update GlSurfaceView:onPause/Resume docs

fixes: 22448595

Also delete some epically outdated code to
match the documented behavior

Change-Id: I2bb5b475433ebff8ca82db385e228fef11e32e20

1 files changed, 31 insertions, 131 deletions

diff --git a/opengl/java/android/opengl/GLSurfaceView.java b/opengl/java/android/opengl/GLSurfaceView.java
index 38ed9321653d..0f5dd3aa5667 100644
--- a/opengl/java/android/opengl/GLSurfaceView.java
+++ b/opengl/java/android/opengl/GLSurfaceView.java
@@ -16,6 +16,13 @@
 
 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;
@@ -29,15 +36,6 @@ import javax.microedition.khronos.egl.EGLSurface;
 import javax.microedition.khronos.opengles.GL;
 import javax.microedition.khronos.opengles.GL10;
 
-import android.content.Context;
-import android.content.pm.ConfigurationInfo;
-import android.os.SystemProperties;
-import android.os.Trace;
-import android.util.AttributeSet;
-import android.util.Log;
-import android.view.SurfaceHolder;
-import android.view.SurfaceView;
-
 /**
  * An implementation of SurfaceView that uses the dedicated surface for
  * displaying OpenGL rendering.
@@ -119,9 +117,9 @@ import android.view.SurfaceView;
  * {@link #setRenderMode}. The default is continuous rendering.
  * <p>
  * <h3>Activity Life-cycle</h3>
- * A GLSurfaceView must be notified when the activity is paused and resumed. GLSurfaceView clients
- * are required to call {@link #onPause()} when the activity pauses and
- * {@link #onResume()} when the activity resumes. These calls allow GLSurfaceView to
+ * 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>
@@ -294,10 +292,12 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
      * resumed.
      * <p>
      * If set to true, then the EGL context may be preserved when the GLSurfaceView is paused.
-     * Whether the EGL context is actually preserved or not depends upon whether the
-     * Android device that the program is running on can support an arbitrary number of EGL
-     * contexts or not. Devices that can only support a limited number of EGL contexts must
-     * release the  EGL context in order to allow multiple applications to share the GPU.
+     * <p>
+     * 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.
@@ -554,9 +554,13 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
 
 
     /**
-     * Inform the view that the activity is paused. The owner of this view must
-     * call this method when the activity is paused. Calling this method will
-     * pause the rendering thread.
+     * 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() {
@@ -564,10 +568,12 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
     }
 
     /**
-     * Inform the view that the activity is resumed. The owner of this view must
-     * call this method when the activity is resumed. Calling this method will
-     * recreate the OpenGL display and resume the rendering
-     * thread.
+     * 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() {
@@ -1354,7 +1360,7 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                                 GLSurfaceView view = mGLSurfaceViewWeakRef.get();
                                 boolean preserveEglContextOnPause = view == null ?
                                         false : view.mPreserveEGLContextOnPause;
-                                if (!preserveEglContextOnPause || sGLThreadManager.shouldReleaseEGLContextWhenPausing()) {
+                                if (!preserveEglContextOnPause) {
                                     stopEglContextLocked();
                                     if (LOG_SURFACE) {
                                         Log.i("GLThread", "releasing EGL context because paused tid=" + getId());
@@ -1362,16 +1368,6 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                                 }
                             }
 
-                            // When pausing, optionally terminate EGL:
-                            if (pausing) {
-                                if (sGLThreadManager.shouldTerminateEGLWhenPausing()) {
-                                    mEglHelper.finish();
-                                    if (LOG_SURFACE) {
-                                        Log.i("GLThread", "terminating EGL because paused tid=" + getId());
-                                    }
-                                }
-                            }
-
                             // Have we lost the SurfaceView surface?
                             if ((! mHasSurface) && (! mWaitingForSurface)) {
                                 if (LOG_SURFACE) {
@@ -1411,7 +1407,7 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                                 if (! mHaveEglContext) {
                                     if (askedToReleaseEglContext) {
                                         askedToReleaseEglContext = false;
-                                    } else if (sGLThreadManager.tryAcquireEglContextLocked(this)) {
+                                    } else {
                                         try {
                                             mEglHelper.start();
                                         } catch (RuntimeException t) {
@@ -1506,7 +1502,6 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                     if (createGlInterface) {
                         gl = (GL10) mEglHelper.createGL();
 
-                        sGLThreadManager.checkGLDriver(gl);
                         createGlInterface = false;
                     }
 
@@ -1888,111 +1883,16 @@ public class GLSurfaceView extends SurfaceView implements SurfaceHolder.Callback
                 Log.i("GLThread", "exiting tid=" +  thread.getId());
             }
             thread.mExited = true;
-            if (mEglOwner == thread) {
-                mEglOwner = null;
-            }
             notifyAll();
         }
 
         /*
-         * Tries once to acquire the right to use an EGL
-         * context. Does not block. Requires that we are already
-         * in the sGLThreadManager monitor when this is called.
-         *
-         * @return true if the right to use an EGL context was acquired.
-         */
-        public boolean tryAcquireEglContextLocked(GLThread thread) {
-            if (mEglOwner == thread || mEglOwner == null) {
-                mEglOwner = thread;
-                notifyAll();
-                return true;
-            }
-            checkGLESVersion();
-            if (mMultipleGLESContextsAllowed) {
-                return true;
-            }
-            // Notify the owning thread that it should release the context.
-            // TODO: implement a fairness policy. Currently
-            // if the owning thread is drawing continuously it will just
-            // reacquire the EGL context.
-            if (mEglOwner != null) {
-                mEglOwner.requestReleaseEglContextLocked();
-            }
-            return false;
-        }
-
-        /*
          * Releases the EGL context. Requires that we are already in the
          * sGLThreadManager monitor when this is called.
          */
         public void releaseEglContextLocked(GLThread thread) {
-            if (mEglOwner == thread) {
-                mEglOwner = null;
-            }
             notifyAll();
         }
-
-        public synchronized boolean shouldReleaseEGLContextWhenPausing() {
-            // Release the EGL context when pausing even if
-            // the hardware supports multiple EGL contexts.
-            // Otherwise the device could run out of EGL contexts.
-            return mLimitedGLESContexts;
-        }
-
-        public synchronized boolean shouldTerminateEGLWhenPausing() {
-            checkGLESVersion();
-            return !mMultipleGLESContextsAllowed;
-        }
-
-        public synchronized void checkGLDriver(GL10 gl) {
-            if (! mGLESDriverCheckComplete) {
-                checkGLESVersion();
-                String renderer = gl.glGetString(GL10.GL_RENDERER);
-                if (mGLESVersion < kGLES_20) {
-                    mMultipleGLESContextsAllowed =
-                        ! renderer.startsWith(kMSM7K_RENDERER_PREFIX);
-                    notifyAll();
-                }
-                mLimitedGLESContexts = !mMultipleGLESContextsAllowed;
-                if (LOG_SURFACE) {
-                    Log.w(TAG, "checkGLDriver renderer = \"" + renderer + "\" multipleContextsAllowed = "
-                        + mMultipleGLESContextsAllowed
-                        + " mLimitedGLESContexts = " + mLimitedGLESContexts);
-                }
-                mGLESDriverCheckComplete = true;
-            }
-        }
-
-        private void checkGLESVersion() {
-            if (! mGLESVersionCheckComplete) {
-                mGLESVersion = SystemProperties.getInt(
-                        "ro.opengles.version",
-                        ConfigurationInfo.GL_ES_VERSION_UNDEFINED);
-                if (mGLESVersion >= kGLES_20) {
-                    mMultipleGLESContextsAllowed = true;
-                }
-                if (LOG_SURFACE) {
-                    Log.w(TAG, "checkGLESVersion mGLESVersion =" +
-                            " " + mGLESVersion + " mMultipleGLESContextsAllowed = " + mMultipleGLESContextsAllowed);
-                }
-                mGLESVersionCheckComplete = true;
-            }
-        }
-
-        /**
-         * This check was required for some pre-Android-3.0 hardware. Android 3.0 provides
-         * support for hardware-accelerated views, therefore multiple EGL contexts are
-         * supported on all Android 3.0+ EGL drivers.
-         */
-        private boolean mGLESVersionCheckComplete;
-        private int mGLESVersion;
-        private boolean mGLESDriverCheckComplete;
-        private boolean mMultipleGLESContextsAllowed;
-        private boolean mLimitedGLESContexts;
-        private static final int kGLES_20 = 0x20000;
-        private static final String kMSM7K_RENDERER_PREFIX =
-            "Q3Dimension MSM7500 ";
-        private GLThread mEglOwner;
     }
 
     private static final GLThreadManager sGLThreadManager = new GLThreadManager();