avoid linking against the OpenGL libs when only using the window

This lets us avoid to link libsclo against all the OpenGL libraries and
only link against libvcl_opengl. Only code actually using the context
will need to link against the OpenGL libs.

Change-Id: Ia47f4c651702a7fb8517073cda6fb113e7e26e50

include/vcl/openglwin.hxx

@@ -11,16 +11,23 @@
 #define INCLUDED_VCL_OPENGLWIN_HXX
 
 #include <vcl/syschild.hxx>
-#include <vcl/opengl/OpenGLContext.hxx>
+#include <vcl/vclopengl_dllapi.hxx>
 
-class OpenGLWindow : public SystemChildWindow
+#include <boost/scoped_ptr.hpp>
+
+class OpenGLContext;
+class OpenGLWindowImpl;
+
+// pImpl Pattern to avoid linking against OpenGL libs when using the class without the context
+class VCLOPENGL_DLLPUBLIC OpenGLWindow : public SystemChildWindow
 {
 public:
     OpenGLWindow(Window* pParent);
-    OpenGLContext& getContext();
+    ~OpenGLWindow();
+    OpenGLContext* getContext();
 
 private:
-    OpenGLContext maContext;
+    boost::scoped_ptr<OpenGLWindowImpl> mpImpl;
 };
 
 #endif

vcl/source/window/openglwin.cxx

@@ -8,15 +8,40 @@
  */
 
 #include <vcl/openglwin.hxx>
+#include <vcl/opengl/OpenGLContext.hxx>
+
+class OpenGLWindowImpl
+{
+public:
+    OpenGLWindowImpl(SystemChildWindow* pWindow);
+    OpenGLContext* getContext();
+private:
+    OpenGLContext maContext;
+};
+
+OpenGLWindowImpl::OpenGLWindowImpl(SystemChildWindow* pWindow)
+{
+    maContext.init(pWindow);
+}
+
+OpenGLContext* OpenGLWindowImpl::getContext()
+{
+    return &maContext;
+}
 
 OpenGLWindow::OpenGLWindow(Window* pParent):
-    SystemChildWindow(pParent, 0)
+    SystemChildWindow(pParent, 0),
+    mpImpl(new OpenGLWindowImpl(this))
+{
+}
+
+OpenGLWindow::~OpenGLWindow()
 {
 }
 
-OpenGLContext& OpenGLWindow::getContext()
+OpenGLContext* OpenGLWindow::getContext()
 {
-    return maContext;
+    return mpImpl->getContext();
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */