Fuji

Fuji is an Objective-C 2D game framework that is simple, extensible, and documented. It strives for simplicity by following convention over configuration, but without loosing any flexibility through many points of extensibility. It also tries to offer quality documentation that is always complete and up to date.

Fuji is based on GLKit and therefore requires iOS 5.0. Support for OS X 10.8 is planned.

Features

• Flexible entity-component model.
• Powerful and expressive animation system.
• Intelligent asset management.

Installation

Fuji uses CocoaPods. If you have never used it before, these steps will get you started:

1. Create an empty Xcode project.

2. Run the following commands from the project directory:

   $ sudo gem install cocoapods --pre
   $ pod setup
   $ echo -e "platform :ios, '5.0'\n\ndependency 'Fuji'" > Podfile
   $ pod install

3. Open and work from the newly created Xcode Workspace.

Setup

Here is an example of setting up Fuji in the application:didFinishLaunchingWithOptions: method.

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions
{
	FUDirector* director = [FUDirector new];
	[director setPreferredFramesPerSecond:60];

	UIWindow* window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
	[window setRootViewController:director];
	[window makeKeyAndVisible];
	return YES;
}

FUDirector is a subclass of GLKViewController, so we can call setPreferredFramesPerSecond: on it and set it as the rootViewController.

Entities and Components

Fuji follows an entity-component model. Each object in a scene is represented by an instance of the FUEntity class, and each entity is defined by it's components, instances of the FUComponent class. They model the behavior and properties of that entity. Here's a sample code that creates and positios a sprite in the scene:

FUEntity* entity = [scene createEntity];
			
FUSpriteRenderer* renderer = [entity addComponentWithClass:[FUSpriteRenderer class]];
[renderer setTexture:@"Sprite.png"];
[renderer setColor:FURandomColor()];
			
FUTransform* transform = [entity transform];
[transform setPosition:GLKVector2Make(120.0f, 240.0f))];

Actions

Actions are strongly influenced by cocos2d actions but with three key differences:

• They use a different function-based syntax.
• They are not tied to components (nodes in cocos2d). This allows sequences/spawns/groups of actions to affect different components.
• Time can flow backwards without having to reverse an action.

Here is an example that runs a couple of actions:

GLKVector2 targetPosition = GLKVector2Make(0.0f, 0.0f);
id moveRotateAction = FUSpeed(FUSpawn(FUMoveTo(2.0, entity, targetPosition), FURotateBy(1.5, entity, M_PI), 1.0f);
[[scene animator] runAction:moveRotateAction];

id timeModificationAction = FUTweenTo(2.0, moveRotateAction, @"speed", -1.0f);
[[scene animator] runAction:timeModificationAction];

• The FUSpeed action runs the FUSpawn action at a speed of 1.0f.
• The FUSpawn action runs the FUMoveTo and FURotateBy actions in parallel.
• The FUMoveTo action will move the entity to the targetPosition in 2.0 seconds.
• The FURotateBy action will rotate the entity by M_PI in 1.5 seconds.
• The FUTweenTo action will interpolate the speed property of the FUSpeed action to the value -1.0f in 2.0 seconds. This will slow down the moveRotateAction until it stops after 1.0f seconds and it will then slowly reverse it until it reaches it's start state.

Acknowledgments

I'd like to thank the developers of the following engines that have greatly influenced me:

• Unity3D
• XNA Framework
• cocos2d