tdf#94281 - don't mix legacy and VCL OpenGLContext's.

Each has rather different assumptions about how life should be.

Change-Id: I85fffc77d14f3a5335a077fcb541a2b31c372043

include/vcl/opengl/OpenGLContext.hxx

@@ -240,6 +240,11 @@ public:
         return mbInitialized;
     }
 
+    bool requestedLegacy()
+    {
+        return mbRequestLegacyContext;
+    }
+
     bool supportMultiSampling() const;
 
     static SystemWindowData generateWinData(vcl::Window* pParent, bool bRequestLegacyContext);

vcl/inc/openglgdiimpl.hxx

@@ -59,6 +59,9 @@ 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);
+
     // clipping
     vcl::Region maClipRegion;
     bool mbUseScissor;

vcl/opengl/gdiimpl.cxx

@@ -1870,4 +1870,11 @@ OpenGLContext *OpenGLSalGraphicsImpl::beginPaint()
         return mpContext.get();
 }
 
+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

@@ -39,7 +39,7 @@ rtl::Reference<OpenGLContext> WinOpenGLSalGraphicsImpl::CreateWinContext()
 
 bool WinOpenGLSalGraphicsImpl::UseContext( const rtl::Reference<OpenGLContext> &pContext )
 {
-    if( !pContext.is() || !pContext->isInitialized() )
+    if( !pContext.is() || !pContext->isInitialized() || IsForeignContext( pContext ) )
         return false;
     if( IsOffscreen() )
         return true;

vcl/opengl/x11/gdiimpl.cxx

@@ -62,9 +62,8 @@ bool X11OpenGLSalGraphicsImpl::UseContext( const rtl::Reference<OpenGLContext> &
 {
     X11WindowProvider *pProvider = dynamic_cast<X11WindowProvider*>(mrParent.m_pFrame);
 
-    if( !pContext->isInitialized() )
+    if( !pContext->isInitialized() || IsForeignContext( pContext ) )
         return false;
-
     if( !pProvider )
         return pContext->getOpenGLWindow().win != None;
     else