cocos2d for iPhone

Arguably the most unknown cocos2d feature is the tests/samples.
cocos2d contains almost a test for each feature that it has. These tests are grouped by component. eg:

• Sprite Test: It tests the CCSprite and CCSpriteSheet functionality like anchorPoint, visibility, parenting, reordering, honor Transform, etc…
• Action Test: It tests the CCMove, CCRotate, CCTint, CCCamera, CCSequence, CCSpawn, etc..
• Menu Test: It tests all kind of menus
• CocosDenshion: It tests the Sound Engine
• Chipmunk Accel Touch Test: It tests integration with Chipmunk physics engine using accelerometer and multi touches.
• Particle Test: It tests all kind of particles (quad particles, point particles, sun, meteor, galaxy, smoke, fire, etc…)
• etc…

Although these tests were coded for testing purposes they can also be used as examples. Not only they use the API in the recommended way, but some of them, also contain useful tips in the commentaries.

In order to run the tests, you should do:

1. Open the cocos2d Xcode project
2. Select the test target: Xcode -> Project -> Set Active Target -> eg: TransitionTest
3. Make sure that the running executable is correct: Xcode -> Project -> Set Active Executable -> eg: TransitionTest
4. Build and run: Xcode -> Build and run

Another quick way of doing it by customizing the toolbar:

1. Xcode -> Right click on the toolbar -> Customize Toolbar
2. Drag & drop the Active Target button to the toolbar
3. Drag & drop the Active Executable button to the toolbar

The source code of the samples are in the tests subdirectory.

So, let’s say you want to learn how to use Tiled maps. What you should do is:

1. Select the TileMapTest target
2. Make sure that the TileMapTest executable is selected
3. Build & Run.
4. Try all the subtests. The TileMapTest has more than 10 subtests. Eg: Hexagonal test, Isometric test, Orthogonal tests, read-write tile tests, etc…
5. See the TileMapTest source code: tests/TileMapTest.m
6. Modify the source code and go to step 2.

Although it is possible to reuse the cocos2d v0.8 animation code, v0.99 introduces a new way to deal with animations (and sprites in general).

v0.99 has a new class named CCSpriteFrameCache that, as the name suggests, it is the cache of all the sprite frames.
You can load sprites frames to the CCSpriteFrameCache with:

• a plist filename (generated by Zwoptex editor)
• a plist filename (generated by Zwoptex editor) and a CCTexture2D
• a CCSpriteFrame and a sprite frame name

( See the full API here: CCSpriteFrameCache API )

And the CCSpriteFrame object has the following properties:

• a CCTexture2D: which texture should it use.
• a CGRect: the rectangle of the texture (from 1 texture you can create many CCSpriteFrame objects, in fact it is the recommend way to avoid wasting unnecessary memory).

Example:

// Obtain the shared instance of the cache
CCSpriteFrameCache *cache = [CCSpriteFrameCache sharedSpriteFrameCache;
 
// load the frames
[cache addSpriteFramesWithFile:@"frames.plist"];
 
// It loads the frame named "frame1.png".
// IMPORTANT: It doesn't load the image "frame1.png". "frama1.png" is a just the name of the frame
CCSpriteFrame *frame = [cache spriteFrameByName:@"frame1.png"];
[sprite setDisplayFrame:frame];

This was just an introduction to CCSpriteFrameCache.

For further info, please read

• hhamm’s Programming iPhone Games with Cocos2D Part 3
• cocos2d programming guide: Animations

Ray Wenderlich wrote a detailed tutorial about how to make a simple game with cocos2d.

The tutorial includes:

• How to start a cocos2d project
• How to add CCSprite objects
• How to use the CCLayer object
• How to use actions
• How to use touches
• How to detect collisions
• How to handle the main loop
• How to play music and sounds

Turorial: How to make a simple iPhone game with cocos2d

You can also download the XCode project: Cocos2DSimpleGame.zip