Disable hardware acceleration on Android

It serves no purpose and causes tearing.  Uploading the bitmap
to the GPU takes about as long as it does to incrementally
update the surface in software.

* java/AndroidManifest.xml.in: Disable hardware acceleration.
* java/org/gnu/emacs/EmacsActivity.java (EmacsActivity): Make
lastClosedMenu static.
* java/org/gnu/emacs/EmacsDialog.java (toAlertDialog): Enable
hardware acceleration within alert dialogs.
* java/org/gnu/emacs/EmacsSurfaceView.java (onDraw): Describe
why hardware acceleration is disabled.
* java/org/gnu/emacs/EmacsWindow.java (run): Remove redundant
call.

diff --git a/java/AndroidManifest.xml.in b/java/AndroidManifest.xml.in
index e79fb4e46e7c5c12ce957c8d71e1c92d6df9dd6c..f2aede7369c535f4e1990fcda56cf5077a1189d4 100644 (file)
--- a/java/AndroidManifest.xml.in
+++ b/java/AndroidManifest.xml.in
@@ -77,10 +77,14 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
               @ANDROID_SHARED_USER_ID@
               android:extractNativeLibs="true">
 
+    <!-- See EmacsSurfaceView.onDraw for why hardware acceleration is
+         disabled.  -->
+
     <activity android:name="org.gnu.emacs.EmacsActivity"
              android:launchMode="singleInstance"
              android:windowSoftInputMode="adjustResize"
              android:exported="true"
+             android:hardwareAccelerated="false"
              android:configChanges="orientation|screenSize|screenLayout|keyboardHidden">
       <intent-filter>
         <action android:name="android.intent.action.MAIN" />
@@ -173,6 +177,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>. -->
     <activity android:name="org.gnu.emacs.EmacsMultitaskActivity"
              android:windowSoftInputMode="adjustResize"
              android:exported="true"
+             android:hardwareAccelerated="false"
              android:configChanges="orientation|screenSize|screenLayout|keyboardHidden"/>
 
     <activity android:autoRemoveFromRecents="true"

diff --git a/java/org/gnu/emacs/EmacsActivity.java b/java/org/gnu/emacs/EmacsActivity.java
index fa9bff39bb09244ca4fbfd12ccf2307bc38ee0d6..d7b51388929309c9ed93de128be3d7b6c0e7a4cc 100644 (file)
--- a/java/org/gnu/emacs/EmacsActivity.java
+++ b/java/org/gnu/emacs/EmacsActivity.java
@@ -70,7 +70,7 @@ public class EmacsActivity extends Activity
   private boolean isFullscreen;
 
   /* The last context menu to be closed.  */
-  private Menu lastClosedMenu;
+  private static Menu lastClosedMenu;
 
   static
   {

diff --git a/java/org/gnu/emacs/EmacsDialog.java b/java/org/gnu/emacs/EmacsDialog.java
index 5f48a9a5f9fd0c01d4e3202f8e0b4d06db32d5e5..42455ed78f8fa956f6b5dda322fa4cebf5ab2a68 100644 (file)
--- a/java/org/gnu/emacs/EmacsDialog.java
+++ b/java/org/gnu/emacs/EmacsDialog.java
@@ -152,7 +152,7 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
   toAlertDialog (Context context)
   {
     AlertDialog dialog;
-    int size, styleId;
+    int size, styleId, flag;
     int[] attrs;
     EmacsButton button;
     EmacsDialogButtonLayout layout;
@@ -160,6 +160,7 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
     ViewGroup.LayoutParams layoutParams;
     Theme theme;
     TypedArray attributes;
+    Window window;
 
     size = buttons.size ();
     styleId = -1;
@@ -273,6 +274,17 @@ public final class EmacsDialog implements DialogInterface.OnDismissListener
          }
       }
 
+    /* Make sure the dialog is hardware accelerated.  Hardware
+       acceleration is disabled for dialogs by default, because they
+       aren't enabled in EmacsActivity either.  */
+
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB)
+      {
+       flag = WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED;
+       window = dialog.getWindow ();
+       window.addFlags (flag);
+      }
+
     return dialog;
   }
 

diff --git a/java/org/gnu/emacs/EmacsSurfaceView.java b/java/org/gnu/emacs/EmacsSurfaceView.java
index 3f62af4ab99046c256a4b2a4161c9ff764b6f91c..54fe70e1634a882a0265f6326ec176a2cfde9ff5 100644 (file)
--- a/java/org/gnu/emacs/EmacsSurfaceView.java
+++ b/java/org/gnu/emacs/EmacsSurfaceView.java
@@ -176,7 +176,25 @@ public final class EmacsSurfaceView extends View
   onDraw (Canvas canvas)
   {
     /* Paint the view's bitmap; the bitmap might be recycled right
-       now.  */
+       now.
+
+       Hardware acceleration is disabled in AndroidManifest.xml to
+       prevent Android from uploading the front buffer to the GPU from
+       a separate thread.  This is important for two reasons: first,
+       the GPU command queue uses a massive amount of memory (dozens
+       of MiB) to upload bitmaps to the GPU, regardless of how much of
+       the bitmap has actually changed.
+
+       Secondly, asynchronous texturization leads to race conditions
+       when a buffer swap occurs before the front buffer is fully
+       uploaded to the GPU.  Normally, only slight and tolerable
+       tearing should result from this behavior, but Android does not
+       properly interlock the ``generation ID'' used to avoid
+       texturizing unchanged bitmaps with the bitmap contents,
+       consequentially leading to textures in an incomplete state
+       remaining in use to the GPU if a buffer swap happens between
+       the image data being uploaded and the ``generation ID'' being
+       read.  */
 
     if (frontBuffer != null)
       canvas.drawBitmap (frontBuffer, 0f, 0f, uiThreadPaint);

diff --git a/java/org/gnu/emacs/EmacsWindow.java b/java/org/gnu/emacs/EmacsWindow.java
index 5e45275631b9099ca4e6dc3aabf59d1305b9f73b..0e96a8382d0bd15a0c668eef9c8cbe140643c7ed 100644 (file)
--- a/java/org/gnu/emacs/EmacsWindow.java
+++ b/java/org/gnu/emacs/EmacsWindow.java
@@ -1377,7 +1377,7 @@ public final class EmacsWindow extends EmacsHandleObject
 
          if (tem != null)
            {
-             activity = (EmacsActivity) getAttachedConsumer ();
+             activity = (EmacsActivity) tem;
              activity.syncFullscreenWith (EmacsWindow.this);
            }
        }