AndEngine之DEMO學習（零）AndEngine結構

幻魂1990 2013-07-29

展開全文

andEngine結構：
雙線程：業(yè)務線程、渲染線程,，使用ReentrantLock實現(xiàn)兩個線程的交替執(zhí)行,。
渲染線程：使用GLSurfaceView提供的渲染功能，內置渲染繪圖線程,。
第一步：RenderSurfaceView為繼承于GLSurfaceView的GL渲染視圖,，BaseGameActivity作為繼承于Activity的活動，通過setContentView(RenderSurfaceView)將視圖加入活動中,。
BaseGameActivity中主要方法：

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@Override
protected void onCreate(final Bundle pSavedInstanceState) {
if(BuildConfig.DEBUG) {
Debug.d(this.getClass().getSimpleName() ".onCreate" " @(Thread: '" Thread.currentThread().getName() "')");
}
super.onCreate(pSavedInstanceState);
//先處于暫停狀態(tài)
this.mGamePaused = true;
//通過EngineOption定義,，創(chuàng)建Engine
this.mEngine = this.onCreateEngine(this.onCreateEngineOptions());
//應用EngineOption定義到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：將渲染器EngineRenderer的加入RenderSurfaceView中，BaseGameActivity實現(xiàn)IRendererListener接口監(jiān)聽EngineRenderer,。
EngineRenderer中的主要方法：

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@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);
//回調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) {
//確定因為和GL的顯示區(qū)域大小
this.mEngine.setSurfaceSize(pWidth, pHeight);
GLES20.glViewport(0, 0, pWidth, pHeight);
this.mGLState.loadProjectionGLMatrixIdentity();
//回調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 {
//調用引擎中的方法
this.mEngine.onDrawFrame(this.mGLState);
} catch (final InterruptedException e) {
Debug.e("GLThread interrupted!", e);
}
}
}

Engine中的主要方法：

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public void onDrawFrame(final GLState pGLState) throws InterruptedException {
final EngineLock engineLock = this.mEngineLock;
//繪制過程中為引擎加鎖,，等待繪制完成
engineLock.lock();
try {
engineLock.waitUntilCanDraw();
//更新頂點緩存，去除Unloaded的緩存
this.mVertexBufferObjectManager.updateVertexBufferObjects(pGLState);
//更新紋理,，加載紋理到硬件
this.mTextureManager.updateTextures(pGLState);
//更新字體,，繪制所有文字
this.mFontManager.updateFonts(pGLState);
//調用mDrawHandlers中注冊的所有需要繪制的IDrawHandler的onDraw方法
this.onUpdateDrawHandlers(pGLState, this.mCamera);
//逐層調用Scene中IEntity的onDraw方法
this.onDrawScene(pGLState, this.mCamera);
engineLock.notifyCanUpdate();
} finally {
engineLock.unlock();
}
}

業(yè)務線程：Engine的初始化函數(shù)中啟動業(yè)務執(zhí)行線程UpdateThread，為注冊到引擎中,、或注冊到引擎包含的實體中的IUpdateHandler接口執(zhí)行onUpdate()方法,，完成業(yè)務的更新操作。

UpdateThread中主要方法：

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@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：

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void onTickUpdate() throws InterruptedException {
//如果引擎正在運行,，更新所有IUpdateHandler,，否則Thread.sleep(16);什么也不做
if(this.mRunning) {
//從上傳更新已經(jīng)度過的時間（毫秒）
final long secondsElapsed = this.getNanosecondsElapsed();
this.mEngineLock.lock();
try {
//如果引擎已經(jīng)被摧毀,，拋出EngineDestroyedException異常
this.throwOnDestroyed();
//更新業(yè)務
this.onUpdate(secondsElapsed);
//如果引擎已經(jīng)被摧毀，拋出EngineDestroyedException異常
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;
//更新觸摸事件控制
this.mTouchController.onUpdate(pSecondsElapsed);
//更新注冊的IUpdateHandler
this.onUpdateUpdateHandlers(pSecondsElapsed);
//更新屏幕
this.onUpdateScene(pSecondsElapsed);
}