vcl: use a custom tag for VCL OpenGLContext's to avoid re-use.

Other code is out of legacy mode now, so can't legacy as a proxy.

Change-Id: Ie3807a3af680b707f2f08d058db955bc9cae6c2b
Reviewed-on: https://gerrit.libreoffice.org/20647Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Michael Meeks <michael.meeks@collabora.com>

include/vcl/opengl/OpenGLContext.hxx

@@ -204,6 +204,10 @@ public:
         return mbRequestLegacyContext;
     }
 
+    /// VCL promiscuously re-uses its own contexts:
+    void setVCLOnly() { mbVCLOnly = true; }
+    bool isVCLOnly() { return mbVCLOnly; }
+
     bool supportMultiSampling() const;
 
     static SystemWindowData generateWinData(vcl::Window* pParent, bool bRequestLegacyContext);
@@ -229,6 +233,7 @@ private:
     int  mnRefCount;
     bool mbRequestLegacyContext;
     bool mbUseDoubleBufferedRendering;
+    bool mbVCLOnly;
 
     int mnFramebufferCount;
     OpenGLFramebuffer* mpCurrentFramebuffer;

vcl/inc/openglgdiimpl.hxx

@@ -72,9 +72,6 @@ protected:
     OpenGLFramebuffer* mpFramebuffer;
     OpenGLProgram* mpProgram;
 
-    /// Is it someone else's context we shouldn't be fiddling with ?
-    static bool IsForeignContext(const rtl::Reference<OpenGLContext> &xContext);
-
     /// This idle handler is used to swap buffers after rendering.
     OpenGLFlushIdle *mpFlush;
 
@@ -174,7 +171,7 @@ protected:
     bool UseContext( const rtl::Reference<OpenGLContext> &pContext )
     {
         return pContext->isInitialized() &&  // not released by the OS etc.
-               IsForeignContext( pContext ); // a genuine VCL context.
+               pContext->isVCLOnly();
     }
 
 public:

vcl/opengl/gdiimpl.cxx

@@ -2092,11 +2092,4 @@ void OpenGLSalGraphicsImpl::doFlush()
     VCL_GL_INFO( "flushAndSwap - end." );
 }
 
-bool OpenGLSalGraphicsImpl::IsForeignContext(const rtl::Reference<OpenGLContext> &xContext)
-{
-    // so far a blunt heuristic: vcl uses shiny new contexts.
-    return xContext->requestedLegacy();
-}
-
-
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

vcl/opengl/win/gdiimpl.cxx

@@ -29,6 +29,7 @@ void WinOpenGLSalGraphicsImpl::copyBits( const SalTwoRect& rPosAry, SalGraphics*
 rtl::Reference<OpenGLContext> WinOpenGLSalGraphicsImpl::CreateWinContext()
 {
     rtl::Reference<OpenGLContext> pContext = OpenGLContext::Create();
+    pContext->setVCLOnly();
     pContext->init( mrParent.mhLocalDC, mrParent.mhWnd );
     return pContext;
 }

vcl/opengl/x11/gdiimpl.cxx

@@ -53,6 +53,7 @@ rtl::Reference<OpenGLContext> X11OpenGLSalGraphicsImpl::CreateWinContext()
 
     Window aWin = pProvider->GetX11Window();
     rtl::Reference<OpenGLContext> pContext = OpenGLContext::Create();
+    pContext->setVCLOnly();
     pContext->init( mrParent.GetXDisplay(), aWin,
                     mrParent.m_nXScreen.getXScreen() );
     return pContext;

vcl/source/opengl/OpenGLContext.cxx

@@ -62,6 +62,7 @@ OpenGLContext::OpenGLContext():
     mnRefCount(0),
     mbRequestLegacyContext(false),
     mbUseDoubleBufferedRendering(true),
+    mbVCLOnly(false),
     mnFramebufferCount(0),
     mpCurrentFramebuffer(nullptr),
     mpFirstFramebuffer(nullptr),