[freeglut] / src / freeglut_main.c

/*
 * freeglut_main.c
 *
 * The windows message processing methods.
 *
 * Copyright (c) 1999-2000 Pawel W. Olszta. All Rights Reserved.
 * Written by Pawel W. Olszta, <olszta@sourceforge.net>
 * Creation date: Fri Dec 3 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "../include/GL/freeglut.h"
#include "freeglut_internal.h"

#include <limits.h>
#if TARGET_HOST_UNIX_X11
#include <sys/types.h>
#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#elif TARGET_HOST_WIN32
#endif

#ifndef MAX
#define MAX(a,b) (((a)>(b)) ? (a) : (b))
#endif

#ifndef MIN
#define MIN(a,b) (((a)<(b)) ? (a) : (b))
#endif


/*
 * TODO BEFORE THE STABLE RELEASE:
 *
 * There are some issues concerning window redrawing under X11, and maybe
 * some events are not handled. The Win32 version lacks some more features,
 * but seems acceptable for not demanding purposes.
 *
 * Need to investigate why the X11 version breaks out with an error when
 * closing a window (using the window manager, not glutDestroyWindow)...
 */

/* -- PRIVATE FUNCTIONS ---------------------------------------------------- */

/*
 * Calls a window's redraw method. This is used when
 * a redraw is forced by the incoming window messages.
 *
 * XXX We can/should make a "unified" window handle type so that
 * XXX the function headers don't need this silly #ifdef junk.
 * XXX Make the type, say, {fgWindow}.  On UNIX_X11, this is
 * XXX {Window}.  On WIN32, it is {HWND}.  Then do the #ifdef
 * XXX junk *once* in "freeglut_internal.h".
 */
static void fghRedrawWindowByHandle
#if TARGET_HOST_UNIX_X11
    ( Window handle )
#elif TARGET_HOST_WIN32
    ( HWND handle )
#endif
{
    SFG_Window* window = fgWindowByHandle( handle );
    freeglut_return_if_fail( window != NULL );

    /*
     * XXX Other than clearing the Redisplay flag or not,
     * XXX we may as well rely on the INVOK_WCB() doing this
     * XXX pointer-check.
     * XXX
     * XXX If we do not invoke the display because the pointer
     * XXX is not defined (should never happen, really), then
     * XXX we may enter an infinite busy-loop trying to update
     * XXX the window.  Similarly, if we skip because the window
     * XXX is not visible.  However, if the window becomes visible
     * XXX at a later time, the window should get its callback
     * XXX invoked.  I would recommend removing the first check,
     * XXX and making the second check only affect whether the
     * XXX callback is invoked---but always clear the flag, if
     * XXX the {window} pointer is defined.
     */
    freeglut_return_if_fail( FETCH_WCB( *window, Display ) );
    freeglut_return_if_fail( window->State.Visible == TRUE );

    window->State.Redisplay = FALSE;
    INVOKE_WCB( *window, Display, ( ) );
}

/*
 * Handle a window configuration change. When no reshape
 * callback is hooked, the viewport size is updated to
 * match the new window size.
 */
static void fghReshapeWindowByHandle
#if TARGET_HOST_UNIX_X11
    ( Window handle, int width, int height )
#elif TARGET_HOST_WIN32
    ( HWND handle, int width, int height )
#endif
{
    SFG_Window *current_window = fgStructure.Window;

    SFG_Window* window = fgWindowByHandle( handle );
    freeglut_return_if_fail( window != NULL );

    if( !( FETCH_WCB( *window, Reshape ) ) )
    {
        fgSetWindow( window );
        glViewport( 0, 0, width, height );
    }
    else
        INVOKE_WCB( *window, Reshape, ( width, height ) );

    /*
     * Force a window redraw.  In Windows at least this is only a partial
     * solution:  if the window is increasing in size in either dimension,
     * the already-drawn part does not get drawn again and things look funny.
     * But without this we get this bad behaviour whenever we resize the
     * window.
     */
    window->State.Redisplay = TRUE;

    if( window->IsMenu )
        fgSetWindow( current_window );
}

/*
 * A static helper function to execute display callback for a window
 */
static void fghcbDisplayWindow( SFG_Window *window, SFG_Enumerator *enumerator )
{
#if TARGET_HOST_UNIX_X11
    /*
     * XXX Do we need/want to check the callback pointer here?
     * XXX INVOKE_WCB() will check for us.  Arguably, the
     * XXX Redisplay status flag should be cleared regardless
     * XXX of any concern but that {window} is a valid pointer
     * XXX (which this function is assuming anyway).
     * XXX Especially since old GLUT wouldn't even enter its main
     * XXX loop if you didn't have a display callback defined...
     */
    if( ( FETCH_WCB( *window, Display ) ) &&
        ( window->State.Redisplay == TRUE ) &&
        ( window->State.Visible == TRUE ) )
    {
        SFG_Window *current_window = fgStructure.Window ;

        window->State.Redisplay = FALSE;
        INVOKE_WCB( *window, Display, ( ) );
        fgSetWindow( current_window );
    }

#elif TARGET_HOST_WIN32

    if( window->State.NeedToResize )
    {
        SFG_Window *current_window = fgStructure.Window;

        fgSetWindow( window );

        fghReshapeWindowByHandle( 
            window->Window.Handle,
            glutGet( GLUT_WINDOW_WIDTH ),
            glutGet( GLUT_WINDOW_HEIGHT )
        );

        window->State.NeedToResize = FALSE;
        fgSetWindow ( current_window );
    }

    /*
     * XXX See above comment about the Redisplay flag...
     */
    if( ( FETCH_WCB( *window, Display ) ) &&
        ( window->State.Redisplay == TRUE ) &&
        ( window->State.Visible == TRUE ) )
    {
        window->State.Redisplay = FALSE;

        RedrawWindow(
            window->Window.Handle, NULL, NULL, 
            RDW_NOERASE | RDW_INTERNALPAINT | RDW_INVALIDATE | RDW_UPDATENOW
        );
    }

#endif

    fgEnumSubWindows( window, fghcbDisplayWindow, enumerator );
}

/*
 * Make all windows perform a display call
 */
static void fghDisplayAll( void )
{
    SFG_Enumerator enumerator;

    enumerator.found = FALSE;
    enumerator.data  =  NULL;

    fgEnumWindows( fghcbDisplayWindow, &enumerator );
}

/*
 * Window enumerator callback to check for the joystick polling code
 */
static void fghcbCheckJoystickPolls( SFG_Window *window,
                                     SFG_Enumerator *enumerator )
{
    long int checkTime = fgElapsedTime( );

    if( window->State.JoystickLastPoll + window->State.JoystickPollRate <=
        checkTime )
    {
        fgJoystickPollWindow( window );
        window->State.JoystickLastPoll = checkTime;
    }

    fgEnumSubWindows( window, fghcbCheckJoystickPolls, enumerator );
}

/*
 * Check all windows for joystick polling
 */
static void fghCheckJoystickPolls( void )
{
    SFG_Enumerator enumerator;

    enumerator.found = FALSE;
    enumerator.data  =  NULL;

    fgEnumWindows( fghcbCheckJoystickPolls, &enumerator );
}

/*
 * Check the global timers
 */
static void fghCheckTimers( void )
{
    long checkTime = fgElapsedTime( );
    SFG_Timer *timer, *next;
    SFG_List timedOut;

    fgListInit(&timedOut);

    for( timer = (SFG_Timer *)fgState.Timers.First;
         timer;
         timer = (SFG_Timer *)next )
    {
        next = (SFG_Timer *)timer->Node.Next;

        if( timer->TriggerTime <= checkTime )
        {
            fgListRemove( &fgState.Timers, &timer->Node );
            fgListAppend( &timedOut, &timer->Node );
        }
    }

    /*
     * Now feel free to execute all the hooked and timed out timer callbacks
     * And delete the timed out timers...
     */
    while ( (timer = (SFG_Timer *)timedOut.First) )
    {
        if( timer->Callback != NULL )
            timer->Callback( timer->ID );
        fgListRemove( &timedOut, &timer->Node );
        free( timer );
    }
}


/*
 * Elapsed Time
 */
long fgElapsedTime( void )
{
    if (fgState.Time.Set)
    {
#if TARGET_HOST_UNIX_X11
        struct timeval now;
        long elapsed;
    
        gettimeofday( &now, NULL );
    
        elapsed = (now.tv_usec - fgState.Time.Value.tv_usec) / 1000;
        elapsed += (now.tv_sec - fgState.Time.Value.tv_sec) * 1000;
    
        return elapsed;
#elif TARGET_HOST_WIN32
        return timeGetTime() - fgState.Time.Value;
#endif
    }
    else
    {
#if TARGET_HOST_UNIX_X11
        gettimeofday( &fgState.Time.Value, NULL );
#elif TARGET_HOST_WIN32
        fgState.Time.Value = timeGetTime( );
#endif
        fgState.Time.Set = TRUE;
    }
}

/*
 * Error Messages.
 */
void fgError( const char *fmt, ... )
{
    va_list ap;

    va_start( ap, fmt );

    fprintf( stderr, "freeglut ");
    if( fgState.ProgramName )
        fprintf (stderr, "(%s): ", fgState.ProgramName);
    vfprintf( stderr, fmt, ap );
    fprintf( stderr, "\n" );

    va_end( ap );

    exit( 1 );
}

void fgWarning( const char *fmt, ... )
{
    va_list ap;

    va_start( ap, fmt );

    fprintf( stderr, "freeglut ");
    if( fgState.ProgramName )
        fprintf( stderr, "(%s): ", fgState.ProgramName );
    vfprintf( stderr, fmt, ap );
    fprintf( stderr, "\n" );

    va_end( ap );
}

/*
 * Indicates whether Joystick events are being used by ANY window.
 *
 * The current mechanism is to walk all of the windows and ask if
 * there is a joystick callback.  Certainly in some cases, maybe
 * in all cases, the joystick is attached to the system and accessed
 * from ONE point by GLUT/freeglut, so this is not the right way,
 * in general, to do this.  However, the Joystick code is segregated
 * in its own little world, so we can't access the information that
 * we need in order to do that nicely.
 *
 * Some alternatives:
 *  * Store Joystick data into freeglut global state.
 *  * Provide NON-static functions or data from Joystick *.c file.
 *
 * Basically, the RIGHT way to do this requires knowing something
 * about the Joystick.  Right now, the Joystick code is behind
 * an opaque wall.
 *
 */
static void fgCheckJoystickCallback( SFG_Window* w, SFG_Enumerator* e)
{
    if( FETCH_WCB( *w, Joystick ) )
    {
        e->found = TRUE;
        e->data = w;
    }
    fgEnumSubWindows( w, fgCheckJoystickCallback, e );
}
static int fgHaveJoystick( void )
{
    SFG_Enumerator enumerator;
    enumerator.found = FALSE;
    enumerator.data = NULL;
    fgEnumWindows( fgCheckJoystickCallback, &enumerator );
    return !!enumerator.data;
}
static void fgHavePendingRedisplaysCallback( SFG_Window* w, SFG_Enumerator* e)
{
    if( w->State.Redisplay )
    {
        e->found = TRUE;
        e->data = w;
    }
    fgEnumSubWindows( w, fgHavePendingRedisplaysCallback, e );
}        
static int fgHavePendingRedisplays (void)
{
    SFG_Enumerator enumerator;
    enumerator.found = FALSE;
    enumerator.data = NULL;
    fgEnumWindows( fgHavePendingRedisplaysCallback, &enumerator );
    return !!enumerator.data;
}
/*
 * Indicates whether there are any outstanding timers.
 */
static int fgHaveTimers( void )
{
    return !!fgState.Timers.First;
}
/*
 * Returns the number of GLUT ticks (milliseconds) till the next timer event.
 */
static long fgNextTimer( void )
{
    long now = fgElapsedTime();
    long ret = INT_MAX;
    SFG_Timer *timer;

    for( timer = (SFG_Timer *)fgState.Timers.First;
         timer;
         timer = (SFG_Timer *)timer->Node.Next )
        ret = MIN( ret, MAX( 0, (timer->TriggerTime) - now ) );

    return ret;
}
/*
 * Does the magic required to relinquish the CPU until something interesting
 * happens.
 */
static void fgSleepForEvents( void )
{
#if TARGET_HOST_UNIX_X11
    fd_set fdset;
    int err;
    int socket;
    struct timeval wait;
    long msec;    
    
    if( fgState.IdleCallback || fgHavePendingRedisplays( ) )
        return;
    socket = ConnectionNumber( fgDisplay.Display );
    FD_ZERO( &fdset );
    FD_SET( socket, &fdset );
    
    msec = fgNextTimer( );
    if( fgHaveJoystick( ) )
        msec = MIN( msec, 10 );
    
    wait.tv_sec = msec / 1000;
    wait.tv_usec = (msec % 1000) * 1000;
    err = select( socket+1, &fdset, NULL, NULL, &wait );

    if( -1 == err )
        printf( "freeglut select() error: %d\n", errno );
    
#elif TARGET_HOST_WIN32
#endif
}

#if TARGET_HOST_UNIX_X11
/*
 * Returns GLUT modifier mask for an XEvent.
 */
int fgGetXModifiers( XEvent *event )
{
    int ret = 0;

    if( event->xkey.state & ( ShiftMask | LockMask ) )
        ret |= GLUT_ACTIVE_SHIFT;
    if( event->xkey.state & ControlMask )
        ret |= GLUT_ACTIVE_CTRL;
    if( event->xkey.state & Mod1Mask )
        ret |= GLUT_ACTIVE_ALT;
    
    return ret;
}
#endif


/* -- INTERFACE FUNCTIONS -------------------------------------------------- */

/*
 * Executes a single iteration in the freeglut processing loop.
 */
void FGAPIENTRY glutMainLoopEvent( void )
{
#if TARGET_HOST_UNIX_X11
    SFG_Window* window;
    XEvent event;

    /*
     * This code was repeated constantly, so here it goes into a definition:
     */
#define GETWINDOW(a)                             \
    window = fgWindowByHandle( event.a.window ); \
    if( window == NULL )                         \
        break;

#define GETMOUSE(a)                              \
    window->State.MouseX = event.a.x;            \
    window->State.MouseY = event.a.y;

    freeglut_assert_ready;

    while( XPending( fgDisplay.Display ) )
    {
        XNextEvent( fgDisplay.Display, &event );

        switch( event.type )
        {
        case ClientMessage:
            /*
             * Destroy the window when the WM_DELETE_WINDOW message arrives
             */
            if( (Atom) event.xclient.data.l[ 0 ] == fgDisplay.DeleteWindow )
            {
                GETWINDOW( xclient ); 

                fgCloseWindow ( window ) ;
                fgAddToWindowDestroyList ( window, FALSE );
            }
            break;

            /*
             * CreateNotify causes a configure-event so that sub-windows are
             * handled compatibly with GLUT.  Otherwise, your sub-windows
             * (in freeglut only) will not get an initial reshape event,
             * which can break things.
             *
             * XXX NOTE that it is possible that you will more than one Reshape
             * XXX event for your top-level window, but something like this
             * XXX appears to be required for compatbility.
             *
             * GLUT presumably does this because it generally tries to treat
             * sub-windows the same as windows.
             */
        case CreateNotify:
        case ConfigureNotify:
            fghReshapeWindowByHandle(
                event.xconfigure.window,
                event.xconfigure.width,
                event.xconfigure.height
            );
            break;

        case DestroyNotify:
            /*
             * This is sent to confirm the XDestroyWindow call.
             * XXX WHY is this commented out?  Should we re-enable it?
             */
            /* fgAddToWindowDestroyList ( window, FALSE ); */
            break;

        case Expose:
            /*
             * We are too dumb to process partial exposes...
             * XXX Well, we could do it.  However, it seems to only
             * XXX be potentially useful for single-buffered (since
             * XXX double-buffered does not respect viewport when we
             * XXX do a buffer-swap).
             */
            if( event.xexpose.count == 0 )
                fghRedrawWindowByHandle( event.xexpose.window );
            break;

        case MapNotify:
        case UnmapNotify:
            /*
             * If we never do anything with this, can we just not ask to
             * get these messages?
             */
            break;

        case MappingNotify:
            /*
             * Have the client's keyboard knowledge updated (xlib.ps,
             * page 206, says that's a good thing to do)
             */
            XRefreshKeyboardMapping( (XMappingEvent *) &event );
            break;

        case VisibilityNotify:
        {
            GETWINDOW( xvisibility ); 
            if( ! FETCH_WCB( *window, WindowStatus ) )
                break;
            fgSetWindow( window );

            /*
             * Sending this event, the X server can notify us that the window
             * has just acquired one of the three possible visibility states:
             * VisibilityUnobscured, VisibilityPartiallyObscured or
             * VisibilityFullyObscured
             */
            switch( event.xvisibility.state )
            {
            case VisibilityUnobscured:
                INVOKE_WCB( *window, WindowStatus, ( GLUT_FULLY_RETAINED ) );
                window->State.Visible = TRUE;
                break;
                
            case VisibilityPartiallyObscured:
                INVOKE_WCB( *window, WindowStatus,
                            ( GLUT_PARTIALLY_RETAINED ) );
                window->State.Visible = TRUE;
                break;
                
            case VisibilityFullyObscured:
                INVOKE_WCB( *window, WindowStatus, ( GLUT_FULLY_COVERED ) );
                window->State.Visible = FALSE;
                break;

            default:
                fgWarning( "Uknown X visibility state: %d",
                           event.xvisibility.state );
                break;
            }
        }
        break;

        case EnterNotify:
        case LeaveNotify:
            GETWINDOW( xcrossing );
            GETMOUSE( xcrossing );
            INVOKE_WCB( *window, Entry, ( ( EnterNotify == event.type ) ?
                                          GLUT_ENTERED :
                                          GLUT_LEFT ) );
            break;

        case MotionNotify:
        {
            GETWINDOW( xmotion );
            GETMOUSE( xmotion );

            if( window->ActiveMenu )
            {
                if( window == window->ActiveMenu->ParentWindow )
                {
                    window->ActiveMenu->Window->State.MouseX =
                        event.xmotion.x_root - window->ActiveMenu->X;
                    window->ActiveMenu->Window->State.MouseY =
                        event.xmotion.y_root - window->ActiveMenu->Y;
                }
                window->ActiveMenu->Window->State.Redisplay = TRUE ;
                fgSetWindow( window->ActiveMenu->ParentWindow ) ;

                break;
            }

            /*
             * XXX For more than 5 buttons, just check {event.xmotion.state},
             * XXX rather than a host of bit-masks?
             */
            if( (event.xmotion.state & Button1Mask) ||
                (event.xmotion.state & Button2Mask) ||
                (event.xmotion.state & Button3Mask) ||
                (event.xmotion.state & Button4Mask) ||
                (event.xmotion.state & Button5Mask) )
                INVOKE_WCB( *window, Motion, ( event.xmotion.x,
                                               event.xmotion.y ) );
            else
                INVOKE_WCB( *window, Passive, ( event.xmotion.x,
                                                event.xmotion.y ) );
        }
        break;

        case ButtonRelease:
        case ButtonPress:
        {
            GLboolean pressed = TRUE;
            int button;

            if( event.type == ButtonRelease )
                pressed = FALSE ;

            /*
             * A mouse button has been pressed or released. Traditionally,
             * break if the window was found within the freeglut structures.
             */
            GETWINDOW( xbutton );
            GETMOUSE( xbutton );
          
            /*
             * An X button (at least in XFree86) is numbered from 1.
             * A GLUT button is numbered from 0.
             * Old GLUT passed through buttons other than just the first
             * three, though it only gave symbolic names and official
             * support to the first three.
             */
            button = event.xbutton.button - 1;

            /*
             * XXX This comment is replicated in the WIN32 section and
             * XXX maybe also in the menu code.  Can we move the info
             * XXX to one central place and *reference* it from here?
             *
             * Do not execute the application's mouse callback if a menu
             * is hooked to this button.  In that case an appropriate
             * private call should be generated.
             * Near as I can tell, this is the menu behaviour:
             *  - Down-click the menu button, menu not active:  activate
             *    the menu with its upper left-hand corner at the mouse
             *    location.
             *  - Down-click any button outside the menu, menu active:
             *    deactivate the menu
             *  - Down-click any button inside the menu, menu active:
             *    select the menu entry and deactivate the menu
             *  - Up-click the menu button, menu not active:  nothing happens
             *  - Up-click the menu button outside the menu, menu active:
             *    nothing happens
             *  - Up-click the menu button inside the menu, menu active:
             *    select the menu entry and deactivate the menu
             */
            /* Window has an active menu, it absorbs any mouse click */
            if( window->ActiveMenu )
            {
                if( window == window->ActiveMenu->ParentWindow )
                {
                    window->ActiveMenu->Window->State.MouseX =
                        event.xbutton.x_root - window->ActiveMenu->X;
                    window->ActiveMenu->Window->State.MouseY =
                        event.xbutton.y_root - window->ActiveMenu->Y;
                }
              
                /* In the menu, invoke the callback and deactivate the menu*/
                if( fgCheckActiveMenu( window->ActiveMenu->Window,
                                       window->ActiveMenu ) == TRUE )
                {
                    /*
                     * Save the current window and menu and set the current
                     * window to the window whose menu this is
                     */
                    SFG_Window *save_window = fgStructure.Window;
                    SFG_Menu *save_menu = fgStructure.Menu;
                    SFG_Window *parent_window =
                        window->ActiveMenu->ParentWindow;
                    fgSetWindow( parent_window );
                    fgStructure.Menu = window->ActiveMenu;

                    /* Execute the menu callback */
                    fgExecuteMenuCallback( window->ActiveMenu );
                    fgDeactivateMenu( parent_window );

                    /* Restore the current window and menu */
                    fgSetWindow( save_window );
                    fgStructure.Menu = save_menu;
                }
                else if( pressed )
                    /*
                     * Outside the menu, deactivate if it's a downclick
                     * XXX This isn't enough.  A downclick outside of
                     * XXX the interior of our freeglut windows should also
                     * XXX deactivate the menu.  This is more complicated.
                     */
                    fgDeactivateMenu( window->ActiveMenu->ParentWindow );
              
                window->State.Redisplay = TRUE;
                break;
            }

            /*
             * No active menu, let's check whether we need to activate one.
             */
            if( ( 0 <= button ) &&
                ( 2 >= button ) &&
                ( window->Menu[ button ] ) &&
                pressed )
            {
                window->State.Redisplay = TRUE;
                fgSetWindow( window );
                fgActivateMenu( window, button );
                break;
            }

            /*
             * Check if there is a mouse or mouse wheel callback hooked to the
             * window
             */
            if( ! FETCH_WCB( *window, Mouse ) &&
                ! FETCH_WCB( *window, MouseWheel ) )
                break;

            /*
             * XXX Why don't we use {window}?  Other code here does...
             */
            fgStructure.Window->State.Modifiers = fgGetXModifiers( &event );

            /*
             * Finally execute the mouse or mouse wheel callback
             *
             * XXX Use a symbolic constant, *not* "4"!
             */
            if( ( button < 3 ) || ( ! FETCH_WCB( *window, MouseWheel ) ) )
                INVOKE_WCB( *window, Mouse, ( button,
                                              pressed ? GLUT_DOWN : GLUT_UP,
                                              event.xbutton.x,
                                              event.xbutton.y )
                );
            else
            {
                /*
                 * Map 4 and 5 to wheel zero; EVEN to +1, ODD to -1
                 *  "  6 and 7 "    "   one; ...
                 *
                 * XXX This *should* be behind some variables/macros,
                 * XXX since the order and numbering isn't certain
                 * XXX See XFree86 configuration docs (even back in the
                 * XXX 3.x days, and especially with 4.x).
                 *
                 * XXX Note that {button} has already been decremeted
                 * XXX in mapping from X button numbering to GLUT.
                 */
                int wheel_number = (button - 3) / 2;
                int direction = -1;
                if( button % 2 )
                    direction = 1;
                
                if( pressed )
                    INVOKE_WCB( *window, MouseWheel, ( wheel_number,
                                                       direction,
                                                       event.xbutton.x,
                                                       event.xbutton.y )
                    );
            }

            /*
             * Trash the modifiers state
             */
            fgStructure.Window->State.Modifiers = 0xffffffff;
        }
        break;

        case KeyRelease:
        case KeyPress:
        {
            FGCBKeyboard keyboard_cb;
            FGCBSpecial special_cb;

            GETWINDOW( xkey );
            GETMOUSE( xkey );

            if( event.type == KeyPress )
            {
                keyboard_cb = FETCH_WCB( *window, Keyboard );
                special_cb  = FETCH_WCB( *window, Special  );
            }
            else
            {
                keyboard_cb = FETCH_WCB( *window, KeyboardUp );
                special_cb  = FETCH_WCB( *window, SpecialUp  );
            }

            /*
             * Is there a keyboard/special callback hooked for this window?
             */
            if( keyboard_cb || special_cb )
            {
                XComposeStatus composeStatus;
                char asciiCode[ 32 ];
                KeySym keySym;
                int len;

                /*
                 * Check for the ASCII/KeySym codes associated with the event:
                 */
                len = XLookupString( &event.xkey, asciiCode, sizeof(asciiCode),
                                     &keySym, &composeStatus );

                /*
                 * GLUT API tells us to have two separate callbacks...
                 */
                if( len > 0 )
                {
                    /*
                     * ...one for the ASCII translateable keypresses...
                     */
                    if( keyboard_cb )
                    {
                        fgSetWindow( window );
                        window->State.Modifiers = fgGetXModifiers( &event );
                        keyboard_cb( asciiCode[ 0 ],
                                     event.xkey.x, event.xkey.y );
                        window->State.Modifiers = 0xffffffff;
                    }
                }
                else
                {
                    int special = -1;

                    /*
                     * ...and one for all the others, which need to be
                     * translated to GLUT_KEY_Xs...
                     */
                    switch( keySym )
                    {
                    case XK_F1:     special = GLUT_KEY_F1;     break;
                    case XK_F2:     special = GLUT_KEY_F2;     break;
                    case XK_F3:     special = GLUT_KEY_F3;     break;
                    case XK_F4:     special = GLUT_KEY_F4;     break;
                    case XK_F5:     special = GLUT_KEY_F5;     break;
                    case XK_F6:     special = GLUT_KEY_F6;     break;
                    case XK_F7:     special = GLUT_KEY_F7;     break;
                    case XK_F8:     special = GLUT_KEY_F8;     break;
                    case XK_F9:     special = GLUT_KEY_F9;     break;
                    case XK_F10:    special = GLUT_KEY_F10;    break;
                    case XK_F11:    special = GLUT_KEY_F11;    break;
                    case XK_F12:    special = GLUT_KEY_F12;    break;

                    case XK_Left:   special = GLUT_KEY_LEFT;   break;
                    case XK_Right:  special = GLUT_KEY_RIGHT;  break;
                    case XK_Up:     special = GLUT_KEY_UP;     break;
                    case XK_Down:   special = GLUT_KEY_DOWN;   break;

                    case XK_KP_Prior:
                    case XK_Prior:  special = GLUT_KEY_PAGE_UP; break;
                    case XK_KP_Next:
                    case XK_Next:   special = GLUT_KEY_PAGE_DOWN; break;
                    case XK_KP_Home:
                    case XK_Home:   special = GLUT_KEY_HOME;   break;
                    case XK_KP_End:
                    case XK_End:    special = GLUT_KEY_END;    break;
                    case XK_KP_Insert:
                    case XK_Insert: special = GLUT_KEY_INSERT; break;
                    }

                    /*
                     * Execute the callback (if one has been specified),
                     * given that the special code seems to be valid...
                     */
                    if( special_cb && (special != -1) )
                    {
                        fgSetWindow( window );
                        window->State.Modifiers = fgGetXModifiers( &event );
                        special_cb( special, event.xkey.x, event.xkey.y );
                        window->State.Modifiers = 0xffffffff;
                    }
                }
            }
        }
        break;

        case ReparentNotify:
            break; /* XXX Should disable this event */

        default:
            fgWarning ("Unknown X event type: %d", event.type);
            break;
        }
    }

#elif TARGET_HOST_WIN32

    MSG stMsg;

    while( PeekMessage( &stMsg, NULL, 0, 0, PM_NOREMOVE ) )
    {
        if( GetMessage( &stMsg, NULL, 0, 0 ) == 0 )
            fgState.ExecState = GLUT_EXEC_STATE_STOP ;

        TranslateMessage( &stMsg );
        DispatchMessage( &stMsg );
    }
#endif

    fghCheckTimers( );
    fghCheckJoystickPolls( );
    fghDisplayAll( );

    fgCloseWindows( );
}

/*
 * Enters the freeglut processing loop.
 * Stays until the "ExecState" changes to "GLUT_EXEC_STATE_STOP".
 */
void FGAPIENTRY glutMainLoop( void )
{
#if TARGET_HOST_WIN32
    SFG_Window *window = (SFG_Window *)fgStructure.Windows.First ;
#endif

    freeglut_assert_ready;

#if TARGET_HOST_WIN32
    /*
     * Processing before the main loop:  If there is a window which is open and
     * which has a visibility callback, call it.  I know this is an ugly hack,
     * but I'm not sure what else to do about it.  Ideally we should leave
     * something uninitialized in the create window code and initialize it in
     * the main loop, and have that initialization create a "WM_ACTIVATE"
     * message.  Then we would put the visibility callback code in the
     * "case WM_ACTIVATE" block below.         - John Fay -- 10/24/02
     */
    while( window )
    {
        if ( FETCH_WCB( *window, Visibility ) )
        {
            SFG_Window *current_window = fgStructure.Window ;

            INVOKE_WCB( *window, Visibility, ( window->State.Visible ) );
            fgSetWindow( current_window );
        }
        
        window = (SFG_Window *)window->Node.Next ;
    }
#endif

    fgState.ExecState = GLUT_EXEC_STATE_RUNNING ;
    while( fgState.ExecState == GLUT_EXEC_STATE_RUNNING )
    {
        glutMainLoopEvent( );

        if( fgStructure.Windows.First == NULL )
            fgState.ExecState = GLUT_EXEC_STATE_STOP;
        else
        {
            if( fgState.IdleCallback )
                fgState.IdleCallback( );

            fgSleepForEvents();
        }
    }

    {
        fgExecutionState execState = fgState.ExecState;
        
        /*
         * When this loop terminates, destroy the display, state and structure
         * of a freeglut session, so that another glutInit() call can happen
         */
        fgDeinitialize( );

        if( execState == GLUT_ACTION_EXIT )
            exit( 0 ) ;
    }
}

/*
 * Leaves the freeglut processing loop.
 */
void FGAPIENTRY glutLeaveMainLoop( void )
{
    fgState.ExecState = GLUT_EXEC_STATE_STOP ;
}


#if TARGET_HOST_WIN32
/*
 * Determine a GLUT modifer mask based on MS-WINDOWS system info.
 */
int fgGetWin32Modifiers (void)
{
    return
        ( ( ( GetKeyState( VK_LSHIFT   ) < 0 ) ||
            ( GetKeyState( VK_RSHIFT   ) < 0 )) ? GLUT_ACTIVE_SHIFT : 0 ) |
        ( ( ( GetKeyState( VK_LCONTROL ) < 0 ) ||
            ( GetKeyState( VK_RCONTROL ) < 0 )) ? GLUT_ACTIVE_CTRL  : 0 ) |
        ( ( ( GetKeyState( VK_LMENU    ) < 0 ) ||
            ( GetKeyState( VK_RMENU    ) < 0 )) ? GLUT_ACTIVE_ALT   : 0 );
}

/*
 * The window procedure for handling Win32 events
 */
LRESULT CALLBACK fgWindowProc( HWND hWnd, UINT uMsg, WPARAM wParam,
                               LPARAM lParam )
{
    SFG_Window* window = fgWindowByHandle( hWnd );
    PAINTSTRUCT ps;
    LONG lRet = 1;

    if ( ( window == NULL ) && ( uMsg != WM_CREATE ) )
      return( DefWindowProc( hWnd, uMsg, wParam, lParam ) );

    /* printf ( "Window %3d message <%04x> %12d %12d\n", window?window->ID:0,
             uMsg, wParam, lParam ); */
    switch( uMsg )
    {
    case WM_CREATE:
        /*
         * The window structure is passed as the creation structure paramter...
         */
        window = (SFG_Window *) (((LPCREATESTRUCT) lParam)->lpCreateParams);
        assert( window != NULL );

        window->Window.Handle = hWnd;
        window->Window.Device = GetDC( hWnd );
        if( fgState.BuildingAMenu )
        {
            unsigned int current_DisplayMode = fgState.DisplayMode;
            fgState.DisplayMode = GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH;
            fgSetupPixelFormat( window, FALSE, PFD_MAIN_PLANE );
            fgState.DisplayMode = current_DisplayMode;

            if( fgStructure.MenuContext )
                wglMakeCurrent( window->Window.Device,
                                fgStructure.MenuContext->Context ) ;
            else
            {
                fgStructure.MenuContext =
                    (SFG_MenuContext *)malloc( sizeof(SFG_MenuContext) );
                fgStructure.MenuContext->Context =
                    wglCreateContext( window->Window.Device );
            }

            /* window->Window.Context = wglGetCurrentContext () ;   */
            window->Window.Context = wglCreateContext( window->Window.Device );
        }
        else
        {
            fgSetupPixelFormat( window, FALSE, PFD_MAIN_PLANE );

            if( fgState.UseCurrentContext != TRUE )
                window->Window.Context =
                    wglCreateContext( window->Window.Device );
            else
            {
                window->Window.Context = wglGetCurrentContext( );
                if( ! window->Window.Context )
                    window->Window.Context =
                        wglCreateContext( window->Window.Device );
            }
        }

        window->State.NeedToResize = TRUE;
        ReleaseDC( window->Window.Handle, window->Window.Device );
        break;

    case WM_SIZE:
        /*
         * We got resized... But check if the window has been already added...
         */
        fghReshapeWindowByHandle( hWnd, LOWORD(lParam), HIWORD(lParam) );
        break;
#if 0
    case WM_SETFOCUS: 
        printf("WM_SETFOCUS: %p\n", window );
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;

    case WM_ACTIVATE: 
        if (LOWORD(wParam) != WA_INACTIVE)
        {
            /* glutSetCursor( fgStructure.Window->State.Cursor ); */
            printf("WM_ACTIVATE: glutSetCursor( %p, %d)\n", window,
                   window->State.Cursor );
            glutSetCursor( window->State.Cursor );
        }

        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;
#endif

    case WM_SETCURSOR: 
        /*
         * Windows seems to need reminding to erase the cursor for NONE.
         */
#if 0
        if ((LOWORD(lParam) == HTCLIENT) &&
            (fgStructure.Window->State.Cursor == GLUT_CURSOR_NONE))
          SetCursor( NULL );
#else

        /* Set the cursor AND change it for this window class. */
#define MAP_CURSOR(a,b)                 \
    case a:                             \
    SetCursor( LoadCursor( NULL, b ) ); \
    break;

        /* Nuke the cursor AND change it for this window class. */
#define ZAP_CURSOR(a,b) \
    case a:             \
    SetCursor( NULL );  \
    break;

        if( LOWORD( lParam ) == HTCLIENT )
            switch( window->State.Cursor )
            {
                MAP_CURSOR( GLUT_CURSOR_RIGHT_ARROW, IDC_ARROW     );
                MAP_CURSOR( GLUT_CURSOR_LEFT_ARROW,  IDC_ARROW     );
                MAP_CURSOR( GLUT_CURSOR_INFO,        IDC_HELP      );
                MAP_CURSOR( GLUT_CURSOR_DESTROY,     IDC_CROSS     );
                MAP_CURSOR( GLUT_CURSOR_HELP,        IDC_HELP      );
                MAP_CURSOR( GLUT_CURSOR_CYCLE,       IDC_SIZEALL   );
                MAP_CURSOR( GLUT_CURSOR_SPRAY,       IDC_CROSS     );
                MAP_CURSOR( GLUT_CURSOR_WAIT,        IDC_WAIT      );
                MAP_CURSOR( GLUT_CURSOR_TEXT,        IDC_UPARROW   );
                MAP_CURSOR( GLUT_CURSOR_CROSSHAIR,   IDC_CROSS     );
                /* MAP_CURSOR( GLUT_CURSOR_NONE,        IDC_NO         ); */
                ZAP_CURSOR( GLUT_CURSOR_NONE,        NULL          );

            default:
                MAP_CURSOR( GLUT_CURSOR_UP_DOWN,     IDC_ARROW     );
            }
#endif
        else
            lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;

    case WM_SHOWWINDOW:
        window->State.Visible = TRUE;
        window->State.Redisplay = TRUE;
        break;

    case WM_PAINT:
        /* Turn on the visibility in case it was turned off somehow */
        window->State.Visible = GL_TRUE;
        BeginPaint( hWnd, &ps );
        fghRedrawWindowByHandle( hWnd );
        EndPaint( hWnd, &ps );
        break;

    case WM_CLOSE:
        /*
         * Make sure we don't close a window with current context active
         */
        if( fgStructure.Window == window )
        {
            int used = FALSE ;
            SFG_Window *iter ;

            wglMakeCurrent( NULL, NULL );
            /*
             * Step through the list of windows.  If the rendering context
             * is not being used by another window, then we delete it.
             */
            for( iter = (SFG_Window *)fgStructure.Windows.First;
                 iter;
                 iter = (SFG_Window *)iter->Node.Next )
            {
                if( ( iter->Window.Context == window->Window.Context ) &&
                    ( iter != window ) )
                    used = TRUE;
            }

            if( used == FALSE )
                wglDeleteContext( window->Window.Context );
        }

        /*
         * Put on a linked list of windows to be removed after all the
         * callbacks have returned
         */
        fgAddToWindowDestroyList( window, FALSE );
        DestroyWindow( hWnd );
        break;

    case WM_DESTROY:
        /*
         * The window already got destroyed, so don't bother with it.
         */
        return 0;

    case WM_MOUSEMOVE:
    {
        window->State.MouseX = LOWORD( lParam );
        window->State.MouseY = HIWORD( lParam );
        
        if ( window->ActiveMenu )
        {
            window->State.Redisplay = TRUE;
            fgSetWindow ( window->ActiveMenu->ParentWindow );
            break;
        }

        window->State.Modifiers = fgGetWin32Modifiers( );

        if( ( wParam & MK_LBUTTON ) ||
            ( wParam & MK_MBUTTON ) ||
            ( wParam & MK_RBUTTON ) )
            INVOKE_WCB( *window, Motion, ( window->State.MouseX,
                                           window->State.MouseY ) );
        else
            INVOKE_WCB( *window, Passive, ( window->State.MouseX,
                                            window->State.MouseY ) );

        window->State.Modifiers = 0xffffffff;
    }
    break;

    case WM_LBUTTONDOWN:
    case WM_MBUTTONDOWN:
    case WM_RBUTTONDOWN:
    case WM_LBUTTONUP:
    case WM_MBUTTONUP:
    case WM_RBUTTONUP:
    {
        GLboolean pressed = TRUE;
        int button;

        window->State.MouseX = LOWORD( lParam );
        window->State.MouseY = HIWORD( lParam );

        switch( uMsg )
        {
        case WM_LBUTTONDOWN:
            pressed = TRUE;  button = GLUT_LEFT_BUTTON;   break;
        case WM_MBUTTONDOWN:
            pressed = TRUE;  button = GLUT_MIDDLE_BUTTON; break;
        case WM_RBUTTONDOWN:
            pressed = TRUE;  button = GLUT_RIGHT_BUTTON;  break;
        case WM_LBUTTONUP:
            pressed = FALSE; button = GLUT_LEFT_BUTTON;   break;
        case WM_MBUTTONUP:
            pressed = FALSE; button = GLUT_MIDDLE_BUTTON; break;
        case WM_RBUTTONUP:
            pressed = FALSE; button = GLUT_RIGHT_BUTTON;  break;
        default:
            pressed = FALSE; button = -1;                 break;
        }

        if( GetSystemMetrics( SM_SWAPBUTTON ) )
            if( button == GLUT_LEFT_BUTTON )
                button = GLUT_RIGHT_BUTTON;
            else if( button == GLUT_RIGHT_BUTTON )
                button = GLUT_LEFT_BUTTON;

        if( button == -1 )
            return DefWindowProc( hWnd, uMsg, lParam, wParam );

        /*
         * Do not execute the application's mouse callback if a
         * menu is hooked to this button.
         * In that case an appropriate private call should be generated.
         * Near as I can tell, this is the menu behaviour:
         *  - Down-click the menu button, menu not active:  activate
         *    the menu with its upper left-hand corner at the mouse location.
         *  - Down-click any button outside the menu, menu active:
         *    deactivate the menu
         *  - Down-click any button inside the menu, menu active:
         *    select the menu entry and deactivate the menu
         *  - Up-click the menu button, menu not active:  nothing happens
         *  - Up-click the menu button outside the menu, menu active:
         *    nothing happens
         *  - Up-click the menu button inside the menu, menu active:
         *    select the menu entry and deactivate the menu
         */
        /* Window has an active menu, it absorbs any mouse click */
        if( window->ActiveMenu )
        {
            /* Inside the menu, invoke the callback and deactivate the menu*/
            if( fgCheckActiveMenu( window, window->ActiveMenu ) == TRUE )
            {
                /*
                 * Save the current window and menu and set the current
                 * window to the window whose menu this is
                 */
                SFG_Window *save_window = fgStructure.Window;
                SFG_Menu *save_menu = fgStructure.Menu;
                SFG_Window *parent_window = window->ActiveMenu->ParentWindow;
                fgSetWindow( parent_window );
                fgStructure.Menu = window->ActiveMenu;

                /* Execute the menu callback */
                fgExecuteMenuCallback( window->ActiveMenu );
                fgDeactivateMenu( parent_window );

                /* Restore the current window and menu */
                fgSetWindow( save_window );
                fgStructure.Menu = save_menu;
            }
            else  /* Out of menu, deactivate the menu if it's a downclick */
            {
                if( pressed == TRUE )
                    fgDeactivateMenu( window->ActiveMenu->ParentWindow );
            }

            /*
             * Let's make the window redraw as a result of the mouse
             * click and menu activity.
             */
            if( ! window->IsMenu )
                window->State.Redisplay = TRUE;

            break;
        }

        if ( ( window->Menu[ button ] ) && ( pressed == TRUE ) )
        {
            window->State.Redisplay = TRUE;
            fgSetWindow( window );
            fgActivateMenu( window, button );

            break;
        }

        if( ! FETCH_WCB( *window, Mouse ) )
            break;

        fgSetWindow( window );
        fgStructure.Window->State.Modifiers = fgGetWin32Modifiers( );

        INVOKE_WCB(
            *window, Mouse,
            ( button,
              pressed == TRUE ? GLUT_DOWN : GLUT_UP,
              window->State.MouseX,
              window->State.MouseY
            )
        );

        fgStructure.Window->State.Modifiers = 0xffffffff;
    }
    break;

    case 0x020a:
        /* Should be WM_MOUSEWHEEL but my compiler doesn't recognize it */
    {
        int wheel_number = LOWORD( wParam );
        /* THIS IS SPECULATIVE -- John Fay, 10/2/03 */
        short ticks = ( short )HIWORD( wParam ) / 120;
        /* Should be WHEEL_DELTA instead of 120 */
        int direction = 1;

        if( ticks < 0 )
        {
            direction = -1;
            ticks = -ticks;
        }

        /*
         * The mouse cursor has moved. Remember the new mouse cursor's position
         */
        /*        window->State.MouseX = LOWORD( lParam ); */
        /* Need to adjust by window position, */
        /*        window->State.MouseY = HIWORD( lParam ); */
        /* change "lParam" to other parameter */

        if( ! FETCH_WCB( *window, MouseWheel ) &&
            ! FETCH_WCB( *window, Mouse ) )
            break;

        fgSetWindow( window );
        fgStructure.Window->State.Modifiers = fgGetWin32Modifiers( );

        while( ticks-- )
            if( FETCH_WCB( *window, MouseWheel ) )
                INVOKE_WCB( *window, MouseWheel,
                            ( wheel_number,
                              direction,
                              window->State.MouseX,
                              window->State.MouseY
                            )
                );
            else  /* No mouse wheel, call the mouse button callback twice */
            {
                /*
                 * XXX The below assumes that you have no more than 3 mouse
                 * XXX buttons.  Sorry.
                 */
                int button = wheel_number*2 + 4;
                if( direction > 0 )
                    ++button;
                INVOKE_WCB( *window, Mouse,
                            ( button, GLUT_DOWN,
                              window->State.MouseX, window->State.MouseY )
                );
                INVOKE_WCB( *window, Mouse,
                            ( button, GLUT_UP,
                              window->State.MouseX, window->State.MouseX )
                );
            }

        fgStructure.Window->State.Modifiers = 0xffffffff;
    }
    break ;

    case WM_SYSKEYDOWN:
    case WM_KEYDOWN:
    {
        int keypress = -1;
        POINT mouse_pos ;

        if( fgState.IgnoreKeyRepeat && (lParam & KF_REPEAT) )
            break;

        /*
         * Remember the current modifiers state. This is done here in order 
         * to make sure the VK_DELETE keyboard callback is executed properly.
         */
        window->State.Modifiers = fgGetWin32Modifiers( );

        GetCursorPos( &mouse_pos );
        ScreenToClient( window->Window.Handle, &mouse_pos );

        window->State.MouseX = mouse_pos.x;
        window->State.MouseY = mouse_pos.y;

        /*
         * Convert the Win32 keystroke codes to GLUTtish way
         */
#       define KEY(a,b) case a: keypress = b; break;

        switch( wParam )
        {
            KEY( VK_F1,     GLUT_KEY_F1        );
            KEY( VK_F2,     GLUT_KEY_F2        );
            KEY( VK_F3,     GLUT_KEY_F3        );
            KEY( VK_F4,     GLUT_KEY_F4        );
            KEY( VK_F5,     GLUT_KEY_F5        );
            KEY( VK_F6,     GLUT_KEY_F6        );
            KEY( VK_F7,     GLUT_KEY_F7        );
            KEY( VK_F8,     GLUT_KEY_F8        );
            KEY( VK_F9,     GLUT_KEY_F9        );
            KEY( VK_F10,    GLUT_KEY_F10       );
            KEY( VK_F11,    GLUT_KEY_F11       );
            KEY( VK_F12,    GLUT_KEY_F12       );
            KEY( VK_PRIOR,  GLUT_KEY_PAGE_UP   );
            KEY( VK_NEXT,   GLUT_KEY_PAGE_DOWN );
            KEY( VK_HOME,   GLUT_KEY_HOME      );
            KEY( VK_END,    GLUT_KEY_END       );
            KEY( VK_LEFT,   GLUT_KEY_LEFT      );
            KEY( VK_UP,     GLUT_KEY_UP        );
            KEY( VK_RIGHT,  GLUT_KEY_RIGHT     );
            KEY( VK_DOWN,   GLUT_KEY_DOWN      );
            KEY( VK_INSERT, GLUT_KEY_INSERT    );

        case VK_DELETE:
            /*
             * The delete key should be treated as an ASCII keypress:
             */
            INVOKE_WCB( *window, Keyboard,
                        ( 127, window->State.MouseX, window->State.MouseY )
            );
        }

        if( keypress != -1 )
            INVOKE_WCB( *window, Special,
                        ( keypress,
                          window->State.MouseX, window->State.MouseY )
            );

        window->State.Modifiers = 0xffffffff;
    }
    break;

    case WM_SYSKEYUP:
    case WM_KEYUP:
    {
        int keypress = -1;
        POINT mouse_pos;

        /*
         * Remember the current modifiers state. This is done here in order 
         * to make sure the VK_DELETE keyboard callback is executed properly.
         */
        window->State.Modifiers = fgGetWin32Modifiers( );

        GetCursorPos( &mouse_pos );
        ScreenToClient( window->Window.Handle, &mouse_pos );

        window->State.MouseX = mouse_pos.x;
        window->State.MouseY = mouse_pos.y;

        /*
         * Convert the Win32 keystroke codes to GLUTtish way.
         * "KEY(a,b)" was defined under "WM_KEYDOWN"
         */

        switch( wParam )
        {
            KEY( VK_F1,     GLUT_KEY_F1        );
            KEY( VK_F2,     GLUT_KEY_F2        );
            KEY( VK_F3,     GLUT_KEY_F3        );
            KEY( VK_F4,     GLUT_KEY_F4        );
            KEY( VK_F5,     GLUT_KEY_F5        );
            KEY( VK_F6,     GLUT_KEY_F6        );
            KEY( VK_F7,     GLUT_KEY_F7        );
            KEY( VK_F8,     GLUT_KEY_F8        );
            KEY( VK_F9,     GLUT_KEY_F9        );
            KEY( VK_F10,    GLUT_KEY_F10       );
            KEY( VK_F11,    GLUT_KEY_F11       );
            KEY( VK_F12,    GLUT_KEY_F12       );
            KEY( VK_PRIOR,  GLUT_KEY_PAGE_UP   );
            KEY( VK_NEXT,   GLUT_KEY_PAGE_DOWN );
            KEY( VK_HOME,   GLUT_KEY_HOME      );
            KEY( VK_END,    GLUT_KEY_END       );
            KEY( VK_LEFT,   GLUT_KEY_LEFT      );
            KEY( VK_UP,     GLUT_KEY_UP        );
            KEY( VK_RIGHT,  GLUT_KEY_RIGHT     );
            KEY( VK_DOWN,   GLUT_KEY_DOWN      );
            KEY( VK_INSERT, GLUT_KEY_INSERT    );

          case VK_DELETE:
              /*
               * The delete key should be treated as an ASCII keypress:
               */
              INVOKE_WCB( *window, KeyboardUp,
                          ( 127, window->State.MouseX, window->State.MouseY )
              );
              break;

        default:
        {
            BYTE state[ 256 ];
            WORD code[ 2 ];
            
            GetKeyboardState( state );
            
            if( ToAscii( wParam, 0, state, code, 0 ) == 1 )
                wParam=code[ 0 ];

            INVOKE_WCB( *window, KeyboardUp,
                        ( (char)wParam,
                          window->State.MouseX, window->State.MouseY )
            );
        }
        }

        if( keypress != -1 )
            INVOKE_WCB( *window, SpecialUp,
                        ( keypress,
                          window->State.MouseX, window->State.MouseY )
            );

        window->State.Modifiers = 0xffffffff;
    }
    break;

    case WM_SYSCHAR:
    case WM_CHAR:
    {
        if( fgState.IgnoreKeyRepeat && (lParam & KF_REPEAT) )
            break;

        /*
         * XXX INVOKE_WCB() takes care of the callback-pointer check.
         * XXX We could just uncoditionally find/trash the Modifiers
         * XXX and get rid of the "if( ... ) {" and "}".  Unconditinal
         * XXX code is simpler code.  (^&
         */
        if( FETCH_WCB( *window, Keyboard ) )
        {
            window->State.Modifiers = fgGetWin32Modifiers( );
            INVOKE_WCB( *window, Keyboard,
                        ( (char)wParam,
                          window->State.MouseX, window->State.MouseY )
            );
            window->State.Modifiers = 0xffffffff;
        }
    }
    break;

    case WM_CAPTURECHANGED:
        /* User has finished resizing the window, force a redraw */
        INVOKE_WCB( *window, Display, ( ) );

        /*lRet = DefWindowProc( hWnd, uMsg, wParam, lParam ) ; */
        break;

        /*
         * Other messages that I have seen and which are not handled already
         */
    case WM_SETTEXT:  /* 0x000c */
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        /* Pass it on to "DefWindowProc" to set the window text */
        break;

    case WM_GETTEXT:  /* 0x000d */
        /* Ideally we would copy the title of the window into "lParam" */
        /* strncpy ( (char *)lParam, "Window Title", wParam );
           lRet = ( wParam > 12 ) ? 12 : wParam;  */
        /* the number of characters copied */
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;

    case WM_GETTEXTLENGTH:  /* 0x000e */
        /* Ideally we would get the length of the title of the window */
        lRet = 12;
        /* the number of characters in "Window Title\0" (see above) */
        break;

    case WM_ERASEBKGND:  /* 0x0014 */
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;

    case WM_SYNCPAINT:  /* 0x0088 */
        /* Another window has moved, need to update this one */
        window->State.Redisplay = TRUE;
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        /* Help screen says this message must be passed to "DefWindowProc" */
        break;

    case WM_NCPAINT:  /* 0x0085 */
      /* Need to update the border of this window */
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        /* Pass it on to "DefWindowProc" to repaint a standard border */
        break;

    case WM_SYSCOMMAND :  /* 0x0112 */
        {
          /*
           * We have received a system command message.  Try to act on it.
           * The commands are passed in through the "lParam" parameter:
           * Clicking on a corner to resize the window gives a "F004" message
           * but this is not defined in my header file.
           */
            switch ( lParam )
            {
            case SC_SIZE       :
                break ;

            case SC_MOVE       :
                break ;

            case SC_MINIMIZE   :
                /* User has clicked on the "-" to minimize the window */
                /* Turn off the visibility */
                window->State.Visible = GL_FALSE ;

                break ;

            case SC_MAXIMIZE   :
                break ;

            case SC_NEXTWINDOW :
                break ;

            case SC_PREVWINDOW :
                break ;

            case SC_CLOSE      :
                /* Followed very closely by a WM_CLOSE message */
                break ;

            case SC_VSCROLL    :
                break ;

            case SC_HSCROLL    :
                break ;

            case SC_MOUSEMENU  :
                break ;

            case SC_KEYMENU    :
                break ;

            case SC_ARRANGE    :
                break ;

            case SC_RESTORE    :
                break ;

            case SC_TASKLIST   :
                break ;

            case SC_SCREENSAVE :
                break ;

            case SC_HOTKEY     :
                break ;
            }
        }

        /* We need to pass the message on to the operating system as well */
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;

    default:
        /*
         * Handle unhandled messages
         */
        lRet = DefWindowProc( hWnd, uMsg, wParam, lParam );
        break;
    }

    return lRet;
}
#endif

/*** END OF FILE ***/