GLTextureView

GLTextureView.java

package jp.wasabeef.sample;

import android.content.Context;
import android.graphics.SurfaceTexture;
import android.opengl.GLDebugHelper;
import android.util.AttributeSet;
import android.util.Log;
import android.view.TextureView;
import android.view.View;
import java.io.Writer;
import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.List;
import javax.microedition.khronos.egl.EGL10;
import javax.microedition.khronos.egl.EGL11;
import javax.microedition.khronos.egl.EGLConfig;
import javax.microedition.khronos.egl.EGLContext;
import javax.microedition.khronos.egl.EGLDisplay;
import javax.microedition.khronos.egl.EGLSurface;
import javax.microedition.khronos.opengles.GL;
import javax.microedition.khronos.opengles.GL10;

/*
 * Copyright (C) 2018 Wasabeef
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
public class GLTextureView extends TextureView
    implements TextureView.SurfaceTextureListener, View.OnLayoutChangeListener {

  private final static String TAG = GLTextureView.class.getSimpleName();

  private final static boolean LOG_ATTACH_DETACH = false;
  private final static boolean LOG_THREADS = false;
  private final static boolean LOG_PAUSE_RESUME = false;
  private final static boolean LOG_SURFACE = false;
  private final static boolean LOG_RENDERER = false;
  private final static boolean LOG_RENDERER_DRAW_FRAME = false;
  private final static boolean LOG_EGL = false;

  /**
   * The renderer only renders
   * when the surface is created, or when {@link #requestRender} is called.
   *
   * @see #getRenderMode()
   * @see #setRenderMode(int)
   * @see #requestRender()
   */
  public final static int RENDERMODE_WHEN_DIRTY = 0;
  /**
   * The renderer is called
   * continuously to re-render the scene.
   *
   * @see #getRenderMode()
   * @see #setRenderMode(int)
   */
  public final static int RENDERMODE_CONTINUOUSLY = 1;

  /**
   * Check glError() after every GL call and throw an exception if glError indicates
   * that an error has occurred. This can be used to help track down which OpenGL ES call
   * is causing an error.
   *
   * @see #getDebugFlags
   * @see #setDebugFlags
   */
  public final static int DEBUG_CHECK_GL_ERROR = 1;

  /**
   * Log GL calls to the system log at "verbose" level with tag "GLTextureView".
   *
   * @see #getDebugFlags
   * @see #setDebugFlags
   */
  public final static int DEBUG_LOG_GL_CALLS = 2;

  /**
   * Standard View constructor. In order to render something, you
   * must call {@link #setRenderer} to register a renderer.
   */
  public GLTextureView(Context context) {
    super(context);
    init();
  }

  /**
   * Standard View constructor. In order to render something, you
   * must call {@link #setRenderer} to register a renderer.
   */
  public GLTextureView(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  @Override protected void finalize() throws Throwable {
    try {
      if (glThread != null) {
        // GLThread may still be running if this view was never
        // attached to a window.
        glThread.requestExitAndWait();
      }
    } finally {
      super.finalize();
    }
  }

  private void init() {
    setSurfaceTextureListener(this);
  }

  /**
   * Set the glWrapper. If the glWrapper is not null, its
   * {@link GLWrapper#wrap(javax.microedition.khronos.opengles.GL)} method is called
   * whenever a surface is created. A GLWrapper can be used to wrap
   * the GL object that's passed to the renderer. Wrapping a GL
   * object enables examining and modifying the behavior of the
   * GL calls made by the renderer.
   * <p>
   * Wrapping is typically used for debugging purposes.
   * <p>
   * The default value is null.
   *
   * @param glWrapper the new GLWrapper
   */
  public void setGLWrapper(GLWrapper glWrapper) {
    this.glWrapper = glWrapper;
  }

  /**
   * Set the debug flags to a new value. The value is
   * constructed by OR-together zero or more
   * of the DEBUG_CHECK_* constants. The debug flags take effect
   * whenever a surface is created. The default value is zero.
   *
   * @param debugFlags the new debug flags
   * @see #DEBUG_CHECK_GL_ERROR
   * @see #DEBUG_LOG_GL_CALLS
   */
  public void setDebugFlags(int debugFlags) {
    this.debugFlags = debugFlags;
  }

  /**
   * Get the current value of the debug flags.
   *
   * @return the current value of the debug flags.
   */
  public int getDebugFlags() {
    return debugFlags;
  }

  /**
   * Control whether the EGL context is preserved when the GLTextureView is paused and
   * resumed.
   * <p>
   * If set to true, then the EGL context may be preserved when the GLTextureView is paused.
   * Whether the EGL context is actually preserved or not depends upon whether the
   * Android device that the program is running on can support an arbitrary number of EGL
   * contexts or not. Devices that can only support a limited number of EGL contexts must
   * release the  EGL context in order to allow multiple applications to share the GPU.
   * <p>
   * If set to false, the EGL context will be released when the GLTextureView is paused,
   * and recreated when the GLTextureView is resumed.
   * <p>
   *
   * The default is false.
   *
   * @param preserveOnPause preserve the EGL context when paused
   */
  public void setPreserveEGLContextOnPause(boolean preserveOnPause) {
    preserveEGLContextOnPause = preserveOnPause;
  }

  /**
   * @return true if the EGL context will be preserved when paused
   */
  public boolean getPreserveEGLContextOnPause() {
    return preserveEGLContextOnPause;
  }

  /**
   * Set the renderer associated with this view. Also starts the thread that
   * will call the renderer, which in turn causes the rendering to start.
   * <p>This method should be called once and only once in the life-cycle of
   * a GLTextureView.
   * <p>The following GLTextureView methods can only be called <em>before</em>
   * setRenderer is called:
   * <ul>
   * <li>{@link #setEGLConfigChooser(boolean)}
   * <li>{@link #setEGLConfigChooser(EGLConfigChooser)}
   * <li>{@link #setEGLConfigChooser(int, int, int, int, int, int)}
   * </ul>
   * <p>
   * The following GLTextureView methods can only be called <em>after</em>
   * setRenderer is called:
   * <ul>
   * <li>{@link #getRenderMode()}
   * <li>{@link #onPause()}
   * <li>{@link #onResume()}
   * <li>{@link #queueEvent(Runnable)}
   * <li>{@link #requestRender()}
   * <li>{@link #setRenderMode(int)}
   * </ul>
   *
   * @param renderer the renderer to use to perform OpenGL drawing.
   */
  public void setRenderer(Renderer renderer) {
    checkRenderThreadState();
    if (eglConfigChooser == null) {
      eglConfigChooser = new SimpleEGLConfigChooser(true);
    }
    if (eglContextFactory == null) {
      eglContextFactory = new DefaultContextFactory();
    }
    if (eglWindowSurfaceFactory == null) {
      eglWindowSurfaceFactory = new DefaultWindowSurfaceFactory();
    }
    this.renderer = renderer;
    glThread = new GLThread(mThisWeakRef);
    glThread.start();
  }

  /**
   * Install a custom EGLContextFactory.
   * <p>If this method is
   * called, it must be called before {@link #setRenderer(Renderer)}
   * is called.
   * <p>
   * If this method is not called, then by default
   * a context will be created with no shared context and
   * with a null attribute list.
   */
  public void setEGLContextFactory(EGLContextFactory factory) {
    checkRenderThreadState();
    eglContextFactory = factory;
  }

  /**
   * Install a custom EGLWindowSurfaceFactory.
   * <p>If this method is
   * called, it must be called before {@link #setRenderer(Renderer)}
   * is called.
   * <p>
   * If this method is not called, then by default
   * a window surface will be created with a null attribute list.
   */
  public void setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory factory) {
    checkRenderThreadState();
    eglWindowSurfaceFactory = factory;
  }

  /**
   * Install a custom EGLConfigChooser.
   * <p>If this method is
   * called, it must be called before {@link #setRenderer(Renderer)}
   * is called.
   * <p>
   * If no setEGLConfigChooser method is called, then by default the
   * view will choose an EGLConfig that is compatible with the current
   * android.view.Surface, with a depth buffer depth of
   * at least 16 bits.
   */
  public void setEGLConfigChooser(EGLConfigChooser configChooser) {
    checkRenderThreadState();
    eglConfigChooser = configChooser;
  }

  /**
   * Install a config chooser which will choose a config
   * as close to 16-bit RGB as possible, with or without an optional depth
   * buffer as close to 16-bits as possible.
   * <p>If this method is
   * called, it must be called before {@link #setRenderer(Renderer)}
   * is called.
   * <p>
   * If no setEGLConfigChooser method is called, then by default the
   * view will choose an RGB_888 surface with a depth buffer depth of
   * at least 16 bits.
   */
  public void setEGLConfigChooser(boolean needDepth) {
    setEGLConfigChooser(new SimpleEGLConfigChooser(needDepth));
  }

  /**
   * Install a config chooser which will choose a config
   * with at least the specified depthSize and stencilSize,
   * and exactly the specified redSize, greenSize, blueSize and alphaSize.
   * <p>If this method is
   * called, it must be called before {@link #setRenderer(Renderer)}
   * is called.
   * <p>
   * If no setEGLConfigChooser method is called, then by default the
   * view will choose an RGB_888 surface with a depth buffer depth of
   * at least 16 bits.
   */
  public void setEGLConfigChooser(int redSize, int greenSize, int blueSize, int alphaSize,
      int depthSize, int stencilSize) {
    setEGLConfigChooser(
        new ComponentSizeChooser(redSize, greenSize, blueSize, alphaSize, depthSize, stencilSize));
  }

  /**
   * Inform the default EGLContextFactory and default EGLConfigChooser
   * which EGLContext client version to pick.
   * <p>Use this method to create an OpenGL ES 2.0-compatible context.
   * Example:
   * <pre class="prettyprint">
   * public MyView(Context context) {
   * super(context);
   * setEGLContextClientVersion(2); // Pick an OpenGL ES 2.0 context.
   * setRenderer(new MyRenderer());
   * }
   * </pre>
   * <p>Note: Activities which require OpenGL ES 2.0 should indicate this by
   * setting @lt;uses-feature android:glEsVersion="0x00020000" /> in the activity's
   * AndroidManifest.xml file.
   * <p>If this method is called, it must be called before {@link #setRenderer(Renderer)}
   * is called.
   * <p>This method only affects the behavior of the default EGLContexFactory and the
   * default EGLConfigChooser. If
   * {@link #setEGLContextFactory(EGLContextFactory)} has been called, then the supplied
   * EGLContextFactory is responsible for creating an OpenGL ES 2.0-compatible context.
   * If
   * {@link #setEGLConfigChooser(EGLConfigChooser)} has been called, then the supplied
   * EGLConfigChooser is responsible for choosing an OpenGL ES 2.0-compatible config.
   *
   * @param version The EGLContext client version to choose. Use 2 for OpenGL ES 2.0
   */
  public void setEGLContextClientVersion(int version) {
    checkRenderThreadState();
    eglContextClientVersion = version;
  }

  /**
   * Set the rendering mode. When renderMode is
   * RENDERMODE_CONTINUOUSLY, the renderer is called
   * repeatedly to re-render the scene. When renderMode
   * is RENDERMODE_WHEN_DIRTY, the renderer only rendered when the surface
   * is created, or when {@link #requestRender} is called. Defaults to RENDERMODE_CONTINUOUSLY.
   * <p>
   * Using RENDERMODE_WHEN_DIRTY can improve battery life and overall system performance
   * by allowing the GPU and CPU to idle when the view does not need to be updated.
   * <p>
   * This method can only be called after {@link #setRenderer(Renderer)}
   *
   * @param renderMode one of the RENDERMODE_X constants
   * @see #RENDERMODE_CONTINUOUSLY
   * @see #RENDERMODE_WHEN_DIRTY
   */
  public void setRenderMode(int renderMode) {
    glThread.setRenderMode(renderMode);
  }

  /**
   * Get the current rendering mode. May be called
   * from any thread. Must not be called before a renderer has been set.
   *
   * @return the current rendering mode.
   * @see #RENDERMODE_CONTINUOUSLY
   * @see #RENDERMODE_WHEN_DIRTY
   */
  public int getRenderMode() {
    return glThread.getRenderMode();
  }

  /**
   * Request that the renderer render a frame.
   * This method is typically used when the render mode has been set to
   * {@link #RENDERMODE_WHEN_DIRTY}, so that frames are only rendered on demand.
   * May be called
   * from any thread. Must not be called before a renderer has been set.
   */
  public void requestRender() {
    glThread.requestRender();
  }

  /**
   * This method is part of the SurfaceHolder.Callback interface, and is
   * not normally called or subclassed by clients of GLTextureView.
   */
  public void surfaceCreated(SurfaceTexture texture) {
    glThread.surfaceCreated();
  }

  /**
   * This method is part of the SurfaceHolder.Callback interface, and is
   * not normally called or subclassed by clients of GLTextureView.
   */
  public void surfaceDestroyed(SurfaceTexture texture) {
    // Surface will be destroyed when we return
    glThread.surfaceDestroyed();
  }

  /**
   * This method is part of the SurfaceHolder.Callback interface, and is
   * not normally called or subclassed by clients of GLTextureView.
   */
  public void surfaceChanged(SurfaceTexture texture, int format, int w, int h) {
    glThread.onWindowResize(w, h);
  }

  /**
   * Inform the view that the activity is paused. The owner of this view must
   * call this method when the activity is paused. Calling this method will
   * pause the rendering thread.
   * Must not be called before a renderer has been set.
   */
  public void onPause() {
    glThread.onPause();
  }

  /**
   * Inform the view that the activity is resumed. The owner of this view must
   * call this method when the activity is resumed. Calling this method will
   * recreate the OpenGL display and resume the rendering
   * thread.
   * Must not be called before a renderer has been set.
   */
  public void onResume() {
    glThread.onResume();
  }

  /**
   * Queue a runnable to be run on the GL rendering thread. This can be used
   * to communicate with the Renderer on the rendering thread.
   * Must not be called before a renderer has been set.
   *
   * @param r the runnable to be run on the GL rendering thread.
   */
  public void queueEvent(Runnable r) {
    glThread.queueEvent(r);
  }

  /**
   * This method is used as part of the View class and is not normally
   * called or subclassed by clients of GLTextureView.
   */
  @Override protected void onAttachedToWindow() {
    super.onAttachedToWindow();
    if (LOG_ATTACH_DETACH) {
      Log.d(TAG, "onAttachedToWindow reattach =" + detached);
    }
    if (detached && (renderer != null)) {
      int renderMode = RENDERMODE_CONTINUOUSLY;
      if (glThread != null) {
        renderMode = glThread.getRenderMode();
      }
      glThread = new GLThread(mThisWeakRef);
      if (renderMode != RENDERMODE_CONTINUOUSLY) {
        glThread.setRenderMode(renderMode);
      }
      glThread.start();
    }
    detached = false;
  }

  /**
   * This method is used as part of the View class and is not normally
   * called or subclassed by clients of GLTextureView.
   * Must not be called before a renderer has been set.
   */
  @Override protected void onDetachedFromWindow() {
    if (LOG_ATTACH_DETACH) {
      Log.d(TAG, "onDetachedFromWindow");
    }
    if (glThread != null) {
      glThread.requestExitAndWait();
    }
    detached = true;
    super.onDetachedFromWindow();
  }

  public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft,
      int oldTop, int oldRight, int oldBottom) {
    surfaceChanged(getSurfaceTexture(), 0, right - left, bottom - top);
  }

  public void addSurfaceTextureListener(SurfaceTextureListener listener) {
    surfaceTextureListeners.add(listener);
  }

  public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
    surfaceCreated(surface);
    surfaceChanged(surface, 0, width, height);

    for (SurfaceTextureListener l : surfaceTextureListeners) {
      l.onSurfaceTextureAvailable(surface, width, height);
    }
  }

  public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
    surfaceChanged(surface, 0, width, height);

    for (SurfaceTextureListener l : surfaceTextureListeners) {
      l.onSurfaceTextureSizeChanged(surface, width, height);
    }
  }

  public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
    surfaceDestroyed(surface);

    for (SurfaceTextureListener l : surfaceTextureListeners) {
      l.onSurfaceTextureDestroyed(surface);
    }

    return true;
  }

  public void onSurfaceTextureUpdated(SurfaceTexture surface) {
    requestRender();

    for (SurfaceTextureListener l : surfaceTextureListeners) {
      l.onSurfaceTextureUpdated(surface);
    }
  }

  // ----------------------------------------------------------------------

  /**
   * An interface used to wrap a GL interface.
   * <p>Typically
   * used for implementing debugging and tracing on top of the default
   * GL interface. You would typically use this by creating your own class
   * that implemented all the GL methods by delegating to another GL instance.
   * Then you could add your own behavior before or after calling the
   * delegate. All the GLWrapper would do was instantiate and return the
   * wrapper GL instance:
   * <pre class="prettyprint">
   * class MyGLWrapper implements GLWrapper {
   * GL wrap(GL gl) {
   * return new MyGLImplementation(gl);
   * }
   * static class MyGLImplementation implements GL,GL10,GL11,... {
   * ...
   * }
   * }
   * </pre>
   *
   * @see #setGLWrapper(GLWrapper)
   */
  public interface GLWrapper {
    /**
     * Wraps a gl interface in another gl interface.
     *
     * @param gl a GL interface that is to be wrapped.
     * @return either the input argument or another GL object that wraps the input argument.
     */
    GL wrap(GL gl);
  }

  /**
   * A generic renderer interface.
   * <p>
   * The renderer is responsible for making OpenGL calls to render a frame.
   * <p>
   * GLTextureView clients typically create their own classes that implement
   * this interface, and then call {@link GLTextureView#setRenderer} to
   * register the renderer with the GLTextureView.
   * <p>
   *
   * <div class="special reference">
   * <h3>Developer Guides</h3>
   * <p>For more information about how to use OpenGL, read the
   * <a href="{@docRoot}guide/topics/graphics/opengl.html">OpenGL</a> developer guide.</p>
   * </div>
   *
   * <h3>Threading</h3>
   * The renderer will be called on a separate thread, so that rendering
   * performance is decoupled from the UI thread. Clients typically need to
   * communicate with the renderer from the UI thread, because that's where
   * input events are received. Clients can communicate using any of the
   * standard Java techniques for cross-thread communication, or they can
   * use the {@link GLTextureView#queueEvent(Runnable)} convenience method.
   * <p>
   * <h3>EGL Context Lost</h3>
   * There are situations where the EGL rendering context will be lost. This
   * typically happens when device wakes up after going to sleep. When
   * the EGL context is lost, all OpenGL resources (such as textures) that are
   * associated with that context will be automatically deleted. In order to
   * keep rendering correctly, a renderer must recreate any lost resources
   * that it still needs. The {@link #onSurfaceCreated(javax.microedition.khronos.opengles.GL10,
   * javax.microedition.khronos.egl.EGLConfig)} method
   * is a convenient place to do this.
   *
   * @see #setRenderer(Renderer)
   */
  public interface Renderer {
    /**
     * Called when the surface is created or recreated.
     * <p>
     * Called when the rendering thread
     * starts and whenever the EGL context is lost. The EGL context will typically
     * be lost when the Android device awakes after going to sleep.
     * <p>
     * Since this method is called at the beginning of rendering, as well as
     * every time the EGL context is lost, this method is a convenient place to put
     * code to create resources that need to be created when the rendering
     * starts, and that need to be recreated when the EGL context is lost.
     * Textures are an example of a resource that you might want to create
     * here.
     * <p>
     * Note that when the EGL context is lost, all OpenGL resources associated
     * with that context will be automatically deleted. You do not need to call
     * the corresponding "glDelete" methods such as glDeleteTextures to
     * manually delete these lost resources.
     * <p>
     *
     * @param gl the GL interface. Use <code>instanceof</code> to
     * test if the interface supports GL11 or higher interfaces.
     * @param config the EGLConfig of the created surface. Can be used
     * to create matching pbuffers.
     */
    void onSurfaceCreated(GL10 gl, EGLConfig config);

    /**
     * Called when the surface changed size.
     * <p>
     * Called after the surface is created and whenever
     * the OpenGL ES surface size changes.
     * <p>
     * Typically you will set your viewport here. If your camera
     * is fixed then you could also set your projection matrix here:
     * <pre class="prettyprint">
     * void onSurfaceChanged(GL10 gl, int width, int height) {
     * gl.glViewport(0, 0, width, height);
     * // for a fixed camera, set the projection too
     * float ratio = (float) width / height;
     * gl.glMatrixMode(GL10.GL_PROJECTION);
     * gl.glLoadIdentity();
     * gl.glFrustumf(-ratio, ratio, -1, 1, 1, 10);
     * }
     * </pre>
     *
     * @param gl the GL interface. Use <code>instanceof</code> to
     * test if the interface supports GL11 or higher interfaces.
     */
    void onSurfaceChanged(GL10 gl, int width, int height);

    /**
     * Called to draw the current frame.
     * <p>
     * This method is responsible for drawing the current frame.
     * <p>
     * The implementation of this method typically looks like this:
     * <pre class="prettyprint">
     * void onDrawFrame(GL10 gl) {
     * gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
     * //... other gl calls to render the scene ...
     * }
     * </pre>
     *
     * @param gl the GL interface. Use <code>instanceof</code> to
     * test if the interface supports GL11 or higher interfaces.
     */
    void onDrawFrame(GL10 gl);
  }

  /**
   * An interface for customizing the eglCreateContext and eglDestroyContext calls.
   * <p>
   * This interface must be implemented by clients wishing to call
   * {@link GLTextureView#setEGLContextFactory(EGLContextFactory)}
   */
  public interface EGLContextFactory {
    EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig eglConfig);

    void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context);
  }

  private class DefaultContextFactory implements EGLContextFactory {
    private int EGL_CONTEXT_CLIENT_VERSION = 0x3098;

    public EGLContext createContext(EGL10 egl, EGLDisplay display, EGLConfig config) {
      int[] attrib_list = {
          EGL_CONTEXT_CLIENT_VERSION, eglContextClientVersion, EGL10.EGL_NONE
      };

      return egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT,
          eglContextClientVersion != 0 ? attrib_list : null);
    }

    public void destroyContext(EGL10 egl, EGLDisplay display, EGLContext context) {
      if (!egl.eglDestroyContext(display, context)) {
        Log.e("DefaultContextFactory", "display:" + display + " context: " + context);
        if (LOG_THREADS) {
          Log.i("DefaultContextFactory", "tid=" + Thread.currentThread().getId());
        }
        EglHelper.throwEglException("eglDestroyContex", egl.eglGetError());
      }
    }
  }

  /**
   * An interface for customizing the eglCreateWindowSurface and eglDestroySurface calls.
   * <p>
   * This interface must be implemented by clients wishing to call
   * {@link GLTextureView#setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory)}
   */
  public interface EGLWindowSurfaceFactory {
    /**
     * @return null if the surface cannot be constructed.
     */
    EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display, EGLConfig config,
        Object nativeWindow);

    void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface);
  }

  private static class DefaultWindowSurfaceFactory implements EGLWindowSurfaceFactory {

    public EGLSurface createWindowSurface(EGL10 egl, EGLDisplay display, EGLConfig config,
        Object nativeWindow) {
      EGLSurface result = null;
      try {
        result = egl.eglCreateWindowSurface(display, config, nativeWindow, null);
      } catch (IllegalArgumentException e) {
        // This exception indicates that the surface flinger surface
        // is not valid. This can happen if the surface flinger surface has
        // been torn down, but the application has not yet been
        // notified via SurfaceHolder.Callback.surfaceDestroyed.
        // In theory the application should be notified first,
        // but in practice sometimes it is not. See b/4588890
        Log.e(TAG, "eglCreateWindowSurface", e);
      }
      return result;
    }

    public void destroySurface(EGL10 egl, EGLDisplay display, EGLSurface surface) {
      egl.eglDestroySurface(display, surface);
    }
  }

  /**
   * An interface for choosing an EGLConfig configuration from a list of
   * potential configurations.
   * <p>
   * This interface must be implemented by clients wishing to call
   * {@link GLTextureView#setEGLConfigChooser(EGLConfigChooser)}
   */
  public interface EGLConfigChooser {
    /**
     * Choose a configuration from the list. Implementors typically
     * implement this method by calling
     * {@link EGL10#eglChooseConfig} and iterating through the results. Please consult the
     * EGL specification available from The Khronos Group to learn how to call eglChooseConfig.
     *
     * @param egl the EGL10 for the current display.
     * @param display the current display.
     * @return the chosen configuration.
     */
    EGLConfig chooseConfig(EGL10 egl, EGLDisplay display);
  }

  private abstract class BaseConfigChooser implements EGLConfigChooser {
    public BaseConfigChooser(int[] configSpec) {
      mConfigSpec = filterConfigSpec(configSpec);
    }

    public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display) {
      int[] num_config = new int[1];
      if (!egl.eglChooseConfig(display, mConfigSpec, null, 0, num_config)) {
        throw new IllegalArgumentException("eglChooseConfig failed");
      }

      int numConfigs = num_config[0];

      if (numConfigs <= 0) {
        throw new IllegalArgumentException("No configs match configSpec");
      }

      EGLConfig[] configs = new EGLConfig[numConfigs];
      if (!egl.eglChooseConfig(display, mConfigSpec, configs, numConfigs, num_config)) {
        throw new IllegalArgumentException("eglChooseConfig#2 failed");
      }
      EGLConfig config = chooseConfig(egl, display, configs);
      if (config == null) {
        throw new IllegalArgumentException("No config chosen");
      }
      return config;
    }

    abstract EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs);

    protected int[] mConfigSpec;

    private int[] filterConfigSpec(int[] configSpec) {
      if (eglContextClientVersion != 2) {
        return configSpec;
      }
            /* We know none of the subclasses define EGL_RENDERABLE_TYPE.
             * And we know the configSpec is well formed.
             */
      int len = configSpec.length;
      int[] newConfigSpec = new int[len + 2];
      System.arraycopy(configSpec, 0, newConfigSpec, 0, len - 1);
      newConfigSpec[len - 1] = EGL10.EGL_RENDERABLE_TYPE;
      newConfigSpec[len] = 0x0004; /* EGL_OPENGL_ES2_BIT */
      newConfigSpec[len + 1] = EGL10.EGL_NONE;
      return newConfigSpec;
    }
  }

  /**
   * Choose a configuration with exactly the specified r,g,b,a sizes,
   * and at least the specified depth and stencil sizes.
   */
  private class ComponentSizeChooser extends BaseConfigChooser {
    public ComponentSizeChooser(int redSize, int greenSize, int blueSize, int alphaSize,
        int depthSize, int stencilSize) {
      super(new int[] {
          EGL10.EGL_RED_SIZE, redSize, EGL10.EGL_GREEN_SIZE, greenSize, EGL10.EGL_BLUE_SIZE,
          blueSize, EGL10.EGL_ALPHA_SIZE, alphaSize, EGL10.EGL_DEPTH_SIZE, depthSize,
          EGL10.EGL_STENCIL_SIZE, stencilSize, EGL10.EGL_NONE
      });
      value = new int[1];
      this.redSize = redSize;
      this.greenSize = greenSize;
      this.blueSize = blueSize;
      this.alphaSize = alphaSize;
      this.depthSize = depthSize;
      this.stencilSize = stencilSize;
    }

    @Override public EGLConfig chooseConfig(EGL10 egl, EGLDisplay display, EGLConfig[] configs) {
      for (EGLConfig config : configs) {
        int d = findConfigAttrib(egl, display, config, EGL10.EGL_DEPTH_SIZE, 0);
        int s = findConfigAttrib(egl, display, config, EGL10.EGL_STENCIL_SIZE, 0);
        if ((d >= depthSize) && (s >= stencilSize)) {
          int r = findConfigAttrib(egl, display, config, EGL10.EGL_RED_SIZE, 0);
          int g = findConfigAttrib(egl, display, config, EGL10.EGL_GREEN_SIZE, 0);
          int b = findConfigAttrib(egl, display, config, EGL10.EGL_BLUE_SIZE, 0);
          int a = findConfigAttrib(egl, display, config, EGL10.EGL_ALPHA_SIZE, 0);
          if ((r == redSize) && (g == greenSize) && (b == blueSize) && (a == alphaSize)) {
            return config;
          }
        }
      }
      return null;
    }

    private int findConfigAttrib(EGL10 egl, EGLDisplay display, EGLConfig config, int attribute,
        int defaultValue) {

      if (egl.eglGetConfigAttrib(display, config, attribute, value)) {
        return value[0];
      }
      return defaultValue;
    }

    private int[] value;
    // Subclasses can adjust these values:
    protected int redSize;
    protected int greenSize;
    protected int blueSize;
    protected int alphaSize;
    protected int depthSize;
    protected int stencilSize;
  }

  /**
   * This class will choose a RGB_888 surface with
   * or without a depth buffer.
   */
  private class SimpleEGLConfigChooser extends ComponentSizeChooser {
    public SimpleEGLConfigChooser(boolean withDepthBuffer) {
      super(8, 8, 8, 0, withDepthBuffer ? 16 : 0, 0);
    }
  }

  /**
   * An EGL helper class.
   */

  private static class EglHelper {
    public EglHelper(WeakReference<GLTextureView> glTextureViewWeakReference) {
      this.glTextureViewWeakRef = glTextureViewWeakReference;
    }

    /**
     * Initialize EGL for a given configuration spec.
     */
    public void start() {
      if (LOG_EGL) {
        Log.w("EglHelper", "start() tid=" + Thread.currentThread().getId());
      }
            /*
             * Get an EGL instance
             */
      egl = (EGL10) EGLContext.getEGL();

            /*
             * Get to the default display.
             */
      eglDisplay = egl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);

      if (eglDisplay == EGL10.EGL_NO_DISPLAY) {
        throw new RuntimeException("eglGetDisplay failed");
      }

            /*
             * We can now initialize EGL for that display
             */
      int[] version = new int[2];
      if (!egl.eglInitialize(eglDisplay, version)) {
        throw new RuntimeException("eglInitialize failed");
      }
      GLTextureView view = glTextureViewWeakRef.get();
      if (view == null) {
        eglConfig = null;
        eglContext = null;
      } else {
        eglConfig = view.eglConfigChooser.chooseConfig(egl, eglDisplay);

                /*
                * Create an EGL context. We want to do this as rarely as we can, because an
                * EGL context is a somewhat heavy object.
                */
        eglContext = view.eglContextFactory.createContext(egl, eglDisplay, eglConfig);
      }
      if (eglContext == null || eglContext == EGL10.EGL_NO_CONTEXT) {
        eglContext = null;
        throwEglException("createContext");
      }
      if (LOG_EGL) {
        Log.w("EglHelper",
            "createContext " + eglContext + " tid=" + Thread.currentThread().getId());
      }

      eglSurface = null;
    }

    /**
     * Create an egl surface for the current SurfaceHolder surface. If a surface
     * already exists, destroy it before creating the new surface.
     *
     * @return true if the surface was created successfully.
     */
    public boolean createSurface() {
      if (LOG_EGL) {
        Log.w("EglHelper", "createSurface()  tid=" + Thread.currentThread().getId());
      }
            /*
             * Check preconditions.
             */
      if (egl == null) {
        throw new RuntimeException("egl not initialized");
      }
      if (eglDisplay == null) {
        throw new RuntimeException("eglDisplay not initialized");
      }
      if (eglConfig == null) {
        throw new RuntimeException("eglConfig not initialized");
      }

            /*
             *  The window size has changed, so we need to create a new
             *  surface.
             */
      destroySurfaceImp();

            /*
             * Create an EGL surface we can render into.
             */
      GLTextureView view = glTextureViewWeakRef.get();
      if (view != null) {
        eglSurface = view.eglWindowSurfaceFactory.createWindowSurface(egl, eglDisplay, eglConfig,
            view.getSurfaceTexture());
      } else {
        eglSurface = null;
      }

      if (eglSurface == null || eglSurface == EGL10.EGL_NO_SURFACE) {
        int error = egl.eglGetError();
        if (error == EGL10.EGL_BAD_NATIVE_WINDOW) {
          Log.e("EglHelper", "createWindowSurface returned EGL_BAD_NATIVE_WINDOW.");
        }
        return false;
      }

            /*
             * Before we can issue GL commands, we need to make sure
             * the context is current and bound to a surface.
             */
      if (!egl.eglMakeCurrent(eglDisplay, eglSurface, eglSurface, eglContext)) {
                /*
                 * Could not make the context current, probably because the underlying
                 * TextureView surface has been destroyed.
                 */
        logEglErrorAsWarning("EGLHelper", "eglMakeCurrent", egl.eglGetError());
        return false;
      }

      return true;
    }

    /**
     * Create a GL object for the current EGL context.
     */
    GL createGL() {

      GL gl = eglContext.getGL();
      GLTextureView view = glTextureViewWeakRef.get();
      if (view != null) {
        if (view.glWrapper != null) {
          gl = view.glWrapper.wrap(gl);
        }

        if ((view.debugFlags & (DEBUG_CHECK_GL_ERROR | DEBUG_LOG_GL_CALLS)) != 0) {
          int configFlags = 0;
          Writer log = null;
          if ((view.debugFlags & DEBUG_CHECK_GL_ERROR) != 0) {
            configFlags |= GLDebugHelper.CONFIG_CHECK_GL_ERROR;
          }
          if ((view.debugFlags & DEBUG_LOG_GL_CALLS) != 0) {
            log = new LogWriter();
          }
          gl = GLDebugHelper.wrap(gl, configFlags, log);
        }
      }
      return gl;
    }

    /**
     * Display the current render surface.
     *
     * @return the EGL error code from eglSwapBuffers.
     */
    public int swap() {
      if (!egl.eglSwapBuffers(eglDisplay, eglSurface)) {
        return egl.eglGetError();
      }
      return EGL10.EGL_SUCCESS;
    }

    public void destroySurface() {
      if (LOG_EGL) {
        Log.w("EglHelper", "destroySurface()  tid=" + Thread.currentThread().getId());
      }
      destroySurfaceImp();
    }

    private void destroySurfaceImp() {
      if (eglSurface != null && eglSurface != EGL10.EGL_NO_SURFACE) {
        egl.eglMakeCurrent(eglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE,
            EGL10.EGL_NO_CONTEXT);
        GLTextureView view = glTextureViewWeakRef.get();
        if (view != null) {
          view.eglWindowSurfaceFactory.destroySurface(egl, eglDisplay, eglSurface);
        }
        eglSurface = null;
      }
    }

    public void finish() {
      if (LOG_EGL) {
        Log.w("EglHelper", "finish() tid=" + Thread.currentThread().getId());
      }
      if (eglContext != null) {
        GLTextureView view = glTextureViewWeakRef.get();
        if (view != null) {
          view.eglContextFactory.destroyContext(egl, eglDisplay, eglContext);
        }
        eglContext = null;
      }
      if (eglDisplay != null) {
        egl.eglTerminate(eglDisplay);
        eglDisplay = null;
      }
    }

    private void throwEglException(String function) {
      throwEglException(function, egl.eglGetError());
    }

    public static void throwEglException(String function, int error) {
      String message = formatEglError(function, error);
      if (LOG_THREADS) {
        Log.e("EglHelper",
            "throwEglException tid=" + Thread.currentThread().getId() + " " + message);
      }
      throw new RuntimeException(message);
    }

    public static void logEglErrorAsWarning(String tag, String function, int error) {
      Log.w(tag, formatEglError(function, error));
    }

    public static String formatEglError(String function, int error) {
      return function + " failed: " + error;
    }

    private WeakReference<GLTextureView> glTextureViewWeakRef;
    EGL10 egl;
    EGLDisplay eglDisplay;
    EGLSurface eglSurface;
    EGLConfig eglConfig;
    EGLContext eglContext;
  }

  /**
   * A generic GL Thread. Takes care of initializing EGL and GL. Delegates
   * to a Renderer instance to do the actual drawing. Can be configured to
   * render continuously or on request.
   *
   * All potentially blocking synchronization is done through the
   * glThreadManager object. This avoids multiple-lock ordering issues.
   */
  static class GLThread extends Thread {
    GLThread(WeakReference<GLTextureView> glTextureViewWeakRef) {
      super();
      width = 0;
      height = 0;
      requestRender = true;
      renderMode = RENDERMODE_CONTINUOUSLY;
      this.glTextureViewWeakRef = glTextureViewWeakRef;
    }

    @Override public void run() {
      setName("GLThread " + getId());
      if (LOG_THREADS) {
        Log.i("GLThread", "starting tid=" + getId());
      }

      try {
        guardedRun();
      } catch (InterruptedException e) {
        // fall thru and exit normally
      } finally {
        glThreadManager.threadExiting(this);
      }
    }

    /*
     * This private method should only be called inside a
     * synchronized(glThreadManager) block.
     */
    private void stopEglSurfaceLocked() {
      if (haveEglSurface) {
        haveEglSurface = false;
        eglHelper.destroySurface();
      }
    }

    /*
     * This private method should only be called inside a
     * synchronized(glThreadManager) block.
     */
    private void stopEglContextLocked() {
      if (haveEglContext) {
        eglHelper.finish();
        haveEglContext = false;
        glThreadManager.releaseEglContextLocked(this);
      }
    }

    private void guardedRun() throws InterruptedException {
      eglHelper = new EglHelper(glTextureViewWeakRef);
      haveEglContext = false;
      haveEglSurface = false;
      try {
        GL10 gl = null;
        boolean createEglContext = false;
        boolean createEglSurface = false;
        boolean createGlInterface = false;
        boolean lostEglContext = false;
        boolean sizeChanged = false;
        boolean wantRenderNotification = false;
        boolean doRenderNotification = false;
        boolean askedToReleaseEglContext = false;
        int w = 0;
        int h = 0;
        Runnable event = null;

        while (true) {
          synchronized (glThreadManager) {
            while (true) {
              if (shouldExit) {
                return;
              }

              if (!eventQueue.isEmpty()) {
                event = eventQueue.remove(0);
                break;
              }

              // Update the pause state.
              boolean pausing = false;
              if (paused != requestPaused) {
                pausing = requestPaused;
                paused = requestPaused;
                glThreadManager.notifyAll();
                if (LOG_PAUSE_RESUME) {
                  Log.i("GLThread", "paused is now " + paused + " tid=" + getId());
                }
              }

              // Do we need to give up the EGL context?
              if (shouldReleaseEglContext) {
                if (LOG_SURFACE) {
                  Log.i("GLThread", "releasing EGL context because asked to tid=" + getId());
                }
                stopEglSurfaceLocked();
                stopEglContextLocked();
                shouldReleaseEglContext = false;
                askedToReleaseEglContext = true;
              }

              // Have we lost the EGL context?
              if (lostEglContext) {
                stopEglSurfaceLocked();
                stopEglContextLocked();
                lostEglContext = false;
              }

              // When pausing, release the EGL surface:
              if (pausing && haveEglSurface) {
                if (LOG_SURFACE) {
                  Log.i("GLThread", "releasing EGL surface because paused tid=" + getId());
                }
                stopEglSurfaceLocked();
              }

              // When pausing, optionally release the EGL Context:
              if (pausing && haveEglContext) {
                GLTextureView view = glTextureViewWeakRef.get();
                boolean preserveEglContextOnPause =
                    view == null ? false : view.preserveEGLContextOnPause;
                if (!preserveEglContextOnPause
                    || glThreadManager.shouldReleaseEGLContextWhenPausing()) {
                  stopEglContextLocked();
                  if (LOG_SURFACE) {
                    Log.i("GLThread", "releasing EGL context because paused tid=" + getId());
                  }
                }
              }

              // When pausing, optionally terminate EGL:
              if (pausing) {
                if (glThreadManager.shouldTerminateEGLWhenPausing()) {
                  eglHelper.finish();
                  if (LOG_SURFACE) {
                    Log.i("GLThread", "terminating EGL because paused tid=" + getId());
                  }
                }
              }

              // Have we lost the TextureView surface?
              if ((!hasSurface) && (!waitingForSurface)) {
                if (LOG_SURFACE) {
                  Log.i("GLThread", "noticed textureView surface lost tid=" + getId());
                }
                if (haveEglSurface) {
                  stopEglSurfaceLocked();
                }
                waitingForSurface = true;
                surfaceIsBad = false;
                glThreadManager.notifyAll();
              }

              // Have we acquired the surface view surface?
              if (hasSurface && waitingForSurface) {
                if (LOG_SURFACE) {
                  Log.i("GLThread", "noticed textureView surface acquired tid=" + getId());
                }
                waitingForSurface = false;
                glThreadManager.notifyAll();
              }

              if (doRenderNotification) {
                if (LOG_SURFACE) {
                  Log.i("GLThread", "sending render notification tid=" + getId());
                }
                wantRenderNotification = false;
                doRenderNotification = false;
                renderComplete = true;
                glThreadManager.notifyAll();
              }

              // Ready to draw?
              if (readyToDraw()) {

                // If we don't have an EGL context, try to acquire one.
                if (!haveEglContext) {
                  if (askedToReleaseEglContext) {
                    askedToReleaseEglContext = false;
                  } else if (glThreadManager.tryAcquireEglContextLocked(this)) {
                    try {
                      eglHelper.start();
                    } catch (RuntimeException t) {
                      glThreadManager.releaseEglContextLocked(this);
                      throw t;
                    }
                    haveEglContext = true;
                    createEglContext = true;

                    glThreadManager.notifyAll();
                  }
                }

                if (haveEglContext && !haveEglSurface) {
                  haveEglSurface = true;
                  createEglSurface = true;
                  createGlInterface = true;
                  sizeChanged = true;
                }

                if (haveEglSurface) {
                  if (this.sizeChanged) {
                    sizeChanged = true;
                    w = width;
                    h = height;
                    wantRenderNotification = true;
                    if (LOG_SURFACE) {
                      Log.i("GLThread", "noticing that we want render notification tid=" + getId());
                    }

                    // Destroy and recreate the EGL surface.
                    createEglSurface = true;

                    this.sizeChanged = false;
                  }
                  requestRender = false;
                  glThreadManager.notifyAll();
                  break;
                }
              }

              // By design, this is the only place in a GLThread thread where we wait().
              if (LOG_THREADS) {
                Log.i("GLThread", "waiting tid=" + getId() + " haveEglContext: " + haveEglContext
                    + " haveEglSurface: " + haveEglSurface + " paused: " + paused + " hasSurface: "
                    + hasSurface + " surfaceIsBad: " + surfaceIsBad + " waitingForSurface: "
                    + waitingForSurface + " width: " + width + " height: " + height
                    + " requestRender: " + requestRender + " renderMode: " + renderMode);
              }
              glThreadManager.wait();
            }
          } // end of synchronized(glThreadManager)

          if (event != null) {
            event.run();
            event = null;
            continue;
          }

          if (createEglSurface) {
            if (LOG_SURFACE) {
              Log.w("GLThread", "egl createSurface");
            }
            if (!eglHelper.createSurface()) {
              synchronized (glThreadManager) {
                surfaceIsBad = true;
                glThreadManager.notifyAll();
              }
              continue;
            }
            createEglSurface = false;
          }

          if (createGlInterface) {
            gl = (GL10) eglHelper.createGL();

            glThreadManager.checkGLDriver(gl);
            createGlInterface = false;
          }

          if (createEglContext) {
            if (LOG_RENDERER) {
              Log.w("GLThread", "onSurfaceCreated");
            }
            GLTextureView view = glTextureViewWeakRef.get();
            if (view != null) {
              view.renderer.onSurfaceCreated(gl, eglHelper.eglConfig);
            }
            createEglContext = false;
          }

          if (sizeChanged) {
            if (LOG_RENDERER) {
              Log.w("GLThread", "onSurfaceChanged(" + w + ", " + h + ")");
            }
            GLTextureView view = glTextureViewWeakRef.get();
            if (view != null) {
              view.renderer.onSurfaceChanged(gl, w, h);
            }
            sizeChanged = false;
          }

          if (LOG_RENDERER_DRAW_FRAME) {
            Log.w("GLThread", "onDrawFrame tid=" + getId());
          }
          {
            GLTextureView view = glTextureViewWeakRef.get();
            if (view != null) {
              view.renderer.onDrawFrame(gl);
            }
          }
          int swapError = eglHelper.swap();
          switch (swapError) {
            case EGL10.EGL_SUCCESS:
              break;
            case EGL11.EGL_CONTEXT_LOST:
              if (LOG_SURFACE) {
                Log.i("GLThread", "egl context lost tid=" + getId());
              }
              lostEglContext = true;
              break;
            default:
              // Other errors typically mean that the current surface is bad,
              // probably because the TextureView surface has been destroyed,
              // but we haven't been notified yet.
              // Log the error to help developers understand why rendering stopped.
              EglHelper.logEglErrorAsWarning("GLThread", "eglSwapBuffers", swapError);

              synchronized (glThreadManager) {
                surfaceIsBad = true;
                glThreadManager.notifyAll();
              }
              break;
          }

          if (wantRenderNotification) {
            doRenderNotification = true;
          }
        }
      } finally {
                /*
                 * clean-up everything...
                 */
        synchronized (glThreadManager) {
          stopEglSurfaceLocked();
          stopEglContextLocked();
        }
      }
    }

    public boolean ableToDraw() {
      return haveEglContext && haveEglSurface && readyToDraw();
    }

    private boolean readyToDraw() {
      return (!paused) && hasSurface && (!surfaceIsBad) && (width > 0) && (height > 0) && (
          requestRender || (renderMode == RENDERMODE_CONTINUOUSLY));
    }

    public void setRenderMode(int renderMode) {
      if (!((RENDERMODE_WHEN_DIRTY <= renderMode) && (renderMode <= RENDERMODE_CONTINUOUSLY))) {
        throw new IllegalArgumentException("renderMode");
      }
      synchronized (glThreadManager) {
        this.renderMode = renderMode;
        glThreadManager.notifyAll();
      }
    }

    public int getRenderMode() {
      synchronized (glThreadManager) {
        return renderMode;
      }
    }

    public void requestRender() {
      synchronized (glThreadManager) {
        requestRender = true;
        glThreadManager.notifyAll();
      }
    }

    public void surfaceCreated() {
      synchronized (glThreadManager) {
        if (LOG_THREADS) {
          Log.i("GLThread", "surfaceCreated tid=" + getId());
        }
        hasSurface = true;
        glThreadManager.notifyAll();
        while ((waitingForSurface) && (!exited)) {
          try {
            glThreadManager.wait();
          } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
          }
        }
      }
    }

    public void surfaceDestroyed() {
      synchronized (glThreadManager) {
        if (LOG_THREADS) {
          Log.i("GLThread", "surfaceDestroyed tid=" + getId());
        }
        hasSurface = false;
        glThreadManager.notifyAll();
        while ((!waitingForSurface) && (!exited)) {
          try {
            glThreadManager.wait();
          } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
          }
        }
      }
    }

    public void onPause() {
      synchronized (glThreadManager) {
        if (LOG_PAUSE_RESUME) {
          Log.i("GLThread", "onPause tid=" + getId());
        }
        requestPaused = true;
        glThreadManager.notifyAll();
        while ((!exited) && (!paused)) {
          if (LOG_PAUSE_RESUME) {
            Log.i("Main thread", "onPause waiting for paused.");
          }
          try {
            glThreadManager.wait();
          } catch (InterruptedException ex) {
            Thread.currentThread().interrupt();
          }
        }
      }
    }

    public void onResume() {
      synchronized (glThreadManager) {
        if (LOG_PAUSE_RESUME) {
          Log.i("GLThread", "onResume tid=" + getId());
        }
        requestPaused = false;
        requestRender = true;
        renderComplete = false;
        glThreadManager.notifyAll();
        while ((!exited) && paused && (!renderComplete)) {
          if (LOG_PAUSE_RESUME) {
            Log.i("Main thread", "onResume waiting for !paused.");
          }
          try {
            glThreadManager.wait();
          } catch (InterruptedException ex) {
            Thread.currentThread().interrupt();
          }
        }
      }
    }

    public void onWindowResize(int w, int h) {
      synchronized (glThreadManager) {
        width = w;
        height = h;
        sizeChanged = true;
        requestRender = true;
        renderComplete = false;
        glThreadManager.notifyAll();

        // Wait for thread to react to resize and render a frame
        while (!exited && !paused && !renderComplete && ableToDraw()) {
          if (LOG_SURFACE) {
            Log.i("Main thread", "onWindowResize waiting for render complete from tid=" + getId());
          }
          try {
            glThreadManager.wait();
          } catch (InterruptedException ex) {
            Thread.currentThread().interrupt();
          }
        }
      }
    }

    public void requestExitAndWait() {
      // don't call this from GLThread thread or it is a guaranteed
      // deadlock!
      synchronized (glThreadManager) {
        shouldExit = true;
        glThreadManager.notifyAll();
        while (!exited) {
          try {
            glThreadManager.wait();
          } catch (InterruptedException ex) {
            Thread.currentThread().interrupt();
          }
        }
      }
    }

    public void requestReleaseEglContextLocked() {
      shouldReleaseEglContext = true;
      glThreadManager.notifyAll();
    }

    /**
     * Queue an "event" to be run on the GL rendering thread.
     *
     * @param r the runnable to be run on the GL rendering thread.
     */
    public void queueEvent(Runnable r) {
      if (r == null) {
        throw new IllegalArgumentException("r must not be null");
      }
      synchronized (glThreadManager) {
        eventQueue.add(r);
        glThreadManager.notifyAll();
      }
    }

    // Once the thread is started, all accesses to the following member
    // variables are protected by the glThreadManager monitor
    private boolean shouldExit;
    private boolean exited;
    private boolean requestPaused;
    private boolean paused;
    private boolean hasSurface;
    private boolean surfaceIsBad;
    private boolean waitingForSurface;
    private boolean haveEglContext;
    private boolean haveEglSurface;
    private boolean shouldReleaseEglContext;
    private int width;
    private int height;
    private int renderMode;
    private boolean requestRender;
    private boolean renderComplete;
    private ArrayList<Runnable> eventQueue = new ArrayList<>();
    private boolean sizeChanged = true;

    // End of member variables protected by the glThreadManager monitor.

    private EglHelper eglHelper;

    /**
     * Set once at thread construction time, nulled out when the parent view is garbage
     * called. This weak reference allows the GLTextureView to be garbage collected while
     * the GLThread is still alive.
     */
    private WeakReference<GLTextureView> glTextureViewWeakRef;
  }

  static class LogWriter extends Writer {

    @Override public void close() {
      flushBuilder();
    }

    @Override public void flush() {
      flushBuilder();
    }

    @Override public void write(char[] buf, int offset, int count) {
      for (int i = 0; i < count; i++) {
        char c = buf[offset + i];
        if (c == '\n') {
          flushBuilder();
        } else {
          builder.append(c);
        }
      }
    }

    private void flushBuilder() {
      if (builder.length() > 0) {
        Log.v("GLTextureView", builder.toString());
        builder.delete(0, builder.length());
      }
    }

    private StringBuilder builder = new StringBuilder();
  }

  private void checkRenderThreadState() {
    if (glThread != null) {
      throw new IllegalStateException("setRenderer has already been called for this instance.");
    }
  }

  private static class GLThreadManager {
    private static String TAG = "GLThreadManager";

    public synchronized void threadExiting(GLThread thread) {
      if (LOG_THREADS) {
        Log.i("GLThread", "exiting tid=" + thread.getId());
      }
      thread.exited = true;
      if (eglOwner == thread) {
        eglOwner = null;
      }
      notifyAll();
    }

    /*
     * Tries once to acquire the right to use an EGL
     * context. Does not block. Requires that we are already
     * in the glThreadManager monitor when this is called.
     *
     * @return true if the right to use an EGL context was acquired.
     */
    public boolean tryAcquireEglContextLocked(GLThread thread) {
      if (eglOwner == thread || eglOwner == null) {
        eglOwner = thread;
        notifyAll();
        return true;
      }
      checkGLESVersion();
      if (multipleGLESContextsAllowed) {
        return true;
      }
      // Notify the owning thread that it should release the context.
      // TODO: implement a fairness policy. Currently
      // if the owning thread is drawing continuously it will just
      // reacquire the EGL context.
      if (eglOwner != null) {
        eglOwner.requestReleaseEglContextLocked();
      }
      return false;
    }

    /*
     * Releases the EGL context. Requires that we are already in the
     * glThreadManager monitor when this is called.
     */
    public void releaseEglContextLocked(GLThread thread) {
      if (eglOwner == thread) {
        eglOwner = null;
      }
      notifyAll();
    }

    public synchronized boolean shouldReleaseEGLContextWhenPausing() {
      // Release the EGL context when pausing even if
      // the hardware supports multiple EGL contexts.
      // Otherwise the device could run out of EGL contexts.
      return limitedGLESContexts;
    }

    public synchronized boolean shouldTerminateEGLWhenPausing() {
      checkGLESVersion();
      return !multipleGLESContextsAllowed;
    }

    public synchronized void checkGLDriver(GL10 gl) {
      if (!glesDriverCheckComplete) {
        checkGLESVersion();
        String renderer = gl.glGetString(GL10.GL_RENDERER);
        if (glesVersion < kGLES_20) {
          multipleGLESContextsAllowed = !renderer.startsWith(kMSM7K_RENDERER_PREFIX);
          notifyAll();
        }
        limitedGLESContexts = !multipleGLESContextsAllowed;
        if (LOG_SURFACE) {
          Log.w(TAG, "checkGLDriver renderer = \"" + renderer + "\" multipleContextsAllowed = "
              + multipleGLESContextsAllowed + " limitedGLESContexts = " + limitedGLESContexts);
        }
        glesDriverCheckComplete = true;
      }
    }

    private void checkGLESVersion() {
      if (!glesVersionCheckComplete) {
        glesVersionCheckComplete = true;
      }
    }

    /**
     * This check was required for some pre-Android-3.0 hardware. Android 3.0 provides
     * support for hardware-accelerated views, therefore multiple EGL contexts are
     * supported on all Android 3.0+ EGL drivers.
     */
    private boolean glesVersionCheckComplete;
    private int glesVersion;
    private boolean glesDriverCheckComplete;
    private boolean multipleGLESContextsAllowed;
    private boolean limitedGLESContexts;
    private static final int kGLES_20 = 0x20000;
    private static final String kMSM7K_RENDERER_PREFIX = "Q3Dimension MSM7500 ";
    private GLThread eglOwner;
  }

  private static final GLThreadManager glThreadManager = new GLThreadManager();

  private final WeakReference<GLTextureView> mThisWeakRef = new WeakReference<>(this);
  private GLThread glThread;
  private Renderer renderer;
  private boolean detached;
  private EGLConfigChooser eglConfigChooser;
  private EGLContextFactory eglContextFactory;
  private EGLWindowSurfaceFactory eglWindowSurfaceFactory;
  private GLWrapper glWrapper;
  private int debugFlags;
  private int eglContextClientVersion;
  private boolean preserveEGLContextOnPause;
  private List<SurfaceTextureListener> surfaceTextureListeners = new ArrayList<>();
}