AndEngine之DEMO学习（零）AndEngine结构

最新推荐文章于 2025-12-02 23:01:17 发布

最新推荐文章于 2025-12-02 23:01:17 发布 · 159 阅读

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本文深入解析AndEngine的双线程结构，包括渲染线程、业务线程的运行机制及Entity的更新流程。详细介绍了Engine的初始化、渲染视图的设置、EngineRenderer的实现、以及UpdateThread的执行过程，帮助开发者理解AndEngine的内部运作原理。

andEngine结构：
双线程：业务线程、渲染线程，使用ReentrantLock实现两个线程的交替执行。
渲染线程：使用GLSurfaceView提供的渲染功能，内置渲染绘图线程。
第一步：RenderSurfaceView为继承于GLSurfaceView的GL渲染视图，BaseGameActivity作为继承于Activity的活动，通过setContentView(RenderSurfaceView)将视图加入活动中。
BaseGameActivity中主要方法：

@Override
 protected void onCreate(final Bundle pSavedInstanceState) {
  if(BuildConfig.DEBUG) {
   Debug.d(this.getClass().getSimpleName() + ".onCreate" + " @(Thread: '" + Thread.currentThread().getName() + "')");
  }

  super.onCreate(pSavedInstanceState);
  //先处于暂停状态
  this.mGamePaused = true;
  //通过EngineOption定义，创建Engine
  this.mEngine = this.onCreateEngine(this.onCreateEngineOptions());
  //应用EngineOption定义到Activity
  this.applyEngineOptions();
  //添加RenderSurfaceView到Activity
  this.onSetContentView();
 }
 
 protected void onSetContentView() {
  this.mRenderSurfaceView = new RenderSurfaceView(this);
  this.mRenderSurfaceView.setRenderer(this.mEngine, this);

  this.setContentView(this.mRenderSurfaceView, BaseGameActivity.createSurfaceViewLayoutParams());
 }

第二步：将渲染器EngineRenderer的加入RenderSurfaceView中，BaseGameActivity实现IRendererListener接口监听EngineRenderer。
EngineRenderer中的主要方法：

@Override
 public void onSurfaceCreated(final GL10 pGL, final EGLConfig pEGLConfig) {
  synchronized(GLState.class) {
   final RenderOptions renderOptions = this.mEngine.getEngineOptions().getRenderOptions();
   this.mGLState.reset(renderOptions, this.mConfigChooser, pEGLConfig);

   // TODO Check if available and make available through EngineOptions-RenderOptions
//   GLES20.glEnable(GLES20.GL_POLYGON_SMOOTH);
//   GLES20.glHint(GLES20.GL_POLYGON_SMOOTH_HINT, GLES20.GL_NICEST);
//   GLES20.glEnable(GLES20.GL_LINE_SMOOTH);
//   GLES20.glHint(GLES20.GL_LINE_SMOOTH_HINT, GLES20.GL_NICEST);
//   GLES20.glEnable(GLES20.GL_POINT_SMOOTH);
//   GLES20.glHint(GLES20.GL_POINT_SMOOTH_HINT, GLES20.GL_NICEST);
   
   //2D不需要深度
   this.mGLState.disableDepthTest();
   this.mGLState.enableBlend();
   this.mGLState.setDitherEnabled(renderOptions.isDithering());

   /* Enabling culling doesn't really make sense, because triangles are never drawn 'backwards' on purpose. */
//   this.mGLState.enableCulling();
//   GLES20.glFrontFace(GLES20.GL_CCW);
//   GLES20.glCullFace(GLES20.GL_BACK);
   
   //回调BaseGameActivity中onSurfaceCreated
   if(this.mRendererListener != null) {
    this.mRendererListener.onSurfaceCreated(this.mGLState);
   }
  }
 }

 @Override
 public void onSurfaceChanged(final GL10 pGL, final int pWidth, final int pHeight) {
  //确定因为和GL的显示区域大小
  this.mEngine.setSurfaceSize(pWidth, pHeight);
  GLES20.glViewport(0, 0, pWidth, pHeight);
  this.mGLState.loadProjectionGLMatrixIdentity();

  //回调BaseGameActivity中onSurfaceChanged
  if(this.mRendererListener != null) {
   this.mRendererListener.onSurfaceChanged(this.mGLState, pWidth, pHeight);
  }
 }

 @Override
 public void onDrawFrame(final GL10 pGL) {
  synchronized(GLState.class) {
   if (this.mMultiSampling && this.mConfigChooser.isCoverageMultiSampling()) {
    final int GL_COVERAGE_BUFFER_BIT_NV = 0x8000;
    GLES20.glClear(GL_COVERAGE_BUFFER_BIT_NV);
   }

   try {
    //调用引擎中的方法
    this.mEngine.onDrawFrame(this.mGLState);
   } catch (final InterruptedException e) {
    Debug.e("GLThread interrupted!", e);
   }
  }
 }

Engine中的主要方法：

public void onDrawFrame(final GLState pGLState) throws InterruptedException {
  final EngineLock engineLock = this.mEngineLock;

  //绘制过程中为引擎加锁，等待绘制完成
  engineLock.lock();
  try {
   engineLock.waitUntilCanDraw();

   //更新顶点缓存，去除Unloaded的缓存
   this.mVertexBufferObjectManager.updateVertexBufferObjects(pGLState);
   //更新纹理，加载纹理到硬件
   this.mTextureManager.updateTextures(pGLState);
   //更新字体，绘制所有文字
   this.mFontManager.updateFonts(pGLState);

   //调用mDrawHandlers中注册的所有需要绘制的IDrawHandler的onDraw方法
   this.onUpdateDrawHandlers(pGLState, this.mCamera);
   //逐层调用Scene中IEntity的onDraw方法
   this.onDrawScene(pGLState, this.mCamera);

   engineLock.notifyCanUpdate();
  } finally {
   engineLock.unlock();
  }
 }

业务线程：Engine的初始化函数中启动业务执行线程UpdateThread，为注册到引擎中、或注册到引擎包含的实体中的IUpdateHandler接口执行onUpdate()方法，完成业务的更新操作。

UpdateThread中主要方法：

  @Override
  public void run() {
   android.os.Process.setThreadPriority(this.mEngine.getEngineOptions().getUpdateThreadPriority());
   try {
    while(true) {
     this.mRunnableHandler.onUpdate(0);
     this.mEngine.onTickUpdate();
    }
   } catch (final InterruptedException e) {
    if(BuildConfig.DEBUG) {
     Debug.d(this.getClass().getSimpleName() + " interrupted. Don't worry - this " + e.getClass().getSimpleName() + " is most likely expected!", e);
    }
    this.interrupt();
   }
  }

Engine中的主要方法：

void onTickUpdate() throws InterruptedException {
  //如果引擎正在运行，更新所有IUpdateHandler，否则Thread.sleep(16);什么也不做
  if(this.mRunning) {
   //从上传更新已经度过的时间（毫秒）
   final long secondsElapsed = this.getNanosecondsElapsed();

   this.mEngineLock.lock();
   try {
    //如果引擎已经被摧毁，抛出EngineDestroyedException异常
    this.throwOnDestroyed();

    //更新业务
    this.onUpdate(secondsElapsed);

    //如果引擎已经被摧毁，抛出EngineDestroyedException异常
    this.throwOnDestroyed();

    this.mEngineLock.notifyCanDraw();
    this.mEngineLock.waitUntilCanUpdate();
   } finally {
    this.mEngineLock.unlock();
   }
  } else {
   this.mEngineLock.lock();
   try {
    this.throwOnDestroyed();

    this.mEngineLock.notifyCanDraw();
    this.mEngineLock.waitUntilCanUpdate();
   } finally {
    this.mEngineLock.unlock();
   }

   Thread.sleep(16);
  }
 }
 
 public void onUpdate(final long pNanosecondsElapsed) throws InterruptedException {
  final float pSecondsElapsed = pNanosecondsElapsed * TimeConstants.SECONDS_PER_NANOSECOND;

  this.mSecondsElapsedTotal += pSecondsElapsed;
  this.mLastTick += pNanosecondsElapsed;

  //更新触摸事件控制
  this.mTouchController.onUpdate(pSecondsElapsed);
  //更新注册的IUpdateHandler
  this.onUpdateUpdateHandlers(pSecondsElapsed);
  //更新屏幕
  this.onUpdateScene(pSecondsElapsed);
 }

Entity中的主要方法：

  @Override
 public final void onUpdate(final float pSecondsElapsed) {
  if(!this.mIgnoreUpdate) {
   this.onManagedUpdate(pSecondsElapsed);
  }
 }
 
 /**
  * 对实体的onUpdate方法的实际处理函数
  * 
  * @param pSecondsElapsed  间隔秒数
  */
 protected void onManagedUpdate(final float pSecondsElapsed) {
  //本身注册的实体修改器的onUpdate
  if(this.mEntityModifiers != null) {
   this.mEntityModifiers.onUpdate(pSecondsElapsed);
  }
  //本身注册IUpdateHandler对象的onUpdate
  if(this.mUpdateHandlers != null) {
   this.mUpdateHandlers.onUpdate(pSecondsElapsed);
  }

  //调用子实体的onUpdate方法
  if((this.mChildren != null) && !this.mChildrenIgnoreUpdate) {
   final SmartList<IEntity> entities = this.mChildren;
   final int entityCount = entities.size();
   for(int i = 0; i < entityCount; i++) {
    entities.get(i).onUpdate(pSecondsElapsed);
   }
  }
 }

andEngine继承关系：