tools for developing android games
DESCRIPTION
Slides from the workshop: Tools for developing Android Games, held on March 24th, 2012 at Amsterdam.TRANSCRIPT
Summary
● Introduction to game development● Engines
● AndEngine● jPCT-AE
● Scores / Achievements● Monetization systems
Game Architecture (Simplified)
Game Engine
Game Objects Update ThreadDraw 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 OpenGL?
Performance
Why use any Engine
You don’t want to start from scratch
AndEngine
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● ...
Games built with AndEngine
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
Game Objects Update ThreadDraw Thread
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);
Creating the Scene (2/3)
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);
Creating the Scene (3/3)
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
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● ...
Games built with jPCT-AE
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
Game Objects Update ThreadDraw Thread
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
The 3D axis
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
Scores / Achievements
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
