freeglut_internal.h

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2018, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#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 4
#define VERSION_PATCH 0

/* Freeglut is meant to be available under all Unix/X11 and Win32 platforms. */
#if defined(_WIN32_WCE)
#define TARGET_HOST_UNIX_X11 0
#define TARGET_HOST_WIN32 0
#define TARGET_HOST_WINCE 1
#elif defined(_MSC_VER) || defined(__CYGWIN__) || defined(__MINGW32__)
#define TARGET_HOST_UNIX_X11 0
#define TARGET_HOST_WIN32 1
#define TARGET_HOST_WINCE 0
#else
#define TARGET_HOST_UNIX_X11 1
#define TARGET_HOST_WIN32 0
#define TARGET_HOST_WINCE 0
#endif

#define FREEGLUT_MAX_MENUS 3

/* Somehow all Win32 include headers depend on this one: */
#if TARGET_HOST_WIN32
#include <windows.h>
#include <windowsx.h>
#include <mmsystem.h>
#include <TCHAR.H>
#endif

#if defined(_MSC_VER)
#define strdup _strdup
#endif

/* Those files should be available on every platform. */
#include <GL/gl.h>
#include <GL/glu.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#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>
#else
#if HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#endif

/* The system-dependant include files should go here: */
#if TARGET_HOST_UNIX_X11
#include <GL/glx.h>
#include <X11/Xlib.h>
#include <X11/Xatom.h>
#include <X11/keysym.h>

#ifdef HAVE_X11_EXTENSIONS_XF86VMODE_H
#include <X11/extensions/xf86vmode.h>
#endif
#endif

/* Microsoft VisualC++ 5.0's <math.h> does not define the PI */
#ifndef M_PI
#define M_PI 3.14159265358979323846
#endif

#ifndef TRUE
#define TRUE 1
#endif

#ifndef FALSE
#define FALSE 0
#endif

/* -- 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.          */
};

/* A helper structure holding a timeval and a boolean */
typedef struct tagSFG_Time SFG_Time;
struct tagSFG_Time
{
#if TARGET_HOST_WIN32 || TARGET_HOST_WINCE
    DWORD Value;
#else
    struct timeval Value;
#endif
    GLboolean Set;
};

/*
 * 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       */

    SFG_Time 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
                                 */
};

/* The structure used by display initialization in freeglut_init.c */
typedef struct tagSFG_Display SFG_Display;
struct tagSFG_Display
{
#if TARGET_HOST_UNIX_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          */

#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

#elif TARGET_HOST_WIN32 || TARGET_HOST_WINCE
    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_UNIX_X11

typedef Window SFG_WindowHandleType;
typedef GLXContext SFG_WindowContextType;

#elif TARGET_HOST_WIN32 || TARGET_HOST_WINCE

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_UNIX_X11
    XVisualInfo* VisualInfo; /* The window's visual information     */
#elif TARGET_HOST_WIN32 || TARGET_HOST_WINCE
    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 IsGameMode; /* Is this the game mode window?     */
    GLboolean NeedToResize; /* Do we need to resize the window?  */
};

/*
 * 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_WIN32
#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,
    CB_SpaceRotation,
    CB_SpaceButton,
    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
{
#if TARGET_HOST_UNIX_X11
    XVisualInfo* VisualInfo; /* The window's visual information */
#endif

    SFG_WindowContextType Context; /* 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* GameMode; /* 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_UNIX_X11
XVisualInfo* fgChooseVisual(void);
#endif

/* The window procedure for Win32 events handling */
#if TARGET_HOST_WIN32 || TARGET_HOST_WINCE
LRESULT CALLBACK
    fgWindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam);
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, int x, int y, int w, int h,
    GLboolean gameMode, GLboolean isMenu);
void fgSetWindow(SFG_Window* window);
void fgOpenWindow(
    SFG_Window* window, const char* title, int x, int y, 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);

/* More joystick functions.  Should these go into the API?  */
int glutJoystickGetNumAxes(int ident);
int glutJoystickGetNumButtons(int ident);
int glutJoystickNotWorking(int ident);

/* 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);

/* 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, ...);

#endif /* FREEGLUT_INTERNAL_H */

/*** END OF FILE ***/