HPAVC/HPAVC CD-ROM.iso/DSIKDEMO.ZIP/MANUAL.TXT

Text File | 1994-07-18 | 50KB | 1,297 lines

                  Digital Sound Interface Kit (DSIK)
                          Version 1.01a

                       ── User's Manual ──

                      (C) 1994  Carlos Hasan


Contents:

        1.      Introduction
        1.1     What's in this Manual?
        1.2     Hardware Requirements
        1.3     Contacting the Author

        2.      Tutorial
        2.1     Initializing DSIK
        2.2     Playing Digital Samples
        2.3     Playing a Music Module
        2.4     Playing Sound Effects over Music

        3.      Programming Guide
        3.1     Initializing DSIK
        3.2     Openining Voice Channels
        3.3     Mixing Voices
        3.4     Playing Music
        3.4.1   Loading a Module
        3.4.2   Playing the Module
        3.4.3   Stopping the Module
        3.5     Sound Effects
        3.5.1   Channels
        3.5.2   Available Channels
        3.5.3   Playing Sounds
        3.5.4   Altering the Playing Sounds
        3.6     Digital Sound Module Format
        3.6.1   Converting Modules
        3.7     Getting Information from DSIK
        3.8     Interrupts
        3.9     Using Timer Services

        4.      Reference Guide
        4.1     Functions
        4.2     Structures



Chapter 1. Introduction
─────────────────────────────────────────────────────────────────────────────

    The Digital Sound Interface Kit (DSIK) is an interface library by which
    you can play digital music and sound effects on PCs, and is currently
    available for Borland C++ and Borland Pascal compilers.

1.1 What's in this Manual?

    This manual has three parts: Tutorial, Programming Guide and Reference
    Guide sections. The tutorial section of this manual will show you only
    the most basic functions of DSIK. You should read the Programming Guide
    section to learn more about the DSIK's capabilities. For more detailed
    information about every function, structure and equates defined in DSIK
    you should read the Reference Guide section of this manual.

1.2 Hardware and Software Requirements

    In order to work with DSIK you need at least an 386SX and a soundcard.
    The supported soundcards are Sound Blaster, Sound Blaster Pro, Sound
    Blaster 16, Gravis Ultrasound and all cards that are 100% compatible
    with any of the above.
    The DSIK library was compiled with Borland C++ version 3.1, but all the
    C source code is included so you can recompile it for older versions of
    Borland C++ compiler (or Turbo C++ compiler).

1.3 Contacting the Author

    If you encounter problems, find a bug in this package or want to suggest
    something, use the following Internet email addresses:

        Carlos Hasan
        [e-mail]
        [e-mail]


Chapter 2. Tutorial
─────────────────────────────────────────────────────────────────────────────

    This tutorial will show you how to use DSIK in your own applications
    by providing some simple example programs. These example programs
    will be built from scratch and new features will be added step by
    step through the tutorial.

2.1 Initializing DSIK

    Before using any of the DSIK's routines it has to be initialized. First
    you need your soundcard hardware parameters. To ease things there is an
    external program called SETUP which will ask to the user the soundcard
    parameters and will save them into your disk. After, you can load these
    hardware parameters from disk in your own programs. When you have all
    the soundcard parameters, call the routine DSMInit to initialize the
    DSIK sound system.
    Now the program would be able to play sounds on different channels,
    and music modules of course.

    Here is an example code for initializing DSIK:

    #include <stdio.h>
    #include <stdlib.h>
    #include "sound.h"

    int main()
    {
      DSMCard Card;
      if (DSMLoadSetup(&Card)) {
        printf("please run SETUP.EXE to configure.\n");
        exit(EXIT_FAILURE);
      }
      if (DSMInit(&Card)) {
        printf("error initializing DSIK.\n");
        exit(EXIT_FAILURE);
      }
      :
      :
      DSMDone();
    }

    If everything went alright and DSMInit found the specified soundcard it
    returns zero. After DSMInit has initialized the system, you must call
    the deinit routine DSMDone before exiting your program.

2.2 Playing Digital Samples

    DSIK is now initialized and waits for your instructions. But first you
    have to setup the amount of voices you are going to use and the master
    volume level for all those channels:

    DSMSetupVoices(4,96);

    Now you have four independant channels to play sounds. To play a digital
    sample (or instrument) you have to load the sample from disk, then pass
    it to DSMPlaySample to start playing the sample. DSIK currently supports
    standard RIFF/WAVE digital sample files which can be loaded from disk
    using the routine DSMLoadSample.

    #include <stdio.h>
    #include <stdlib.h>
    #include <conio.h>
    #include "sound.h"

    int main()
    {
      DSMCard Card;
      DSMInst *Drum;
      if (DSMLoadSetup(&Card) || DSMInit(&Card))
        exit(EXIT_FAILURE);
      DSMSetupVoices(4,96);
      Drum = DSMLoadSample("DRUM.WAV",0L);  /* load sample from disk */
      DSMPlaySample(0,Drum);                /* play at default frequency */
      while (!kbhit()) DSMPoll();           /* wait any key */
      DSMStopSample(0);                     /* stop voice */
      DSMFreeSample(Drum);                  /* free sample from memory */
      DSMDone();
    }

    The previous code loads a digital instrument from disk and plays it on
    the first audio channel at the default frequency and volume.

2.3 Playing a Music Module

    Module is a music file format first used in the Amiga computer. There are
    many music formats around like: ProTracker, FastTracker, Scream Tracker,
    Composer 669 and MultiTracker file formats. But DSIK only knows the DSM
    module format, so to play MODs, STMs, S3Ms, 669s, and MTMs they need to
    be converted into DSM format using the utility program CONV.EXE included
    in the DSIK package.

    Here is an simple example program to play an DSM module:

    #include <stdio.h>
    #include <stdlib.h>
    #include <conio.h>
    #include "sound.h"

    int main()
    {
      DSMCard Card;
      DSM *Module;
      if (DSMLoadSetup(&Card) || DSMInit(&Card))
        exit(EXIT_FAILURE);
      Module = DSMLoad("EXAMPLE.DSM",0L);
      DSMSetupVoices(Module->Song.NumChannels,Module->Song.MasterVolume);
      DSMPlayMusic(Module);
      while (!kbhit()) DSMPoll();
      DSMStopMusic();
      DSMFree(Module);
      DSMDone();
    }

    When running the program it should play the EXAMPLE.DSM module. If there
    are problems, check that the module exists in the current directory.

2.4 Playing Sound Effects over Music

    With DSIK it's possible to play sound effects over the music. All you have
    to do is to open more channels than your module needs. The extra channels
    can be used to play sound effects. Remember that DSIK always uses the first
    channels from the beginning to play the music. For example, for an module
    which uses 4 channels, the channels 0, 1, 2 and 3 will be used to play the
    module. You can use all the unused open channels to play sound effects.


Chapter 3. Programming Guide
─────────────────────────────────────────────────────────────────────────────

    In this section you will learn more about all the DSIK's capabilities.
    It describes not only what DSIK can do, but also how. For more details
    about every function and structures defined in DSIK you should read the
    Reference Guide section of this manual.

3.1 Initializing DSIK

    The first thing you should do to initialize DSIK is to get the soundcard
    hardware parameters (I/O port, IRQ line, DMA channel, mixing rate). The
    structure DSMCard must be filled with these parameters:

    typedef struct {
        byte    CardID;             /* Sound card ID */
        word    IOAddr;             /* Port address  */
        byte    IRQNum;             /* IRQ line      */
        byte    DRQNum;             /* DMA channel   */
        word    MixRate;            /* Mixing rate   */
    } DSMCard;

    The identification number ID is unique for each card. Here is a list of
    the identification numbers for the currently supported soundcards:

    #define ID_NONE     0           /* No soundcard       */
    #define ID_SB       1           /* Sound Blaster      */
    #define ID_SB201    2           /* Sound Blaster 2.01 */
    #define ID_SBPRO    3           /* Sound Blaster Pro  */
    #define ID_SB16     4           /* Sound Blaster 16   */
    #define ID_GUS      5           /* Gravis Ultrasound  */

    There are parameters which are unused for some soundcards (for example,
    the GUS soundcard does not requires the mixing rate). Also, the virtual
    soundcard ID_NONE is useful for users without any sound device, because
    your program can use all the DSIK functions without problems, but no
    sound will be heard though.

    When the DSMCard structure is filled, call DSMInit with it and check the
    returned value. If the value is zero, then everything went alright and
    DSIK is initialized. Otherwite an error occured.

    After initializing DSIK you should make sure that DSMDone is called upon
    exit. The easiest way to do it is to call the routine atexit with the
    address of the DSMDone routine.

3.2 Opening Voice Channels

    Now DSIK is initialized, but you can't play any sound with it yet. First
    you will have to call DSMSetupVoices to specify the amount of channel
    voices your program needs and the global master volume level:

    DSMSetupVoices(8,96);

    The above code will open 8 channel voices and sets the master volume
    level to 96, which is a pretty nice value for that amount of open
    channels. Actually, the master volume parameter is only used in the
    Sound Blaster cards and has no effect in the GUS soundcard.

3.3 Mixing Voices

    When everything is initialized it's time to start playing some sounds.
    Before any sound can be heard it has to be loaded from disk. Because
    DSIK supports many more channels than your soundcard supports (except
    for the GUS), DSIK has to combine many channels into a single channel.
    This process is called digital mixing.

    DSIK lets you do the mixing whenever you want to do it. It does not
    force you to use the timer interrupt, all that DSIK requires is to call
    the function DSMPoll frequently. Actually this is not required if you are
    using the GUS soundcard which uses his own interrupt service to poll the
    sound system.

    To play music and sound effects in background, you only need to call
    DSMPoll regularly. About 50 or 70 times per second should be enough
    in most cases. For higher mixing rates you need to call this routine
    more times than for lower mixing rates.

    If you want a timer interrupt to handle all the mixing, you can easily
    hook the DSMPoll into a timer interrupt service:

    #include <stdio.h>
    #include <stdlib.h>
    #include "sound.h"
    #include "ts.h"

    int main()
    {
      DSMCard Card;
      Module *Module;
      if (DSMLoadSetup(&Card) || DSMInit(&Card))
        exit(EXIT_FAILURE);
      TSInit();
      TSSetRate(70);
      TSSetRoutine(DSMPoll);
      :
      :
      TSDone();
      TSRestoreTime();
      DSMDone();
    }

    The previous code will use the timer interrupt to call DSMPoll 70 times
    per second. Notice that the BIOS clock will be updated while using the
    timer services. Anyway, you may call TSRestoreTime() to update the clock
    and date (this routine uses the CMOS real time clock to update the
    software BIOS clock and date).

    Here is a short summary of how to initialize DSIK:

    - Load the soundcard parameters into the DSMCard structure.
    - Call DSMInit to initialize (be sure to call DSMDone before
      exiting your program).
    - Select the maximum number amount of simultaneos channels
      and the master volume level with DSMSetupVoices.

3.4 Playing Music

    After DSIK has been setup to play sounds, you are allowed to play music
    modules. As DSIK uses his own music module format, it's necessary to use
    the utility CONV.EXE to convert standard MODs, STMs, 669s, S3Ms and MTMs
    to the DSM file format.

3.4.1 Loading a Module

    Before any music can be played it has to be loaded from the disk into
    system memory (and soundcard memory for the GUS driver). The module
    loader is called as follows:

    Module = DSMLoad(FileName,FileOffset);

    The FileName is the full path name to the module and FileOffset is where
    the module starts itself in the file (its useful if you have packed all
    your module files into a huge resource file).
    The loader returns a pointer to a DSM structure. If something went wrong,
    NULL is returned and the global variable DSMStatus is set to one of the
    following values to indicate the error occurred:

    #define ERR_OK      0           /* no error */
    #define ERR_NORAM   1           /* not enough system memory */
    #define ERR_NODRAM  2           /* not enough soundcard memory */
    #define ERR_NOFILE  3           /* module/sample file not found */
    #define ERR_FORMAT  4           /* invalid file format */
    #define ERR_ACCESS  5           /* file corrupted */

    The DSM structure contains all the information about the module, so it
    is totally possible to load multiple modules into memory.

3.4.2 Playing the Module

    When the module has been loaded into memory it can be played with a
    single function call:

    DSMPlayMusic(Module);

    The parameter is a pointer to a variable of type DSM. IF you have set up
    DSIK correctly and mixing routines are called frequently, you should hear
    the music playing in background. If you don't hear any music and no error
    was detected, then something went wrong during initialization (probably
    the soundcard hardware parameters are wrong).

3.4.3 Stopping the Module

    If you want to stop the module which is currently being played, call the
    routine DSMStopMusic. The module is always played with looping, which
    means that it will never end until DSMStopMusic is called.

3.5 Sound effects

    Playing modules in the background is a thing that can be achieved with
    DSIK, but also you can play sound effects simultaneous with music.

3.5.1 Channels

    First you need to know the amount of channels that your program will
    need to play the music and sound effects. For example, if you are going
    to play a 4 channels module and also you want stereo sound effects, you
    need to open 6 channels (four for music and two for the sound effect
    channels). To open the desired amount of channels you does:

    DSMSetupVoices(NumChannels,MasterVolume);

    The first parameter is the number of channels you want, and the second
    parameter is the master volume level. DSIK currently supports up to 16
    different channels, and they are zero based. That means that the first
    voice channel number is 0, the second is 1, and so on.

    DSMSetupVoices can be called multiple times. However, it can't be called
    while music or sound effects are being played. So be sure to stop all
    the channels before changing the amount of channels.

    If you try to call DSMSetupVoices while the system is playing music or
    sound effects, you will hear a small crack and the channel frequencies
    will be wrong for a while if you are using the GUS soundcard.

3.5.2 Available Channels

    You have opened six channels and DSIK is playing a four channel module,
    so the channels four and five are available for your own sound effects.
    DSIK always uses the first channels starting from zero, so you can be
    sure that playing a sample on channel four or five will not interfere
    with the music.

3.5.3 Playing Sounds

    When you want to play a sample, you must load it from disk. The function
    DSMLoadSample loads standard RIFF/WAVE files from disk. If you want to
    write your own sample loader for a different sample file format, do the
    following basic steps:

    - Allocate memory for the sample
    - Load the sample into memory
    - Create a DSMInst structure for it
    - Upload the sample to the soundcard memory and release it from
      system memory, if the current soundcard has on board memory.

    To learn more about how to load samples into memory, look at the DSIK
    loading routine sources included in the package.

    The DSMInst structure contains all the information about a sample
    instrument. Here is the definition of this structure:

    typedef struct {
        char    FileName[13];
        word    Flags;
        byte    Volume;
        dword   Length;
        dword   LoopStart;
        dword   LoopEnd;
        void    far *Address;
        word    MidCRate;
        word    Period;
        char    SampleName[28];
    } DSMInst;

    After the sample has been loaded in memory, you can play it calling
    the DSMPlaySample function:

    DSMPlaySample(Voice,Sample);

    where Voice is the channel number and Sample is a pointer to a DSMInst
    sample structure. This function will play the sample at the default
    frequency and volume specified in the DSMInst sample structure (fields
    Period and Volume).

    DSIK internally uses period values instead of frequencies. The formula
    to translate frequency values to periods is:

    Period = 8363*428/Hertz

    Also, DSIK uses volume levels from 0 to 64. These parameters come from
    the Amiga computer and the standard MOD ProTracker file format.

3.5.4 Altering the Playing Sounds

    Now that the sample is being played, it would be nice to change the
    frequency and the volume of the sample. DSIK has functions to make it
    possible. Changing the period and volume is as simple as calling:

    DSMSetPeriod(Voice,Period);
    DSMSetVolume(Voice,Volume);

    Also you can change the channel panning (or balance):

    DSMSetBalance(Voice,Balance);

    where Balance is a number between 0 (left panned) and 128 (right panned),
    also you can use surround effects setting the balance to 228. There some
    useful equates which you can use to set the balance or panning:

    #define PAN_LEFT    0x00        /* left panning    */
    #define PAN_RIGHT   0x80        /* right panning   */
    #define PAN_DOLBY   0xA4        /* surround effect */

    Notice that this routine will take effect only in stereo cards, also the
    surround effect works only in SB cards currently.

3.6 Digital Sound Module Format (DSM)

    DSIK uses his own music module file format. It was designed to cope with
    a variety of different module formats like MOD, STM, 669, S3M, and MTM.
    It would have been very hard to write a system that supports all those
    module formats, so I have made a system that supports just one format,
    but with a utility to convert other module formats into this format
    called Digital Sound Module Format, or DSM for short.

3.6.1 Converting Modules

    As DSIK only supports the DSM format, you need to convert MODs, STMs,
    669s, S3Ms and MTMs into DSM before playing. You can do this manually
    using the CONV.EXE utility. Here is the command line syntaxis:

    CONV source[.ext] [dest[.dsm]]

    For example, CONV FEEDBACK.S3M will create the FEEDBACK.DSM module file,
    which can be played with the DSIK sound system.

3.7 Getting Information from DSIK

    DSIK can give you information about what is going on. There is a routine
    called DSMGetMusicInfo which returns a pointer to the following structure
    which hold a lot of useful information:

    typedef struct {
        word    ActiveTracks;
        Track   Tracks[MAXTRACKS];
        byte    OrderPosition;
        byte    OrderLength;
        byte    PatternNumber;
        byte    PatternRow;
        byte    BreakFlag;
        byte    Tempo;
        byte    TempoCount;
        byte    BPM;
        word    CardStatus;
        word    PlayStatus;
        dword   SongPtr;
        byte    SyncMark;
    } DSMMusicInfo;

    For synchronization with music you can use the SyncMark field. You need
    to place special synchronization marks in your modules. You can use
    Scream Tracker 3.01 command Z to put these marks. The command parameter
    should be a byte value between 0 and 127. When DSIK encounters this
    command, it sets the internal variable SyncMark with the value of the
    command parameter. So the variable SyncMark always have the previous
    synchronization mark value.

    With the Tracks array you get everything you need to know about what is
    currently playing. The structure of each Track is defined as:

    typedef struct {
        byte    Note;
        byte    Sample;
        byte    Volume;
        word    Effect;
        byte    EQBar;
    } Track;

    The first field is the current note playing on the track. The following
    field is the current instrument number. For example, if you need to know
    the name of the current instrument being played in the track, you can use
    the following code:

    Name = Module->Inst[TrackPtr->Sample-1]->SampleName;

    The Volume field is self explaining, and the Effect field is the current
    standard Protracker command which is being interpreted.
    There are other internal fields defined in the Track structure, but that
    are not actually very useful for the user programs.

3.8 Interrupts

    DSIK doesn't require interrupts. Normally you would poll DSIK in an
    interrupt occuring about 50-70 times per second, which will decrease
    the overhead caused by the interrupt service.

3.9 Using Timer Services

    The Timer Service (TS) library was designed for easy handling of the
    timer interrupt service. This library was included because DSIK doesn't
    give you any routine to easily play music and sounds in background.
    With this library you can hook your own routines to be called by the
    timer interrupt service at the specified rates. For example, you can
    hook the DSMPoll routine to be called 70 times per second.

    When the TS services are installed the previous BIOS service is called
    at 18.2 Hz, so the BIOS clock time and date are updated normally. You
    may call the routine TSRestoreTime before exiting your application to
    update the BIOS clock and date if required.

    First, to initialize the TS routines you must call TSInit and be sure
    to call TSDone to deinitialize the routines upon exit. Now you can hook
    your own service routine with TSSetRoutine and change the timer speed:

    TSSetRoutine(MyTimer);
    TSSetRate(70);

    This code setup TS to call MyTimer 70 times per second. The speed value
    is given in times per seconds (or hertz) and the minimum value is 19 Hz.
    Your timer service routine must preserve all the CPU registers and return
    using a far stack frame (using the RETF opcode).


Chapter 4. Reference Guide
─────────────────────────────────────────────────────────────────────────────

    This section of the manual will describe the functions, structures and
    equates defined in DSIK. Functions are listed where each entry contains
    a detailed description on that particular function.


4.1 Functions

DSMInit
─────────────────────────────────────────────────────────────────────────────
Function:       Initializes the DSIK sound system.

Prototype:      int DSMInit(DSMCard *Card)

Parameters:     Card    - Soundcard configuration structure.

Returns:        On success, returns a zero value.
                On error, returns a non zero value.

Remarks:        This function must be called to initialize the sound
                system. When initialized you should make sure that the
                system will be deinitialized calling DSMDone upon exit.

See Also:       DSMDone.


DSMDone
─────────────────────────────────────────────────────────────────────────────
Function:       Shutdown the DSIK sound system.

Prototype:      void DSMDone(void)

Parameters:     None.

Returns:        None.

Remarks:        This function must be called to deinitialize the sound
                system upon exit. It will close all the audio channels
                and will close the current soundcard output.

See Also:       DSMInit.


DSMPoll
─────────────────────────────────────────────────────────────────────────────
Function:       Polls the DSIK sound system.

Prototype:      void DSMPoll(void)

Parameters:     None.

Returns:        None.

Remarks:        This function should be called regularly to play music
                and sound effects in background. About 50-70 times per
                second is enough in most cases.
                This routine is NOT reentrant, so if you are calling it
                in background using the timer services, do not try call
                it in foreground from your program.

See Also:       None.


DSMSetupVoices
─────────────────────────────────────────────────────────────────────────────
Function:       Setup the amount of voice channels.

Prototype:      void DSMSetupVoices(word MaxVoices, word MastVolume)

Parameters:     MaxVoices   - Number of channels to be opened
                MastVolume  - Master volume level

Returns:        None.

Remarks:        This function must be called before any sound can be
                played. You can call this function many times, but only
                while the voice channels are stopped. Currently DSIK
                supports upto 16 different channels, and the master
                volume level goes from 0 to 255. Actually the master
                volume parameter has effect only in SB soundcards.
                A recommended value for the master volume is:
                    MastVolume = 384/MaxVoices
                where MaxVoices is the amount of opened channels.

See Also:       DSMInit, DSMStopVoices.


DSMStopVoices
─────────────────────────────────────────────────────────────────────────────
Function:       Stops all the voice channels.

Prototype:      void DSMStopVoices(void)

Parameters:     Note.

Returns:        None.

Remarks:        This routine will stop all the currently active voice
                channels. You should call this routine before changing
                the amount of voices with DSMSetupVoices.
                However, this routine won't stop playing the current
                music module, to do that you should call DSMStopMusic.

See Also:       DSMSetupVoices, DSMStopMusic.


DSMTypeOfRAM
─────────────────────────────────────────────────────────────────────────────
Function:       Returns the type of RAM used by the soundcard driver.

Prototype:      int DSMTypeOfRAM(void)

Parameters:     Note.

Returns:        RAM_NONE    - Driver not initialized
                RAM_SYSTEM  - Driver uses system memory
                RAM_CARD    - Driver uses soundcard memory

Remarks:        This is an internal routine used to know which kind of
                memory the soundcard uses. For example, the GUS soundcard
                uses his own soundcard memory, so the loading routines
                will upload the sample digital data to the soundcard
                and then release it from system memory.

See Also:       DSMAllocSampleData, DSMFreeSampleData.


DSMAllocSampleData
─────────────────────────────────────────────────────────────────────────────
Function:       Allocates and uploads the sample to the soundcard memory.

Prototype:      int DSMAllocSampleData(DSMInst *Inst)

Parameters:     Inst        - Sample instrument structure

Returns:        On success, returns a zero value.
                On error, returns a non zero value.

Remarks:        This is an internal routine used to allocate and upload
                the digital sample data to the soundcard. This function
                has no effect for soundcards which are using only system
                memory to hold digital samples.

See Also:       DSMTypeOfRAM, DSMFreeSampleData.


DSMFreeSampleData
─────────────────────────────────────────────────────────────────────────────
Function:       Frees the sample from the soundcard memory.

Prototype:      void DSMFreeSampleData(DSMInst *Inst)

Parameters:     Inst        - Sample instrument structure

Returns:        None.

Remarks:        This is an internal routine used to free the sample data
                from the soundcard memory, which was allocated using the
                DSMAllocSampleData routine.

See Also:       DSMTypeOfRAM, DSMAllocSampleData.


DSMPlaySample
─────────────────────────────────────────────────────────────────────────────
Function:       Play a sample instrument.

Prototype:      void DSMPlaySample(word Voice, DSMInst *Inst)

Parameters:     Voice       - Voice channel number
                Inst        - Sample instrument structure

Returns:        None.

Remarks:        This routine will play the specified sample into the
                desired voice channel number at the default frequency
                and volume, which are included in the sample instrument
                structure (fields Period and Volume).

See Also:       DSMStopSample, DSMSetPeriod, DSMSetVolume, DSMSetBalance,
                DSMSetSoundVolume, DSMSetupVoices, DSMStopVoices.


DSMStopSample
─────────────────────────────────────────────────────────────────────────────
Function:       Stops a sample instrument.

Prototype:      void DSMStopSample(word Voice)

Parameters:     Voice       - Voice channel number

Returns:        None.

Remarks:        This routine will stop the sample which is being played
                at the specified channel number.

See Also:       DSMPlaySample, DSMSetPeriod, DSMSetVolume, DSMSetBalance,
                DSMSetSoundVolume, DSMSetupVoices, DSMStopVoices.


DSMSetPeriod
─────────────────────────────────────────────────────────────────────────────
Function:       Changes the channel period value.

Prototype:      void DSMSetPeriod(word Voice, word Period)

Parameters:     Voice       - Voice channel number
                Period      - Period value (28-6848)

Returns:        None.

Remarks:        This routine will change the period of the specified voice
                channel number. You can translate frequency values in hertz
                to period values using the following formula:
                    Period = 8363*428/Hertz

See Also:       DSMPlaySample, DSMStopSample, DSMSetVolume, DSMSetBalance,
                DSMSetSoundVolume, DSMSetupVoices, DSMStopVoices.


DSMSetVolume
─────────────────────────────────────────────────────────────────────────────
Function:       Changes the channel volume level.

Prototype:      void DSMSetVolume(word Voice, word Volume)

Parameters:     Voice       - Voice channel number
                Volume      - Volume level (0-64)

Returns:        None.

Remarks:        This routine will change the volume of the specified voice
                channel number. The volume level goes from 0 to 64.

See Also:       DSMPlaySample, DSMStopSample, DSMSetPeriod, DSMSetBalance,
                DSMSetSoundVolume, DSMSetupVoices, DSMStopVoices.


DSMSetBalance
─────────────────────────────────────────────────────────────────────────────
Function:       Changes the channel panning position.

Prototype:      void DSMSetBalance(word Voice, word Balance)

Parameters:     Voice       - Voice channel number
                Balance     - Vanning position (0-128,228)

Returns:        None.

Remarks:        This routine will change the panning position of the
                specified voice channel number. The panning value goes
                from 0x00 to 0x80 (left to right panning) and 0xA4 for
                surround effects. Here is a list of defined equates:

                Constant    Value   Meaning
                ────────────────────────────────────
                PAN_LEFT    0x00    Left panning
                PAN_RIGHT   0x80    Right panning
                PAN_DOLBY   0xA4    Surround effect

                This routine has effect only in stereo soundcards.

See Also:       DSMPlaySample, DSMStopSample, DSMSetPeriod, DSMSetVolume,
                DSMSetSoundVolume, DSMSetupVoices, DSMStopVoices.


DSMSetMusicVolume
─────────────────────────────────────────────────────────────────────────────
Function:       Changes the global volume for all the music channels.

Prototype:      void DSMSetMusicVolume(word Volume)

Parameters:     Volume      - Volume level (0-255)

Returns:        None.

Remarks:        This routine will change the global music volume for
                all the music channels. It's very useful to do fades
                and for games which are playing sounds over music.
                Notice that this volume level goes from 0 to 255
                (not from 0 to 64 like for individual channels).

See Also:       DSMPlayMusic, DSMSetSoundVolume, DSMSetupVoices.


DSMSetSoundVolume
─────────────────────────────────────────────────────────────────────────────
Function:       Changes the global volume for the sound effects channels.

Prototype:      void DSMSetSoundVolume(word Volume)

Parameters:     Volume      - Volume level (0-255)

Returns:        None.

Remarks:        This routine will change the global sound effects volume
                for all the non-music channels. The sound effect channels
                are those which are not used to play the current music
                module.

See Also:       DSMPlayMusic, DSMSetMusicVolume, DSMSetupVoices.


DSMPlayMusic
─────────────────────────────────────────────────────────────────────────────
Function:       Start playing a music module.

Prototype:      void DSMPlayMusic(DSM *Module)

Parameters:     Module      - Music module address

Returns:        None.

Remarks:        This routine will start playing the music module. You should
                be sure to have enough channels opened to play the music, or
                you won't hear some of the music track channels.

See Also:       DSMStopMusic, DSMSetMusicVolume, DSMSetupVoices.


DSMStopMusic
─────────────────────────────────────────────────────────────────────────────
Function:       Stops playing the current music module.

Prototype:      void DSMStopMusic(void)

Parameters:     Note.

Returns:        None.

Remarks:        This routine will stop playing the current music module.
                You must call this routine before calling DSMPlayMusic
                to play another music module.

See Also:       DSMPlayMusic, DSMSetMusicVolume, DSMSetupVoices.


DSMGetMusicStatus
─────────────────────────────────────────────────────────────────────────────
Function:       Returns the current playing status of the music.

Prototype:      int DSMGetMusicStatus(void)

Parameters:     Note.

Returns:        PS_STOPPED  - No music is being played
                PS_PLAYING  - Music is being played

Remarks:        None.

See Also:       DSMPlayMusic, DSMStopMusic.


DSMGetMusicInfo
─────────────────────────────────────────────────────────────────────────────
Function:       Returns the music information structure.

Prototype:      DSMMusicInfo *DSMGetMusicStatus(void)

Parameters:     Note.

Returns:        Static music information structure address.

Remarks:        This routine is useful to get all the information that
                you will need to know what is going on (tracks data,
                current pattern, tempo, speed, etc).

See Also:       DSMMusicInfo.


DSMLoad
─────────────────────────────────────────────────────────────────────────────
Function:       Loads a DSM music module from disk.

Prototype:      DSM *DSMLoad(char *FileName, dword FileOffset)

Parameters:     FileName    - Full path filename
                FileOffset  - Start of the module within the file

Returns:        The module address in memory or NULL if an error occurred
                while loading it from disk.

Remarks:        This routine will load an DSM file from disk. You should
                convert different file formats like MODs, S3Ms, etc. to
                DSM files using the CONV.EXE utility.
                If something went wrong while loading the module file, this
                function returns NULL and the global variable DSMStatus is
                set to one of the following values:

                Constant    Value   Meaning
                ────────────────────────────────────────────────
                ERR_NORAM   1       Not enough system memory
                ERR_NODRAM  2       Not enough soundcard memory
                ERR_NOFILE  3       Module file not found
                ERR_FORMAT  4       Invalid file format
                ERR_ACCESS  5       File corrupted

See Also:       DSMFree.


DSMFree
─────────────────────────────────────────────────────────────────────────────
Function:       Frees a music module from memory.

Prototype:      void DSMFree(DSM *Module)

Parameters:     Module      - Music module

Returns:        None.

Remarks:        This routine will free an DSM module from memory. You
                cannot free a module while it's being played.

See Also:       DSMLoad.


DSMLoadSample
─────────────────────────────────────────────────────────────────────────────
Function:       Loads a WAVE sample instrument file from disk.

Prototype:      DSMInst *DSMLoadSample(char *FileName, dword FileOffset)

Parameters:     FileName    - Full path filename
                FileOffset  - Start of the sample within the file

Returns:        The sample instrument address or NULL if an error occurred
                while loading it from disk.

Remarks:        This routine will loads an standard RIFF/WAVE sample file
                from disk. You should convert other sample file formats
                like VOC, AU, etc. to WAV using any third-party conversion
                utility.
                If something went wrong, the function returns NULL and the
                global variable DSMStatus is set with the error type.

See Also:       DSMFreeSample, DSMLoad.


DSMFreeSample
─────────────────────────────────────────────────────────────────────────────
Function:       Frees a sample instrument file from memory.

Prototype:      void DSMLoadSample(DSMInst *Inst)

Parameters:     Inst        - Sample instrument

Returns:        None.

Remarks:        This routine will free the sample instrument from memory.
                You cannot free it while it's being played.

See Also:       DSMLoadSample.


DSMLoadSetup
─────────────────────────────────────────────────────────────────────────────
Function:       Loads the soundcard configuration file from disk.

Prototype:      int DSMLoadSetup(DSMCard *Card)

Parameters:     Card        - Soundcard configuration structure

Returns:        On success, returns a zero value.
                On error, returns a non zero value.

Remarks:        This routine will loads the file called SOUND.CFG with
                the soundcard hardware parameters. This file is created
                with the external program SETUP.EXE, or calling the
                function DSMSaveSetup.

See Also:       DSMSaveSetup.


DSMSaveSetup
─────────────────────────────────────────────────────────────────────────────
Function:       Saves the soundcard configuration file to disk.

Prototype:      int DSMSaveSetup(DSMCard *Card)

Parameters:     Card        - Soundcard configuration structure

Returns:        On success, returns a zero value.
                On error, returns a non zero value.

Remarks:        This routine will save the soundcard structure to the
                file called SOUND.CFG.

See Also:       DSMLoadSetup.


4.2 Structures

DSM structure
─────────────────────────────────────────────────────────────────────────────
Declaration:    typedef struct {
                    DSMSong Song;
                    DSMInst far *Inst[MAXSAMPLES];
                    DSMPatt far *Patt[MAXORDERS];
                } DSM;

Function:       DSM is a structure which holds all the information about
                the music module loaded in memory. This structure is loaded
                from disk by DSMLoad and is used by DSMPlayMusic.

Fields:         Song        - Main structure which holds the information
                              about the module music
                Inst        - List of sample instruments used by the module
                Patt        - List of patterns used by the module

See Also:       DSMSong, DSMInst, DSMLoad.


DSMSong structure
─────────────────────────────────────────────────────────────────────────────
Declaration:    typedef struct {
                    char    SongName[28];
                    word    Version;
                    word    Flags;
                    dword   Pad;
                    word    NumOrders;
                    word    NumSamples;
                    word    NumPatterns;
                    word    NumChannels;
                    byte    GlobalVolume;
                    byte    MasterVolume;
                    byte    InitTempo;
                    byte    InitBPM;
                    byte    ChanMap[MAXTRACKS];
                    byte    Orders[MAXORDERS];
                } DSMSong;

Function:       This structure holds information about the module like
                the amount of samples, patterns, orders, etc. This is
                the main body of the music module, which uses the other
                resources, like the samples and patterns, to interpret
                and playback the music theme.

Fields:         SongName    - Name of the music module song
                Version     - Module file format
                Flags       - Module flags
                NumOrders   - Length of the order list
                NumSamples  - Number of sample instruments
                NumPatterns - Number of pattern sheets
                GlobVolume  - Global music volume
                MastVolume  - Master volume
                InitTempo   - Initial tempo value
                InitBPM     - Initial BPM value
                ChanMap     - Initial track's panning values
                Orders      - Order list

See Also:       DSM, DSMLoad.


DSMInst structure
─────────────────────────────────────────────────────────────────────────────
Declaration:    typedef struct {
                    char    FileName[13];
                    word    Flags;
                    byte    Volume;
                    dword   Length;
                    dword   LoopStart;
                    dword   LoopEnd;
                    void    far *Address;
                    word    MidCRate;
                    word    Period;
                    char    SampleName[28];
                } DSMInst;

Function:       DSMInst is a structure which holds all the information
                about an sample instrument. You can load individual
                samples from disk using DSMLoadSample.
                The sample bit flags are defined as follows:

                Constant    Value   Meaning
                ──────────────────────────────────────
                INST_LOOPED 0x01    Looping enabled
                INST_SIGNED 0x02    Signed samples
                INST_PACKED 0x04    Packed samples

Fields:         FileName    - File name of the sample instrument
                Flags       - Sample bit flags.
                Volume      - Default volume
                Length      - Length of the sample
                LoopStart   - Loop start point
                LoopEnd     - Loop end point
                Address     - Used internally to hold the address of
                              the raw sample data in system memory
                              or soundcard memory.
                MidCRate    - Middle-C frequency finetune value
                Period      - Default period value
                SampleName  - Name of the sample instrument

See Also:       DSM, DSMLoad, DSMLoadSample, DSMPlaySample.


DSMCard structure
─────────────────────────────────────────────────────────────────────────────
Declaration:    typedef struct {
                    byte    CardID;
                    word    IOAddr;
                    byte    IRQNum;
                    byte    DRQNum;
                    word    MixRate;
                } DSMCard;

Function:       DSMCard holds the soundcard configuration parameters. This
                structure is required by DSMInit to initialize the sound
                system. Here is the list of supported soundcards:

                Constant    Value   Soundcard Device
                ────────────────────────────────────────
                ID_NONE     0       None
                ID_SB       1       Sound Blaster
                ID_SB201    2       Sound Blaster 2.01
                ID_SBPRO    3       Sound Blaster Pro
                ID_SB16     4       Sound Blaster 16
                ID_GUS      5       Gravis Ultrasound

Fields:         CardID      - Soundcard ID number
                IOAddr      - I/O port address
                IRQNum      - IRQ line
                DRQNum      - DMA channel
                MixRate     - Mixing rate

See Also:       DSMInit, DSMLoadSetup, DSMSaveSetup.


DSMMusicInfo structure
─────────────────────────────────────────────────────────────────────────────
Declaration:    typedef struct {
                    word    ActiveTracks;
                    Track   Tracks[MAXTRACKS];
                    byte    OrderPosition;
                    byte    OrderLength;
                    byte    PatternNumber;
                    byte    PatternRow;
                    byte    BreakFlag;
                    byte    Tempo;
                    byte    TempoCount;
                    byte    BPM;
                    word    CardStatus;
                    word    PlayStatus;
                    dword   SongPtr;
                    byte    SyncMark;
                } DSMMusicInfo;

Function:       This structure is used internally by the system to keep
                track of everything that is needed to play a music module.
                You can access the static instance of this structure used
                by the system using the function DSMGetMusicInfo.

Fields:         ActiveTracks    - Number of active tracks
                Tracks          - Tracks data
                OrderPosition   - Current playing position
                OrderLength     - Length of the order list
                PatternNumber   - Current playing pattern
                PatternRow      - Current pattern row
                BreakFlag       - Flag used to break patterns
                                  and for jump position commands
                Tempo           - Current speed of the music
                BPM             - Current BPM of the music
                SyncMark        - The last synchronization mark
                                  encountered in the patterns
                SongPtr         - Address of the playing module

See Also:       DSMGetMusicInfo, Track.


Track structure
─────────────────────────────────────────────────────────────────────────────
Declaration:    typedef struct {
                    word    NoteEvent;
                    byte    VolumeEvent;
                    byte    Note;
                    byte    Sample;
                    byte    Volume;
                    word    Effect;
                    word    Period;
                    byte    EQBar;
                    byte    Reserved[...];
                } Track;

Function:       Track is a structure which hold all the information of
                each music track channel. There is an array of Tracks
                in the DSMMusicInfo structure which is used by the
                system to interpret the music patterns.

Fields:         NoteEvent   - Last note and sample readed from the patterns
                VolumeEvent - Last volume field readed from the patterns
                Note        - Note index number
                Sample      - Sample instrument number
                Volume      - Volume level
                Effect      - Effect command
                Period      - Period value
                EQBar       - Equalizer level

See Also:       DSMMusicInfo.