OpenGL hardware typically provides some overlay bit planes, which are very useful for drawing UI controls atop your 3D graphics. If the overlay hardware is not provided, FLTK tries to simulate the overlay, This works pretty well if your graphics are double buffered, but not very well for single-buffered.
Please note that the FLTK drawing and clipping functions will not work inside an Fl_Gl_Window. All drawing should be done using OpenGL calls exclusively. Even though Fl_Gl_Window is derived from Fl_Group, it is not useful to add other FLTK Widgets as children, unless those Widgets are modified to draw using OpenGL calls. */ class FL_EXPORT Fl_Gl_Window : public Fl_Window { int mode_; const int *alist; Fl_Gl_Choice *g; GLContext context_; char valid_f_; char damage1_; // damage() of back buffer virtual void draw_overlay(); void init(); void *overlay; void make_overlay(); friend class _Fl_Gl_Overlay; static int can_do(int, const int *); int mode(int, const int *); public: void show(); void show(int a, char **b) {Fl_Window::show(a,b);} void flush(); void hide(); void resize(int,int,int,int); /** Is turned off when FLTK creates a new context for this window or when the window resizes, and is turned on after draw() is called. You can use this inside your draw() method to avoid unneccessarily initializing the OpenGL context. Just do this: \code void mywindow::draw() { if (!valid()) { glViewport(0,0,w(),h()); glFrustum(...); ...other initialization... } if (!context_valid()) { ...load textures, etc. ... } ... draw your geometry here ... } \endcode You can turn valid() on by calling valid(1). You should only do this after fixing the transformation inside a draw() or after make_current(). This is done automatically after draw() returns. */ char valid() const {return valid_f_ & 1;} /** See char Fl_Gl_Window::valid() const */ void valid(char v) {if (v) valid_f_ |= 1; else valid_f_ &= 0xfe;} void invalidate(); /** Will only be set if the OpenGL context is created or recreated. It differs from Fl_Gl_Window::valid() which is also set whenever the context changes size. */ char context_valid() const {return valid_f_ & 2;} /** See char Fl_Gl_Window::context_valid() const */ void context_valid(char v) {if (v) valid_f_ |= 2; else valid_f_ &= 0xfd;} /** Returns non-zero if the hardware supports the given or current OpenGL mode. */ static int can_do(int m) {return can_do(m,0);} /** Returns non-zero if the hardware supports the given or current OpenGL mode. */ static int can_do(const int *m) {return can_do(0, m);} /** Returns non-zero if the hardware supports the given or current OpenGL mode. */ int can_do() {return can_do(mode_,alist);} /** Set or change the OpenGL capabilites of the window. The value can be any of the following OR'd together: - \c FL_RGB - RGB color (not indexed) - \c FL_RGB8 - RGB color with at least 8 bits of each color - \c FL_INDEX - Indexed mode - \c FL_SINGLE - not double buffered - \c FL_DOUBLE - double buffered - \c FL_ACCUM - accumulation buffer - \c FL_ALPHA - alpha channel in color - \c FL_DEPTH - depth buffer - \c FL_STENCIL - stencil buffer - \c FL_MULTISAMPLE - multisample antialiasing FL_RGB and FL_SINGLE have a value of zero, so they are "on" unless you give FL_INDEX or FL_DOUBLE. If the desired combination cannot be done, FLTK will try turning off FL_MULTISAMPLE. If this also fails the show() will call Fl::error() and not show the window. You can change the mode while the window is displayed. This is most useful for turning double-buffering on and off. Under X this will cause the old X window to be destroyed and a new one to be created. If this is a top-level window this will unfortunately also cause the window to blink, raise to the top, and be de-iconized, and the xid() will change, possibly breaking other code. It is best to make the GL window a child of another window if you wish to do this! mode() must not be called within draw() since it changes the current context. */ Fl_Mode mode() const {return (Fl_Mode)mode_;} /** See Fl_Mode mode() const */ int mode(int a) {return mode(a,0);} /** See Fl_Mode mode() const */ int mode(const int *a) {return mode(0, a);} /** void See void context(void* v, int destroy_flag) */ void* context() const {return context_;} void context(void*, int destroy_flag = 0); void make_current(); void swap_buffers(); void ortho(); /** Returns true if the hardware overlay is possible. If this is false, FLTK will try to simulate the overlay, with significant loss of update speed. Calling this will cause FLTK to open the display. */ int can_do_overlay(); /** This method causes draw_overlay to be called at a later time. Initially the overlay is clear, if you want the window to display something in the overlay when it first appears, you must call this immediately after you show() your window. */ void redraw_overlay(); void hide_overlay(); /** The make_overlay_current() method selects the OpenGL context for the widget's overlay. It is called automatically prior to the draw_overlay() method being called and can also be used to implement feedback and/or selection within the handle() method. */ void make_overlay_current(); ~Fl_Gl_Window(); /** Creates a new Fl_Gl_Window widget using the given size, and label string. The default boxtype is FL_NO_BOX. The default mode is FL_RGB|FL_DOUBLE|FL_DEPTH. */ Fl_Gl_Window(int W, int H, const char *l=0) : Fl_Window(W,H,l) {init();} /** Creates a new Fl_Gl_Window widget using the given position, size, and label string. The default boxtype is FL_NO_BOX. The default mode is FL_RGB|FL_DOUBLE|FL_DEPTH. */ Fl_Gl_Window(int X, int Y, int W, int H, const char *l=0) : Fl_Window(X,Y,W,H,l) {init();} // you *must* override the draw method virtual void draw(); }; #endif // // End of "$Id$". //