fix multisample support in OpenGL

Change-Id: I7e530f5ae8d83d275df554781847b525b38bf4c7

chart2/source/view/main/OpenGLRender.cxx

@@ -235,6 +235,7 @@ GLfloat texCoords[] = {
 int OpenGLRender::InitOpenGL(GLWindow aWindow)
 {
     glWin = aWindow;
+    mbArbMultisampleSupported = glWin.bMultiSampleSupported;
     if(!bGlewInit)
     {
         glewExperimental = GL_TRUE;

include/vcl/OpenGLContext.hxx

@@ -65,6 +65,7 @@ struct GLWindow
     unsigned int            Width;
     unsigned int            Height;
     const GLubyte*          GLExtensions;
+    bool bMultiSampleSupported;
 
     bool HasGLExtension( const char* name ) { return gluCheckExtension( (const GLubyte*) name, GLExtensions ); }
 
@@ -86,7 +87,8 @@ struct GLWindow
         bpp(0),
         Width(0),
         Height(0),
-        GLExtensions(NULL)
+        GLExtensions(NULL),
+        bMultiSampleSupported(false)
     {
     }
 };

vcl/source/opengl/OpenGLContext.cxx

@@ -369,6 +369,7 @@ bool OpenGLContext::init()
     bool bMultiSampleSupport = InitMultisample(PixelFormatFront, WindowPix);
     if (bMultiSampleSupport)
     {
+        m_aGLWin.bMultiSampleSupported = true;
     }
     else
     {
@@ -568,6 +569,9 @@ bool OpenGLContext::initWindow()
         XFree( pVi );
     }
 
+    if(best_num_samp > 0)
+        m_aGLWin.bMultiSampleSupported = true;
+
     XVisualInfo* vi = glXGetVisualFromFBConfig( m_aGLWin.dpy, pFBC[best_fbc] );
     if( vi )
     {