annotate docs/man3/SDL_SetTimer.3 @ 4223:63fd67e17705 SDL-1.2

Fixed bug #727 Lorenzo Desole 2009-04-19 07:36:10 PDT I am one of the developers of a multimedia application (My Media System MMS), which uses SDL. MMS is normally running in fullscreen mode but it switches it off before launching external applications (mplayer, xine, etc.). The problem with fullscreen is that when the latter is switched off either via SDL_WM_ToggleFullScreen() or SDL_SetVideoMode(), SDL compares the current screen sizes with the ones saved when the video system was initted, and if they don't match, it calls XF86VidModeSwitchToMode() to switch to the old modeline. This makes it impossible for external programs and for MMS itself to use RandR to change the screen size, because next time fullscreen mode is turned off, it bombs out with the following error: X Error of failed request: BadValue (integer parameter out of range for operation) Major opcode of failed request: 136 (XFree86-VidModeExtension) Minor opcode of failed request: 10 (XF86VidModeSwitchToMode) [...] Obviously this happens only if the new screen resolution is smaller than the original one and XF86VidModeSwitchToMode() can't succeed. I couldn't find any way to inform SDL that the screen resolution it uses as reference is no longer valid. This can be fixed by adding "save_mode(this)" to ./src/video/x11/SDL_x11modes.c, API X11_EnterFullScreen(_THIS), like this: int X11_EnterFullScreen(_THIS) { int okay; + save_mode(this); I can't rule out possible side effects, but I don't see any. While I admit this is a minor issue for the general users, it is a major showstopper for our program where the ability to change screen resolution and refresh rate according to the movie being played, is very important. Thanks in advance.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 11:14:36 +0000
parents 4e3b250c950e
children 1238da4a7112
rev   line source
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1 .TH "SDL_SetTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_SetTimer \- Set a callback to run after the specified number of milliseconds has elapsed\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 .sp
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8 \fBint \fBSDL_SetTimer\fP\fR(\fBUint32 interval, SDL_TimerCallback callback\fR);
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9 .SH "CALLBACK"
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10 .PP
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11 /* Function prototype for the timer callback function */ typedef Uint32 (*SDL_TimerCallback)(Uint32 interval);
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12 .SH "DESCRIPTION"
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13 .PP
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14 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\&.
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15 .PP
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16 To cancel a currently running timer, call \fBSDL_SetTimer(0, NULL);\fP
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17 .PP
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18 The timer callback function may run in a different thread than your main constant, and so shouldn\&'t call any functions from within itself\&.
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19 .PP
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20 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 (see example below)\&.
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21 .PP
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22 If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fBSDL_Init()\fP\&.
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23 .PP
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24 .RS
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25 \fBNote:
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26 .PP
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27 This function is kept for compatibility but has been superseded by the new timer functions \fISDL_AddTimer\fR and \fISDL_RemoveTimer\fR which support multiple timers\&.
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28 .RE
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29 .SH "EXAMPLES"
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30 .PP
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31 .PP
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32 .nf
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33 \f(CWSDL_SetTimer((33/10)*10, my_callback);\fR
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34 .fi
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35 .PP
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36 .SH "SEE ALSO"
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37 .PP
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38 \fI\fBSDL_AddTimer\fP\fR
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39 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01