view include/SDL_timer.h @ 1259:36f24cdfcda7

te: Thu, 17 Apr 2003 11:25:26 -0700 From: "Jim" Subject: [SDL] Frame buffer patches... Would seem that GCC 3.2.2 promotes all signed values to unsigned if any single vlaue is unsigned in an expression... for instance when calculating an elo touch position....evertyhign is an (int) except for cach_vinfo.xres which is unsigned. THerefore if y ou reverse the SDL_ELO_MIN_X and SDL_ELO_MAX_X values the resulging negative value pegs the expression to it's max. Attached it the accumu lated patch to typecast the unsigned values to (int) - *dx = (cache_vinfo.xres - (cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); + *dx = ((int)cache_vinfo.xres - ((int)cache_vinfo.xres * (input_x - ELO_MIN_X)) / width); and also to provide quite failure to operations which have the screen currently locked... The touch screen I'm using the original values were exactly opposite of any position I touched on the screen - evaluating the math the expr ession SHOULD have handled reversing the min and max values - and after casting the unsigned .xres and .yres to a signed int - worked well. .. Jim
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Jan 2006 06:36:43 +0000
parents 5ba65305c954
children c9b51268668f
line wrap: on
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

#ifndef _SDL_timer_h
#define _SDL_timer_h

/* Header for the SDL time management routines */

#include "SDL_main.h"
#include "SDL_types.h"

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

/* This is the OS scheduler timeslice, in milliseconds */
#define SDL_TIMESLICE		10

/* This is the maximum resolution of the SDL timer on all platforms */
#define TIMER_RESOLUTION	10	/* Experimentally determined */

/* Get the number of milliseconds since the SDL library initialization.
 * Note that this value wraps if the program runs for more than ~49 days.
 */ 
extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void);

/* Wait a specified number of milliseconds before returning */
extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms);

/* Function prototype for the timer callback function */
typedef Uint32 (SDLCALL *SDL_TimerCallback)(Uint32 interval);

/* Set a callback to run after the specified number of milliseconds has
 * elapsed. The callback function is passed the current timer interval
 * and returns the next timer interval.  If the returned value is the 
 * same as the one passed in, the periodic alarm continues, otherwise a
 * new alarm is scheduled.  If the callback returns 0, the periodic alarm
 * is cancelled.
 *
 * To cancel a currently running timer, call SDL_SetTimer(0, NULL);
 *
 * The timer callback function may run in a different thread than your
 * main code, and so shouldn't call any functions from within itself.
 *
 * The maximum resolution of this timer is 10 ms, which means that if
 * you request a 16 ms timer, your callback will run approximately 20 ms
 * later on an unloaded system.  If you wanted to set a flag signaling
 * a frame update at 30 frames per second (every 33 ms), you might set a 
 * timer for 30 ms:
 *   SDL_SetTimer((33/10)*10, flag_update);
 *
 * If you use this function, you need to pass SDL_INIT_TIMER to SDL_Init().
 *
 * Under UNIX, you should not use raise or use SIGALRM and this function
 * in the same program, as it is implemented using setitimer().  You also
 * should not use this function in multi-threaded applications as signals
 * to multi-threaded apps have undefined behavior in some implementations.
 *
 * This function returns 0 if successful, or -1 if there was an error.
 */
extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval, SDL_TimerCallback callback);

/* New timer API, supports multiple timers
 * Written by Stephane Peter <megastep@lokigames.com>
 */

/* Function prototype for the new timer callback function.
 * The callback function is passed the current timer interval and returns
 * the next timer interval.  If the returned value is the same as the one
 * passed in, the periodic alarm continues, otherwise a new alarm is
 * scheduled.  If the callback returns 0, the periodic alarm is cancelled.
 */
typedef Uint32 (SDLCALL *SDL_NewTimerCallback)(Uint32 interval, void *param);

/* Definition of the timer ID type */
typedef struct _SDL_TimerID *SDL_TimerID;

/* Add a new timer to the pool of timers already running.
   Returns a timer ID, or NULL when an error occurs.
 */
extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param);

/* Remove one of the multiple timers knowing its ID.
 * Returns a boolean value indicating success.
 */
extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t);

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

#endif /* _SDL_timer_h */