text: /*
   * freeglut_internal.h
   *
   * The freeglut library private include file.
   *
   * Copyright (c) 1999-2000 Pawel W. Olszta. All Rights Reserved.
   * Written by Pawel W. Olszta, <olszta@sourceforge.net>
   * Creation date: Thu Dec 2 1999
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included
   * in all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
   * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
   * PAWEL W. OLSZTA BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
   * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
   */
  
  #ifndef  FREEGLUT_INTERNAL_H
  #define  FREEGLUT_INTERNAL_H
  
  #if HAVE_CONFIG_H
  #    include "config.h"
  #endif
  
  /* XXX Update these for each release! */
  #define  VERSION_MAJOR 2
  #define  VERSION_MINOR 6
  #define  VERSION_PATCH 0
  
  /* Freeglut is intended to function under all Unix/X11 and Win32 platforms. */
  /* XXX: Don't all MS-Windows compilers (except Cygwin) have _WIN32 defined?
   * XXX: If so, remove the first set of defined()'s below.
   */
  #if defined(_MSC_VER) || defined(__WATCOMC__) || defined(__MINGW32__) \
      || defined(_WIN32) || defined(_WIN32_WCE) \
      || ( defined(__CYGWIN__) && defined(X_DISPLAY_MISSING) )
  #   define  TARGET_HOST_MS_WINDOWS 1
  
  #elif defined(__posix__) || defined(__unix__) || defined(__linux__)
  #   define  TARGET_HOST_POSIX_X11  1
  
  #elif defined(__APPLE__)
  /* This is a placeholder until we get native OSX support ironed out -- JFF 11/18/09 */
  #   define  TARGET_HOST_POSIX_X11  1
  /* #   define  TARGET_HOST_MAC_OSX    1 */
  
  #else
  #   error "Unrecognized target host!"
  */
  #endif
  
  /* Detect both SunPro and gcc compilers on Sun Solaris */
  #if defined (__SVR4) && defined (__sun)
  #   define TARGET_HOST_SOLARIS 1
  #endif
  
  #ifndef TARGET_HOST_MS_WINDOWS
  #   define  TARGET_HOST_MS_WINDOWS 0
  #endif
  
  #ifndef  TARGET_HOST_POSIX_X11
  #   define  TARGET_HOST_POSIX_X11  0
  #endif
  
  #ifndef  TARGET_HOST_MAC_OSX
  #   define  TARGET_HOST_MAC_OSX    0
  #endif
  
  #ifndef  TARGET_HOST_SOLARIS
  #   define  TARGET_HOST_SOLARIS    0
  #endif
  
  /* -- FIXED CONFIGURATION LIMITS ------------------------------------------- */
  
  #define  FREEGLUT_MAX_MENUS         3
  
  /* -- PLATFORM-SPECIFIC INCLUDES ------------------------------------------- */
  
  /* All Win32 headers depend on the huge Windows.h recursive include.
   * Note: Let's use proper case for MS-Win headers. Even though it's
   * not required due to case insensitivity, it's a good habit to keep
   * because the cross-platform includes are case sensitive.
   */
  #if TARGET_HOST_MS_WINDOWS && !defined(_WIN32_WCE)
  #    include <Windows.h>
  #    include <WindowsX.h>
  #    include <MMSystem.h>
  /* CYGWIN does not have tchar.h, but has TEXT(x), defined in winnt.h. */
  #    ifndef __CYGWIN__
  #      include <tchar.h>
  #    else
  #      define _TEXT(x) TEXT(x)
  #      define _T(x)    TEXT(x)
  #    endif
  
  #elif TARGET_HOST_POSIX_X11
  #    include <GL/glx.h>
  #    include <X11/Xlib.h>
  #    include <X11/Xatom.h>
  #    include <X11/keysym.h>
  #    include <X11/extensions/XInput.h>
  #    ifdef HAVE_X11_EXTENSIONS_XF86VMODE_H
  #        include <X11/extensions/xf86vmode.h>
  #    endif
  /* If GLX is too old, we will fail during runtime when multisampling
     is requested, but at least freeglut compiles. */
  #    ifndef GLX_SAMPLE_BUFFERS
  #        define GLX_SAMPLE_BUFFERS 0x80A8
  #    endif
  #    ifndef GLX_SAMPLES
  #        define GLX_SAMPLES 0x80A9
  #    endif
  
  #endif
  
  /* These files should be available on every platform. */
  #include <stdio.h>
  #include <string.h>
  #include <math.h>
  #include <stdlib.h>
  
  /* These are included based on autoconf directives. */
  #if HAVE_SYS_TYPES_H
  #    include <sys/types.h>
  #endif
  #if HAVE_UNISTD_H
  #    include <unistd.h>
  #endif
  #if TIME_WITH_SYS_TIME
  #    include <sys/time.h>
  #    include <time.h>
  #elif HAVE_SYS_TIME_H
  #    include <sys/time.h>
  #else
  #    include <time.h>
  #endif
  
  /* -- AUTOCONF HACKS --------------------------------------------------------*/
  
  /* XXX: Update autoconf to avoid these.
   * XXX: Are non-POSIX platforms intended not to use autoconf?
   * If so, perhaps there should be a config_guess.h for them. Alternatively,
   * config guesses could be placed above, just after the config.h exclusion.
   */
  #if defined(__FreeBSD__) || defined(__NetBSD__)
  #    define HAVE_USB_JS 1
  #    if defined(__NetBSD__) || ( defined(__FreeBSD__) && __FreeBSD_version >= 500000)
  #        define HAVE_USBHID_H 1
  #    endif
  #endif
  
  #if TARGET_HOST_MS_WINDOWS
  #    define  HAVE_VPRINTF 1
  #endif
  
  #if !defined(HAVE_VPRINTF) && !defined(HAVE_DOPRNT)
  /* XXX warning directive here? */
  #    define  HAVE_VPRINTF 1
  #endif
  
  /* MinGW may lack a prototype for ChangeDisplaySettingsEx() (depending on the version?) */
  #if TARGET_HOST_MS_WINDOWS && !defined(ChangeDisplaySettingsEx)
  LONG WINAPI ChangeDisplaySettingsExA(LPCSTR,LPDEVMODEA,HWND,DWORD,LPVOID);
  LONG WINAPI ChangeDisplaySettingsExW(LPCWSTR,LPDEVMODEW,HWND,DWORD,LPVOID);
  #    ifdef UNICODE
  #        define ChangeDisplaySettingsEx ChangeDisplaySettingsExW
  #    else
  #        define ChangeDisplaySettingsEx ChangeDisplaySettingsExA
  #    endif
  #endif
  
  #if defined(_MSC_VER) || defined(__WATCOMC__)
  /* strdup() is non-standard, for all but POSIX-2001 */
  #define strdup   _strdup
  #endif
  
  /* M_PI is non-standard (defined by BSD, not ISO-C) */
  #ifndef M_PI
  #    define  M_PI  3.14159265358979323846
  #endif
  
  #ifndef TRUE
  #    define  TRUE  1
  #endif
  
  #ifndef FALSE
  #    define  FALSE  0
  #endif
  
  /* General defines */
  
  #define INVALID_MODIFIERS 0xffffffff
  
  /* -- GLOBAL TYPE DEFINITIONS ---------------------------------------------- */
  
  /* Freeglut callbacks type definitions */
  typedef void (* FGCBDisplay       )( void );
  typedef void (* FGCBReshape       )( int, int );
  typedef void (* FGCBVisibility    )( int );
  typedef void (* FGCBKeyboard      )( unsigned char, int, int );
  typedef void (* FGCBSpecial       )( int, int, int );
  typedef void (* FGCBMouse         )( int, int, int, int );
  typedef void (* FGCBMouseWheel    )( int, int, int, int );
  typedef void (* FGCBMotion        )( int, int );
  typedef void (* FGCBPassive       )( int, int );
  typedef void (* FGCBEntry         )( int );
  typedef void (* FGCBWindowStatus  )( int );
  typedef void (* FGCBSelect        )( int, int, int );
  typedef void (* FGCBJoystick      )( unsigned int, int, int, int );
  typedef void (* FGCBKeyboardUp    )( unsigned char, int, int );
  typedef void (* FGCBSpecialUp     )( int, int, int );
  typedef void (* FGCBOverlayDisplay)( void );
  typedef void (* FGCBSpaceMotion   )( int, int, int );
  typedef void (* FGCBSpaceRotation )( int, int, int );
  typedef void (* FGCBSpaceButton   )( int, int );
  typedef void (* FGCBDials         )( int, int );
  typedef void (* FGCBButtonBox     )( int, int );
  typedef void (* FGCBTabletMotion  )( int, int );
  typedef void (* FGCBTabletButton  )( int, int, int, int );
  typedef void (* FGCBDestroy       )( void );
  
  /* The global callbacks type definitions */
  typedef void (* FGCBIdle          )( void );
  typedef void (* FGCBTimer         )( int );
  typedef void (* FGCBMenuState     )( int );
  typedef void (* FGCBMenuStatus    )( int, int, int );
  
  /* The callback used when creating/using menus */
  typedef void (* FGCBMenu          )( int );
  
  
  /* A list structure */
  typedef struct tagSFG_List SFG_List;
  struct tagSFG_List
  {
      void *First;
      void *Last;
  };
  
  /* A list node structure */
  typedef struct tagSFG_Node SFG_Node;
  struct tagSFG_Node
  {
      void *Next;
      void *Prev;
  };
  
  /* A helper structure holding two ints and a boolean */
  typedef struct tagSFG_XYUse SFG_XYUse;
  struct tagSFG_XYUse
  {
      GLint           X, Y;               /* The two integers...               */
      GLboolean       Use;                /* ...and a single boolean.          */
  };
  
  /*
   * An enumeration containing the state of the GLUT execution:
   * initializing, running, or stopping
   */
  typedef enum
  {
    GLUT_EXEC_STATE_INIT,
    GLUT_EXEC_STATE_RUNNING,
    GLUT_EXEC_STATE_STOP
  } fgExecutionState ;
  
  /* This structure holds different freeglut settings */
  typedef struct tagSFG_State SFG_State;
  struct tagSFG_State
  {
      SFG_XYUse        Position;             /* The default windows' position  */
      SFG_XYUse        Size;                 /* The default windows' size      */
      unsigned int     DisplayMode;          /* Display mode for new windows   */
  
      GLboolean        Initialised;          /* freeglut has been initialised  */
  
      int              DirectContext;        /* Direct rendering state         */
  
      GLboolean        ForceIconic;          /* New top windows are iconified  */
      GLboolean        UseCurrentContext;    /* New windows share with current */
  
      GLboolean        GLDebugSwitch;        /* OpenGL state debugging switch  */
      GLboolean        XSyncSwitch;          /* X11 sync protocol switch       */
  
      int              KeyRepeat;            /* Global key repeat mode.        */
      int              Modifiers;            /* Current ALT/SHIFT/CTRL state   */
  
      GLuint           FPSInterval;          /* Interval between FPS printfs   */
      GLuint           SwapCount;            /* Count of glutSwapBuffer calls  */
      GLuint           SwapTime;             /* Time of last SwapBuffers       */
  
      unsigned long    Time;                 /* Time that glutInit was called  */
      SFG_List         Timers;               /* The freeglut timer hooks       */
      SFG_List         FreeTimers;           /* The unused timer hooks         */
  
      FGCBIdle         IdleCallback;         /* The global idle callback       */
  
      int              ActiveMenus;          /* Num. of currently active menus */
      FGCBMenuState    MenuStateCallback;    /* Menu callbacks are global      */
      FGCBMenuStatus   MenuStatusCallback;
  
      SFG_XYUse        GameModeSize;         /* Game mode screen's dimensions  */
      int              GameModeDepth;        /* The pixel depth for game mode  */
      int              GameModeRefresh;      /* The refresh rate for game mode */
  
      int              ActionOnWindowClose; /* Action when user closes window  */
  
      fgExecutionState ExecState;           /* Used for GLUT termination       */
      char            *ProgramName;         /* Name of the invoking program    */
      GLboolean        JoysticksInitialised;  /* Only initialize if application calls for them */
      GLboolean        InputDevsInitialised;  /* Only initialize if application calls for them */
  
      int              AuxiliaryBufferNumber;  /* Number of auxiliary buffers */
      int              SampleNumber;         /*  Number of samples per pixel  */
  
      int              MajorVersion;         /* Major OpenGL context version  */
      int              MinorVersion;         /* Minor OpenGL context version  */
      int              ContextFlags;         /* OpenGL context flags          */
      int              ContextProfile;       /* OpenGL context profile        */
  };
  
  /* The structure used by display initialization in freeglut_init.c */
  typedef struct tagSFG_Display SFG_Display;
  struct tagSFG_Display
  {
  #if TARGET_HOST_POSIX_X11
      Display*        Display;            /* The display we are being run in.  */
      int             Screen;             /* The screen we are about to use.   */
      Window          RootWindow;         /* The screen's root window.         */
      int             Connection;         /* The display's connection number   */
      Atom            DeleteWindow;       /* The window deletion atom          */
      Atom            State;              /* The state atom                    */
      Atom            StateFullScreen;    /* The full screen atom              */
  
  #ifdef X_XF86VidModeGetModeLine
      /*
       * XF86VidMode may be compilable even if it fails at runtime.  Therefore,
       * the validity of the VidMode has to be tracked
       */
      int             DisplayModeValid;   /* Flag that indicates runtime status*/
      XF86VidModeModeLine DisplayMode;    /* Current screen's display settings */
      int             DisplayModeClock;   /* The display mode's refresh rate   */
      int             DisplayViewPortX;   /* saved X location of the viewport  */
      int             DisplayViewPortY;   /* saved Y location of the viewport  */
      int             DisplayPointerX;    /* saved X location of the pointer   */
      int             DisplayPointerY;    /* saved Y location of the pointer   */
  
  #endif /* X_XF86VidModeGetModeLine */
  
  #elif TARGET_HOST_MS_WINDOWS
      HINSTANCE        Instance;          /* The application's instance        */
      DEVMODE         DisplayMode;        /* Desktop's display settings        */
  
  #endif
  
      int             ScreenWidth;        /* The screen's width in pixels      */
      int             ScreenHeight;       /* The screen's height in pixels     */
      int             ScreenWidthMM;      /* The screen's width in milimeters  */
      int             ScreenHeightMM;     /* The screen's height in milimeters */
  };
  
  
  /* The user can create any number of timer hooks */
  typedef struct tagSFG_Timer SFG_Timer;
  struct tagSFG_Timer
  {
      SFG_Node        Node;
      int             ID;                 /* The timer ID integer              */
      FGCBTimer       Callback;           /* The timer callback                */
      long            TriggerTime;        /* The timer trigger time            */
  };
  
  /*
   * Make "freeglut" window handle and context types so that we don't need so
   * much conditionally-compiled code later in the library.
   */
  #if TARGET_HOST_POSIX_X11
  
  typedef Window     SFG_WindowHandleType ;
  typedef GLXContext SFG_WindowContextType ;
  
  #elif TARGET_HOST_MS_WINDOWS
  
  typedef HWND    SFG_WindowHandleType ;
  typedef HGLRC   SFG_WindowContextType ;
  
  #endif
  
  /*
   * A window and its OpenGL context. The contents of this structure
   * are highly dependant on the target operating system we aim at...
   */
  typedef struct tagSFG_Context SFG_Context;
  struct tagSFG_Context
  {
      SFG_WindowHandleType  Handle;    /* The window's handle                 */
      SFG_WindowContextType Context;   /* The window's OpenGL/WGL context     */
  
  #if TARGET_HOST_POSIX_X11
      GLXFBConfig*    FBConfig;        /* The window's FBConfig               */
  #elif TARGET_HOST_MS_WINDOWS
      HDC             Device;          /* The window's device context         */
  #endif
  
      int             DoubleBuffered;  /* Treat the window as double-buffered */
  };
  
  /* Window's state description. This structure should be kept portable. */
  typedef struct tagSFG_WindowState SFG_WindowState;
  struct tagSFG_WindowState
  {
      int             Width;              /* Window's width in pixels          */
      int             Height;             /* The same about the height         */
      int             OldWidth;           /* Window width from before a resize */
      int             OldHeight;          /*   "    height  "    "    "   "    */
  
      GLboolean       Redisplay;          /* Do we have to redisplay?          */
      GLboolean       Visible;            /* Is the window visible now         */
  
      int             Cursor;             /* The currently selected cursor     */
  
      long            JoystickPollRate;   /* The joystick polling rate         */
      long            JoystickLastPoll;   /* When the last poll happened       */
  
      int             MouseX, MouseY;     /* The most recent mouse position    */
  
      GLboolean       IgnoreKeyRepeat;    /* Whether to ignore key repeat.     */
      GLboolean       KeyRepeating;       /* Currently in repeat mode          */
  
      GLboolean       NeedToResize;       /* Do we need to resize the window?  */
  
      GLboolean       IsFullscreen;       /* is the window fullscreen? */
  };
  
  
  /*
   * A generic function pointer.  We should really use the GLUTproc type
   * defined in freeglut_ext.h, but if we include that header in this file
   * a bunch of other stuff (font-related) blows up!
   */
  typedef void (*SFG_Proc)();
  
  
  /*
   * SET_WCB() is used as:
   *
   *     SET_WCB( window, cbname, func );
   *
   * ...where {window} is the freeglut window to set the callback,
   *          {cbname} is the window-specific callback to set,
   *          {func} is a function-pointer.
   *
   * Originally, {FETCH_WCB( ... ) = func} was rather sloppily used,
   * but this can cause warnings because the FETCH_WCB() macro type-
   * casts its result, and a type-cast value shouldn't be an lvalue.
   *
   * The {if( FETCH_WCB( ... ) != func )} test is to do type-checking
   * and for no other reason.  Since it's hidden in the macro, the
   * ugliness is felt to be rather benign.
   */
  #define SET_WCB(window,cbname,func)                            \
  do                                                             \
  {                                                              \
      if( FETCH_WCB( window, cbname ) != (SFG_Proc)(func) )      \
          (((window).CallBacks[CB_ ## cbname]) = (SFG_Proc)(func)); \
  } while( 0 )
  
  /*
   * FETCH_WCB() is used as:
   *
   *     FETCH_WCB( window, cbname );
   *
   * ...where {window} is the freeglut window to fetch the callback from,
   *          {cbname} is the window-specific callback to fetch.
   *
   * The result is correctly type-cast to the callback function pointer
   * type.
   */
  #define FETCH_WCB(window,cbname) \
      ((window).CallBacks[CB_ ## cbname])
  
  /*
   * INVOKE_WCB() is used as:
   *
   *     INVOKE_WCB( window, cbname, ( arg_list ) );
   *
   * ...where {window} is the freeglut window,
   *          {cbname} is the window-specific callback to be invoked,
   *          {(arg_list)} is the parameter list.
   *
   * The callback is invoked as:
   *
   *    callback( arg_list );
   *
   * ...so the parentheses are REQUIRED in the {arg_list}.
   *
   * NOTE that it does a sanity-check and also sets the
   * current window.
   *
   */
  #if TARGET_HOST_MS_WINDOWS && !defined(_WIN32_WCE) /* FIXME: also WinCE? */
  #define INVOKE_WCB(window,cbname,arg_list)    \
  do                                            \
  {                                             \
      if( FETCH_WCB( window, cbname ) )         \
      {                                         \
          FGCB ## cbname func = (FGCB ## cbname)(FETCH_WCB( window, cbname )); \
          fgSetWindow( &window );               \
          func arg_list;                        \
      }                                         \
  } while( 0 )
  #else
  #define INVOKE_WCB(window,cbname,arg_list)    \
  do                                            \
  {                                             \
      if( FETCH_WCB( window, cbname ) )         \
      {                                         \
          fgSetWindow( &window );               \
          ((FGCB ## cbname)FETCH_WCB( window, cbname )) arg_list; \
      }                                         \
  } while( 0 )
  #endif
  
  /*
   * The window callbacks the user can supply us with. Should be kept portable.
   *
   * This enumeration provides the freeglut CallBack numbers.
   * The symbolic constants are indices into a window's array of
   * function callbacks.  The names are formed by splicing a common
   * prefix onto the callback's base name.  (This was originally
   * done so that an early stage of development could live side-by-
   * side with the old callback code.  The old callback code used
   * the bare callback's name as a structure member, so I used a
   * prefix for the array index name.)
   *
   * XXX For consistancy, perhaps the prefix should match the
   * XXX FETCH* and INVOKE* macro suffices.  I.e., WCB_, rather than
   * XXX CB_.
   */
  enum
  {
      CB_Display,
      CB_Reshape,
      CB_Keyboard,
      CB_KeyboardUp,
      CB_Special,
      CB_SpecialUp,
      CB_Mouse,
      CB_MouseWheel,
      CB_Motion,
      CB_Passive,
      CB_Entry,
      CB_Visibility,
      CB_WindowStatus,
      CB_Joystick,
      CB_Destroy,
  
      /* Presently ignored */
      CB_Select,
      CB_OverlayDisplay,
      CB_SpaceMotion,     /* presently implemented only on UNIX/X11 */
      CB_SpaceRotation,   /* presently implemented only on UNIX/X11 */
      CB_SpaceButton,     /* presently implemented only on UNIX/X11 */
      CB_Dials,
      CB_ButtonBox,
      CB_TabletMotion,
      CB_TabletButton,
  
      /* Always make this the LAST one */
      TOTAL_CALLBACKS
  };
  
  
  /* This structure holds the OpenGL rendering context for all the menu windows */
  typedef struct tagSFG_MenuContext SFG_MenuContext;
  struct tagSFG_MenuContext
  {
      SFG_WindowContextType MContext;       /* The menu window's WGL context   */
  };
  
  /* This structure describes a menu */
  typedef struct tagSFG_Window SFG_Window;
  typedef struct tagSFG_MenuEntry SFG_MenuEntry;
  typedef struct tagSFG_Menu SFG_Menu;
  struct tagSFG_Menu
  {
      SFG_Node            Node;
      void               *UserData;     /* User data passed back at callback   */
      int                 ID;           /* The global menu ID                  */
      SFG_List            Entries;      /* The menu entries list               */
      FGCBMenu            Callback;     /* The menu callback                   */
      FGCBDestroy         Destroy;      /* Destruction callback                */
      GLboolean           IsActive;     /* Is the menu selected?               */
      int                 Width;        /* Menu box width in pixels            */
      int                 Height;       /* Menu box height in pixels           */
      int                 X, Y;         /* Menu box raster position            */
  
      SFG_MenuEntry      *ActiveEntry;  /* Currently active entry in the menu  */
      SFG_Window         *Window;       /* Window for menu                     */
      SFG_Window         *ParentWindow; /* Window in which the menu is invoked */
  };
  
  /* This is a menu entry */
  struct tagSFG_MenuEntry
  {
      SFG_Node            Node;
      int                 ID;                     /* The menu entry ID (local) */
      int                 Ordinal;                /* The menu's ordinal number */
      char*               Text;                   /* The text to be displayed  */
      SFG_Menu*           SubMenu;                /* Optional sub-menu tree    */
      GLboolean           IsActive;               /* Is the entry highlighted? */
      int                 Width;                  /* Label's width in pixels   */
  };
  
  /*
   * A window, making part of freeglut windows hierarchy.
   * Should be kept portable.
   *
   * NOTE that ActiveMenu is set to menu itself if the window is a menu.
   */
  struct tagSFG_Window
  {
      SFG_Node            Node;
      int                 ID;                     /* Window's ID number        */
  
      SFG_Context         Window;                 /* Window and OpenGL context */
      SFG_WindowState     State;                  /* The window state          */
      SFG_Proc            CallBacks[ TOTAL_CALLBACKS ]; /* Array of window callbacks */
      void               *UserData ;              /* For use by user           */
  
      SFG_Menu*       Menu[ FREEGLUT_MAX_MENUS ]; /* Menus appended to window  */
      SFG_Menu*       ActiveMenu;                 /* The window's active menu  */
  
      SFG_Window*         Parent;                 /* The parent to this window */
      SFG_List            Children;               /* The subwindows d.l. list  */
  
      GLboolean           IsMenu;                 /* Set to 1 if we are a menu */
  };
  
  
  /* A linked list structure of windows */
  typedef struct tagSFG_WindowList SFG_WindowList ;
  struct tagSFG_WindowList
  {
      SFG_Node node;
      SFG_Window *window ;
  };
  
  /* This holds information about all the windows, menus etc. */
  typedef struct tagSFG_Structure SFG_Structure;
  struct tagSFG_Structure
  {
      SFG_List        Windows;         /* The global windows list            */
      SFG_List        Menus;           /* The global menus list              */
      SFG_List        WindowsToDestroy;
  
      SFG_Window*     CurrentWindow;   /* The currently set window          */
      SFG_Menu*       CurrentMenu;     /* Same, but menu...                 */
  
      SFG_MenuContext* MenuContext;    /* OpenGL rendering context for menus */
  
      SFG_Window*      GameModeWindow; /* The game mode window               */
  
      int              WindowID;       /* The new current window ID          */
      int              MenuID;         /* The new current menu ID            */
  };
  
  /*
   * This structure is used for the enumeration purposes.
   * You can easily extend its functionalities by declaring
   * a structure containing enumerator's contents and custom
   * data, then casting its pointer to (SFG_Enumerator *).
   */
  typedef struct tagSFG_Enumerator SFG_Enumerator;
  struct tagSFG_Enumerator
  {
      GLboolean   found;                          /* Used to terminate search  */
      void*       data;                           /* Custom data pointer       */
  };
  typedef void (* FGCBenumerator  )( SFG_Window *, SFG_Enumerator * );
  
  /* The bitmap font structure */
  typedef struct tagSFG_Font SFG_Font;
  struct tagSFG_Font
  {
      char*           Name;         /* The source font name             */
      int             Quantity;     /* Number of chars in font          */
      int             Height;       /* Height of the characters         */
      const GLubyte** Characters;   /* The characters mapping           */
  
      float           xorig, yorig; /* Relative origin of the character */
  };
  
  /* The stroke font structures */
  
  typedef struct tagSFG_StrokeVertex SFG_StrokeVertex;
  struct tagSFG_StrokeVertex
  {
      GLfloat         X, Y;
  };
  
  typedef struct tagSFG_StrokeStrip SFG_StrokeStrip;
  struct tagSFG_StrokeStrip
  {
      int             Number;
      const SFG_StrokeVertex* Vertices;
  };
  
  typedef struct tagSFG_StrokeChar SFG_StrokeChar;
  struct tagSFG_StrokeChar
  {
      GLfloat         Right;
      int             Number;
      const SFG_StrokeStrip* Strips;
  };
  
  typedef struct tagSFG_StrokeFont SFG_StrokeFont;
  struct tagSFG_StrokeFont
  {
      char*           Name;                       /* The source font name      */
      int             Quantity;                   /* Number of chars in font   */
      GLfloat         Height;                     /* Height of the characters  */
      const SFG_StrokeChar** Characters;          /* The characters mapping    */
  };
  
  /* -- GLOBAL VARIABLES EXPORTS --------------------------------------------- */
  
  /* Freeglut display related stuff (initialized once per session) */
  extern SFG_Display fgDisplay;
  
  /* Freeglut internal structure */
  extern SFG_Structure fgStructure;
  
  /* The current freeglut settings */
  extern SFG_State fgState;
  
  
  /* -- PRIVATE FUNCTION DECLARATIONS ---------------------------------------- */
  
  /*
   * A call to this function makes us sure that the Display and Structure
   * subsystems have been properly initialized and are ready to be used
   */
  #define  FREEGLUT_EXIT_IF_NOT_INITIALISED( string )               \
    if ( ! fgState.Initialised )                                    \
    {                                                               \
      fgError ( " ERROR:  Function <%s> called"                     \
                " without first calling 'glutInit'.", (string) ) ;  \
    }
  
  #define  FREEGLUT_INTERNAL_ERROR_EXIT_IF_NOT_INITIALISED( string )  \
    if ( ! fgState.Initialised )                                      \
    {                                                                 \
      fgError ( " ERROR:  Internal <%s> function called"              \
                " without first calling 'glutInit'.", (string) ) ;    \
    }
  
  #define  FREEGLUT_INTERNAL_ERROR_EXIT( cond, string, function )  \
    if ( ! ( cond ) )                                              \
    {                                                              \
      fgError ( " ERROR:  Internal error <%s> in function %s",     \
                (string), (function) ) ;                           \
    }
  
  /*
   * Following definitions are somewhat similiar to GLib's,
   * but do not generate any log messages:
   */
  #define  freeglut_return_if_fail( expr ) \
      if( !(expr) )                        \
          return;
  #define  freeglut_return_val_if_fail( expr, val ) \
      if( !(expr) )                                 \
          return val ;
  
  /*
   * A call to those macros assures us that there is a current
   * window set, respectively:
   */
  #define  FREEGLUT_EXIT_IF_NO_WINDOW( string )                   \
    if ( ! fgStructure.CurrentWindow )                            \
    {                                                             \
      fgError ( " ERROR:  Function <%s> called"                   \
                " with no current window defined.", (string) ) ;  \
    }
  
  /*
   * The deinitialize function gets called on glutMainLoop() end. It should clean up
   * everything inside of the freeglut
   */
  void fgDeinitialize( void );
  
  /*
   * Those two functions are used to create/destroy the freeglut internal
   * structures. This actually happens when calling glutInit() and when
   * quitting the glutMainLoop() (which actually happens, when all windows
   * have been closed).
   */
  void fgCreateStructure( void );
  void fgDestroyStructure( void );
  
  /* A helper function to check if a display mode is possible to use */
  #if TARGET_HOST_POSIX_X11
  GLXFBConfig* fgChooseFBConfig( void );
  #endif
  
  /* The window procedure for Win32 events handling */
  #if TARGET_HOST_MS_WINDOWS
  LRESULT CALLBACK fgWindowProc( HWND hWnd, UINT uMsg,
                                 WPARAM wParam, LPARAM lParam );
  void fgNewWGLCreateContext( SFG_Window* window );
  GLboolean fgSetupPixelFormat( SFG_Window* window, GLboolean checkOnly,
                                unsigned char layer_type );
  #endif
  
  /*
   * Window creation, opening, closing and destruction.
   * Also CallBack clearing/initialization.
   * Defined in freeglut_structure.c, freeglut_window.c.
   */
  SFG_Window* fgCreateWindow( SFG_Window* parent, const char* title,
                              GLboolean positionUse, int x, int y,
                              GLboolean sizeUse, int w, int h,
                              GLboolean gameMode, GLboolean isMenu );
  void        fgSetWindow ( SFG_Window *window );
  void        fgOpenWindow( SFG_Window* window, const char* title,
                            GLboolean positionUse, int x, int y,
                            GLboolean sizeUse, int w, int h,
                            GLboolean gameMode, GLboolean isSubWindow );
  void        fgCloseWindow( SFG_Window* window );
  void        fgAddToWindowDestroyList ( SFG_Window* window );
  void        fgCloseWindows ();
  void        fgDestroyWindow( SFG_Window* window );
  
  /* Menu creation and destruction. Defined in freeglut_structure.c */
  SFG_Menu*   fgCreateMenu( FGCBMenu menuCallback );
  void        fgDestroyMenu( SFG_Menu* menu );
  
  /* Joystick device management functions, defined in freeglut_joystick.c */
  int         fgJoystickDetect( void );
  void        fgInitialiseJoysticks( void );
  void        fgJoystickClose( void );
  void        fgJoystickPollWindow( SFG_Window* window );
  
  /* InputDevice Initialisation and Closure */
  int         fgInputDeviceDetect( void );
  void        fgInitialiseInputDevices( void );
  void        fgInputDeviceClose( void );
  
  /* spaceball device functions, defined in freeglut_spaceball.c */
  void        fgInitialiseSpaceball( void );
  void        fgSpaceballClose( void );
  void        fgSpaceballSetWindow( SFG_Window *window );
  
  int         fgHasSpaceball( void );
  int         fgSpaceballNumButtons( void );
  
  #if TARGET_HOST_POSIX_X11
  int         fgIsSpaceballXEvent( const XEvent *ev );
  void        fgSpaceballHandleXEvent( const XEvent *ev );
  #endif
  
  /* Setting the cursor for a given window */
  void fgSetCursor ( SFG_Window *window, int cursorID );
  
  /*
   * Helper function to enumerate through all registered windows
   * and one to enumerate all of a window's subwindows...
   *
   * The GFunc callback for those functions will be defined as:
   *
   *      void enumCallback( gpointer window, gpointer enumerator );
   *
   * where window is the enumerated (sub)window pointer (SFG_Window *),
   * and userData is the a custom user-supplied pointer. Functions
   * are defined and exported from freeglut_structure.c file.
   */
  void fgEnumWindows( FGCBenumerator enumCallback, SFG_Enumerator* enumerator );
  void fgEnumSubWindows( SFG_Window* window, FGCBenumerator enumCallback,
                         SFG_Enumerator* enumerator );
  
  /*
   * fgWindowByHandle returns a (SFG_Window *) value pointing to the
   * first window in the queue matching the specified window handle.
   * The function is defined in freeglut_structure.c file.
   */
  SFG_Window* fgWindowByHandle( SFG_WindowHandleType hWindow );
  
  /*
   * This function is similiar to the previous one, except it is
   * looking for a specified (sub)window identifier. The function
   * is defined in freeglut_structure.c file.
   */
  SFG_Window* fgWindowByID( int windowID );
  
  /*
   * Looks up a menu given its ID. This is easier than fgWindowByXXX
   * as all menus are placed in a single doubly linked list...
   */
  SFG_Menu* fgMenuByID( int menuID );
  
  /*
   * The menu activation and deactivation the code. This is the meat
   * of the menu user interface handling code...
   */
  void fgUpdateMenuHighlight ( SFG_Menu *menu );
  GLboolean fgCheckActiveMenu ( SFG_Window *window, int button, GLboolean pressed,
                                int mouse_x, int mouse_y );
  void fgDeactivateMenu( SFG_Window *window );
  
  /*
   * This function gets called just before the buffers swap, so that
   * freeglut can display the pull-down menus via OpenGL. The function
   * is defined in freeglut_menu.c file.
   */
  void fgDisplayMenu( void );
  
  /* Elapsed time as per glutGet(GLUT_ELAPSED_TIME). */
  long fgElapsedTime( void );
  
  /* System time in milliseconds */
  long unsigned fgSystemTime(void);
  
  /* List functions */
  void fgListInit(SFG_List *list);
  void fgListAppend(SFG_List *list, SFG_Node *node);
  void fgListRemove(SFG_List *list, SFG_Node *node);
  int fgListLength(SFG_List *list);
  void fgListInsert(SFG_List *list, SFG_Node *next, SFG_Node *node);
  
  /* Error Message functions */
  void fgError( const char *fmt, ... );
  void fgWarning( const char *fmt, ... );
  
  /*
   * Check if "hint" is present in "property" for "window".  See freeglut_init.c
   */
  #if TARGET_HOST_POSIX_X11
  int fgHintPresent(Window window, Atom property, Atom hint);
  #endif
  
  SFG_Proc fghGetProcAddress( const char *procName );
  
  #if TARGET_HOST_MS_WINDOWS
  extern void (__cdecl *__glutExitFunc)( int return_value );
  #endif
  
  #endif /* FREEGLUT_INTERNAL_H */
  
  /*** END OF FILE ***/
  