view src/cdrom/osf/SDL_syscdrom.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 9719e7f51a3a
children e3b3130f3af8
line wrap: on
line source

/*
    Tru64 audio module for SDL (Simple DirectMedia Layer)
    Copyright (C) 2003

    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


*/


/* Functions for system-level CD-ROM audio control */

//#define DEBUG_CDROM 1

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <io/cam/cdrom.h>
#include <io/cam/rzdisk.h>
#include <io/common/devgetinfo.h>
#include <alloca.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>

#include "SDL_error.h"
#include "SDL_cdrom.h"
#include "SDL_syscdrom.h"

/* 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];
static dev_t SDL_cdmode[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);

/* Check a drive to see if it is a CD-ROM */
/* Caution!! Not tested. */ 
static int CheckDrive(char *drive, struct stat *stbuf)
{
    int cdfd, is_cd = 0;
    struct mode_sel_sns_params msp;
    struct inquiry_info inq;

#ifdef DEBUG_CDROM
    char *devtype[] = {"Disk", "Tape", "Printer", "Processor", "WORM",
	"CD-ROM", "Scanner", "Optical", "Changer", "Comm", "Unknown"};
#endif

    bzero(&msp, sizeof(msp));
    bzero(&inq, sizeof(inq));

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

    if ( (cdfd = open(drive, (O_RDWR|O_NDELAY), 0)) >= 0 ) {
	msp.msp_addr   =   (caddr_t) &inq;
	msp.msp_pgcode =                0;
	msp.msp_pgctrl =                0;
	msp.msp_length =      sizeof(inq);
	msp.msp_setps  =                0;

	if ( ioctl(cdfd, SCSI_GET_INQUIRY_DATA, &msp) )
	    return (0);

#ifdef DEBUG_CDROM
	fprintf(stderr, "Device Type: %s\n", devtype[inq.perfdt]);
	fprintf(stderr, "Vendor: %.8s\n", inq.vndrid);
	fprintf(stderr, "Product: %.8s\n", inq.prodid);
	fprintf(stderr, "Revision: %.8s\n", inq.revlvl);
#endif
	if ( inq.perfdt == DTYPE_RODIRECT )
	    is_cd = 1;
    }

    return(is_cd);
}

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

    if ( SDL_numcds < MAX_DRIVES ) {
	/* Check to make sure it's not already in our list.
	 * This can happen when we see a drive via symbolic link.
	 *
	 */
	for ( i=0; i<SDL_numcds; ++i ) {
	    if ( stbuf->st_rdev == SDL_cdmode[i] ) {
#ifdef DEBUG_CDROM
  fprintf(stderr, "Duplicate drive detected: %s == %s\n", drive, SDL_cdlist[i]);
#endif
	    return;
	    }
	}

	/* 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_cdmode[i] = stbuf->st_rdev;
	++SDL_numcds;
#ifdef DEBUG_CDROM
  fprintf(stderr, "Added CD-ROM drive: %s\n", drive);
#endif
    }
}

int  SDL_SYS_CDInit(void)
{
    /* checklist: /dev/rdisk/cdrom?c
     *
     */
    static char *checklist[] = {
	"?0 rdisk/cdrom?",NULL};
    char drive[32];
    char *SDLcdrom;
    int i, j, exists;
    struct stat stbuf;

    /* 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 = malloc(strlen(SDLcdrom)+1);
	if ( cdpath != NULL ) {
	    strcpy(cdpath, SDLcdrom);
	    SDLcdrom = cdpath;
	    do {
		delim = strchr(SDLcdrom, ':');
		if ( delim ) {
		    *delim++ = '\0';
		}
		if ( CheckDrive(SDLcdrom, &stbuf) > 0 ) {
		    AddDrive(SDLcdrom, &stbuf);
		}
		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 */
    for ( i=0; checklist[i]; ++i ) {
	if ( checklist[i][0] == '?' ) {
	    char *insert;
	    exists = 1;
	    for ( j=checklist[i][1]; exists; ++j ) {
		sprintf(drive, "/dev/%sc", &checklist[i][3]);
		insert = strchr(drive, '?');
		if ( insert != NULL ) {
		    *insert = j;
		}
		switch (CheckDrive(drive, &stbuf)) {
		    /* Drive exists and is a CD-ROM */
		    case 1:
			AddDrive(drive, &stbuf);
			break;
			/* Drive exists, but isn't a CD-ROM */
		    case 0:
			break;
			/* Drive doesn't exist */
		    case -1:
			exists = 0;
			break;
		}
	    }
	} else {
	    sprintf(drive, "/dev/%s", checklist[i]);
	    if ( CheckDrive(drive, &stbuf) > 0 ) {
		AddDrive(drive, &stbuf);
	    }
	}
    }
/*
    SDLcdrom=malloc(sizeof(char) * 32);
    strcpy(SDLcdrom,"/dev/rdisk/cdrom0c");
    SDL_cdlist[0] = SDLcdrom;
    stat(SDLcdrom, &stbuf);
    SDL_cdmode[0] = stbuf.st_rdev;
    SDL_numcds = 1;
 */
    return (0);
}

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

static int SDL_SYS_CDOpen(int drive)
{
    /* O_RDWR: To use ioctl(fd, SCSI_STOP_UNIT) */
    return(open(SDL_cdlist[drive], (O_RDWR|O_NDELAY), 0));
}

static int SDL_SYS_CDGetTOC(SDL_CD *cdrom)
{
    struct cd_toc                  toc;
    struct cd_toc_header           hdr;
    struct cd_toc_entry          *cdte;
    int i;
    int okay = 0;
    if ( ioctl(cdrom->id, CDROM_TOC_HEADER, &hdr) ) {
	fprintf(stderr,"ioctl error CDROM_TOC_HEADER\n");
	return -1;
    }
    cdrom->numtracks = hdr.th_ending_track - hdr.th_starting_track + 1;
    if ( cdrom->numtracks > SDL_MAX_TRACKS ) {
	cdrom->numtracks = SDL_MAX_TRACKS;
    }
#ifdef DEBUG_CDROM
  fprintf(stderr,"hdr.th_data_len1 = %d\n", hdr.th_data_len1);
  fprintf(stderr,"hdr.th_data_len0 = %d\n", hdr.th_data_len0);
  fprintf(stderr,"hdr.th_starting_track = %d\n", hdr.th_starting_track);
  fprintf(stderr,"hdr.th_ending_track = %d\n", hdr.th_ending_track);
  fprintf(stderr,"cdrom->numtracks = %d\n", cdrom->numtracks);
#endif
    toc.toc_address_format = CDROM_LBA_FORMAT;
    toc.toc_starting_track = 0;
    toc.toc_alloc_length = (hdr.th_data_len1 << 8) +
			    hdr.th_data_len0 + sizeof(hdr);
    if ( (toc.toc_buffer = alloca(toc.toc_alloc_length)) == NULL) {
	fprintf(stderr,"cannot allocate toc.toc_buffer\n");
	return -1;
    }

    bzero (toc.toc_buffer, toc.toc_alloc_length);
    if (ioctl(cdrom->id, CDROM_TOC_ENTRYS, &toc)) {
	fprintf(stderr,"ioctl error CDROM_TOC_ENTRYS\n");
	return -1;
    }

    cdte =(struct cd_toc_entry *) ((char *) toc.toc_buffer + sizeof(hdr));
    for (i=0; i <= cdrom->numtracks; ++i) {
	if (i == cdrom->numtracks ) {
	    cdrom->track[i].id = 0xAA;;
	} else {
	    cdrom->track[i].id = hdr.th_starting_track + i;
	}

	cdrom->track[i].type =
	    cdte[i].te_control & CDROM_DATA_TRACK;
	cdrom->track[i].offset =
	    cdte[i].te_absaddr.lba.addr3 << 24 |
	    cdte[i].te_absaddr.lba.addr2 << 16 |
	    cdte[i].te_absaddr.lba.addr1 << 8  |
	    cdte[i].te_absaddr.lba.addr0;
	cdrom->track[i].length = 0;
	if ( i > 0 ) {
	    cdrom->track[i - 1].length =
		cdrom->track[i].offset -
		cdrom->track[i - 1].offset;
	}
    }
#ifdef DEBUG_CDROM
  for (i = 0; i <= cdrom->numtracks; i++) {
    fprintf(stderr,"toc_entry[%d].te_track_number = %d\n",
	    i,cdte[i].te_track_number);
    fprintf(stderr,"cdrom->track[%d].id = %d\n", i,cdrom->track[i].id);
    fprintf(stderr,"cdrom->track[%d].type = %x\n", i,cdrom->track[i].type);
    fprintf(stderr,"cdrom->track[%d].offset = %d\n", i,cdrom->track[i].offset);
    fprintf(stderr,"cdrom->track[%d].length = %d\n", i,cdrom->track[i].length);
  }
#endif
    if ( i == (cdrom->numtracks+1) ) {
	okay = 1;
    }

    return(okay ? 0 : -1);
}

/* Get CD-ROM status */
static CDstatus SDL_SYS_CDStatus(SDL_CD *cdrom, int *position)
{
    CDstatus                     status;
    struct cd_sub_channel            sc;
    struct cd_subc_channel_data     scd;

    sc.sch_address_format = CDROM_LBA_FORMAT;
    sc.sch_data_format    = CDROM_CURRENT_POSITION;
    sc.sch_track_number   = 0;
    sc.sch_alloc_length   = sizeof(scd);
    sc.sch_buffer         = (caddr_t)&scd;
    if ( ioctl(cdrom->id, CDROM_READ_SUBCHANNEL, &sc) ) {
	status = CD_ERROR;
	fprintf(stderr,"ioctl error CDROM_READ_SUBCHANNEL \n");
    } else {
	switch (scd.scd_header.sh_audio_status) {
	    case AS_AUDIO_INVALID:
		status = CD_STOPPED;
		break;
	    case AS_PLAY_IN_PROGRESS:
		status = CD_PLAYING;
		break;
	    case AS_PLAY_PAUSED:
		status = CD_PAUSED;
		break;
	    case AS_PLAY_COMPLETED:
		status = CD_STOPPED;
		break;
	    case AS_PLAY_ERROR:
		status = CD_ERROR;
		break;
	    case AS_NO_STATUS:
		status = CD_STOPPED;
		break;
	    default:
		status = CD_ERROR;
		break;
	}
#ifdef DEBUG_CDROM
  fprintf(stderr,"scd.scd_header.sh_audio_status = %x\n",
	scd.scd_header.sh_audio_status);
#endif
    }
    if (position) {
	if (status == CD_PLAYING || (status == CD_PAUSED) ) {
	    *position =
		scd.scd_position_data.scp_absaddr.lba.addr3 << 24 |
		scd.scd_position_data.scp_absaddr.lba.addr2 << 16 |
		scd.scd_position_data.scp_absaddr.lba.addr1 << 8  |
		scd.scd_position_data.scp_absaddr.lba.addr0;
	} else {
	    *position = 0;
	}
    }

    return status;
}

/* Start play */
static int SDL_SYS_CDPlay(SDL_CD *cdrom, int start, int length)
{
/*
 * Play MSF
 */
    struct cd_play_audio_msf msf;
    int end;

    bzero(&msf, sizeof(msf));
    end = start +length;
    FRAMES_TO_MSF(start + 150, /* LBA = 4500*M + 75*S + F - 150 */
		  &msf.msf_starting_M_unit,
		  &msf.msf_starting_S_unit,
		  &msf.msf_starting_F_unit);
    FRAMES_TO_MSF(end + 150, /* LBA = 4500*M + 75*S + F - 150 */
		  &msf.msf_ending_M_unit,
		  &msf.msf_ending_S_unit,
		  &msf.msf_ending_F_unit);

    return(ioctl(cdrom->id, CDROM_PLAY_AUDIO_MSF, &msf));
}

/* Pause play */
static int SDL_SYS_CDPause(SDL_CD *cdrom)
{
    return(ioctl(cdrom->id, CDROM_PAUSE_PLAY));
}

/* Resume play */
static int SDL_SYS_CDResume(SDL_CD *cdrom)
{
    return(ioctl(cdrom->id, CDROM_RESUME_PLAY));
}

/* Stop play */
static int SDL_SYS_CDStop(SDL_CD *cdrom)
{
    return(ioctl(cdrom->id, SCSI_STOP_UNIT));
}

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

/* 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;
    }
}