view docs/man3/SDL_AddTimer.3 @ 3335:b8d313de8a65

Adam Strzelecki to SDL Since current DirectFB implementation is incomplete for YUV surfaces (actually causes segmentation faults when trying Lock and use YUV planar textures) I decided to fix it a bit. Here's a patch that should make DirectFB properly support YUV both packed and planar (3 planes). (1) Removed SDL_BYTESPERPIXEL at all in favor of DFB_BYTES_PER_PIXEL(SDLToDFBPixelFormat(fmt)) which does return always proper BPP for YUVs too, coz SDL_BYTESPERPIXEL returns incorrect values for FOURCCs (2) Fixed data->pixels allocation for planar YUVs in CreateTexture, it should allocate 150% more space (3) Copy other planes for planar YUVs in UpdateTexture (4) Moved checking if format is supported at all with DirectFB on CreateTexture at the beginning of the code Waiting for comments, -- Adam Strzelecki | nanoant.com
author Sam Lantinga <slouken@libsdl.org>
date Sun, 04 Oct 2009 04:03:37 +0000
parents 546f7c1eb755
children 1238da4a7112
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.TH "SDL_AddTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_AddTimer \- Add a timer which will call a callback after the specified number of milliseconds has elapsed\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBSDL_TimerID \fBSDL_AddTimer\fP\fR(\fBUint32 interval, SDL_NewTimerCallback callback, void *param\fR);
.SH "CALLBACK"
.PP
.nf
\f(CW/* type definition for the "new" timer callback function */
typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);\fR
.fi
.PP
.SH "DESCRIPTION"
.PP
Adds a callback function to be run after the specified number of milliseconds has elapsed\&. The callback function is passed the current timer interval and the user supplied parameter from the \fBSDL_AddTimer\fP call and returns the next timer interval\&. If the returned value from the callback is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled\&.
.PP
To cancel a currently running timer call \fISDL_RemoveTimer\fR with the timer ID returned from \fBSDL_AddTimer\fP\&.
.PP
The timer callback function may run in a different thread than your main program, and so shouldn\&'t call any functions from within itself\&. You may always call \fISDL_PushEvent\fR, however\&.
.PP
The granularity of the timer is platform-dependent, but you should count on it being at least 10 ms as this is the most common number\&. This 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)\&. If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fISDL_Init\fR\&.
.SH "RETURN VALUE"
.PP
Returns an ID value for the added timer or \fBNULL\fR if there was an error\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWmy_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_RemoveTimer\fP\fR, \fI\fBSDL_PushEvent\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01