https://source.android.com/ 
/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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.
 */

package android.opengl;

import android.content.Context;
import android.os.Trace;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

import java.io.Writer;
import java.lang.ref.WeakReference;
import java.util.ArrayList;

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;


An implementation of SurfaceView that uses the dedicated surface for
displaying OpenGL rendering.


A GLSurfaceView provides the following features:



    

  • Manages a surface, which is a special piece of memory that can be
composited into the Android view system.

  • Manages an EGL display, which enables OpenGL to render into a surface.

  • Accepts a user-provided Renderer object that does the actual rendering.

  • Renders on a dedicated thread to decouple rendering performance from the
UI thread.

  • Supports both on-demand and continuous rendering.

  • Optionally wraps, traces, and/or error-checks the renderer's OpenGL calls.





Developer Guides


For more information about how to use OpenGL, read the
OpenGL developer guide.




Using GLSurfaceView


 Typically you use GLSurfaceView by subclassing it and overriding one or more of the View system input event methods. If your application does not need to override event methods then GLSurfaceView can be used as-is. For the most part GLSurfaceView behavior is customized by calling "set" methods rather than by subclassing. For example, unlike a regular View, drawing is delegated to a separate Renderer object which is registered with the GLSurfaceView using the setRenderer(Renderer) call. 


Initializing GLSurfaceView
 All you have to do to initialize a GLSurfaceView is call setRenderer(Renderer). However, if desired, you can modify the default behavior of GLSurfaceView by calling one or more of these methods before calling setRenderer: 



Specifying the android.view.Surface

By default GLSurfaceView will create a PixelFormat.RGB_888 format surface. If a translucent
surface is required, call getHolder().setFormat(PixelFormat.TRANSLUCENT).
The exact format of a TRANSLUCENT surface is device dependent, but it will be
a 32-bit-per-pixel surface with 8 bits per component.



Choosing an EGL Configuration

A given Android device may support multiple EGLConfig rendering configurations.
The available configurations may differ in how many channels of data are present, as
well as how many bits are allocated to each channel. Therefore, the first thing
GLSurfaceView has to do when starting to render is choose what EGLConfig to use.


By default GLSurfaceView chooses a EGLConfig that has an RGB_888 pixel format,
with at least a 16-bit depth buffer and no stencil.


If you would prefer a different EGLConfig
you can override the default behavior by calling one of the
setEGLConfigChooser methods.



Debug Behavior
 You can optionally modify the behavior of GLSurfaceView by calling one or more of the debugging methods setDebugFlags(int), and setGLWrapper. These methods may be called before and/or after setRenderer, but typically they are called before setRenderer so that they take effect immediately. 


Setting a Renderer
 Finally, you must call setRenderer to register a Renderer. The renderer is responsible for doing the actual OpenGL rendering. 


Rendering Mode
 Once the renderer is set, you can control whether the renderer draws continuously or on-demand by calling setRenderMode. The default is continuous rendering. 


Activity Life-cycle
 A GLSurfaceView must be notified when to pause and resume rendering. GLSurfaceView clients are required to call onPause() when the activity stops and onResume() when the activity starts. These calls allow GLSurfaceView to pause and resume the rendering thread, and also allow GLSurfaceView to release and recreate the OpenGL display. 


Handling events


 To handle an event you will typically subclass GLSurfaceView and override the appropriate method, just as you would with any other View. However, when handling the event, you may need to communicate with the Renderer object that's running in the rendering thread. You can do this using any standard Java cross-thread communication mechanism. In addition, one relatively easy way to communicate with your renderer is to call queueEvent(Runnable). For example: 
class MyGLSurfaceView extends GLSurfaceView {
    private MyRenderer mMyRenderer;
    public void start() {
        mMyRenderer = ...;
        setRenderer(mMyRenderer);
    }
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
            queueEvent(new Runnable() {
                // This method will be called on the rendering
                // thread:
                public void run() {
                    mMyRenderer.handleDpadCenter();
                }});
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}



/**
 * An implementation of SurfaceView that uses the dedicated surface for
 * displaying OpenGL rendering.
 * <p>
 * A GLSurfaceView provides the following features:
 * <p>
 * <ul>
 * <li>Manages a surface, which is a special piece of memory that can be
 * composited into the Android view system.
 * <li>Manages an EGL display, which enables OpenGL to render into a surface.
 * <li>Accepts a user-provided Renderer object that does the actual rendering.
 * <li>Renders on a dedicated thread to decouple rendering performance from the
 * UI thread.
 * <li>Supports both on-demand and continuous rendering.
 * <li>Optionally wraps, traces, and/or error-checks the renderer's OpenGL calls.
 * </ul>
 *
 * <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>Using GLSurfaceView</h3>
 * <p>
 * Typically you use GLSurfaceView by subclassing it and overriding one or more of the
 * View system input event methods. If your application does not need to override event
 * methods then GLSurfaceView can be used as-is. For the most part
 * GLSurfaceView behavior is customized by calling "set" methods rather than by subclassing.
 * For example, unlike a regular View, drawing is delegated to a separate Renderer object which
 * is registered with the GLSurfaceView
 * using the {@link #setRenderer(Renderer)} call.
 * <p>
 * <h3>Initializing GLSurfaceView</h3>
 * All you have to do to initialize a GLSurfaceView is call {@link #setRenderer(Renderer)}.
 * However, if desired, you can modify the default behavior of GLSurfaceView by calling one or
 * more of these methods before calling setRenderer:
 * <ul>
 * <li>{@link #setDebugFlags(int)}
 * <li>{@link #setEGLConfigChooser(boolean)}
 * <li>{@link #setEGLConfigChooser(EGLConfigChooser)}
 * <li>{@link #setEGLConfigChooser(int, int, int, int, int, int)}
 * <li>{@link #setGLWrapper(GLWrapper)}
 * </ul>
 * <p>
 * <h4>Specifying the android.view.Surface</h4>
 * By default GLSurfaceView will create a PixelFormat.RGB_888 format surface. If a translucent
 * surface is required, call getHolder().setFormat(PixelFormat.TRANSLUCENT).
 * The exact format of a TRANSLUCENT surface is device dependent, but it will be
 * a 32-bit-per-pixel surface with 8 bits per component.
 * <p>
 * <h4>Choosing an EGL Configuration</h4>
 * A given Android device may support multiple EGLConfig rendering configurations.
 * The available configurations may differ in how many channels of data are present, as
 * well as how many bits are allocated to each channel. Therefore, the first thing
 * GLSurfaceView has to do when starting to render is choose what EGLConfig to use.
 * <p>
 * By default GLSurfaceView chooses a EGLConfig that has an RGB_888 pixel format,
 * with at least a 16-bit depth buffer and no stencil.
 * <p>
 * If you would prefer a different EGLConfig
 * you can override the default behavior by calling one of the
 * setEGLConfigChooser methods.
 * <p>
 * <h4>Debug Behavior</h4>
 * You can optionally modify the behavior of GLSurfaceView by calling
 * one or more of the debugging methods {@link #setDebugFlags(int)},
 * and {@link #setGLWrapper}. These methods may be called before and/or after setRenderer, but
 * typically they are called before setRenderer so that they take effect immediately.
 * <p>
 * <h4>Setting a Renderer</h4>
 * Finally, you must call {@link #setRenderer} to register a {@link Renderer}.
 * The renderer is
 * responsible for doing the actual OpenGL rendering.
 * <p>
 * <h3>Rendering Mode</h3>
 * Once the renderer is set, you can control whether the renderer draws
 * continuously or on-demand by calling
 * {@link #setRenderMode}. The default is continuous rendering.
 * <p>
 * <h3>Activity Life-cycle</h3>
 * A GLSurfaceView must be notified when to pause and resume rendering. GLSurfaceView clients
 * are required to call {@link #onPause()} when the activity stops and
 * {@link #onResume()} when the activity starts. These calls allow GLSurfaceView to
 * pause and resume the rendering thread, and also allow GLSurfaceView to release and recreate
 * the OpenGL display.
 * <p>
 * <h3>Handling events</h3>
 * <p>
 * To handle an event you will typically subclass GLSurfaceView and override the
 * appropriate method, just as you would with any other View. However, when handling
 * the event, you may need to communicate with the Renderer object
 * that's running in the rendering thread. You can do this using any
 * standard Java cross-thread communication mechanism. In addition,
 * one relatively easy way to communicate with your renderer is
 * to call
 * {@link #queueEvent(Runnable)}. For example:
 * <pre class="prettyprint">
 * class MyGLSurfaceView extends GLSurfaceView {
 *
 *     private MyRenderer mMyRenderer;
 *
 *     public void start() {
 *         mMyRenderer = ...;
 *         setRenderer(mMyRenderer);
 *     }
 *
 *     public boolean onKeyDown(int keyCode, KeyEvent event) {
 *         if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
 *             queueEvent(new Runnable() {
 *                 // This method will be called on the rendering
 *                 // thread:
 *                 public void run() {
 *                     mMyRenderer.handleDpadCenter();
 *                 }});
 *             return true;
 *         }
 *         return super.onKeyDown(keyCode, event);
 *     }
 * }
 * </pre>
 *
 */
public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback2 {
    private final static String TAG = "GLSurfaceView";
    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 requestRender is called. 
See Also:
/**
     * 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 Also:
/**
     * 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 Also:
/**
     * 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 "GLSurfaceView".

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

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

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

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

    private void init() {
        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed
        SurfaceHolder holder = getHolder();
        holder.addCallback(this);
        // setFormat is done by SurfaceView in SDK 2.3 and newer. Uncomment
        // this statement if back-porting to 2.2 or older:
        // holder.setFormat(PixelFormat.RGB_565);
        //
        // setType is not needed for SDK 2.0 or newer. Uncomment this
        // statement if back-porting this code to older SDKs.
        // holder.setType(SurfaceHolder.SURFACE_TYPE_GPU);
    }

    
Set the glWrapper. If the glWrapper is not null, its GLWrapper.wrap(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. 

Wrapping is typically used for debugging purposes.


The default value is null.

Params:
  • glWrapper – the new GLWrapper
/**
     * Set the glWrapper. If the glWrapper is not null, its
     * {@link GLWrapper#wrap(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) {
        mGLWrapper = 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.

Params:
  • debugFlags – the new debug flags
See Also:
/**
     * 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) {
        mDebugFlags = debugFlags;
    }

    
Get the current value of the debug flags.

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

    
Control whether the EGL context is preserved when the GLSurfaceView is paused and
resumed.


If set to true, then the EGL context may be preserved when the GLSurfaceView is paused.


Prior to API level 11, whether the EGL context is actually preserved or not
depends upon whether the Android device 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.


If set to false, the EGL context will be released when the GLSurfaceView is paused,
and recreated when the GLSurfaceView is resumed.


The default is false.

Params:
  • preserveOnPause – preserve the EGL context when paused
/**
     * Control whether the EGL context is preserved when the GLSurfaceView is paused and
     * resumed.
     * <p>
     * If set to true, then the EGL context may be preserved when the GLSurfaceView is paused.
     * <p>
     * Prior to API level 11, whether the EGL context is actually preserved or not
     * depends upon whether the Android device 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 GLSurfaceView is paused,
     * and recreated when the GLSurfaceView is resumed.
     * <p>
     *
     * The default is false.
     *
     * @param preserveOnPause preserve the EGL context when paused
     */
    public void setPreserveEGLContextOnPause(boolean preserveOnPause) {
        mPreserveEGLContextOnPause = preserveOnPause;
    }

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

    
Set the renderer associated with this view. Also starts the thread that
will call the renderer, which in turn causes the rendering to start.

This method should be called once and only once in the life-cycle of
a GLSurfaceView.

The following GLSurfaceView methods can only be called before
setRenderer is called:




The following GLSurfaceView methods can only be called after
setRenderer is called:



Params:
  • renderer – the renderer to use to perform OpenGL drawing.
/**
     * 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 GLSurfaceView.
     * <p>The following GLSurfaceView 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 GLSurfaceView 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 (mEGLConfigChooser == null) {
            mEGLConfigChooser = new SimpleEGLConfigChooser(true);
        }
        if (mEGLContextFactory == null) {
            mEGLContextFactory = new DefaultContextFactory();
        }
        if (mEGLWindowSurfaceFactory == null) {
            mEGLWindowSurfaceFactory = new DefaultWindowSurfaceFactory();
        }
        mRenderer = renderer;
        mGLThread = new GLThread(mThisWeakRef);
        mGLThread.start();
    }

    
Install a custom EGLContextFactory.

If this method is called, it must be called before setRenderer(Renderer) is called. 

If this method is not called, then by default
a context will be created with no shared context and
with a null attribute list.

/**
     * 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();
        mEGLContextFactory = factory;
    }

    
Install a custom EGLWindowSurfaceFactory.

If this method is called, it must be called before setRenderer(Renderer) is called. 

If this method is not called, then by default
a window surface will be created with a null attribute list.

/**
     * 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();
        mEGLWindowSurfaceFactory = factory;
    }

    
Install a custom EGLConfigChooser.

If this method is called, it must be called before setRenderer(Renderer) is called. 

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.

Params:
  • configChooser – 
/**
     * 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.
     * @param configChooser
     */
    public void setEGLConfigChooser(EGLConfigChooser configChooser) {
        checkRenderThreadState();
        mEGLConfigChooser = 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.

If this method is called, it must be called before setRenderer(Renderer) is called. 

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.

Params:
  • needDepth – 
/**
     * 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.
     *
     * @param needDepth
     */
    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.

If this method is called, it must be called before setRenderer(Renderer) is called. 

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.

/**
     * 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.

Use this method to create an OpenGL ES 2.0-compatible context.
Example:

    public MyView(Context context) {
        super(context);
        setEGLContextClientVersion(2); // Pick an OpenGL ES 2.0 context.
        setRenderer(new MyRenderer());
    }



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.

If this method is called, it must be called before setRenderer(Renderer) is called. 
This method only affects the behavior of the default EGLContexFactory and the default EGLConfigChooser. If setEGLContextFactory(EGLContextFactory) has been called, then the supplied EGLContextFactory is responsible for creating an OpenGL ES 2.0-compatible context. If setEGLConfigChooser(EGLConfigChooser) has been called, then the supplied EGLConfigChooser is responsible for choosing an OpenGL ES 2.0-compatible config. 
Params:
  • version – The EGLContext client version to choose. Use 2 for OpenGL ES 2.0
/**
     * 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();
        mEGLContextClientVersion = 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 requestRender is called. Defaults to RENDERMODE_CONTINUOUSLY. 

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.

 This method can only be called after setRenderer(Renderer) 
Params:
  • renderMode – one of the RENDERMODE_X constants
See Also:
/**
     * 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) {
        mGLThread.setRenderMode(renderMode);
    }

    
Get the current rendering mode. May be called
from any thread. Must not be called before a renderer has been set.

See Also:
Returns:the current rendering mode.
/**
     * 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 mGLThread.getRenderMode();
    }

    
Request that the renderer render a frame. This method is typically used when the render mode has been set to 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. 
/**
     * 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() {
        mGLThread.requestRender();
    }

    
This method is part of the SurfaceHolder.Callback interface, and is
not normally called or subclassed by clients of GLSurfaceView.

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

    
This method is part of the SurfaceHolder.Callback interface, and is
not normally called or subclassed by clients of GLSurfaceView.

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

    
This method is part of the SurfaceHolder.Callback interface, and is
not normally called or subclassed by clients of GLSurfaceView.

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

    
This method is part of the SurfaceHolder.Callback2 interface, and is
not normally called or subclassed by clients of GLSurfaceView.

/**
     * This method is part of the SurfaceHolder.Callback2 interface, and is
     * not normally called or subclassed by clients of GLSurfaceView.
     */
    @Override
    public void surfaceRedrawNeededAsync(SurfaceHolder holder, Runnable finishDrawing) {
        if (mGLThread != null) {
            mGLThread.requestRenderAndNotify(finishDrawing);
        }
    }

    
This method is part of the SurfaceHolder.Callback2 interface, and is
not normally called or subclassed by clients of GLSurfaceView.

/**
     * This method is part of the SurfaceHolder.Callback2 interface, and is
     * not normally called or subclassed by clients of GLSurfaceView.
     */
    @Deprecated
    @Override
    public void surfaceRedrawNeeded(SurfaceHolder holder) {
        // Since we are part of the framework we know only surfaceRedrawNeededAsync
        // will be called.
    }


    
Pause the rendering thread, optionally tearing down the EGL context depending upon the value of setPreserveEGLContextOnPause(boolean). This method should be called when it is no longer desirable for the GLSurfaceView to continue rendering, such as in response to Activity.onStop. Must not be called before a renderer has been set. 
/**
     * Pause the rendering thread, optionally tearing down the EGL context
     * depending upon the value of {@link #setPreserveEGLContextOnPause(boolean)}.
     *
     * This method should be called when it is no longer desirable for the
     * GLSurfaceView to continue rendering, such as in response to
     * {@link android.app.Activity#onStop Activity.onStop}.
     *
     * Must not be called before a renderer has been set.
     */
    public void onPause() {
        mGLThread.onPause();
    }

    
Resumes the rendering thread, re-creating the OpenGL context if necessary. It is the counterpart to onPause(). This method should typically be called in Activity.onStart. Must not be called before a renderer has been set. 
/**
     * Resumes the rendering thread, re-creating the OpenGL context if necessary. It
     * is the counterpart to {@link #onPause()}.
     *
     * This method should typically be called in
     * {@link android.app.Activity#onStart Activity.onStart}.
     *
     * Must not be called before a renderer has been set.
     */
    public void onResume() {
        mGLThread.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.

Params:
  • r – the runnable to be run on the GL rendering thread.
/**
     * 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) {
        mGLThread.queueEvent(r);
    }

    
This method is used as part of the View class and is not normally
called or subclassed by clients of GLSurfaceView.

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

    @Override
    protected void onDetachedFromWindow() {
        if (LOG_ATTACH_DETACH) {
            Log.d(TAG, "onDetachedFromWindow");
        }
        if (mGLThread != null) {
            mGLThread.requestExitAndWait();
        }
        mDetached = true;
        super.onDetachedFromWindow();
    }

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

    
An interface used to wrap a GL interface.

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:

class MyGLWrapper implements GLWrapper {
    GL wrap(GL gl) {
        return new MyGLImplementation(gl);
    }
    static class MyGLImplementation implements GL,GL10,GL11,... {
        ...
    }
}



See Also:
  • setGLWrapper(GLWrapper)
/**
     * 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.

Params:
  • gl – a GL interface that is to be wrapped.
Returns:either the input argument or another GL object that wraps the input argument.
/**
         * 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.


The renderer is responsible for making OpenGL calls to render a frame.

 GLSurfaceView clients typically create their own classes that implement this interface, and then call GLSurfaceView.setRenderer to register the renderer with the GLSurfaceView. 




Developer Guides


For more information about how to use OpenGL, read the
OpenGL developer guide.




Threading
 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 GLSurfaceView.queueEvent(Runnable) convenience method. 


EGL Context Lost
 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 onSurfaceCreated(GL10, EGLConfig) method is a convenient place to do this. 
See Also:
/**
     * A generic renderer interface.
     * <p>
     * The renderer is responsible for making OpenGL calls to render a frame.
     * <p>
     * GLSurfaceView clients typically create their own classes that implement
     * this interface, and then call {@link GLSurfaceView#setRenderer} to
     * register the renderer with the GLSurfaceView.
     * <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 GLSurfaceView#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(GL10, EGLConfig)} method
     * is a convenient place to do this.
     *
     *
     * @see #setRenderer(Renderer)
     */
    public interface Renderer {
        
Called when the surface is created or recreated.


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.


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.


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.



Params:
  • gl – the GL interface. Use instanceof to
test if the interface supports GL11 or higher interfaces.
  • config – the EGLConfig of the created surface. Can be used
to create matching pbuffers.
/**
         * 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.


Called after the surface is created and whenever
the OpenGL ES surface size changes.


Typically you will set your viewport here. If your camera
is fixed then you could also set your projection matrix here:

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);
}



Params:
  • gl – the GL interface. Use instanceof to
test if the interface supports GL11 or higher interfaces.
  • width – 
  • height – 
/**
         * 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.
         * @param width
         * @param height
         */
        void onSurfaceChanged(GL10 gl, int width, int height);

        
Called to draw the current frame.


This method is responsible for drawing the current frame.


The implementation of this method typically looks like this:

void onDrawFrame(GL10 gl) {
    gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
    //... other gl calls to render the scene ...
}



Params:
  • gl – the GL interface. Use instanceof to
test if the interface supports GL11 or higher interfaces.
/**
         * 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.

 This interface must be implemented by clients wishing to call GLSurfaceView.setEGLContextFactory(EGLContextFactory) 
/**
     * An interface for customizing the eglCreateContext and eglDestroyContext calls.
     * <p>
     * This interface must be implemented by clients wishing to call
     * {@link GLSurfaceView#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, mEGLContextClientVersion,
                    EGL10.EGL_NONE };

            return egl.eglCreateContext(display, config, EGL10.EGL_NO_CONTEXT,
                    mEGLContextClientVersion != 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.

 This interface must be implemented by clients wishing to call GLSurfaceView.setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory) 
/**
     * An interface for customizing the eglCreateWindowSurface and eglDestroySurface calls.
     * <p>
     * This interface must be implemented by clients wishing to call
     * {@link GLSurfaceView#setEGLWindowSurfaceFactory(EGLWindowSurfaceFactory)}
     */
    public interface EGLWindowSurfaceFactory {
        
 @return null if the surface cannot be constructed.

/**
         *  @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.

 This interface must be implemented by clients wishing to call GLSurfaceView.setEGLConfigChooser(EGLConfigChooser) 
/**
     * 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 GLSurfaceView#setEGLConfigChooser(EGLConfigChooser)}
     */
    public interface EGLConfigChooser {
        
Choose a configuration from the list. Implementors typically implement this method by calling EGL10.eglChooseConfig and iterating through the results. Please consult the EGL specification available from The Khronos Group to learn how to call eglChooseConfig. 
Params:
  • egl – the EGL10 for the current display.
  • display – the current display.
Returns:the chosen configuration.
/**
         * 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 (mEGLContextClientVersion != 2 && mEGLContextClientVersion != 3) {
                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;
            if (mEGLContextClientVersion == 2) {
                newConfigSpec[len] = EGL14.EGL_OPENGL_ES2_BIT;  /* EGL_OPENGL_ES2_BIT */
            } else {
                newConfigSpec[len] = EGLExt.EGL_OPENGL_ES3_BIT_KHR; /* EGL_OPENGL_ES3_BIT_KHR */
            }
            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.

/**
     * 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});
            mValue = new int[1];
            mRedSize = redSize;
            mGreenSize = greenSize;
            mBlueSize = blueSize;
            mAlphaSize = alphaSize;
            mDepthSize = depthSize;
            mStencilSize = 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 >= mDepthSize) && (s >= mStencilSize)) {
                    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 == mRedSize) && (g == mGreenSize)
                            && (b == mBlueSize) && (a == mAlphaSize)) {
                        return config;
                    }
                }
            }
            return null;
        }

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

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

        private int[] mValue;
        // Subclasses can adjust these values:
        protected int mRedSize;
        protected int mGreenSize;
        protected int mBlueSize;
        protected int mAlphaSize;
        protected int mDepthSize;
        protected int mStencilSize;
        }

    
This class will choose a RGB_888 surface with
or without a depth buffer.

/**
     * 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.

/**
     * An EGL helper class.
     */

    private static class EglHelper {
        public EglHelper(WeakReference<GLSurfaceView> glSurfaceViewWeakRef) {
            mGLSurfaceViewWeakRef = glSurfaceViewWeakRef;
        }

        
Initialize EGL for a given configuration spec.

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

            /*
             * Get to the default display.
             */
            mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY);

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

            /*
             * We can now initialize EGL for that display
             */
            int[] version = new int[2];
            if(!mEgl.eglInitialize(mEglDisplay, version)) {
                throw new RuntimeException("eglInitialize failed");
            }
            GLSurfaceView view = mGLSurfaceViewWeakRef.get();
            if (view == null) {
                mEglConfig = null;
                mEglContext = null;
            } else {
                mEglConfig = view.mEGLConfigChooser.chooseConfig(mEgl, mEglDisplay);

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

            mEglSurface = null;
        }

        
Create an egl surface for the current SurfaceHolder surface. If a surface
already exists, destroy it before creating the new surface.

Returns:true if the surface was created successfully.
/**
         * 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 (mEgl == null) {
                throw new RuntimeException("egl not initialized");
            }
            if (mEglDisplay == null) {
                throw new RuntimeException("eglDisplay not initialized");
            }
            if (mEglConfig == null) {
                throw new RuntimeException("mEglConfig not initialized");
            }

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

            /*
             * Create an EGL surface we can render into.
             */
            GLSurfaceView view = mGLSurfaceViewWeakRef.get();
            if (view != null) {
                mEglSurface = view.mEGLWindowSurfaceFactory.createWindowSurface(mEgl,
                        mEglDisplay, mEglConfig, view.getHolder());
            } else {
                mEglSurface = null;
            }

            if (mEglSurface == null || mEglSurface == EGL10.EGL_NO_SURFACE) {
                int error = mEgl.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 (!mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext)) {
                /*
                 * Could not make the context current, probably because the underlying
                 * SurfaceView surface has been destroyed.
                 */
                logEglErrorAsWarning("EGLHelper", "eglMakeCurrent", mEgl.eglGetError());
                return false;
            }

            return true;
        }

        
Create a GL object for the current EGL context.

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

            GL gl = mEglContext.getGL();
            GLSurfaceView view = mGLSurfaceViewWeakRef.get();
            if (view != null) {
                if (view.mGLWrapper != null) {
                    gl = view.mGLWrapper.wrap(gl);
                }

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

        
Display the current render surface.

Returns:the EGL error code from eglSwapBuffers.
/**
         * Display the current render surface.
         * @return the EGL error code from eglSwapBuffers.
         */
        public int swap() {
            if (! mEgl.eglSwapBuffers(mEglDisplay, mEglSurface)) {
                return mEgl.eglGetError();
            }
            return EGL10.EGL_SUCCESS;
        }

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

        private void destroySurfaceImp() {
            if (mEglSurface != null && mEglSurface != EGL10.EGL_NO_SURFACE) {
                mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE,
                        EGL10.EGL_NO_SURFACE,
                        EGL10.EGL_NO_CONTEXT);
                GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                if (view != null) {
                    view.mEGLWindowSurfaceFactory.destroySurface(mEgl, mEglDisplay, mEglSurface);
                }
                mEglSurface = null;
            }
        }

        public void finish() {
            if (LOG_EGL) {
                Log.w("EglHelper", "finish() tid=" + Thread.currentThread().getId());
            }
            if (mEglContext != null) {
                GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                if (view != null) {
                    view.mEGLContextFactory.destroyContext(mEgl, mEglDisplay, mEglContext);
                }
                mEglContext = null;
            }
            if (mEglDisplay != null) {
                mEgl.eglTerminate(mEglDisplay);
                mEglDisplay = null;
            }
        }

        private void throwEglException(String function) {
            throwEglException(function, mEgl.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: " + EGLLogWrapper.getErrorString(error);
        }

        private WeakReference<GLSurfaceView> mGLSurfaceViewWeakRef;
        EGL10 mEgl;
        EGLDisplay mEglDisplay;
        EGLSurface mEglSurface;
        EGLConfig mEglConfig;
        EGLContext mEglContext;

    }

    
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
sGLThreadManager object. This avoids multiple-lock ordering issues.

/**
     * 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
     * sGLThreadManager object. This avoids multiple-lock ordering issues.
     *
     */
    static class GLThread extends Thread {
        GLThread(WeakReference<GLSurfaceView> glSurfaceViewWeakRef) {
            super();
            mWidth = 0;
            mHeight = 0;
            mRequestRender = true;
            mRenderMode = RENDERMODE_CONTINUOUSLY;
            mWantRenderNotification = false;
            mGLSurfaceViewWeakRef = glSurfaceViewWeakRef;
        }

        @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 {
                sGLThreadManager.threadExiting(this);
            }
        }

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

        /*
         * This private method should only be called inside a
         * synchronized(sGLThreadManager) block.
         */
        private void stopEglContextLocked() {
            if (mHaveEglContext) {
                mEglHelper.finish();
                mHaveEglContext = false;
                sGLThreadManager.releaseEglContextLocked(this);
            }
        }
        private void guardedRun() throws InterruptedException {
            mEglHelper = new EglHelper(mGLSurfaceViewWeakRef);
            mHaveEglContext = false;
            mHaveEglSurface = false;
            mWantRenderNotification = 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;
                Runnable finishDrawingRunnable = null;

                while (true) {
                    synchronized (sGLThreadManager) {
                        while (true) {
                            if (mShouldExit) {
                                return;
                            }

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

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

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

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

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

                            // When pausing, optionally release the EGL Context:
                            if (pausing && mHaveEglContext) {
                                GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                                boolean preserveEglContextOnPause = view == null ?
                                        false : view.mPreserveEGLContextOnPause;
                                if (!preserveEglContextOnPause) {
                                    stopEglContextLocked();
                                    if (LOG_SURFACE) {
                                        Log.i("GLThread", "releasing EGL context because paused tid=" + getId());
                                    }
                                }
                            }

                            // Have we lost the SurfaceView surface?
                            if ((! mHasSurface) && (! mWaitingForSurface)) {
                                if (LOG_SURFACE) {
                                    Log.i("GLThread", "noticed surfaceView surface lost tid=" + getId());
                                }
                                if (mHaveEglSurface) {
                                    stopEglSurfaceLocked();
                                }
                                mWaitingForSurface = true;
                                mSurfaceIsBad = false;
                                sGLThreadManager.notifyAll();
                            }

                            // Have we acquired the surface view surface?
                            if (mHasSurface && mWaitingForSurface) {
                                if (LOG_SURFACE) {
                                    Log.i("GLThread", "noticed surfaceView surface acquired tid=" + getId());
                                }
                                mWaitingForSurface = false;
                                sGLThreadManager.notifyAll();
                            }

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

                            if (mFinishDrawingRunnable != null) {
                                finishDrawingRunnable = mFinishDrawingRunnable;
                                mFinishDrawingRunnable = null;
                            }

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

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

                                        sGLThreadManager.notifyAll();
                                    }
                                }

                                if (mHaveEglContext && !mHaveEglSurface) {
                                    mHaveEglSurface = true;
                                    createEglSurface = true;
                                    createGlInterface = true;
                                    sizeChanged = true;
                                }

                                if (mHaveEglSurface) {
                                    if (mSizeChanged) {
                                        sizeChanged = true;
                                        w = mWidth;
                                        h = mHeight;
                                        mWantRenderNotification = true;
                                        if (LOG_SURFACE) {
                                            Log.i("GLThread",
                                                    "noticing that we want render notification tid="
                                                    + getId());
                                        }

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

                                        mSizeChanged = false;
                                    }
                                    mRequestRender = false;
                                    sGLThreadManager.notifyAll();
                                    if (mWantRenderNotification) {
                                        wantRenderNotification = true;
                                    }
                                    break;
                                }
                            } else {
                                if (finishDrawingRunnable != null) {
                                    Log.w(TAG, "Warning, !readyToDraw() but waiting for " +
                                            "draw finished! Early reporting draw finished.");
                                    finishDrawingRunnable.run();
                                    finishDrawingRunnable = null;
                                }
                            }
                            // By design, this is the only place in a GLThread thread where we wait().
                            if (LOG_THREADS) {
                                Log.i("GLThread", "waiting tid=" + getId()
                                    + " mHaveEglContext: " + mHaveEglContext
                                    + " mHaveEglSurface: " + mHaveEglSurface
                                    + " mFinishedCreatingEglSurface: " + mFinishedCreatingEglSurface
                                    + " mPaused: " + mPaused
                                    + " mHasSurface: " + mHasSurface
                                    + " mSurfaceIsBad: " + mSurfaceIsBad
                                    + " mWaitingForSurface: " + mWaitingForSurface
                                    + " mWidth: " + mWidth
                                    + " mHeight: " + mHeight
                                    + " mRequestRender: " + mRequestRender
                                    + " mRenderMode: " + mRenderMode);
                            }
                            sGLThreadManager.wait();
                        }
                    } // end of synchronized(sGLThreadManager)

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

                    if (createEglSurface) {
                        if (LOG_SURFACE) {
                            Log.w("GLThread", "egl createSurface");
                        }
                        if (mEglHelper.createSurface()) {
                            synchronized(sGLThreadManager) {
                                mFinishedCreatingEglSurface = true;
                                sGLThreadManager.notifyAll();
                            }
                        } else {
                            synchronized(sGLThreadManager) {
                                mFinishedCreatingEglSurface = true;
                                mSurfaceIsBad = true;
                                sGLThreadManager.notifyAll();
                            }
                            continue;
                        }
                        createEglSurface = false;
                    }

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

                        createGlInterface = false;
                    }

                    if (createEglContext) {
                        if (LOG_RENDERER) {
                            Log.w("GLThread", "onSurfaceCreated");
                        }
                        GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                        if (view != null) {
                            try {
                                Trace.traceBegin(Trace.TRACE_TAG_VIEW, "onSurfaceCreated");
                                view.mRenderer.onSurfaceCreated(gl, mEglHelper.mEglConfig);
                            } finally {
                                Trace.traceEnd(Trace.TRACE_TAG_VIEW);
                            }
                        }
                        createEglContext = false;
                    }

                    if (sizeChanged) {
                        if (LOG_RENDERER) {
                            Log.w("GLThread", "onSurfaceChanged(" + w + ", " + h + ")");
                        }
                        GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                        if (view != null) {
                            try {
                                Trace.traceBegin(Trace.TRACE_TAG_VIEW, "onSurfaceChanged");
                                view.mRenderer.onSurfaceChanged(gl, w, h);
                            } finally {
                                Trace.traceEnd(Trace.TRACE_TAG_VIEW);
                            }
                        }
                        sizeChanged = false;
                    }

                    if (LOG_RENDERER_DRAW_FRAME) {
                        Log.w("GLThread", "onDrawFrame tid=" + getId());
                    }
                    {
                        GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                        if (view != null) {
                            try {
                                Trace.traceBegin(Trace.TRACE_TAG_VIEW, "onDrawFrame");
                                view.mRenderer.onDrawFrame(gl);
                                if (finishDrawingRunnable != null) {
                                    finishDrawingRunnable.run();
                                    finishDrawingRunnable = null;
                                }
                            } finally {
                                Trace.traceEnd(Trace.TRACE_TAG_VIEW);
                            }
                        }
                    }
                    int swapError = mEglHelper.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 SurfaceView 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(sGLThreadManager) {
                                mSurfaceIsBad = true;
                                sGLThreadManager.notifyAll();
                            }
                            break;
                    }

                    if (wantRenderNotification) {
                        doRenderNotification = true;
                        wantRenderNotification = false;
                    }
                }

            } finally {
                /*
                 * clean-up everything...
                 */
                synchronized (sGLThreadManager) {
                    stopEglSurfaceLocked();
                    stopEglContextLocked();
                }
            }
        }

        public boolean ableToDraw() {
            return mHaveEglContext && mHaveEglSurface && readyToDraw();
        }

        private boolean readyToDraw() {
            return (!mPaused) && mHasSurface && (!mSurfaceIsBad)
                && (mWidth > 0) && (mHeight > 0)
                && (mRequestRender || (mRenderMode == RENDERMODE_CONTINUOUSLY));
        }

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

        public int getRenderMode() {
            synchronized(sGLThreadManager) {
                return mRenderMode;
            }
        }

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

        public void requestRenderAndNotify(Runnable finishDrawing) {
            synchronized(sGLThreadManager) {
                // If we are already on the GL thread, this means a client callback
                // has caused reentrancy, for example via updating the SurfaceView parameters.
                // We will return to the client rendering code, so here we don't need to
                // do anything.
                if (Thread.currentThread() == this) {
                    return;
                }

                mWantRenderNotification = true;
                mRequestRender = true;
                mRenderComplete = false;
                mFinishDrawingRunnable = finishDrawing;

                sGLThreadManager.notifyAll();
            }
        }

        public void surfaceCreated() {
            synchronized(sGLThreadManager) {
                if (LOG_THREADS) {
                    Log.i("GLThread", "surfaceCreated tid=" + getId());
                }
                mHasSurface = true;
                mFinishedCreatingEglSurface = false;
                sGLThreadManager.notifyAll();
                while (mWaitingForSurface
                       && !mFinishedCreatingEglSurface
                       && !mExited) {
                    try {
                        sGLThreadManager.wait();
                    } catch (InterruptedException e) {
                        Thread.currentThread().interrupt();
                    }
                }
            }
        }

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

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

        public void onResume() {
            synchronized (sGLThreadManager) {
                if (LOG_PAUSE_RESUME) {
                    Log.i("GLThread", "onResume tid=" + getId());
                }
                mRequestPaused = false;
                mRequestRender = true;
                mRenderComplete = false;
                sGLThreadManager.notifyAll();
                while ((! mExited) && mPaused && (!mRenderComplete)) {
                    if (LOG_PAUSE_RESUME) {
                        Log.i("Main thread", "onResume waiting for !mPaused.");
                    }
                    try {
                        sGLThreadManager.wait();
                    } catch (InterruptedException ex) {
                        Thread.currentThread().interrupt();
                    }
                }
            }
        }

        public void onWindowResize(int w, int h) {
            synchronized (sGLThreadManager) {
                mWidth = w;
                mHeight = h;
                mSizeChanged = true;
                mRequestRender = true;
                mRenderComplete = false;

                // If we are already on the GL thread, this means a client callback
                // has caused reentrancy, for example via updating the SurfaceView parameters.
                // We need to process the size change eventually though and update our EGLSurface.
                // So we set the parameters and return so they can be processed on our
                // next iteration.
                if (Thread.currentThread() == this) {
                    return;
                }

                sGLThreadManager.notifyAll();

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

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

        public void requestReleaseEglContextLocked() {
            mShouldReleaseEglContext = true;
            sGLThreadManager.notifyAll();
        }

        
Queue an "event" to be run on the GL rendering thread.

Params:
  • r – the runnable to be run on the GL rendering thread.
/**
         * 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(sGLThreadManager) {
                mEventQueue.add(r);
                sGLThreadManager.notifyAll();
            }
        }

        // Once the thread is started, all accesses to the following member
        // variables are protected by the sGLThreadManager monitor
        private boolean mShouldExit;
        private boolean mExited;
        private boolean mRequestPaused;
        private boolean mPaused;
        private boolean mHasSurface;
        private boolean mSurfaceIsBad;
        private boolean mWaitingForSurface;
        private boolean mHaveEglContext;
        private boolean mHaveEglSurface;
        private boolean mFinishedCreatingEglSurface;
        private boolean mShouldReleaseEglContext;
        private int mWidth;
        private int mHeight;
        private int mRenderMode;
        private boolean mRequestRender;
        private boolean mWantRenderNotification;
        private boolean mRenderComplete;
        private ArrayList<Runnable> mEventQueue = new ArrayList<Runnable>();
        private boolean mSizeChanged = true;
        private Runnable mFinishDrawingRunnable = null;

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

        private EglHelper mEglHelper;

        
Set once at thread construction time, nulled out when the parent view is garbage
called. This weak reference allows the GLSurfaceView to be garbage collected while
the GLThread is still alive.

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

    }

    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 {
                    mBuilder.append(c);
                }
            }
        }

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

        private StringBuilder mBuilder = new StringBuilder();
    }


    private void checkRenderThreadState() {
        if (mGLThread != 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.mExited = true;
            notifyAll();
        }

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

    private static final GLThreadManager sGLThreadManager = new GLThreadManager();

    private final WeakReference<GLSurfaceView> mThisWeakRef =
            new WeakReference<GLSurfaceView>(this);
    private GLThread mGLThread;
    private Renderer mRenderer;
    private boolean mDetached;
    private EGLConfigChooser mEGLConfigChooser;
    private EGLContextFactory mEGLContextFactory;
    private EGLWindowSurfaceFactory mEGLWindowSurfaceFactory;
    private GLWrapper mGLWrapper;
    private int mDebugFlags;
    private int mEGLContextClientVersion;
    private boolean mPreserveEGLContextOnPause;
}