view include/SDL_events.h @ 4157:baf615f9f2a0 SDL-1.2

Date: Thu, 16 Oct 2008 20:27:34 +0400 From: "Ilya Kasnacheev" <ilya.kasnacheev@gmail.com> To: sdl@lists.libsdl.org Subject: [SDL] SDL for Windows CE: a few GAPI patches Hi *! I've just ported a POWDER roguelike ( http://www.zincland.com/powder/ ) to Windows CE (PDAs, Windows Mobile/Pocket PC). To do that, I had to get libsdl working. Thanks for the awesome project files, it built without a hitch. Nevertheless, I've found quite a few bugs in Windows CE (GAPI) SDL implementation, which I've solved and now present as a serie of patches. I'll try carefully annotate them. Please annotate them so I can work toward accepting them into the main source tree since without them SDL isn't really working on Windows CE (I wonder why nobody fixed them before, btw: why isn't SDL popular as a way to develop Windows CE games? Where are no ports?) These changes can't be considered flawless, but they can be considered working because I've yet to hear complains about things I fixed and POWDER build for Windows CE is now considered stable. Note: my comments start with !!, delete them before applying. diff -bru SDL-1.2.13/src/video/gapi/SDL_gapivideo.c SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.c --- SDL-1.2.13/src/video/gapi/SDL_gapivideo.c 2007-12-31 07:48:00.000000000 +0300 +++ SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.c 2008-10-16 20:02:11.000000000 +0400 @@ -643,6 +643,7 @@ } gapi->userOrientation = SDL_ORIENTATION_UP; + gapi->systemOrientation = SDL_ORIENTATION_UP; video->flags = SDL_FULLSCREEN; /* Clear flags, GAPI supports fullscreen only */ /* GAPI or VGA? */ @@ -661,18 +662,21 @@ } /* detect user landscape mode */ - if( (width > height) && (GetSystemMetrics(SM_CXSCREEN) < GetSystemMetrics(SM_CYSCREEN))) + if( (width > height) && (gapi->gxProperties.cxWidth < gapi->gxProperties.cyHeight)) gapi->userOrientation = SDL_ORIENTATION_RIGHT; + if(GetSystemMetrics(SM_CYSCREEN) < GetSystemMetrics(SM_CXSCREEN)) + gapi->systemOrientation = SDL_ORIENTATION_RIGHT; + /* shall we apply hires fix? for example when we do not use hires resource */ gapi->hiresFix = 0; - if( gapi->userOrientation == SDL_ORIENTATION_RIGHT ) + if( gapi->systemOrientation == gapi->userOrientation ) { - if( (width > GetSystemMetrics(SM_CYSCREEN)) || (height > GetSystemMetrics(SM_CXSCREEN))) + if( (width > GetSystemMetrics(SM_CXSCREEN)) || (height > GetSystemMetrics(SM_CYSCREEN))) gapi->hiresFix = 1; } else - if( (width > GetSystemMetrics(SM_CXSCREEN)) || (height > GetSystemMetrics(SM_CYSCREEN))) - if( !((width == GetSystemMetrics(SM_CYSCREEN)) && (height == GetSystemMetrics(SM_CXSCREEN)))) // user portrait, device landscape + if( (width > GetSystemMetrics(SM_CYSCREEN)) || (height > GetSystemMetrics(SM_CXSCREEN))) +// if( !((width == gapi->gxProperties.cyHeight) && (height == gapi->gxProperties.cxWidth))) // user portrait, device landscape gapi->hiresFix = 1; switch( gapi->userOrientation ) !! It used to query system metrics which return dimensions according to screen !! orientation, which can really be portrait, left landscape or right landscape. !! This is presumably incorrect because we couldn't care less about user mode !! dimensions - all we want are the GAPI framebuffer dimensions, which only match !! user dimensions in one of possible orientations. !! There's a fair dose of cargo cult programming involved in this fix, but it !! used to work only in one orientation (portrait for PDAs, where frame-buffer !! have same orientation as user screen), and now it works on all orientations. @@ -742,21 +746,30 @@ WIN_FlushMessageQueue(); /* Open GAPI display */ - if( !gapi->useVga && this->hidden->useGXOpenDisplay ) + if( !gapi->useVga && this->hidden->useGXOpenDisplay && !this->hidden->alreadyGXOpened ) + { + this->hidden->alreadyGXOpened = 1; if( !gapi->gxFunc.GXOpenDisplay(SDL_Window, GX_FULLSCREEN) ) { SDL_SetError("Couldn't initialize GAPI"); return(NULL); } + } #if REPORT_VIDEO_INFO printf("Video properties:\n"); printf("display bpp: %d\n", gapi->gxProperties.cBPP); printf("display width: %d\n", gapi->gxProperties.cxWidth); printf("display height: %d\n", gapi->gxProperties.cyHeight); + printf("system display width: %d\n", GetSystemMetrics(SM_CXSCREEN)); + printf("system display height: %d\n", GetSystemMetrics(SM_CYSCREEN)); printf("x pitch: %d\n", gapi->gxProperties.cbxPitch); printf("y pitch: %d\n", gapi->gxProperties.cbyPitch); printf("gapi flags: 0x%x\n", gapi->gxProperties.ffFormat); + printf("user orientation: %d\n", gapi->userOrientation); + printf("system orientation: %d\n", gapi->userOrientation); + printf("gapi orientation: %d\n", gapi->gapiOrientation); + if( !gapi->useVga && this->hidden->useGXOpenDisplay && gapi->needUpdate) { !! Previous version used to call gapi->gxFunc.GXOpenDisplay each time the video !! mode would be changed. You shouldn't, because this call has a meaning "Lock the !! GAPI framebuffer, designate it as busy", so the second call will fail (it is !! already locked/busy). !! Testing might not find that because most programs set up the video mode only !! once, but POWDER does this once in a while, so it crashed when in 320x240 mode !! (640x480 mode doesn't use that code, it worked fine). diff -bru SDL-1.2.13/src/video/gapi/SDL_gapivideo.h SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.h --- SDL-1.2.13/src/video/gapi/SDL_gapivideo.h 2007-12-31 07:48:00.000000000 +0300 +++ SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.h 2008-10-16 20:02:11.000000000 +0400 @@ -132,12 +132,17 @@ #define NUM_MODELISTS 4 /* 8, 16, 24, and 32 bits-per-pixel */ int SDL_nummodes[NUM_MODELISTS]; SDL_Rect **SDL_modelist[NUM_MODELISTS]; + // The orientation of the video mode user wants to get + // Probably restricted to UP and RIGHT enum SDL_ScreenOrientation userOrientation; int invert; char hiresFix; // using hires mode without defining hires resource // -------------- int useGXOpenDisplay; /* use GXOpenDispplay */ + int alreadyGXOpened; int w, h; + // The orientation of GAPI framebuffer. + // Never changes on the same device. enum SDL_ScreenOrientation gapiOrientation; void *buffer; // may be 8, 16, 24, 32 bpp @@ -153,6 +158,10 @@ int startOffset; // in bytes int useVga; int suspended; // do not pu anything into video memory + // The orientation of the system, as defined by SM_CXSCREEN and SM_CYSCREEN + // User can change it by using 'screen layout' in system options + // Restricted to UP or RIGHT + enum SDL_ScreenOrientation systemOrientation; }; !! This is a flag variable, see the previous comment !! And yet another orientation: now we have to keep three of them in mind. diff -bru SDL-1.2.13/src/video/wincommon/SDL_sysevents.c SDL-1.2.13-new/src/video/wincommon/SDL_sysevents.c --- SDL-1.2.13/src/video/wincommon/SDL_sysevents.c 2007-12-31 07:48:02.000000000 +0300 +++ SDL-1.2.13-new/src/video/wincommon/SDL_sysevents.c 2008-10-16 20:02:12.000000000 +0400 @@ -160,10 +160,22 @@ #endif */ } break; + // FIXME: Older version used just SDL_VideoSurface->(w, h) + // w and h are "clipped" while x and y are "raw", which caused + // x in former and y in latter case to be clipped in a wrong direction, + // thus offsetting the coordinate on 2 x clip pixels + // (like, 128 for 640 -> 512 clipping). + // We will now try to extract and use raw values. + // The way to do that RIGHT is do (orientation-dependent) clipping before + // doing this transform, but it's hardly possible. + + // SEE SDL_mouse.c /ClipOffset to understand these calculations. case SDL_ORIENTATION_RIGHT: if (!SDL_VideoSurface) break; - rotatedX = SDL_VideoSurface->w - *y; + rotatedX = (2 * ((SDL_VideoSurface->offset%SDL_VideoSurface->pitch)/ + SDL_VideoSurface->format->BytesPerPixel)) + + SDL_VideoSurface->w - *y; rotatedY = *x; *x = rotatedX; *y = rotatedY; @@ -172,7 +184,8 @@ if (!SDL_VideoSurface) break; rotatedX = *y; - rotatedY = SDL_VideoSurface->h - *x; + rotatedY = (2 * (SDL_VideoSurface->offset/SDL_VideoSurface->pitch)) + + SDL_VideoSurface->h - *x; *x = rotatedX; *y = rotatedY; break; !! That's the trickest part, hence the long comment. !! GAPI would really support only 320x240 or 640x480 mode, if application !! requested the different screen size (as POWDER did, wishing 256x192), then SDL !! is going to grab the first mode that fits the requested, and pad the screen !! with black bars (as they do with wide-screen films). !! It would also get, say, 240x320 mode, and to turn it into 256x192 it would !! need to rotate mouse clicks. !! It worked, but one bug slipped through: it would receive mouse clicks !! unpadded, then rotate them, and then pad the black bars. The problem is: rotate !! is done by GAPI driver while padding is done by SDL core. SDL core doesn't know !! anything about rotating, so it would pad one of dimensions incorrectly. I understand that some of my claims (or code) might seem unbacked, but you can always grab the POWDER binary, compile your own libsdl with one or more of those fixes turned off, and see how weird it would misbehave. I can even supply you with those custom builds of libsdl if you don't want to set up the build environment for windows ce, you'll just need a PDA or a smartphone with it. I plan to take care of SDL on Windows CE as long as I maintain the POWDER port. POWDER is good for that because it: Employs both padded (with centered image, black bars) and unpadded (image occupies full screen) graphics; initializes video more than once; uses both 320x240 and 640x480 video; uses both stylus and buttons. There's still a list of unresolved issues which I'm planning to fix: 1) Arrow buttons on PDA return weird scancodes compared to PC, this caused the game to misbehave before I've fixed that. You can see it on those diagrams: http://wrar.name/upload/powder-htc.png http://wrar.name/upload/powder-pda.png 2) SDL (or underlying windows) doesn't care to rotate arrow presses when we're in a low-res GAPI mode, but it will rotate them in VGA mode (because of different screen orientations, the same arrow buttons can suddently mean different directions). Solution: we should stick to GAPI user orientation (the orientation the program supposedly wants) and rotate the keys on our own. _______________________________________________ SDL mailing list SDL@lists.libsdl.org http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org
author Sam Lantinga <slouken@libsdl.org>
date Fri, 07 Nov 2008 04:15:36 +0000
parents c71e05b4dc2e
children 782fd950bd46 c121d94672cb a1b03ba2fcd0
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/* Include file for SDL event handling */

#ifndef _SDL_events_h
#define _SDL_events_h

#include "SDL_stdinc.h"
#include "SDL_error.h"
#include "SDL_active.h"
#include "SDL_keyboard.h"
#include "SDL_mouse.h"
#include "SDL_joystick.h"
#include "SDL_quit.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/* General keyboard/mouse state definitions */
#define SDL_RELEASED	0
#define SDL_PRESSED	1

/* Event enumerations */
typedef enum {
       SDL_NOEVENT = 0,			/* Unused (do not remove) */
       SDL_ACTIVEEVENT,			/* Application loses/gains visibility */
       SDL_KEYDOWN,			/* Keys pressed */
       SDL_KEYUP,			/* Keys released */
       SDL_MOUSEMOTION,			/* Mouse moved */
       SDL_MOUSEBUTTONDOWN,		/* Mouse button pressed */
       SDL_MOUSEBUTTONUP,		/* Mouse button released */
       SDL_JOYAXISMOTION,		/* Joystick axis motion */
       SDL_JOYBALLMOTION,		/* Joystick trackball motion */
       SDL_JOYHATMOTION,		/* Joystick hat position change */
       SDL_JOYBUTTONDOWN,		/* Joystick button pressed */
       SDL_JOYBUTTONUP,			/* Joystick button released */
       SDL_QUIT,			/* User-requested quit */
       SDL_SYSWMEVENT,			/* System specific event */
       SDL_EVENT_RESERVEDA,		/* Reserved for future use.. */
       SDL_EVENT_RESERVEDB,		/* Reserved for future use.. */
       SDL_VIDEORESIZE,			/* User resized video mode */
       SDL_VIDEOEXPOSE,			/* Screen needs to be redrawn */
       SDL_EVENT_RESERVED2,		/* Reserved for future use.. */
       SDL_EVENT_RESERVED3,		/* Reserved for future use.. */
       SDL_EVENT_RESERVED4,		/* Reserved for future use.. */
       SDL_EVENT_RESERVED5,		/* Reserved for future use.. */
       SDL_EVENT_RESERVED6,		/* Reserved for future use.. */
       SDL_EVENT_RESERVED7,		/* Reserved for future use.. */
       /* Events SDL_USEREVENT through SDL_MAXEVENTS-1 are for your use */
       SDL_USEREVENT = 24,
       /* This last event is only for bounding internal arrays
	  It is the number of bits in the event mask datatype -- Uint32
        */
       SDL_NUMEVENTS = 32
} SDL_EventType;

/* Predefined event masks */
#define SDL_EVENTMASK(X)	(1<<(X))
typedef enum {
	SDL_ACTIVEEVENTMASK	= SDL_EVENTMASK(SDL_ACTIVEEVENT),
	SDL_KEYDOWNMASK		= SDL_EVENTMASK(SDL_KEYDOWN),
	SDL_KEYUPMASK		= SDL_EVENTMASK(SDL_KEYUP),
	SDL_KEYEVENTMASK	= SDL_EVENTMASK(SDL_KEYDOWN)|
	                          SDL_EVENTMASK(SDL_KEYUP),
	SDL_MOUSEMOTIONMASK	= SDL_EVENTMASK(SDL_MOUSEMOTION),
	SDL_MOUSEBUTTONDOWNMASK	= SDL_EVENTMASK(SDL_MOUSEBUTTONDOWN),
	SDL_MOUSEBUTTONUPMASK	= SDL_EVENTMASK(SDL_MOUSEBUTTONUP),
	SDL_MOUSEEVENTMASK	= SDL_EVENTMASK(SDL_MOUSEMOTION)|
	                          SDL_EVENTMASK(SDL_MOUSEBUTTONDOWN)|
	                          SDL_EVENTMASK(SDL_MOUSEBUTTONUP),
	SDL_JOYAXISMOTIONMASK	= SDL_EVENTMASK(SDL_JOYAXISMOTION),
	SDL_JOYBALLMOTIONMASK	= SDL_EVENTMASK(SDL_JOYBALLMOTION),
	SDL_JOYHATMOTIONMASK	= SDL_EVENTMASK(SDL_JOYHATMOTION),
	SDL_JOYBUTTONDOWNMASK	= SDL_EVENTMASK(SDL_JOYBUTTONDOWN),
	SDL_JOYBUTTONUPMASK	= SDL_EVENTMASK(SDL_JOYBUTTONUP),
	SDL_JOYEVENTMASK	= SDL_EVENTMASK(SDL_JOYAXISMOTION)|
	                          SDL_EVENTMASK(SDL_JOYBALLMOTION)|
	                          SDL_EVENTMASK(SDL_JOYHATMOTION)|
	                          SDL_EVENTMASK(SDL_JOYBUTTONDOWN)|
	                          SDL_EVENTMASK(SDL_JOYBUTTONUP),
	SDL_VIDEORESIZEMASK	= SDL_EVENTMASK(SDL_VIDEORESIZE),
	SDL_VIDEOEXPOSEMASK	= SDL_EVENTMASK(SDL_VIDEOEXPOSE),
	SDL_QUITMASK		= SDL_EVENTMASK(SDL_QUIT),
	SDL_SYSWMEVENTMASK	= SDL_EVENTMASK(SDL_SYSWMEVENT)
} SDL_EventMask ;
#define SDL_ALLEVENTS		0xFFFFFFFF

/* Application visibility event structure */
typedef struct SDL_ActiveEvent {
	Uint8 type;	/* SDL_ACTIVEEVENT */
	Uint8 gain;	/* Whether given states were gained or lost (1/0) */
	Uint8 state;	/* A mask of the focus states */
} SDL_ActiveEvent;

/* Keyboard event structure */
typedef struct SDL_KeyboardEvent {
	Uint8 type;	/* SDL_KEYDOWN or SDL_KEYUP */
	Uint8 which;	/* The keyboard device index */
	Uint8 state;	/* SDL_PRESSED or SDL_RELEASED */
	SDL_keysym keysym;
} SDL_KeyboardEvent;

/* Mouse motion event structure */
typedef struct SDL_MouseMotionEvent {
	Uint8 type;	/* SDL_MOUSEMOTION */
	Uint8 which;	/* The mouse device index */
	Uint8 state;	/* The current button state */
	Uint16 x, y;	/* The X/Y coordinates of the mouse */
	Sint16 xrel;	/* The relative motion in the X direction */
	Sint16 yrel;	/* The relative motion in the Y direction */
} SDL_MouseMotionEvent;

/* Mouse button event structure */
typedef struct SDL_MouseButtonEvent {
	Uint8 type;	/* SDL_MOUSEBUTTONDOWN or SDL_MOUSEBUTTONUP */
	Uint8 which;	/* The mouse device index */
	Uint8 button;	/* The mouse button index */
	Uint8 state;	/* SDL_PRESSED or SDL_RELEASED */
	Uint16 x, y;	/* The X/Y coordinates of the mouse at press time */
} SDL_MouseButtonEvent;

/* Joystick axis motion event structure */
typedef struct SDL_JoyAxisEvent {
	Uint8 type;	/* SDL_JOYAXISMOTION */
	Uint8 which;	/* The joystick device index */
	Uint8 axis;	/* The joystick axis index */
	Sint16 value;	/* The axis value (range: -32768 to 32767) */
} SDL_JoyAxisEvent;

/* Joystick trackball motion event structure */
typedef struct SDL_JoyBallEvent {
	Uint8 type;	/* SDL_JOYBALLMOTION */
	Uint8 which;	/* The joystick device index */
	Uint8 ball;	/* The joystick trackball index */
	Sint16 xrel;	/* The relative motion in the X direction */
	Sint16 yrel;	/* The relative motion in the Y direction */
} SDL_JoyBallEvent;

/* Joystick hat position change event structure */
typedef struct SDL_JoyHatEvent {
	Uint8 type;	/* SDL_JOYHATMOTION */
	Uint8 which;	/* The joystick device index */
	Uint8 hat;	/* The joystick hat index */
	Uint8 value;	/* The hat position value:
			    SDL_HAT_LEFTUP   SDL_HAT_UP       SDL_HAT_RIGHTUP
			    SDL_HAT_LEFT     SDL_HAT_CENTERED SDL_HAT_RIGHT
			    SDL_HAT_LEFTDOWN SDL_HAT_DOWN     SDL_HAT_RIGHTDOWN
			   Note that zero means the POV is centered.
			*/
} SDL_JoyHatEvent;

/* Joystick button event structure */
typedef struct SDL_JoyButtonEvent {
	Uint8 type;	/* SDL_JOYBUTTONDOWN or SDL_JOYBUTTONUP */
	Uint8 which;	/* The joystick device index */
	Uint8 button;	/* The joystick button index */
	Uint8 state;	/* SDL_PRESSED or SDL_RELEASED */
} SDL_JoyButtonEvent;

/* The "window resized" event
   When you get this event, you are responsible for setting a new video
   mode with the new width and height.
 */
typedef struct SDL_ResizeEvent {
	Uint8 type;	/* SDL_VIDEORESIZE */
	int w;		/* New width */
	int h;		/* New height */
} SDL_ResizeEvent;

/* The "screen redraw" event */
typedef struct SDL_ExposeEvent {
	Uint8 type;	/* SDL_VIDEOEXPOSE */
} SDL_ExposeEvent;

/* The "quit requested" event */
typedef struct SDL_QuitEvent {
	Uint8 type;	/* SDL_QUIT */
} SDL_QuitEvent;

/* A user-defined event type */
typedef struct SDL_UserEvent {
	Uint8 type;	/* SDL_USEREVENT through SDL_NUMEVENTS-1 */
	int code;	/* User defined event code */
	void *data1;	/* User defined data pointer */
	void *data2;	/* User defined data pointer */
} SDL_UserEvent;

/* If you want to use this event, you should include SDL_syswm.h */
struct SDL_SysWMmsg;
typedef struct SDL_SysWMmsg SDL_SysWMmsg;
typedef struct SDL_SysWMEvent {
	Uint8 type;
	SDL_SysWMmsg *msg;
} SDL_SysWMEvent;

/* General event structure */
typedef union SDL_Event {
	Uint8 type;
	SDL_ActiveEvent active;
	SDL_KeyboardEvent key;
	SDL_MouseMotionEvent motion;
	SDL_MouseButtonEvent button;
	SDL_JoyAxisEvent jaxis;
	SDL_JoyBallEvent jball;
	SDL_JoyHatEvent jhat;
	SDL_JoyButtonEvent jbutton;
	SDL_ResizeEvent resize;
	SDL_ExposeEvent expose;
	SDL_QuitEvent quit;
	SDL_UserEvent user;
	SDL_SysWMEvent syswm;
} SDL_Event;


/* Function prototypes */

/* Pumps the event loop, gathering events from the input devices.
   This function updates the event queue and internal input device state.
   This should only be run in the thread that sets the video mode.
*/
extern DECLSPEC void SDLCALL SDL_PumpEvents(void);

/* Checks the event queue for messages and optionally returns them.
   If 'action' is SDL_ADDEVENT, up to 'numevents' events will be added to
   the back of the event queue.
   If 'action' is SDL_PEEKEVENT, up to 'numevents' events at the front
   of the event queue, matching 'mask', will be returned and will not
   be removed from the queue.
   If 'action' is SDL_GETEVENT, up to 'numevents' events at the front 
   of the event queue, matching 'mask', will be returned and will be
   removed from the queue.
   This function returns the number of events actually stored, or -1
   if there was an error.  This function is thread-safe.
*/
typedef enum {
	SDL_ADDEVENT,
	SDL_PEEKEVENT,
	SDL_GETEVENT
} SDL_eventaction;
/* */
extern DECLSPEC int SDLCALL SDL_PeepEvents(SDL_Event *events, int numevents,
				SDL_eventaction action, Uint32 mask);

/* Polls for currently pending events, and returns 1 if there are any pending
   events, or 0 if there are none available.  If 'event' is not NULL, the next
   event is removed from the queue and stored in that area.
 */
extern DECLSPEC int SDLCALL SDL_PollEvent(SDL_Event *event);

/* Waits indefinitely for the next available event, returning 1, or 0 if there
   was an error while waiting for events.  If 'event' is not NULL, the next
   event is removed from the queue and stored in that area.
 */
extern DECLSPEC int SDLCALL SDL_WaitEvent(SDL_Event *event);

/* Add an event to the event queue.
   This function returns 0 on success, or -1 if the event queue was full
   or there was some other error.
 */
extern DECLSPEC int SDLCALL SDL_PushEvent(SDL_Event *event);

/*
  This function sets up a filter to process all events before they
  change internal state and are posted to the internal event queue.

  The filter is protypted as:
*/
typedef int (SDLCALL *SDL_EventFilter)(const SDL_Event *event);
/*
  If the filter returns 1, then the event will be added to the internal queue.
  If it returns 0, then the event will be dropped from the queue, but the 
  internal state will still be updated.  This allows selective filtering of
  dynamically arriving events.

  WARNING:  Be very careful of what you do in the event filter function, as 
            it may run in a different thread!

  There is one caveat when dealing with the SDL_QUITEVENT event type.  The
  event filter is only called when the window manager desires to close the
  application window.  If the event filter returns 1, then the window will
  be closed, otherwise the window will remain open if possible.
  If the quit event is generated by an interrupt signal, it will bypass the
  internal queue and be delivered to the application at the next event poll.
*/
extern DECLSPEC void SDLCALL SDL_SetEventFilter(SDL_EventFilter filter);

/*
  Return the current event filter - can be used to "chain" filters.
  If there is no event filter set, this function returns NULL.
*/
extern DECLSPEC SDL_EventFilter SDLCALL SDL_GetEventFilter(void);

/*
  This function allows you to set the state of processing certain events.
  If 'state' is set to SDL_IGNORE, that event will be automatically dropped
  from the event queue and will not event be filtered.
  If 'state' is set to SDL_ENABLE, that event will be processed normally.
  If 'state' is set to SDL_QUERY, SDL_EventState() will return the 
  current processing state of the specified event.
*/
#define SDL_QUERY	-1
#define SDL_IGNORE	 0
#define SDL_DISABLE	 0
#define SDL_ENABLE	 1
extern DECLSPEC Uint8 SDLCALL SDL_EventState(Uint8 type, int state);


/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include "close_code.h"

#endif /* _SDL_events_h */