view src/main/win32/SDL_win32_main.c @ 942:41a59de7f2ed

Here are patches for SDL12 and SDL_mixer for 4 or 6 channel surround sound on Linux using the Alsa driver. To use them, naturally you need a sound card that will do 4 or 6 channels and probably also a recent version of the Alsa drivers and library. Since the only SDL output driver that knows about surround sound is the Alsa driver, you���ll want to choose it, using: export SDL_AUDIODRIVER=alsa There are no syntactic changes to the programming API. No new library calls, no differences in arguments. There are two semantic changes: (1) For library calls with number of channels as an argument, formerly you could use only 1 or 2 for the number of channels. Now you can also use 4 or 6. (2) The two "left" and "right" arguments to Mix_SetPanning, for the case of 4 or 6 channels, no longer simply control the volumes of the left and right channels. Now the "left" argument is converted to an angle and Mix_SetPosition is called, and the "right" argu- ment is ignored. With two exceptions, so far as I know, the modified SDL12 and SDL_mixer work the same way as the original versions, when opened for 1 or 2 channel output. The two exceptions are bugs which I fixed. Well, the first, anyway, is a bug for sure. When rate conversions up or down by a factor of two are applied (in src/audio/SDL_audiocvt.c), streams with different numbers of channels (that is, mono and stereo) are treated the same way: either each sample is copied or every other sample is omitted. This is ok for mono, but for stereo, it is frames that should be copied or omitted, where by "frame" I mean a portion of the stream containing one sample for each channel. (In the SDL source, confusingly, sometimes frames are called "samples".) So for these rate conversions, stereo streams have to be treated differently, and they are, in my modified version. The other problem that might be characterized as a bug arises when SDL_mixer is passed a multichannel chunk which does not have an integral number of frames. Due to the way the effect_position code loops over frames, when the chunk ends with a partial frame, memory outside the chunk buffer will be accessed. In the case of stereo, it���s possible that because malloc may give more memory than requested, this potential problem never actually causes a segment fault. I don���t know. For 6 channel chunks, I do know, and it does cause segment faults. If SDL_mixer is passed defective chunks and this causes a segment fault, arguably, that���s not a bug in SDL_mixer. Still, whether or not it counts as a bug, it���s easy to protect against, so why not? I added code in mixer.c to discard any partial frame at the end of a chunk. Then what about when SDL or SDL_mixer is opened for 4 or 6 chan- nel output? What happens with the parts of the current library designed for stereo? I don���t know whether I���ve covered all the bases, but I���ve tried: (1) For playing 2 channel waves, or other cases where SDL knows it has to match up a 2 channel source with a 4 or 6 channel output, I���ve added code in SDL_audiocvt.c to make the necessary conversions. (2) For playing midis using timidity, I���ve converted timidity to do 4 or 6 channel output, upon request. (3) For playing mods using mikmod, I put ad hoc code in music.c to convert the stereo output that mikmod produces to 4 or 6 chan- nels. Obviously it would be better to change the mikmod code to mix down into 4 or 6 channels, but I have a hard time following the code in mikmod, so I didn���t do that. (4) For playing mp3s, I put ad hoc code in smpeg to copy channels in the case when 4 or 6 channel output is needed. (5) There seems to be no problem with .ogg files - stereo .oggs can be up converted as .wavs are. (6) The effect_position code in SDL_mixer is now generalized to in- clude the cases of 4 and 6 channel streams. I���ve done a very limited amount of compatibility testing for some of the games using SDL I happen to have. For details, see the file TESTS. I���ve put into a separate archive, Surround-SDL-testfiles.tgz, a couple of 6 channel wave files for testing and a 6 channel ogg file. If you have the right hardware and version of Alsa, you should be able to play the wave files with the Alsa utility aplay (and hear all channels, except maybe lfe, for chan-id.wav, since it���s rather faint). Don���t expect aplay to give good sound, though. There���s something wrong with the current version of aplay. The canyon.ogg file is to test loading of 6 channel oggs. After patching and compiling, you can play it with playmus. (My version of ogg123 will not play it, and I had to patch mplayer to get it to play 6 channel oggs.) Greg Lee <greg@ling.lll.hawaii.edu> Thus, July 1, 2004
author Sam Lantinga <slouken@libsdl.org>
date Sat, 21 Aug 2004 12:27:02 +0000
parents ed57c876700d
children d7bca8c8161e
line wrap: on
line source

/*
    SDL_main.c, placed in the public domain by Sam Lantinga  4/13/98

    The WinMain function -- calls your program's main() function
*/

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#include <stdlib.h>

#include <windows.h>
#include <malloc.h>			/* For _alloca() */

#ifdef _WIN32_WCE
# define DIR_SEPERATOR TEXT("\\")
# undef _getcwd
# define _getcwd(str,len)	wcscpy(str,TEXT(""))
# define setbuf(f,b)
# define setvbuf(w,x,y,z)
# define fopen		_wfopen
# define freopen	_wfreopen
# define remove(x)	DeleteFile(x)
# define strcat		wcscat
#else
# define DIR_SEPERATOR TEXT("/")
# include <direct.h>
#endif

/* Include the SDL main definition header */
#include "SDL.h"
#include "SDL_main.h"

#ifdef main
# ifndef _WIN32_WCE_EMULATION
#  undef main
# endif /* _WIN32_WCE_EMULATION */
#endif /* main */

/* The standard output files */
#define STDOUT_FILE	TEXT("stdout.txt")
#define STDERR_FILE	TEXT("stderr.txt")

#ifndef NO_STDIO_REDIRECT
# ifdef _WIN32_WCE
  static wchar_t stdoutPath[MAX_PATH];
  static wchar_t stderrPath[MAX_PATH];
# else
  static char stdoutPath[MAX_PATH];
  static char stderrPath[MAX_PATH];
# endif
#endif

#if defined(_WIN32_WCE) && _WIN32_WCE < 300
/* seems to be undefined in Win CE although in online help */
#define isspace(a) (((CHAR)a == ' ') || ((CHAR)a == '\t'))

/* seems to be undefined in Win CE although in online help */
char *strrchr(char *str, int c)
{
	char *p;

	/* Skip to the end of the string */
	p=str;
	while (*p)
		p++;

	/* Look for the given character */
	while ( (p >= str) && (*p != (CHAR)c) )
		p--;

	/* Return NULL if character not found */
	if ( p < str ) {
		p = NULL;
	}
	return p;
}
#endif /* _WIN32_WCE < 300 */

/* Parse a command line buffer into arguments */
static int ParseCommandLine(char *cmdline, char **argv)
{
	char *bufp;
	int argc;

	argc = 0;
	for ( bufp = cmdline; *bufp; ) {
		/* Skip leading whitespace */
		while ( isspace(*bufp) ) {
			++bufp;
		}
		/* Skip over argument */
		if ( *bufp == '"' ) {
			++bufp;
			if ( *bufp ) {
				if ( argv ) {
					argv[argc] = bufp;
				}
				++argc;
			}
			/* Skip over word */
			while ( *bufp && (*bufp != '"') ) {
				++bufp;
			}
		} else {
			if ( *bufp ) {
				if ( argv ) {
					argv[argc] = bufp;
				}
				++argc;
			}
			/* Skip over word */
			while ( *bufp && ! isspace(*bufp) ) {
				++bufp;
			}
		}
		if ( *bufp ) {
			if ( argv ) {
				*bufp = '\0';
			}
			++bufp;
		}
	}
	if ( argv ) {
		argv[argc] = NULL;
	}
	return(argc);
}

/* Show an error message */
static void ShowError(const char *title, const char *message)
{
/* If USE_MESSAGEBOX is defined, you need to link with user32.lib */
#ifdef USE_MESSAGEBOX
	MessageBox(NULL, message, title, MB_ICONEXCLAMATION|MB_OK);
#else
	fprintf(stderr, "%s: %s\n", title, message);
#endif
}

/* Pop up an out of memory message, returns to Windows */
static BOOL OutOfMemory(void)
{
	ShowError("Fatal Error", "Out of memory - aborting");
	return FALSE;
}

/* Remove the output files if there was no output written */
static void __cdecl cleanup_output(void)
{
#ifndef NO_STDIO_REDIRECT
	FILE *file;
	int empty;
#endif

	/* Flush the output in case anything is queued */
	fclose(stdout);
	fclose(stderr);

#ifndef NO_STDIO_REDIRECT
	/* See if the files have any output in them */
	if ( stdoutPath[0] ) {
		file = fopen(stdoutPath, TEXT("rb"));
		if ( file ) {
			empty = (fgetc(file) == EOF) ? 1 : 0;
			fclose(file);
			if ( empty ) {
				remove(stdoutPath);
			}
		}
	}
	if ( stderrPath[0] ) {
		file = fopen(stderrPath, TEXT("rb"));
		if ( file ) {
			empty = (fgetc(file) == EOF) ? 1 : 0;
			fclose(file);
			if ( empty ) {
				remove(stderrPath);
			}
		}
	}
#endif
}

#if defined(_MSC_VER) && !defined(_WIN32_WCE)
/* The VC++ compiler needs main defined */
#define console_main main
#endif

/* This is where execution begins [console apps] */
int console_main(int argc, char *argv[])
{
	int n;
	char *bufp, *appname;

	/* Get the class name from argv[0] */
	appname = argv[0];
	if ( (bufp=strrchr(argv[0], '\\')) != NULL ) {
		appname = bufp+1;
	} else
	if ( (bufp=strrchr(argv[0], '/')) != NULL ) {
		appname = bufp+1;
	}

	if ( (bufp=strrchr(appname, '.')) == NULL )
		n = strlen(appname);
	else
		n = (bufp-appname);

	bufp = (char *)alloca(n+1);
	if ( bufp == NULL ) {
		return OutOfMemory();
	}
	strncpy(bufp, appname, n);
	bufp[n] = '\0';
	appname = bufp;

	/* Load SDL dynamic link library */
	if ( SDL_Init(SDL_INIT_NOPARACHUTE) < 0 ) {
		ShowError("WinMain() error", SDL_GetError());
		return(FALSE);
	}
	atexit(cleanup_output);
	atexit(SDL_Quit);

#ifndef DISABLE_VIDEO
#if 0
	/* Create and register our class *
	   DJM: If we do this here, the user nevers gets a chance to
	   putenv(SDL_WINDOWID).  This is already called later by
	   the (DIB|DX5)_CreateWindow function, so it should be
	   safe to comment it out here.
	if ( SDL_RegisterApp(appname, CS_BYTEALIGNCLIENT, 
	                     GetModuleHandle(NULL)) < 0 ) {
		ShowError("WinMain() error", SDL_GetError());
		exit(1);
	}*/
#else
	/* Sam:
	   We still need to pass in the application handle so that
	   DirectInput will initialize properly when SDL_RegisterApp()
	   is called later in the video initialization.
	 */
	SDL_SetModuleHandle(GetModuleHandle(NULL));
#endif /* 0 */
#endif /* !DISABLE_VIDEO */

	/* Run the application main() code */
	SDL_main(argc, argv);

	/* Exit cleanly, calling atexit() functions */
	exit(0);

	/* Hush little compiler, don't you cry... */
	return(0);
}

/* This is where execution begins [windowed apps] */
#ifdef _WIN32_WCE
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPWSTR szCmdLine, int sw)
#else
int WINAPI WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int sw)
#endif
{
	HINSTANCE handle;
	char **argv;
	int argc;
	char *cmdline;
#ifdef _WIN32_WCE
	wchar_t *bufp;
	int nLen;
#else
	char *bufp;
#endif
#ifndef NO_STDIO_REDIRECT
	FILE *newfp;
#endif

	/* Start up DDHELP.EXE before opening any files, so DDHELP doesn't
	   keep them open.  This is a hack.. hopefully it will be fixed 
	   someday.  DDHELP.EXE starts up the first time DDRAW.DLL is loaded.
	 */
	handle = LoadLibrary(TEXT("DDRAW.DLL"));
	if ( handle != NULL ) {
		FreeLibrary(handle);
	}

#ifndef NO_STDIO_REDIRECT
	_getcwd( stdoutPath, sizeof( stdoutPath ) );
	strcat( stdoutPath, DIR_SEPERATOR STDOUT_FILE );
    
	/* Redirect standard input and standard output */
	newfp = freopen(stdoutPath, TEXT("w"), stdout);

#ifndef _WIN32_WCE
	if ( newfp == NULL ) {	/* This happens on NT */
#if !defined(stdout)
		stdout = fopen(stdoutPath, TEXT("w"));
#else
		newfp = fopen(stdoutPath, TEXT("w"));
		if ( newfp ) {
			*stdout = *newfp;
		}
#endif
	}
#endif /* _WIN32_WCE */

	_getcwd( stderrPath, sizeof( stderrPath ) );
	strcat( stderrPath, DIR_SEPERATOR STDERR_FILE );

	newfp = freopen(stderrPath, TEXT("w"), stderr);
#ifndef _WIN32_WCE
	if ( newfp == NULL ) {	/* This happens on NT */
#if !defined(stderr)
		stderr = fopen(stderrPath, TEXT("w"));
#else
		newfp = fopen(stderrPath, TEXT("w"));
		if ( newfp ) {
			*stderr = *newfp;
		}
#endif
	}
#endif /* _WIN32_WCE */

	setvbuf(stdout, NULL, _IOLBF, BUFSIZ);	/* Line buffered */
	setbuf(stderr, NULL);			/* No buffering */
#endif /* !NO_STDIO_REDIRECT */

#ifdef _WIN32_WCE
	nLen = wcslen(szCmdLine)+128+1;
	bufp = (wchar_t *)alloca(nLen*2);
	wcscpy (bufp, TEXT("\""));
	GetModuleFileName(NULL, bufp+1, 128-3);
	wcscpy (bufp+wcslen(bufp), TEXT("\" "));
	wcsncpy(bufp+wcslen(bufp), szCmdLine,nLen-wcslen(bufp));
	nLen = wcslen(bufp)+1;
	cmdline = (char *)alloca(nLen);
	if ( cmdline == NULL ) {
		return OutOfMemory();
	}
	WideCharToMultiByte(CP_ACP, 0, bufp, -1, cmdline, nLen, NULL, NULL);
#else
	/* Grab the command line (use alloca() on Windows) */
	bufp = GetCommandLine();
	cmdline = (char *)alloca(strlen(bufp)+1);
	if ( cmdline == NULL ) {
		return OutOfMemory();
	}
	strcpy(cmdline, bufp);
#endif

	/* Parse it into argv and argc */
	argc = ParseCommandLine(cmdline, NULL);
	argv = (char **)alloca((argc+1)*(sizeof *argv));
	if ( argv == NULL ) {
		return OutOfMemory();
	}
	ParseCommandLine(cmdline, argv);

	/* Run the main program (after a little SDL initialization) */
	return(console_main(argc, argv));
}