view src/cdrom/beos/SDL_syscdrom.cc @ 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 b8d311d90021
children c9b51268668f
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

/* Functions for system-level CD-ROM audio control on BeOS
   (not completely implemented yet)
 */

#include <sys/types.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <scsi.h>
#include <Directory.h>
#include <Entry.h>
#include <Path.h>

#include "SDL_error.h"
#include "SDL_cdrom.h"
extern "C" {
#include "SDL_syscdrom.h"
}

/* Constants to help us get at the SCSI table-of-contents info */
#define CD_NUMTRACKS(toc)	toc.toc_data[3]
#define CD_TRACK(toc, track)	(&toc.toc_data[6+(track)*8])
#define CD_TRACK_N(toc, track)	CD_TRACK(toc, track)[0]
#define CD_TRACK_M(toc, track)	CD_TRACK(toc, track)[3]
#define CD_TRACK_S(toc, track)	CD_TRACK(toc, track)[4]
#define CD_TRACK_F(toc, track)	CD_TRACK(toc, track)[5]

/* Constants to help us get at the SCSI position info */
#define POS_TRACK(pos)	pos.position[6]
#define POS_ABS_M(pos)	pos.position[9]
#define POS_ABS_S(pos)	pos.position[10]
#define POS_ABS_F(pos)	pos.position[11]
#define POS_REL_M(pos)	pos.position[13]
#define POS_REL_S(pos)	pos.position[14]
#define POS_REL_F(pos)	pos.position[15]

/* The maximum number of CD-ROM drives we'll detect */
#define MAX_DRIVES	16	

/* A list of available CD-ROM drives */
static char *SDL_cdlist[MAX_DRIVES];

/* The system-dependent CD control functions */
static const char *SDL_SYS_CDName(int drive);
static int SDL_SYS_CDOpen(int drive);
static int SDL_SYS_CDGetTOC(SDL_CD *cdrom);
static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position);
static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length);
static int SDL_SYS_CDPause(SDL_CD *cdrom);
static int SDL_SYS_CDResume(SDL_CD *cdrom);
static int SDL_SYS_CDStop(SDL_CD *cdrom);
static int SDL_SYS_CDEject(SDL_CD *cdrom);
static void SDL_SYS_CDClose(SDL_CD *cdrom);
int try_dir(const char *directory);


/* Check a drive to see if it is a CD-ROM */
static int CheckDrive(char *drive)
{
	struct stat stbuf;
	int is_cd, cdfd;
	device_geometry info;

	/* If it doesn't exist, return -1 */
	if ( stat(drive, &stbuf) < 0 ) {
		return(-1);
	}

	/* If it does exist, verify that it's an available CD-ROM */
	is_cd = 0;
	cdfd = open(drive, 0);
	if ( cdfd >= 0 ) {
		if ( ioctl(cdfd, B_GET_GEOMETRY, &info) == B_NO_ERROR ) {
			if ( info.device_type == B_CD ) {
				is_cd = 1;
			}
		}
		close(cdfd);
	} else {
		/* This can happen when the drive is open .. (?) */;
		is_cd = 1;
	}
	return(is_cd);
}

/* Add a CD-ROM drive to our list of valid drives */
static void AddDrive(char *drive)
{
	int i;

	if ( SDL_numcds < MAX_DRIVES ) {
		/* Add this drive to our list */
		i = SDL_numcds;
		SDL_cdlist[i] = (char *)malloc(strlen(drive)+1);
		if ( SDL_cdlist[i] == NULL ) {
			SDL_OutOfMemory();
			return;
		}
		strcpy(SDL_cdlist[i], drive);
		++SDL_numcds;
#ifdef CDROM_DEBUG
  fprintf(stderr, "Added CD-ROM drive: %s\n", drive);
#endif
	}
}

/* IDE bus scanning magic */
enum {
	IDE_GET_DEVICES_INFO = B_DEVICE_OP_CODES_END + 50,
};
struct ide_ctrl_info {
	bool	ide_0_present;
	bool	ide_0_master_present;
	bool	ide_0_slave_present;
	int	ide_0_master_type;
	int	ide_0_slave_type;
	bool	ide_1_present;
	bool	ide_1_master_present;
	bool	ide_1_slave_present;
	int	ide_1_master_type;
	int	ide_1_slave_type;
};

int  SDL_SYS_CDInit(void)
{
	char *SDLcdrom;
	int raw_fd;
	struct ide_ctrl_info info;

	/* Fill in our driver capabilities */
	SDL_CDcaps.Name = SDL_SYS_CDName;
	SDL_CDcaps.Open = SDL_SYS_CDOpen;
	SDL_CDcaps.GetTOC = SDL_SYS_CDGetTOC;
	SDL_CDcaps.Status = SDL_SYS_CDStatus;
	SDL_CDcaps.Play = SDL_SYS_CDPlay;
	SDL_CDcaps.Pause = SDL_SYS_CDPause;
	SDL_CDcaps.Resume = SDL_SYS_CDResume;
	SDL_CDcaps.Stop = SDL_SYS_CDStop;
	SDL_CDcaps.Eject = SDL_SYS_CDEject;
	SDL_CDcaps.Close = SDL_SYS_CDClose;

	/* Look in the environment for our CD-ROM drive list */
	SDLcdrom = getenv("SDL_CDROM");	/* ':' separated list of devices */
	if ( SDLcdrom != NULL ) {
		char *cdpath, *delim;
		cdpath = (char *)malloc(strlen(SDLcdrom)+1);
		if ( cdpath != NULL ) {
			strcpy(cdpath, SDLcdrom);
			SDLcdrom = cdpath;
			do {
				delim = strchr(SDLcdrom, ':');
				if ( delim ) {
					*delim++ = '\0';
				}
				if ( CheckDrive(SDLcdrom) > 0 ) {
					AddDrive(SDLcdrom);
				}
				if ( delim ) {
					SDLcdrom = delim;
				} else {
					SDLcdrom = NULL;
				}
			} while ( SDLcdrom );
			free(cdpath);
		}

		/* If we found our drives, there's nothing left to do */
		if ( SDL_numcds > 0 ) {
			return(0);
		}
	}
	
	/* Scan the system for CD-ROM drives */
	try_dir("/dev/disk");
	return 0;
}


int try_dir(const char *directory)
{ 
	BDirectory dir; 
	dir.SetTo(directory); 
	if(dir.InitCheck() != B_NO_ERROR) { 
		return false; 
	} 
	dir.Rewind(); 
	BEntry entry; 
	while(dir.GetNextEntry(&entry) >= 0) { 
		BPath path; 
		const char *name; 
		entry_ref e; 
		
		if(entry.GetPath(&path) != B_NO_ERROR) 
			continue; 
		name = path.Path(); 
		
		if(entry.GetRef(&e) != B_NO_ERROR) 
			continue; 

		if(entry.IsDirectory()) { 
			if(strcmp(e.name, "floppy") == 0) 
				continue; /* ignore floppy (it is not silent)  */
			int devfd = try_dir(name);
			if(devfd >= 0)
				return devfd;
		} 
		else { 
			int devfd; 
			device_geometry g; 

			if(strcmp(e.name, "raw") != 0) 
				continue; /* ignore partitions */

			devfd = open(name, O_RDONLY); 
			if(devfd < 0) 
				continue; 

			if(ioctl(devfd, B_GET_GEOMETRY, &g, sizeof(g)) >= 0) {
				if(g.device_type == B_CD)
				{
				AddDrive(strdup(name));
				}
			}
			close(devfd);
		} 
	}
	return B_ERROR;
}


/* General ioctl() CD-ROM command function */
static int SDL_SYS_CDioctl(int index, int command, void *arg)
{
	int okay;
	int fd;

	okay = 0;
	fd = open(SDL_cdlist[index], 0);
	if ( fd >= 0 ) {
		if ( ioctl(fd, command, arg) == B_NO_ERROR ) {
			okay = 1;
		}
		close(fd);
	}
	return(okay ? 0 : -1);
}

static const char *SDL_SYS_CDName(int drive)
{
	return(SDL_cdlist[drive]);
} 

static int SDL_SYS_CDOpen(int drive)
{
	return(drive);
}

static int SDL_SYS_CDGetTOC(SDL_CD *cdrom)
{
	int i;
	scsi_toc toc;

	if ( SDL_SYS_CDioctl(cdrom->id, B_SCSI_GET_TOC, &toc) == 0 ) {
		cdrom->numtracks = CD_NUMTRACKS(toc);
		if ( cdrom->numtracks > SDL_MAX_TRACKS ) {
			cdrom->numtracks = SDL_MAX_TRACKS;
		}
		for ( i=0; i<=cdrom->numtracks; ++i ) {
			cdrom->track[i].id = CD_TRACK_N(toc, i);
			/* FIXME:  How do we tell on BeOS? */
			cdrom->track[i].type = SDL_AUDIO_TRACK;
			cdrom->track[i].offset = MSF_TO_FRAMES(
							CD_TRACK_M(toc, i),
							CD_TRACK_S(toc, i),
							CD_TRACK_F(toc, i));
			cdrom->track[i].length = 0;
			if ( i > 0 ) {
				cdrom->track[i-1].length =
						cdrom->track[i].offset-
						cdrom->track[i-1].offset;
			}
		}
		return(0);
	} else {
		return(-1);
	}
}

/* Get CD-ROM status */
static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position)
{
	CDstatus status;
	int fd;
	int cur_frame;
	scsi_position pos;

	fd = open(SDL_cdlist[cdrom->id], 0);
	cur_frame = 0;
	if ( fd >= 0 ) {
		if ( ioctl(fd, B_SCSI_GET_POSITION, &pos) == B_NO_ERROR ) {
			cur_frame = MSF_TO_FRAMES(
				POS_ABS_M(pos), POS_ABS_S(pos), POS_ABS_F(pos));
		}
		if ( ! pos.position[1] || (pos.position[1] >= 0x13) ||
			((pos.position[1] == 0x12) && (!pos.position[6])) ) {
			status = CD_STOPPED;
		} else
		if ( pos.position[1] == 0x11 ) {
			status = CD_PLAYING;
		} else {
			status = CD_PAUSED;
		}
		close(fd);
	} else {
		status = CD_TRAYEMPTY;
	}
	if ( position ) {
		*position = cur_frame;
	}
	return(status);
}

/* Start play */
static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length)
{
	int okay;
	int fd;
	scsi_play_position pos;

	okay = 0;
	fd = open(SDL_cdlist[cdrom->id], 0);
	if ( fd >= 0 ) {
		FRAMES_TO_MSF(start, &pos.start_m, &pos.start_s, &pos.start_f);
		FRAMES_TO_MSF(start+length, &pos.end_m, &pos.end_s, &pos.end_f);
		if ( ioctl(fd, B_SCSI_PLAY_POSITION, &pos) == B_NO_ERROR ) {
			okay = 1;
		}
		close(fd);
	}
	return(okay ? 0 : -1);
}

/* Pause play */
static int SDL_SYS_CDPause(SDL_CD *cdrom)
{
	return(SDL_SYS_CDioctl(cdrom->id, B_SCSI_PAUSE_AUDIO, 0));
}

/* Resume play */
static int SDL_SYS_CDResume(SDL_CD *cdrom)
{
	return(SDL_SYS_CDioctl(cdrom->id, B_SCSI_RESUME_AUDIO, 0));
}

/* Stop play */
static int SDL_SYS_CDStop(SDL_CD *cdrom)
{
	return(SDL_SYS_CDioctl(cdrom->id, B_SCSI_STOP_AUDIO, 0));
}

/* Eject the CD-ROM */
static int SDL_SYS_CDEject(SDL_CD *cdrom)
{
	return(SDL_SYS_CDioctl(cdrom->id, B_SCSI_EJECT, 0));
}

/* Close the CD-ROM handle */
static void SDL_SYS_CDClose(SDL_CD *cdrom)
{
	close(cdrom->id);
}

void SDL_SYS_CDQuit(void)
{
	int i;

	if ( SDL_numcds > 0 ) {
		for ( i=0; i<SDL_numcds; ++i ) {
			free(SDL_cdlist[i]);
		}
		SDL_numcds = 0;
	}
}