[AndEngine学习教程] 第9节 CollisionDetection 实体碰撞检测

1.本节要点

    通过一个可操作的精灵,来与一个固定循环变化的矩形检测是否产生碰撞,当产生碰撞的时候,矩形的颜色为红色,

   否则矩形的颜色为绿色

2.新学内容

 1.学会使用SmoothCamera类,这个类是一个平滑的照相机类,可以满足背景自动填充,平滑过渡的效果.先看看它的构成吧:

public class SmoothCamera extends ZoomCamera 

是继承于SmoothCamera的类,而SmoothCamera从文字上就可以看出它是一个支持缩放效果的类,因此使用起来就很方便了,

构造方法为:

public SmoothCamera(final float pX, final float pY, final float pWidth, final float pHeight, final float pMaxVelocityX, final float pMaxVelocityY, final float pMaxZoomFactorChange) {super(pX, pY, pWidth, pHeight);this.mMaxVelocityX = pMaxVelocityX;this.mMaxVelocityY = pMaxVelocityY;this.mMaxZoomFactorChange = pMaxZoomFactorChange;this.mTargetCenterX = this.getCenterX();this.mTargetCenterY = this.getCenterY();this.mTargetZoomFactor = 1.0f;}

为了体现效果,我刻意的把背景图片做成720*640大小,而手机的屏幕分辨率大小为800*480,但是依然可以看到全屏的效果.相当不错的哦!

以下的是我使用到的背景图片:

  

 2.为场景Scene注册刷新句柄,用来监听每次实体间是否产生碰撞.然后进行相应的事物处理,具体调用方法为:

mScene.registerUpdateHandler(new IUpdateHandler());

3.内部代码初始化设计

1.本节使用到4个实体,一个是人脸,另外一个是矩形,最后2个是控制器,内部成员变量设计为:

private static final int CAMERA_WIDTH = 800;private static final int CAMERA_HEIGHT = 480;private SmoothCamera mCamera;private SpriteBackground mBackground;private TiledTextureRegion mControlBaseRegion;private TiledTextureRegion mControlKnobRegion;private TiledTextureRegion mFaceRegion;

2.引擎资源的加载

@Overridepublic EngineOptions onCreateEngineOptions() {// TODO Auto-generated method stubmCamera = new SmoothCamera(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT, 10, 10, 3);EngineOptions mEngineOptions = new  EngineOptions(true, ScreenOrientation.LANDSCAPE_SENSOR,new RatioResolutionPolicy(CAMERA_WIDTH,CAMERA_HEIGHT),mCamera);return mEngineOptions;}@Overridepublic void onCreateResources(OnCreateResourcesCallback pOnCreateResourcesCallback)throws Exception {// TODO Auto-generated method stubBitmapTextureAtlas mTexture = new BitmapTextureAtlas(getTextureManager(), 1024, 1024, TextureOptions.BILINEAR_PREMULTIPLYALPHA);final TiledTextureRegion mBackgroundRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(mTexture, this, "bg.png", 0, 0, 1, 1);final Sprite mBackgroundSprite = new Sprite(0, 0, CAMERA_WIDTH, CAMERA_HEIGHT, mBackgroundRegion, getVertexBufferObjectManager());mBackground = new SpriteBackground(mBackgroundSprite);mControlBaseRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(mTexture, this, "onscreen_control_base.png", 720, 0, 1, 1);mControlKnobRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(mTexture, this, "onscreen_control_knob.png", 848, 0, 1, 1);mFaceRegion = BitmapTextureAtlasTextureRegionFactory.createTiledFromAsset(mTexture, this, "face_box.png", 912, 0, 1, 1);mTexture.load();pOnCreateResourcesCallback.onCreateResourcesFinished();}

4.场景设计
1.添加多点触摸支持和场景基础设施

if(MultiTouch.isSupported(this)){this.mEngine.setTouchController(new MultiTouchController());//多点触摸}Scene mScene = new Scene();mScene.setBackground(mBackground);final float centerX = (CAMERA_WIDTH - mFaceRegion.getWidth()) / 2;final float centerY = (CAMERA_HEIGHT - mFaceRegion.getHeight()) / 2;

2.构建相应的精灵任务:

    2.1 布置人脸:            

final MySprite mFace = new MySprite(centerX - 50, centerY, 80, 80, mFaceRegion, getVertexBufferObjectManager());

   2.2 不知受碰撞检测的矩形

final Rectangle mRectangle = new Rectangle(centerX + 10, centerY, 80,80,getVertexBufferObjectManager());mRectangle.registerEntityModifier(new LoopEntityModifier(new ParallelEntityModifier(new ScaleModifier(2, 0.5f, 2.0f),new ScaleModifier(2, 2.0f,1.0f),new RotationModifier(4,0.0f,360.0f) )));

     添加相应的modifier后,矩形就会动态的变幻了.

   2.3 布置移动控制器和方向控制器

       

final AnalogOnScreenControl mSpeedController = new AnalogOnScreenControl(30,CAMERA_HEIGHT -  mControlBaseRegion.getHeight() - 20,mCamera, mControlBaseRegion, mControlKnobRegion, 0.1f, 100,getVertexBufferObjectManager(),new IAnalogOnScreenControlListener(){@Overridepublic void onControlChange(BaseOnScreenControl pBaseOnScreenControl,float pValueX, float pValueY) {// TODO Auto-generated method stubif(pValueX == 0 && pValueY == 0){mFace.setVelocity(0, 0);}else{mFace.setVelocity(pValueX*100, pValueY*100);}}@Overridepublic void onControlClick(AnalogOnScreenControl pAnalogOnScreenControl) {// TODO Auto-generated method stub}});final AnalogOnScreenControl mRotationController = new AnalogOnScreenControl(CAMERA_WIDTH - mControlBaseRegion.getWidth() - 30,CAMERA_HEIGHT -  mControlBaseRegion.getHeight() - 20,mCamera, mControlBaseRegion, mControlKnobRegion, 0.1f, 100,getVertexBufferObjectManager(),new IAnalogOnScreenControlListener(){@Overridepublic void onControlChange(BaseOnScreenControl pBaseOnScreenControl,float pValueX, float pValueY) {// TODO Auto-generated method stubif(pValueX == 0 && pValueY == 0){mFace.setRotation(0.0f);}else{mFace.setRotation(MathUtils.radToDeg(MathUtils.atan2(pValueY, pValueX)));}}@Overridepublic void onControlClick(AnalogOnScreenControl pAnalogOnScreenControl) {// TODO Auto-generated method stub}});

      2.4 把所有角色搬到场景中

mSpeedController.getControlBase().setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);mRotationController.getControlBase().setBlendFunction(GL10.GL_SRC_ALPHA, GL10.GL_ONE_MINUS_SRC_ALPHA);mScene.attachChild(mFace);mScene.attachChild(mRectangle);mScene.setChildScene(mSpeedController);mSpeedController.setChildScene(mRotationController);pOnCreateSceneCallback.onCreateSceneFinished(mScene);

5.在场景中注册刷新监听事件

 

mScene.registerUpdateHandler(new IUpdateHandler(){@Overridepublic void onUpdate(float pSecondsElapsed) {// TODO Auto-generated method stubif(mRectangle.collidesWith(mFace)){mRectangle.setColor(1.0f, 0.0f, 0.0f);}else{mRectangle.setColor(0.0f,1.0f,0.0f);}}@Overridepublic void reset() {// TODO Auto-generated method stub}});

有了这个监听后,场景每次的刷新都可以添加处理事件了.所以基本上就完成任务了,呵呵

6.辅助自定义类

public class MySprite extends Sprite{public MySprite(float pX, float pY, float pWidth, float pHeight,ITextureRegion pTextureRegion,VertexBufferObjectManager pVertexBufferObjectManager) {super(pX, pY, pWidth, pHeight, pTextureRegion, pVertexBufferObjectManager);// TODO Auto-generated constructor stub}private float mVelocityX = 0;private float mVelocityY = 0;@Overrideprotected void onManagedUpdate(float pSecondsElapsed) {// TODO Auto-generated method stubthis.mX += mVelocityX * pSecondsElapsed;this.mY += mVelocityY * pSecondsElapsed;this.setPosition(mX, mY);super.onManagedUpdate(pSecondsElapsed);}void setVelocity(float vX, float vY){mVelocityX = vX;mVelocityY = vY;}}

7.运行演示

   通过碰撞检测运行的结果如下:

本例子源代码:http://download.csdn.net/detail/cen616899547/4737237