tdf#94213 - defer glFlushing until we've re-rendered after a re-size.

Avoids a rather horrible flickering problem in GL mode.

Squashing:

tdf#94213 - release offscreen texture properly on re-size.

We need to ensure that we use an initialized context, and that
(when we re-parent) we DeInit and so reset the previous OpenGLContext.
Make UseContext more paranoid as well for good measure.

Squashing:

tdf#94213 - cleanup associated GL contexts properly when DCs released.

Change-Id: I6b9fb899777d8e460999ac3ff038a1302e434bb5
Reviewed-on: https://gerrit.libreoffice.org/18607Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Tor Lillqvist <tml@collabora.com>

vcl/inc/opengl/win/gdiimpl.hxx

@@ -34,6 +34,7 @@ protected:
     virtual bool UseContext( const rtl::Reference<OpenGLContext> &pContext ) SAL_OVERRIDE;
 
 public:
+    virtual void Init() SAL_OVERRIDE;
     virtual void copyBits( const SalTwoRect& rPosAry, SalGraphics* pSrcGraphics ) SAL_OVERRIDE;
 
 

vcl/opengl/gdiimpl.cxx

@@ -115,7 +115,8 @@ void OpenGLSalGraphicsImpl::Init()
     // check if we can simply re-use the same context
     if( mpContext.is() )
     {
-        if( !UseContext( mpContext ) )
+        if( !mpContext->isInitialized() ||
+            !UseContext( mpContext ) )
             ReleaseContext();
     }
 
@@ -124,8 +125,12 @@ void OpenGLSalGraphicsImpl::Init()
         maOffscreenTex.GetWidth()  != GetWidth() ||
         maOffscreenTex.GetHeight() != GetHeight() )
     {
-        if( mpContext.is() ) // valid context
+        if( maOffscreenTex && // don't work to release empty textures
+            mpContext.is() )  // valid context
+        {
+            mpContext->makeCurrent();
             mpContext->ReleaseFramebuffer( maOffscreenTex );
+        }
         maOffscreenTex = OpenGLTexture();
     }
 }

vcl/opengl/win/gdiimpl.cxx

@@ -43,7 +43,24 @@ bool WinOpenGLSalGraphicsImpl::UseContext( const rtl::Reference<OpenGLContext> &
         return false;
     if( IsOffscreen() )
         return true;
-    return pContext->getOpenGLWindow().hWnd == mrParent.mhWnd;
+    return pContext->getOpenGLWindow().hWnd == mrParent.mhWnd &&
+           pContext->getOpenGLWindow().hDC == mrParent.mhLocalDC;
+}
+
+void WinOpenGLSalGraphicsImpl::Init()
+{
+    if ( !IsOffscreen() && mpContext.is() && mpContext->isInitialized() &&
+         ( mpContext->getOpenGLWindow().hWnd != mrParent.mhWnd ||
+           mpContext->getOpenGLWindow().hDC == mrParent.mhLocalDC ) )
+    {
+        // This can legitimiately happen, SalFrame keeps 2x
+        // SalGraphics which share the same hWnd and hDC.
+        // The shape 'Area' dialog does reparenting to trigger this.
+        SAL_WARN("vcl.opengl", "Unusual: Windows handle / DC changed without DeInit");
+        DeInit();
+    }
+
+    OpenGLSalGraphicsImpl::Init();
 }
 
 namespace

vcl/source/opengl/OpenGLContext.cxx

@@ -1690,6 +1690,9 @@ void OpenGLContext::ReleaseFramebuffer( const OpenGLTexture& rTexture )
 {
     OpenGLZone aZone;
 
+    if (!rTexture) // no texture to release.
+        return;
+
     OpenGLFramebuffer* pFramebuffer = mpLastFramebuffer;
 
     while( pFramebuffer )

vcl/source/window/paint.cxx

@@ -651,6 +651,8 @@ IMPL_LINK_NOARG_TYPED(Window, ImplHandlePaintHdl, Idle *, void)
         return;
     }
 
+    BeginPaint();
+
     // save paint events until resizing or initial sizing done
     if (!ImplDoTiledRendering() && mpWindowImpl->mbFrame &&
         (mpWindowImpl->mpFrameData->maResizeIdle.IsActive() ||
@@ -662,12 +664,16 @@ IMPL_LINK_NOARG_TYPED(Window, ImplHandlePaintHdl, Idle *, void)
     {
         ImplCallOverlapPaint();
     }
+
+    EndPaint();
 }
 
 IMPL_LINK_NOARG_TYPED(Window, ImplHandleResizeTimerHdl, Idle *, void)
 {
     if( mpWindowImpl->mbReallyVisible )
     {
+        BeginPaint();
+
         ImplCallResize();
         if( ImplDoTiledRendering() )
         {
@@ -678,6 +684,8 @@ IMPL_LINK_NOARG_TYPED(Window, ImplHandleResizeTimerHdl, Idle *, void)
             mpWindowImpl->mpFrameData->maPaintIdle.Stop();
             mpWindowImpl->mpFrameData->maPaintIdle.GetIdleHdl().Call( NULL );
         }
+
+        EndPaint();
     }
 }
 

vcl/win/source/window/salframe.cxx

@@ -1048,7 +1048,7 @@ void WinSalFrame::ReleaseGraphics( SalGraphics* pGraphics )
             SalData* pSalData = GetSalData();
             if ( mpGraphics2->getDefPal() )
                 SelectPalette( mpGraphics2->getHDC(), mpGraphics2->getDefPal(), TRUE );
-            mpGraphics2->InitGraphics();
+            mpGraphics2->DeInitGraphics();
             SendMessageW( pSalData->mpFirstInstance->mhComWnd,
                              SAL_MSG_RELEASEDC,
                              (WPARAM)mhWnd,
@@ -1498,7 +1498,7 @@ static void ImplSetParentFrame( WinSalFrame* pThis, HWND hNewParentWnd, bool bAs
     {
         if ( pThis->mpGraphics->getDefPal() )
             SelectPalette( pThis->mpGraphics->getHDC(), pThis->mpGraphics->getDefPal(), TRUE );
-        pThis->mpGraphics->InitGraphics();
+        pThis->mpGraphics->DeInitGraphics();
         ReleaseDC( pThis->mhWnd, pThis->mpGraphics->getHDC() );
     }