view src/SDL.c @ 4216:5b99971a27b4 SDL-1.2

Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 09:27:08 +0000
parents a1b03ba2fcd0
children
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Initialization code for SDL */

#include "SDL.h"
#include "SDL_fatal.h"
#if !SDL_VIDEO_DISABLED
#include "video/SDL_leaks.h"
#endif

#if SDL_THREAD_PTH
#include <pth.h>
#endif

/* Initialization/Cleanup routines */
#if !SDL_JOYSTICK_DISABLED
extern int  SDL_JoystickInit(void);
extern void SDL_JoystickQuit(void);
#endif
#if !SDL_CDROM_DISABLED
extern int  SDL_CDROMInit(void);
extern void SDL_CDROMQuit(void);
#endif
#if !SDL_TIMERS_DISABLED
extern void SDL_StartTicks(void);
extern int  SDL_TimerInit(void);
extern void SDL_TimerQuit(void);
#endif

/* The current SDL version */
static SDL_version version = 
	{ SDL_MAJOR_VERSION, SDL_MINOR_VERSION, SDL_PATCHLEVEL };

/* The initialized subsystems */
static Uint32 SDL_initialized = 0;
#if !SDL_TIMERS_DISABLED
static Uint32 ticks_started = 0;
#endif

#ifdef CHECK_LEAKS
int surfaces_allocated = 0;
#endif

int SDL_InitSubSystem(Uint32 flags)
{
#if !SDL_VIDEO_DISABLED
	/* Initialize the video/event subsystem */
	if ( (flags & SDL_INIT_VIDEO) && !(SDL_initialized & SDL_INIT_VIDEO) ) {
		if ( SDL_VideoInit(SDL_getenv("SDL_VIDEODRIVER"),
		                   (flags&SDL_INIT_EVENTTHREAD)) < 0 ) {
			return(-1);
		}
		SDL_initialized |= SDL_INIT_VIDEO;
	}
#else
	if ( flags & SDL_INIT_VIDEO ) {
		SDL_SetError("SDL not built with video support");
		return(-1);
	}
#endif

#if !SDL_AUDIO_DISABLED
	/* Initialize the audio subsystem */
	if ( (flags & SDL_INIT_AUDIO) && !(SDL_initialized & SDL_INIT_AUDIO) ) {
		if ( SDL_AudioInit(SDL_getenv("SDL_AUDIODRIVER")) < 0 ) {
			return(-1);
		}
		SDL_initialized |= SDL_INIT_AUDIO;
	}
#else
	if ( flags & SDL_INIT_AUDIO ) {
		SDL_SetError("SDL not built with audio support");
		return(-1);
	}
#endif

#if !SDL_TIMERS_DISABLED
	/* Initialize the timer subsystem */
	if ( ! ticks_started ) {
		SDL_StartTicks();
		ticks_started = 1;
	}
	if ( (flags & SDL_INIT_TIMER) && !(SDL_initialized & SDL_INIT_TIMER) ) {
		if ( SDL_TimerInit() < 0 ) {
			return(-1);
		}
		SDL_initialized |= SDL_INIT_TIMER;
	}
#else
	if ( flags & SDL_INIT_TIMER ) {
		SDL_SetError("SDL not built with timer support");
		return(-1);
	}
#endif

#if !SDL_JOYSTICK_DISABLED
	/* Initialize the joystick subsystem */
	if ( (flags & SDL_INIT_JOYSTICK) &&
	     !(SDL_initialized & SDL_INIT_JOYSTICK) ) {
		if ( SDL_JoystickInit() < 0 ) {
			return(-1);
		}
		SDL_initialized |= SDL_INIT_JOYSTICK;
	}
#else
	if ( flags & SDL_INIT_JOYSTICK ) {
		SDL_SetError("SDL not built with joystick support");
		return(-1);
	}
#endif

#if !SDL_CDROM_DISABLED
	/* Initialize the CD-ROM subsystem */
	if ( (flags & SDL_INIT_CDROM) && !(SDL_initialized & SDL_INIT_CDROM) ) {
		if ( SDL_CDROMInit() < 0 ) {
			return(-1);
		}
		SDL_initialized |= SDL_INIT_CDROM;
	}
#else
	if ( flags & SDL_INIT_CDROM ) {
		SDL_SetError("SDL not built with cdrom support");
		return(-1);
	}
#endif
	return(0);
}

int SDL_Init(Uint32 flags)
{
#if !SDL_THREADS_DISABLED && SDL_THREAD_PTH
	if (!pth_init()) {
		return -1;
	}
#endif

	/* Clear the error message */
	SDL_ClearError();

	/* Initialize the desired subsystems */
	if ( SDL_InitSubSystem(flags) < 0 ) {
		return(-1);
	}

	/* Everything is initialized */
	if ( !(flags & SDL_INIT_NOPARACHUTE) ) {
		SDL_InstallParachute();
	}
	return(0);
}

void SDL_QuitSubSystem(Uint32 flags)
{
	/* Shut down requested initialized subsystems */
#if !SDL_CDROM_DISABLED
	if ( (flags & SDL_initialized & SDL_INIT_CDROM) ) {
		SDL_CDROMQuit();
		SDL_initialized &= ~SDL_INIT_CDROM;
	}
#endif
#if !SDL_JOYSTICK_DISABLED
	if ( (flags & SDL_initialized & SDL_INIT_JOYSTICK) ) {
		SDL_JoystickQuit();
		SDL_initialized &= ~SDL_INIT_JOYSTICK;
	}
#endif
#if !SDL_TIMERS_DISABLED
	if ( (flags & SDL_initialized & SDL_INIT_TIMER) ) {
		SDL_TimerQuit();
		SDL_initialized &= ~SDL_INIT_TIMER;
	}
#endif
#if !SDL_AUDIO_DISABLED
	if ( (flags & SDL_initialized & SDL_INIT_AUDIO) ) {
		SDL_AudioQuit();
		SDL_initialized &= ~SDL_INIT_AUDIO;
	}
#endif
#if !SDL_VIDEO_DISABLED
	if ( (flags & SDL_initialized & SDL_INIT_VIDEO) ) {
		SDL_VideoQuit();
		SDL_initialized &= ~SDL_INIT_VIDEO;
	}
#endif
}

Uint32 SDL_WasInit(Uint32 flags)
{
	if ( ! flags ) {
		flags = SDL_INIT_EVERYTHING;
	}
	return (SDL_initialized&flags);
}

void SDL_Quit(void)
{
	/* Quit all subsystems */
#ifdef DEBUG_BUILD
  printf("[SDL_Quit] : Enter! Calling QuitSubSystem()\n"); fflush(stdout);
#endif
	SDL_QuitSubSystem(SDL_INIT_EVERYTHING);

#ifdef CHECK_LEAKS
#ifdef DEBUG_BUILD
  printf("[SDL_Quit] : CHECK_LEAKS\n"); fflush(stdout);
#endif

	/* Print the number of surfaces not freed */
	if ( surfaces_allocated != 0 ) {
		fprintf(stderr, "SDL Warning: %d SDL surfaces extant\n", 
							surfaces_allocated);
	}
#endif
#ifdef DEBUG_BUILD
  printf("[SDL_Quit] : SDL_UninstallParachute()\n"); fflush(stdout);
#endif

	/* Uninstall any parachute signal handlers */
	SDL_UninstallParachute();

#if !SDL_THREADS_DISABLED && SDL_THREAD_PTH
	pth_kill();
#endif
#ifdef DEBUG_BUILD
  printf("[SDL_Quit] : Returning!\n"); fflush(stdout);
#endif

}

/* Return the library version number */
const SDL_version * SDL_Linked_Version(void)
{
	return(&version);
}

#if defined(__OS2__)
/* Building for OS/2 */
#ifdef __WATCOMC__

#define INCL_DOSERRORS
#define INCL_DOSEXCEPTIONS
#include <os2.h>

/* Exception handler to prevent the Audio thread hanging, making a zombie process! */
ULONG _System SDL_Main_ExceptionHandler(PEXCEPTIONREPORTRECORD pERepRec,
                                        PEXCEPTIONREGISTRATIONRECORD pERegRec,
                                        PCONTEXTRECORD pCtxRec,
                                        PVOID p)
{
  if (pERepRec->fHandlerFlags & EH_EXIT_UNWIND)
    return XCPT_CONTINUE_SEARCH;
  if (pERepRec->fHandlerFlags & EH_UNWINDING)
    return XCPT_CONTINUE_SEARCH;
  if (pERepRec->fHandlerFlags & EH_NESTED_CALL)
    return XCPT_CONTINUE_SEARCH;

  /* Do cleanup at every fatal exception! */
  if (((pERepRec->ExceptionNum & XCPT_SEVERITY_CODE) == XCPT_FATAL_EXCEPTION) &&
      (pERepRec->ExceptionNum != XCPT_BREAKPOINT) &&
      (pERepRec->ExceptionNum != XCPT_SINGLE_STEP)
     )
  {
    if (SDL_initialized & SDL_INIT_AUDIO)
    {
      /* This removes the zombie audio thread in case of emergency. */
#ifdef DEBUG_BUILD
      printf("[SDL_Main_ExceptionHandler] : Calling SDL_CloseAudio()!\n");
#endif
      SDL_CloseAudio();
    }
  }
  return (XCPT_CONTINUE_SEARCH);
}


EXCEPTIONREGISTRATIONRECORD SDL_Main_xcpthand = {0, SDL_Main_ExceptionHandler};

/* The main DLL entry for DLL Initialization and Uninitialization: */
unsigned _System LibMain(unsigned hmod, unsigned termination)
{
  if (termination)
  {
#ifdef DEBUG_BUILD
/*    printf("[SDL DLL Unintialization] : Removing exception handler\n"); */
#endif
    DosUnsetExceptionHandler(&SDL_Main_xcpthand);
    return 1;
  } else
  {
#ifdef DEBUG_BUILD
    /* Make stdout and stderr unbuffered! */
    setbuf(stdout, NULL);
    setbuf(stderr, NULL);
#endif
    /* Fire up exception handler */
#ifdef DEBUG_BUILD
/*    printf("[SDL DLL Initialization] : Setting exception handler\n"); */
#endif
    /* Set exception handler */
    DosSetExceptionHandler(&SDL_Main_xcpthand);

    return 1;
  }
}
#endif /* __WATCOMC__ */

#elif defined(__WIN32__)  && !defined(__SYMBIAN32__)

#if !defined(HAVE_LIBC) || (defined(__WATCOMC__) && defined(BUILD_DLL))
/* Need to include DllMain() on Watcom C for some reason.. */
#define WIN32_LEAN_AND_MEAN
#include <windows.h>

BOOL APIENTRY _DllMainCRTStartup( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved )
{
	switch (ul_reason_for_call) {
		case DLL_PROCESS_ATTACH:
		case DLL_THREAD_ATTACH:
		case DLL_THREAD_DETACH:
		case DLL_PROCESS_DETACH:
			break;
	}
	return TRUE;
}
#endif /* building DLL with Watcom C */

#endif /* OS/2 elif __WIN32__ */