add possibility to request a compatibility context

Change-Id: I0135e81f925fda19c06144d21d2f2b0efc9e57be

include/vcl/opengl/OpenGLContext.hxx

@@ -149,6 +149,8 @@ public:
     OpenGLContext();
     ~OpenGLContext();
 
+    void requestLegacyContext();
+
     bool init(Window* pParent = 0);
     bool init(SystemChildWindow* pChildWindow);
 
@@ -186,6 +188,7 @@ private:
     SystemChildWindow* m_pChildWindow;
     boost::scoped_ptr<SystemChildWindow> m_pChildWindowGC;
     bool mbInitialized;
+    bool mbRequestLegacyContext;
 };
 
 #endif

vcl/source/opengl/OpenGLContext.cxx

@@ -29,7 +29,8 @@ GLWindow::~GLWindow()
 OpenGLContext::OpenGLContext():
     mpWindow(NULL),
     m_pChildWindow(NULL),
-    mbInitialized(false)
+    mbInitialized(false),
+    mbRequestLegacyContext(false)
 {
 }
 
@@ -60,6 +61,11 @@ OpenGLContext::~OpenGLContext()
 #endif
 }
 
+void OpenGLContext::requestLegacyContext()
+{
+    mbRequestLegacyContext = true;
+}
+
 #if defined( _WIN32 )
 static LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
 {
@@ -491,6 +497,9 @@ bool OpenGLContext::ImplInit()
         (CGLPixelFormatAttribute) 0
         };
 
+    if (mbRequestLegacyContext)
+        pixelFormatAttributes[1] = (CGLPixelFormatAttribute) kCGLOGLPVersion_Legacy;
+
     CGLPixelFormatObj pixelFormat;
     GLint numberOfPixels;
     CGLChoosePixelFormat(pixelFormatAttributes, &pixelFormat, &numberOfPixels);