Tools for developing Android Games

Tools for Android Games

Raul Portales
@sla_shalafi @thepilltree
raul@plattysoft.com http://thepilltree.com

Summary
● Introduction to game development
● Engines
● AndEngine
● jPCT-AE
● Scores / Achievements
● Monetization systems

Game Architecture (Simplified)

Game Engine

Draw Thread Game Objects Update Thread

Performance Tips
● Avoid object creations
● Use pools and pre create them
● Avoid getters and setters
● Public attributes instead
● Avoid collections
● Avoid interfaces
● Use a single Activity

Why use OpenGL?

Performance

Why use any Engine

You don’t want to start from scratch

AndEngine
● http://www.andengine.org/
● 2D Graphics Engine
● LGPL
● Extensions
● Physics Engine (Box2D)
● Live Wallpapers
● etc

Games built with AndEngine
● Chalk Ball
● Bunny Shooter
● Greedy Spiders
● Wheelz
● Farm Tower
● ...

Project setup
● Put the jar under libs
● Add them to the build
path
● Don’t forget “armeabi”
● Get the source
● Import project
● Create res dir

Concepts
● Engine
● Scene
● Sprites + Handlers
● Texture / Texture Atlas
● Sprite
● Body
● Fixture

Game Architecture / AndEngine
Game Engine


Scene UpdateHandler

Sprites

Activity creation flow
● BaseGameActivity
● onLoadEngine
● onLoadResources
● onLoadScene
● onLoadComplete

Creating the Engine (1/2)
public Engine onLoadEngine() {
DisplayMetrics om = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(om);
camWidth = 480;
camHeight = (int) (om.heightPixels*480f / om.widthPixels);
RatioResolutionPolicy rrp = new
RatioResolutionPolicy(camWidth, camHeight);
Camera camera = new Camera(0, 0, camWidth, camHeight);

Creating the Engine (2/2)
EngineOptions options = new EngineOptions(true,
ScreenOrientation.LANDSCAPE, rrp, camera);

options.getRenderOptions()
.disableExtensionVertexBufferObjects();

return new Engine(options);
}

Loading Resources
public void onLoadResources() {
BitmapTextureAtlas bitmapTextureAtlas = new
BitmapTextureAtlas(64, 64,
TextureOptions.BILINEAR_PREMULTIPLYALPHA);
mBoxTextureRegion =
BitmapTextureAtlasTextureRegionFactory
.createFromAsset(bitmapTextureAtlas, this,
"box_icon.png", 0, 0);
mEngine.getTextureManager()
.loadTexture(bitmapTextureAtlas);
}

Texture Atlas
● Quite a pain for AndEngine
● Built by hand
● Size must be a power of 2
● One big or many small ones?

Creating the Scene (1/3)
public Scene onLoadScene() {
Scene scene = new Scene();
PhysicsWorld physicsWorld = new PhysicsWorld(new
Vector2(0, SensorManager.GRAVITY_EARTH), false);
Shape ground = new Rectangle(0, camHeight - 2,
camWidth, 2);
FixtureDef wallFixtureDef =
PhysicsFactory.createFixtureDef(0, 0.5f, 0.5f);
PhysicsFactory.createBoxBody(physicsWorld, ground,
BodyType.StaticBody, wallFixtureDef);
scene.attachChild(ground);

Sprite box = new Sprite(0, 0, mBoxTextureRegion);
FixtureDef boxFixture =
PhysicsFactory.createFixtureDef(1, 0.5f, 0.5f);
Body boxBody =
PhysicsFactory.createBoxBody(physicsWorld, box,
BodyType.DynamicBody, boxFixture);
physicsWorld.registerPhysicsConnector(new
PhysicsConnector(box, boxBody, true, true));

scene.attachChild(box);

scene.registerUpdateHandler(physicsWorld);
scene.registerUpdateHandler(mUpdateHandler);
return scene;
}

Types of bodies
● Dynamic
● It is affected by physics like gravity
● Kinematic
● It moves in a specified way
● Static
● It does not move

More Interesting things
● TiledTextures / Animated Sprites
● Animations
● Sound Engine
● Particle Systems
● Collision Detect
● Polygonal Bodies
● Menus

Intermission

← AndEngine Example apk

jPCT-AE
● http://www.jpct.net/jpct-ae/
● 3D Engine
● 3DObjects
● Lights
● etc
● No physics
● It has collision detection

Games built with jPCT-AE
● SpaceCat
● SkyFrontier
● Forgotten Elements
● Mobialia Chess
● Freddy Budgett
● Alien Runner
● ...

Project setup

Add jpct-ae.jar to libs / Build path

Concepts / Classes
● Renderer / FrameBuffer
● World
● Texture / TextureManager
● Object3D
● Light
● Camera

Game Architecture / jPCT-AE
Game Engine


Renderer World

3DObject

Preparing the GLSurfaceView
mGlView = (GLSurfaceView) findViewById(R.id.glview);
mGlView.setKeepScreenOn(true);
mViewRenderer = new MyRenderer(mGlView, mWorld);
mGlView.setRenderer(mViewRenderer);

Renderer setup
public void onDrawFrame(GL10 gl) {
buffer.clear(back);
synchronized (mWorld) {
mWorld.renderScene(buffer);
mWorld.draw(buffer);
}
buffer.display();
}

Setup the World
mWorld = new World();
mWorld.setAmbientLight(150, 150, 150);

Loading Textures
Resources res = getResources();
Texture texture =
new Texture(res.getDrawable(R.raw.texture));
TextureManager.getInstance()
.addTexture("texture", texture);

Loading Objects
mModel = Loader.load3DS(getResources()
.openRawResource(R.raw.model), 1)[0];
mModel.setTexture("texture");

mWorld.addObject(mModel);
mWorld.buildAllObjects();

Creating Lights
Light sun = new Light(mWorld);
sun.setIntensity(250, 250, 250);
SimpleVector sv = new SimpleVector(0, -100, -100);
sun.setPosition(sv);

Handling the camera
Camera cam = mWorld.getCamera();
cam.setPosition(new SimpleVector(0, 0,-100));
cam.lookAt(mModel.getTransformedCenter());

More about the camera
● It has a position
● Camera.setPosition
● It has a target
● Camera.lookAt
● It has a rotation
● Camera.setRotation

Operations with objects
● Hierarchy
● addChild
● Move
● setPosition / translate
● Rotation
● rotateX, rotateY, rotateZ

More Interesting Things
● Keyframe Animations
● Collision detect (Ellipsoids)
● Billboards
● Transparency
● Culling
● Primitive Objects

And a workaround
● Overlay native layouts
● Menus
● Dialogs

Another Intermission

← jPCT-AE Example apk

Bonus: Other Engines
● PlayN
● https://developers.google.com/playn/
● NME
● http://www.haxenme.org/
● Unity
● http://unity3d.com/
● Game Maker
● http://www.yoyogames.com/make

Why use a Library?
● Not reinventing the wheel
● It is proven that works
● Familiarity for users
● Other games use them
● You do not own the servers
● You don’t, and that is good

Available libraries
● ScoreLoop ● OpenFeint

What do you get?
● Achievements
● Not very impressive
● Leaderboards
● That is interesting
● News Feed
● Friends management
● Improved engagement

Easy to integrate
● Android Library Project
● Initialize with the Application
● Open a specific screen
● 2 lines of code
● Submit a score or achievement
● 2 lines of code

Monetization

Too much to say for a single slide

And now...
● Lunch
● Pitch your game idea
● Gather a team
● Hackaton
● Demos, Pizza & Beer

Tools for developing Android Games

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Tools for developing Android Games