Cleaner access to Fl_Gl_Window_Driver objects.

FL/Fl_Gl_Window.H

@@ -50,13 +50,8 @@ class Fl_Gl_Window_Driver;
 */
 class FL_EXPORT Fl_Gl_Window : public Fl_Window {
   friend class Fl_Gl_Window_Driver;
-  friend class _Fl_Gl_Overlay;
-  friend class Fl_OpenGL_Display_Device;
   Fl_Gl_Window_Driver *pGlWindowDriver;
 
-  /** Returns a pointer to the window's Fl_Gl_Window_Driver object */
-  Fl_Gl_Window_Driver *gl_driver() {return pGlWindowDriver;}
-
   int mode_;
   const int *alist;
   Fl_Gl_Choice *g;

src/Fl_Gl_Window_Driver.H

@@ -100,6 +100,7 @@ public:
   virtual int genlistsize() { return 0; } // support for gl_draw()
   virtual Fl_Font_Descriptor** fontnum_to_fontdescriptor(int fnum);
   virtual Fl_RGB_Image* capture_gl_rectangle(int x, int y, int w, int h);
+  static inline Fl_Gl_Window_Driver* driver(const Fl_Gl_Window *win) {return win->pGlWindowDriver;}
 };
 
 #endif /* Fl_Gl_Window_Driver_H */

src/drivers/OpenGL/Fl_OpenGL_Display_Device.cxx

@@ -40,7 +40,7 @@ Fl_OpenGL_Display_Device::Fl_OpenGL_Display_Device(Fl_OpenGL_Graphics_Driver *gr
 
 Fl_RGB_Image* Fl_OpenGL_Display_Device::capture_gl_rectangle(Fl_Gl_Window* glw, int x, int y, int w, int h)
 {
-  return glw->gl_driver()->capture_gl_rectangle(x, y, w, h);
+  return Fl_Gl_Window_Driver::driver(glw)->capture_gl_rectangle(x, y, w, h);
 }
 
 /* Captures a rectangle of a Fl_Gl_Window and returns it as a RGB image.

src/drivers/X11/Fl_X11_Gl_Window_Driver.cxx

@@ -430,7 +430,7 @@ void _Fl_Gl_Overlay::draw() {
   uchar save_valid = w->valid();
   w->valid(valid());
   Fl_Xlib_Graphics_Driver::fl_overlay = 1;
-  w->gl_driver()->draw_overlay();
+  Fl_Gl_Window_Driver::driver(w)->draw_overlay();
   Fl_Xlib_Graphics_Driver::fl_overlay = 0;
   valid(w->valid());
   w->valid(save_valid);