << 8,
    ZeroPathToTop   = 1 << 9,
    ZeroPathToRight = 1 << 10
} ZeroPath;

5) The way it handles game state saving is also new to me. It's called in "applicationDidEnterBackground" (shown below), "applicationWillResignActive" and "applicationWillTerminate" inside the AppDelegate code.

- (void)applicationDidEnterBackground:(UIApplication *)application {
[[CCDirector sharedDirector] stopAnimation];
[[CCDirector sharedDirector] pause];

// Save GameState
[NSKeyedArchiver archiveRootObject:[iLabyrinth sharedInstance] toFile:[iLabyrinth stateFile]];

6) Also a bit unclear about the concept of "Scene" and "Layer" at the moment, specially about how they interact with each other.

At first look, the game seems to only have one file called "UDGameLayer" which indicates it's a "Layer". But when I looked further down the code, inside quite a few "Scene" files (e.g. "UDGameEndScene.h" shown below), it actually includes a layer too.... hmmm.... that's a bit confusing...

@interface UDGameEndScene : CCScene {



@interface UDGameEndLayer : CCLayer {
CCSpriteBatchNode *_backgroundLayer;


7)This multiple build targets thing - already seen it in the Cocos2D sample project, but still worth mentioning and hopefully can later work out how to do it myself.


There's also a few other things I am still not very clear with Cocos2D and still looking for answers and trying to work out how it's been handled in iLabyrinth...

a) the concept of "storing multiple Sprites inside one big image file and then load the required part accordingly", specially if there's animation involved for each sprite.

b) the best way to structure the code if there's a main character (with different weapons?) and multiple levels to play - probably with different enemies/targets to fight with in each level.

Still lots of things to learn :-( ....


  1. Hi,
    glad you found something interesting :) Code is old so it's not best code I wrote :) Still, if you have some questions you can drop me a line @ rolandas@ud7.com

  2. Appreciate your quick response and offer, as I am sort of still around beginner level, probably still to learn a bit more first before capable of asking not-too-dumb questions! Thanks again for sharing the excellent code!