(转)[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

 @Override
     public EngineOptions onCreateEngineOptions() {
         // TODO Auto-generated method stub
         mCamera = 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;
     }

     @Override
     public void onCreateResources(
             OnCreateResourcesCallback pOnCreateResourcesCallback)
             throws Exception {
         // TODO Auto-generated method stub
         BitmapTextureAtlas 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(){

                     @Override
                     public void onControlChange(
                             BaseOnScreenControl pBaseOnScreenControl,
                             float pValueX, float pValueY) {
                         // TODO Auto-generated method stub
                         if(pValueX == 0 && pValueY == 0){
                             mFace.setVelocity(0, 0);
                         }

                         else
                         {
                             mFace.setVelocity(pValueX*100, pValueY*100);
                         }
                     }

                     @Override
                     public 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(){

                     @Override
                     public void onControlChange(
                             BaseOnScreenControl pBaseOnScreenControl,
                             float pValueX, float pValueY) {
                         // TODO Auto-generated method stub
                         if(pValueX == 0 && pValueY == 0){
                             mFace.setRotation(0.0f);
                         }

                         else
                         {
                             mFace.setRotation(MathUtils.radToDeg(MathUtils.atan2(pValueY, pValueX)));
                         }
                     }

                     @Override
                     public 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(){

             @Override
             public void onUpdate(float pSecondsElapsed) {
                 // TODO Auto-generated method stub
                 if(mRectangle.collidesWith(mFace)){
                     mRectangle.setColor(1.0f, 0.0f, 0.0f);
                 }

                 else
                 {
                     mRectangle.setColor(0.0f,1.0f,0.0f);
                 }
             }

             @Override
             public 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;



         @Override
         protected void onManagedUpdate(float pSecondsElapsed) {
             // TODO Auto-generated method stub
             this.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

转自：http://blog.csdn.net/cen616899547/article/details/8151822