From be4cd1a0785c30e2daeb783dc4af62598d2cfe45 Mon Sep 17 00:00:00 2001
From: Heeyong Song <heeyong.song@samsung.com>
Date: Fri, 29 Jun 2018 16:56:22 +0900
Subject: [PATCH] Fix flickering issue when the window is resized

A viewport is sometimes changed later because event processing is delayed.
Change a render surface size when the viewport is really changed.

Change-Id: I530a0160669aaae4eb9de05dab2c16f22c0863b1
---
 dali/internal/adaptor/common/adaptor-impl.cpp      |  1 -
 .../common/combined-update-render-controller.cpp   | 44 +++++++++-------------
 2 files changed, 17 insertions(+), 28 deletions(-)

diff --git a/dali/internal/adaptor/common/adaptor-impl.cpp b/dali/internal/adaptor/common/adaptor-impl.cpp
index 83d91a1..b660e43 100755
--- a/dali/internal/adaptor/common/adaptor-impl.cpp
+++ b/dali/internal/adaptor/common/adaptor-impl.cpp
@@ -785,7 +785,6 @@ void Adaptor::SurfaceResizeComplete( SurfaceSize surfaceSize )
   // to start processing messages for new camera setup etc as soon as possible
   ProcessCoreEvents();
 
-  // this method blocks until the render thread has completed the resizing.
   mThreadController->ResizeSurface();
 }
 
diff --git a/dali/internal/adaptor/common/combined-update-render-controller.cpp b/dali/internal/adaptor/common/combined-update-render-controller.cpp
index 5af0ca1..eb59399 100644
--- a/dali/internal/adaptor/common/combined-update-render-controller.cpp
+++ b/dali/internal/adaptor/common/combined-update-render-controller.cpp
@@ -292,20 +292,14 @@ void CombinedUpdateRenderController::ResizeSurface()
 {
   LOG_EVENT_TRACE;
 
-  LOG_EVENT( "Starting to resize the surface, event-thread blocked" );
+  LOG_EVENT( "Resize the surface" );
 
-  // Start resizing the surface.
   {
     ConditionalWait::ScopedLock lock( mUpdateRenderThreadWaitCondition );
     mPostRendering = FALSE; // Clear the post-rendering flag as Update/Render thread will resize the surface now
     mSurfaceResized = TRUE;
     mUpdateRenderThreadWaitCondition.Notify( lock );
   }
-
-  // Wait until the surface has been resized
-  sem_wait( &mEventThreadSemaphore );
-
-  LOG_EVENT( "Surface resized, event-thread continuing" );
 }
 
 void CombinedUpdateRenderController::SetRenderRefreshRate( unsigned int numberOfFramesPerRender )
@@ -443,22 +437,9 @@ void CombinedUpdateRenderController::UpdateRenderThread()
       SurfaceReplaced();
     }
 
-    //////////////////////////////
-    // RESIZE SURFACE
-    //////////////////////////////
-
     const bool isRenderingToFbo = renderToFboEnabled && ( ( 0u == frameCount ) || ( 0u != frameCount % renderToFboInterval ) );
     ++frameCount;
 
-    // The resizing will be applied in the next loop
-    bool surfaceResized = ShouldSurfaceBeResized();
-    if( DALI_UNLIKELY( surfaceResized ) )
-    {
-      LOG_UPDATE_RENDER_TRACE_FMT( "Resizing Surface" );
-      mRenderHelper.ResizeSurface();
-      SurfaceResized();
-    }
-
     //////////////////////////////
     // UPDATE
     //////////////////////////////
@@ -497,6 +478,19 @@ void CombinedUpdateRenderController::UpdateRenderThread()
       LOG_UPDATE_RENDER( "Notification Triggered" );
     }
 
+    // Check resize
+    bool surfaceResized = ShouldSurfaceBeResized();
+    if( DALI_UNLIKELY( surfaceResized ) )
+    {
+      // RenderHelper::ResizeSurface() should be called right after a viewport is changed.
+      if( updateStatus.SurfaceRectChanged() )
+      {
+        LOG_UPDATE_RENDER_TRACE_FMT( "Resizing Surface" );
+        mRenderHelper.ResizeSurface();
+        SurfaceResized();
+      }
+    }
+
     // Optional logging of update/render status
     mUpdateStatusLogger.Log( keepUpdatingStatus );
 
@@ -657,17 +651,13 @@ void CombinedUpdateRenderController::SurfaceReplaced()
 bool CombinedUpdateRenderController::ShouldSurfaceBeResized()
 {
   ConditionalWait::ScopedLock lock( mUpdateRenderThreadWaitCondition );
-
-  bool surfaceSized = mSurfaceResized;
-  mSurfaceResized = FALSE;
-
-  return surfaceSized;
+  return mSurfaceResized;
 }
 
 void CombinedUpdateRenderController::SurfaceResized()
 {
-  // Just increment the semaphore
-  sem_post( &mEventThreadSemaphore );
+  ConditionalWait::ScopedLock lock( mUpdateRenderThreadWaitCondition );
+  mSurfaceResized = FALSE;
 }
 
 ///////////////////////////////////////////////////////////////////////////////////////////////////
-- 
2.7.4