发现每次都是要下岗前写博客,真不吉利啊,平时都没有空写。言归正传,上次的讲到RenderView和RootLayer,看起来必须把OpenGL的相关类弄清楚才能理解。
我们知道要使用的OpenGL 是画图的一堆接口(当然包括3D 纹理 渲染很多东西),在用这些的同时,我们的Activity本身还有响应触摸按键事件,重现绘制界面,这两者必须同时良好的运行,怎么做到这些?不用着急,android写好了一个类:android.opengl.GLSurfaceView
这个类有什么用,应该怎么使用呢?
这个类可以调用OpenGL API的接口,并添加自己的渲染器,如果要实现触摸监听等事件,就需要扩展这个类实现触摸监听。
public final class RenderView extends GLSurfaceView implements GLSurfaceView.Renderer, SensorEventListener { }
看下Gallery3d是如何做的
@Override public boolean onKeyDown(int keyCode, KeyEvent event) { if (mRenderView != null) { return mRenderView.onKeyDown(keyCode, event) || super.onKeyDown(keyCode, event); } else { return super.onKeyDown(keyCode, event); } }
不知道大家明白没有,这样的代码意味着,如果mRenderView在的话,只要在mRenderView里面就可以处理这个Activity的按键消息。
为什么?因为Activity的按键消息(onKeyDown的消息) 都被转到mRenderView.onKeyDown中了。
同样的原理在
onPause
onResume
也有类似的代码,意味着这个View和Activity是同步动作的。
但是没有看到触摸的处理,触摸是在哪里处理的呢?
那么需要我们仔细看下我们继承后生成的RenderView里面的实现。
public void setRootLayer(RootLayer layer) { if (mRootLayer != layer) { mRootLayer = layer; mListsDirty = true; if (layer != null) { mRootLayer.setSize(mViewWidth, mViewHeight); } } }
这里实现了mGridLayer变成了mRootLayer,实现了二者的关联。
@Override public void onResume() { super.onResume(); Sensor sensorAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER); if (sensorAccelerometer != null) { mSensorManager.registerListener(this, sensorAccelerometer, SensorManager.SENSOR_DELAY_UI); } if (mRootLayer != null) { mRootLayer.onResume(); } } @Override public void onPause() { super.onPause(); Log.i(TAG, "OnPause RenderView " + this); mSensorManager.unregisterListener(this); if (mRootLayer != null) { mRootLayer.onPause(); } }
在这里面,通过上面这些代码,又将Root层的动作和View层同步。
RenderView要负责刷新和用户输入,而且要处理渲染,他是要新开线程的,看他的构造函数。
public RenderView(final Context context) { super(context); setBackgroundDrawable(null); setFocusable(true); setRenderer(this); mSensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE); if (sCachedTextureLoadThread == null) { for (int i = 0; i != NUM_TEXTURE_LOAD_THREADS; ++i) { TextureLoadThread thread = new TextureLoadThread(); if (i == 0) { sCachedTextureLoadThread = thread; } if (i == 1) { sVideoTextureLoadThread = thread; } sTextureLoadThreads[i] = thread; thread.start(); } } }
这里是循环,NUM_TEXTURE_LOAD_THREADS 值为4,而看到 在0和1时,分别是sCacheTextureLoadThread和sVideoTextureLoadThread,并且又将四个线程放在了sTextureLoadTheads数组里面。
就是用线程刷纹理,什么是纹理,就是一张图片,贴到物体的表面,比如一个木头的纹理图片,贴到一个正方形上,看起来就感觉这个正方形是个木头了。
public void run() { Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); Deque<Texture> inputQueue = (sVideoTextureLoadThread == this) ? sLoadInputQueueVideo : ((sCachedTextureLoadThread == this) ? sLoadInputQueueCached : sLoadInputQueue); Deque<Texture> outputQueue = sLoadOutputQueue; try { for (;;) { // Pop the next texture from the input queue. Texture texture = null; synchronized (inputQueue) { while ((texture = inputQueue.pollFirst()) == null) { inputQueue.wait(); } } if (sCachedTextureLoadThread != this) mIsLoading = true; // Load the texture bitmap. load(texture); mIsLoading = false; // Push the texture onto the output queue. synchronized (outputQueue) { outputQueue.addLast(texture); } } } catch (InterruptedException e) { // Terminate the thread. } }
加载函数
private void load(Texture texture) { // Generate the texture bitmap. RenderView view = RenderView.this; view.loadTextureAsync(texture); view.requestRender(); }
可以看到,纹理的输入队列只有三种情况
1 sLoadInputQueueVideo
2 sLoadInputQueueCached
3 sLoadInputQueue
private void queueLoad(final Texture texture, boolean highPriority) { // Allow the texture to defer queuing. if (!texture.shouldQueue()) { return; } // Change the texture state to loading. texture.mState = Texture.STATE_LOADING; // Push the texture onto the load input queue. Deque<Texture> inputQueue = (texture.isUncachedVideo()) ? sLoadInputQueueVideo : (texture.isCached()) ? sLoadInputQueueCached : sLoadInputQueue; ; synchronized (inputQueue) { if (highPriority) { inputQueue.addFirst(texture); // Enforce the maximum loading count by removing something from the end of // the loading queue, if necessary. if (mLoadingCount >= MAX_LOADING_COUNT) { Texture unloadTexture = inputQueue.pollLast(); unloadTexture.mState = Texture.STATE_UNLOADED; --mLoadingCount; } } else { inputQueue.addLast(texture); } inputQueue.notify(); } ++mLoadingCount; }
onDrawFrame():
每帧都通过该方法进行绘制。绘制时通常先调用 glClear函数来清空 framebuffer,然后在调用 OpenGL ES 的接口进行绘制。
// @Override public void onDrawFrame(GL10 gl1) { GL11 gl = (GL11) gl1; if (!mFirstDraw) { Log.i(TAG, "First Draw"); } mFirstDraw = true; // setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY); // Rebuild the display lists if the render tree has changed. if (mListsDirty) { updateLists(); } boolean wasLoadingExpensiveTextures = isLoadingExpensiveTextures(); boolean loadingExpensiveTextures = false; int numTextureThreads = sTextureLoadThreads.length; for (int i = 2; i < numTextureThreads; ++i) { if (sTextureLoadThreads[i].mIsLoading) { loadingExpensiveTextures = true; break; } } if (loadingExpensiveTextures != wasLoadingExpensiveTextures) { mLoadingExpensiveTexturesStartTime = loadingExpensiveTextures ? SystemClock.uptimeMillis() : 0; } // Upload new textures. processTextures(false); // Update the current time and frame time interval. long now = SystemClock.uptimeMillis(); final float dt = 0.001f * Math.min(50, now - mFrameTime); mFrameInterval = dt; mFrameTime = now; // Dispatch the current touch event. processCurrentEvent(); processTouchEvent(); // Run the update pass. final Lists lists = sLists; synchronized (lists) { final ArrayList<Layer> updateList = lists.updateList; boolean isDirty = false; for (int i = 0, size = updateList.size(); i != size; ++i) { boolean retVal = updateList.get(i).update(this, mFrameInterval); isDirty |= retVal; } if (isDirty) { requestRender(); } // Clear the depth buffer. gl.glClear(GL11.GL_DEPTH_BUFFER_BIT); gl.glEnable(GL11.GL_SCISSOR_TEST); gl.glScissor(0, 0, getWidth(), getHeight()); // Run the opaque pass. gl.glDisable(GL11.GL_BLEND); final ArrayList<Layer> opaqueList = lists.opaqueList; for (int i = opaqueList.size() - 1; i >= 0; --i) { final Layer layer = opaqueList.get(i); if (!layer.mHidden) { layer.renderOpaque(this, gl); } } // Run the blended pass. gl.glEnable(GL11.GL_BLEND); final ArrayList<Layer> blendedList = lists.blendedList; for (int i = 0, size = blendedList.size(); i != size; ++i) { final Layer layer = blendedList.get(i); if (!layer.mHidden) { layer.renderBlended(this, gl); } } gl.glDisable(GL11.GL_BLEND); } }
这段代码有点长,我们分析下,首先是列表如果有改动,会要更新层列表 update opaque blended,为什么只刷这三个层啊?因为只有在这三个列表的层才和刷新相关,更新层,半透明层和不透明层。
然后是处理纹理,将纹理上传到GPU(如果这里不清楚,看OpenGL的概念)
终于我们在这里找到了触摸的处理。
// Dispatch the current touch event. processCurrentEvent(); processTouchEvent();
大家应该还记得,上次我们已经把按键存起来了,触摸的事件保存在一个队列中了,现在可以处理了。
private void processKeyEvent() { // Get the event. final KeyEvent event = mCurrentKeyEvent; boolean result = false; mCurrentKeyEvent = null; // Dispatch the event to the root layer. if (mRootLayer != null) { if (event.getAction() == KeyEvent.ACTION_DOWN) { result = mRootLayer.onKeyDown(event.getKeyCode(), event); } else { result = mRootLayer.onKeyUp(event.getKeyCode(), event); } } mCurrentKeyEventResult = result; }
以上代码说明了一个问题,所有的按键事件都是在Root Layer层中处理的。
再来看触摸的处理
private void processTouchEvent() { MotionEvent event = null; int numEvents = mTouchEventQueue.size(); int i = 0; do { // We look at the touch event queue and process one event at a time synchronized (mTouchEventQueue) { event = mTouchEventQueue.pollFirst(); } if (event == null) return; // Detect the hit layer. final int action = event.getAction(); Layer target; if (action == MotionEvent.ACTION_DOWN) { target = hitTest(event.getX(), event.getY()); mTouchEventTarget = target; } else { target = mTouchEventTarget; } // Dispatch event to the hit layer. if (target != null) { target.onTouchEvent(event); } // Clear the hit layer. if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_CANCEL) { mTouchEventTarget = null; } event.recycle(); ++i; } while (event != null && i < numEvents); synchronized (this) { this.notify(); } }
private Layer hitTest(float x, float y) { final ArrayList<Layer> hitTestList = sLists.hitTestList; for (int i = hitTestList.size() - 1; i >= 0; --i) { final Layer layer = hitTestList.get(i); if (layer != null && !layer.mHidden) { final float layerX = layer.mX; final float layerY = layer.mY; if (x >= layerX && y >= layerY && x < layerX + layer.mWidth && y < layerY + layer.mHeight && layer.containsPoint(x, y)) { return layer; } } } return null; }
这两段代码看完,我们会发现触摸的处理方法。
但是,这个触摸的处理只是针对
hitTestList
这个层的LIST。但这个层的LIST在什么地方关联的?在什么地方添加的其他的层?呵呵,下次讲解。