Skip eglSwapBuffers() call when we do not draw to GL

The fix is to track when we issue GL drawing commands, and to skip the
call to eglSwapBuffers() when a DisplayList does not result in
any actual rendering calls to GL.

Issue #6364143 QuickMuni list items and buttons flicker instead of fade

Change-Id: I60a02c61a58c32d92481a1e814b4c8a49c6a37a3

1 files changed, 8 insertions, 1 deletions

diff --git a/include/private/hwui/DrawGlInfo.h b/include/private/hwui/DrawGlInfo.h
index e33823e..fc810be 100644
--- a/include/private/hwui/DrawGlInfo.h
+++ b/include/private/hwui/DrawGlInfo.h
@@ -72,7 +72,14 @@ struct DrawGlInfo {
         // The functor needs to be invoked again but will
         // not redraw. Only the functor is invoked again
         // (unless another functor requests a redraw.)
-        kStatusInvoke = 0x2
+        kStatusInvoke = 0x2,
+        // DisplayList actually issued GL drawing commands.
+        // This is used to signal the HardwareRenderer that the
+        // buffers should be flipped - otherwise, there were no
+        // changes to the buffer, so no need to flip. Some hardware
+        // has issues with stale buffer contents when no GL
+        // commands are issued.
+        kStatusDrew = 0x4
     };
 }; // struct DrawGlInfo