Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetTimer.3 @ 4168:69bcba65c388 SDL-1.2
Fixed bug #526
Comment #1 From Simon Howard 2009-03-20 16:50:56
Hi,
I'm the author of Chocolate Doom, one of the other source ports that James
mentioned. This is a patch against the current SVN version of SDL 1.2 that
fixes the bug. It has been tested and hopefully should be obviously correct
from examining the changes. I'll give a brief explanation.
When the palette is set with SDL_SetPalette, the IDirectDrawPalette_SetEntries
DirectX function is invoked. However, when this happens, a WM_PALETTECHANGED
message is sent to the window.
A WM_PALETTECHANGED message can also be received if the palette is changed for
some other reason, like if the system palette is changed. Therefore, the
palette change handler (DX5_PaletteChanged) has code to deal with this case.
It distinguishes "expected" palette changes (set with SDL_SetPalette) from
"unexpected" palette changes using the colorchange_expected variable, which is
set before calling IDirectDrawPalette_SetEntries. However, the code to set
this variable is missing in the fullscreen code path. By setting this
variable, the palette change is handled properly and the freezes go away.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 13 Apr 2009 00:53:12 +0000 |
parents | 4e3b250c950e |
children | 1238da4a7112 |
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.TH "SDL_SetTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetTimer \- Set a callback to run after the specified number of milliseconds has elapsed\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_SetTimer\fP\fR(\fBUint32 interval, SDL_TimerCallback callback\fR); .SH "CALLBACK" .PP /* Function prototype for the timer callback function */ typedef Uint32 (*SDL_TimerCallback)(Uint32 interval); .SH "DESCRIPTION" .PP 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\&. .PP To cancel a currently running timer, call \fBSDL_SetTimer(0, NULL);\fP .PP The timer callback function may run in a different thread than your main constant, and so shouldn\&'t call any functions from within itself\&. .PP 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)\&. .PP If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fBSDL_Init()\fP\&. .PP .RS \fBNote: .PP 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\&. .RE .SH "EXAMPLES" .PP .PP .nf \f(CWSDL_SetTimer((33/10)*10, my_callback);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_AddTimer\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01