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Fixed bug #46 Date: Fri, 13 Jan 2006 18:09:45 -0500 From: mhall4400 vipmail kvcc edu Subject: Possible SDL bug Greetings I believe Ive come across a bug in your SDL product (1.2.9), in the CD-ROM control portion of the library. When calling the SDL_CDPlay() function to play the last track of a CD using the offset and length from an SDL_CD structure generated by SDL_CDOpen(), I get the following error from a call to SDL_Error(): mciSendCommand() error: The specified parameter is out of range for the specified command. The code returning the error is: SDL_CDPlay(g_playingDriveSDLCD, g_playingDriveSDLCD->track[trackNumberInt].offset, g_playingDriveSDLCD->track[trackNumberInt].length) Subtracting one from the length of the provided length seems to repair the problem: SDL_CDPlay(g_playingDriveSDLCD, g_playingDriveSDLCD->track[trackNumberInt].offset, (g_playingDriveSDLCD->track[trackNumberInt].length) - 1) Ive replicated this problem on Windows 98 SE (several months since last patch), fully-patched Window ME, seldom-patched Windows XP SP1, and fully-patched Windows XP SP2. While investigating the issue, I came across a line in your librarys win32 source code in file \src\cdrom\win32\SDL_syscdrom.c (source code zip archive from your download page), function: SDL_SYS_CDGetTOC(), line 226 where you add 1 to the value for length to fix MCI last track length bug. This may be the source of the issue (because subtracting 1 from the length seems to resolve the issue). Microsoft may have patched the referenced bug since you wrote that line. Mike Hall
author Sam Lantinga <slouken@libsdl.org>
date Tue, 14 Mar 2006 05:34:39 +0000
parents 355632dca928
children
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>Time based game loop</H2
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>#define TICK_INTERVAL    30

static Uint32 next_time;

Uint32 time_left(void)
{
    Uint32 now;

    now = SDL_GetTicks();
    if(next_time &#60;= now)
        return 0;
    else
        return next_time - now;
}


/* main game loop */

    next_time = SDL_GetTicks() + TICK_INTERVAL;
    while ( game_running ) {
        update_game_state();
        SDL_Delay(time_left());
        next_time += TICK_INTERVAL;
    }&#13;</PRE
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