midi.c

来自「An interactive water fountain. A realis」· C语言 代码 · 共 2,070 行 · 第 1/4 页

/*
Copyright (C) 1994-1995 Apogee Software, Ltd.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program 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 General Public License for more details.

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

Modifications for JonoF's port by Jonathon Fowler ([e-mail])
*/
/**********************************************************************
   module: MIDI.C

   author: James R. Dose
   date:   May 25, 1994

   Midi song file playback routines.

   (c) Copyright 1994 James R. Dose.  All Rights Reserved.
**********************************************************************/

#include <stdlib.h>
#include <string.h>
#include "standard.h"
#include "music.h"
#include "_midi.h"
#include "midi.h"
#include "mpu401.h"
#include "compat.h"

#define WIN32_LEAN_AND_MEAN
#include <windows.h>

extern int32_t MUSIC_SoundDevice;

static const int32_t _MIDI_CommandLengths[ NUM_MIDI_CHANNELS ] =
{
    0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 2, 2, 1, 1, 2, 0
};

static int32_t(*_MIDI_RerouteFunctions[ NUM_MIDI_CHANNELS ])
(
    int32_t event,
    int32_t c1,
    int32_t c2
) =
{
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL,
    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
};

static track *_MIDI_TrackPtr = NULL;
static int32_t    _MIDI_TrackMemSize;
static int32_t    _MIDI_NumTracks;

static int32_t _MIDI_SongActive = FALSE;
static int32_t _MIDI_SongLoaded = FALSE;
static int32_t _MIDI_Loop = FALSE;

static int32_t  _MIDI_Division;
static int32_t  _MIDI_Tick    = 0;
static int32_t  _MIDI_Beat    = 1;
static int32_t  _MIDI_Measure = 1;
static unsigned _MIDI_Time;
static int32_t  _MIDI_BeatsPerMeasure;
static int32_t  _MIDI_TicksPerBeat;
static int32_t  _MIDI_TimeBase;
static int32_t _MIDI_FPSecondsPerTick;
static unsigned _MIDI_TotalTime;
static int32_t  _MIDI_TotalTicks;
static int32_t  _MIDI_TotalBeats;
static int32_t  _MIDI_TotalMeasures;

uint32_t _MIDI_PositionInTicks;
uint32_t _MIDI_GlobalPositionInTicks;

static int32_t  _MIDI_Context;

static int32_t _MIDI_ActiveTracks;
static int32_t _MIDI_TotalVolume = MIDI_MaxVolume;

static int32_t _MIDI_ChannelVolume[ NUM_MIDI_CHANNELS ];
static int32_t _MIDI_UserChannelVolume[ NUM_MIDI_CHANNELS ] =
{
    256, 256, 256, 256, 256, 256, 256, 256,
    256, 256, 256, 256, 256, 256, 256, 256
};

static midifuncs *_MIDI_Funcs = NULL;

static int32_t Reset = FALSE;

int32_t MIDI_Tempo = 120;

char MIDI_PatchMap[ 128 ];


/**********************************************************************

   Memory locked functions:

**********************************************************************/


/*---------------------------------------------------------------------
   Function: _MIDI_ReadNumber

   Reads a variable length number from a MIDI track.
---------------------------------------------------------------------*/

static int32_t _MIDI_ReadNumber
(
    void *from,
    size_t size
)

{
    char *FromPtr;
    int32_t          value;

    if (size > 4)
    {
        size = 4;
    }

    FromPtr = (char *)from;

    value = 0;
    while (size--)
    {
        value <<= 8;
        value += *FromPtr++;
    }

    return(value);
}


/*---------------------------------------------------------------------
   Function: _MIDI_ReadDelta

   Reads a variable length encoded delta delay time from the MIDI data.
---------------------------------------------------------------------*/

static int32_t _MIDI_ReadDelta
(
    track *ptr
)

{
    int32_t          value;
    char c;

    GET_NEXT_EVENT(ptr, value);

    if (value & 0x80)
    {
        value &= 0x7f;
        do
        {
            GET_NEXT_EVENT(ptr, c);
            value = (value << 7) + (c & 0x7f);
        }
        while (c & 0x80);
    }

    return(value);
}


/*---------------------------------------------------------------------
   Function: _MIDI_ResetTracks

   Sets the track pointers to the beginning of the song.
---------------------------------------------------------------------*/

static void _MIDI_ResetTracks
(
    void
)

{
    int32_t    i;
    track *ptr;

    _MIDI_Tick = 0;
    _MIDI_Beat = 1;
    _MIDI_Measure = 1;
    _MIDI_Time = 0;
    _MIDI_BeatsPerMeasure = 4;
    _MIDI_TicksPerBeat = _MIDI_Division;
    _MIDI_TimeBase = 4;

    _MIDI_PositionInTicks = 0;
    //_MIDI_GlobalPositionInTicks = 0;
    _MIDI_ActiveTracks    = 0;
    _MIDI_Context         = 0;

    ptr = _MIDI_TrackPtr;
    for (i = 0; i < _MIDI_NumTracks; i++)
    {
        ptr->pos                    = ptr->start;
        ptr->delay                  = _MIDI_ReadDelta(ptr);
        ptr->active                 = ptr->EMIDI_IncludeTrack;
        ptr->RunningStatus          = 0;
        ptr->currentcontext         = 0;
        ptr->context[ 0 ].loopstart = ptr->start;
        ptr->context[ 0 ].loopcount = 0;

        if (ptr->active)
        {
            _MIDI_ActiveTracks++;
        }

        ptr++;
    }
}


/*---------------------------------------------------------------------
   Function: _MIDI_AdvanceTick

   Increment tick counters.
---------------------------------------------------------------------*/

static void _MIDI_AdvanceTick
(
    void
)

{
    _MIDI_PositionInTicks++;
    _MIDI_Time += _MIDI_FPSecondsPerTick;

    _MIDI_Tick++;
    while (_MIDI_Tick > _MIDI_TicksPerBeat)
    {
        _MIDI_Tick -= _MIDI_TicksPerBeat;
        _MIDI_Beat++;
    }
    while (_MIDI_Beat > _MIDI_BeatsPerMeasure)
    {
        _MIDI_Beat -= _MIDI_BeatsPerMeasure;
        _MIDI_Measure++;
    }
}


/*---------------------------------------------------------------------
   Function: _MIDI_SysEx

   Interpret SysEx Event.
---------------------------------------------------------------------*/

static void _MIDI_SysEx
(
    track *Track
)

{
    int32_t length;

    length = _MIDI_ReadDelta(Track);
    Track->pos += length;
}


/*---------------------------------------------------------------------
   Function: _MIDI_MetaEvent

   Interpret Meta Event.
---------------------------------------------------------------------*/

static void _MIDI_MetaEvent
(
    track *Track
)

{
    int32_t   command;
    int32_t   length;
    int32_t   denominator;
    int32_t  tempo;

    GET_NEXT_EVENT(Track, command);
    GET_NEXT_EVENT(Track, length);

    switch (command)
    {
    case MIDI_END_OF_TRACK :
        Track->active = FALSE;

        _MIDI_ActiveTracks--;
        break;

    case MIDI_TEMPO_CHANGE :
        tempo = 60000000L / _MIDI_ReadNumber(Track->pos, 3);
        MIDI_SetTempo(tempo);
        break;

    case MIDI_TIME_SIGNATURE :
        if ((_MIDI_Tick > 0) || (_MIDI_Beat > 1))
        {
            _MIDI_Measure++;
        }

        _MIDI_Tick = 0;
        _MIDI_Beat = 1;

        _MIDI_BeatsPerMeasure = (int32_t)*Track->pos;
        denominator = (int32_t)*(Track->pos + 1);
        _MIDI_TimeBase = 1;
        while (denominator > 0)
        {
            _MIDI_TimeBase += _MIDI_TimeBase;
            denominator--;
        }
        _MIDI_TicksPerBeat = (_MIDI_Division * 4) / _MIDI_TimeBase;
        break;
    }

    Track->pos += length;
}


/*---------------------------------------------------------------------
   Function: _MIDI_InterpretControllerInfo

   Interprets the MIDI controller info.
---------------------------------------------------------------------*/

static int32_t _MIDI_InterpretControllerInfo
(
    track *Track,
    int32_t   TimeSet,
    int32_t   channel,
    int32_t   c1,
    int32_t   c2
)

{
    track *trackptr;
    int32_t tracknum;
    int32_t loopcount;

    switch (c1)
    {
    case MIDI_MONO_MODE_ON :
        Track->pos++;
        break;

    case MIDI_VOLUME :
        if (!Track->EMIDI_VolumeChange)
        {
            _MIDI_SetChannelVolume(channel, c2);
        }
        break;

    case EMIDI_INCLUDE_TRACK :
    case EMIDI_EXCLUDE_TRACK :
        break;

    case EMIDI_PROGRAM_CHANGE :
        if (Track->EMIDI_ProgramChange)
        {
            _MIDI_Funcs->ProgramChange(channel, MIDI_PatchMap[ c2 & 0x7f ]);
        }
        break;

    case EMIDI_VOLUME_CHANGE :
        if (Track->EMIDI_VolumeChange)
        {
            _MIDI_SetChannelVolume(channel, c2);
        }
        break;

    case EMIDI_CONTEXT_START :
        break;

    case EMIDI_CONTEXT_END :
        if ((Track->currentcontext == _MIDI_Context) ||
                (_MIDI_Context < 0) ||
                (Track->context[ _MIDI_Context ].pos == NULL))
        {
            break;
        }

        Track->currentcontext = _MIDI_Context;
        Track->context[ 0 ].loopstart = Track->context[ _MIDI_Context ].loopstart;
        Track->context[ 0 ].loopcount = Track->context[ _MIDI_Context ].loopcount;
        Track->pos           = Track->context[ _MIDI_Context ].pos;
        Track->RunningStatus = Track->context[ _MIDI_Context ].RunningStatus;

        if (TimeSet)
        {
            break;
        }

        _MIDI_Time             = Track->context[ _MIDI_Context ].time;
        _MIDI_FPSecondsPerTick = Track->context[ _MIDI_Context ].FPSecondsPerTick;
        _MIDI_Tick             = Track->context[ _MIDI_Context ].tick;
        _MIDI_Beat             = Track->context[ _MIDI_Context ].beat;
        _MIDI_Measure          = Track->context[ _MIDI_Context ].measure;
        _MIDI_BeatsPerMeasure  = Track->context[ _MIDI_Context ].BeatsPerMeasure;
        _MIDI_TicksPerBeat     = Track->context[ _MIDI_Context ].TicksPerBeat;
        _MIDI_TimeBase         = Track->context[ _MIDI_Context ].TimeBase;
        TimeSet = TRUE;
        break;

    case EMIDI_LOOP_START :
    case EMIDI_SONG_LOOP_START :
        if (c2 == 0)
        {
            loopcount = EMIDI_INFINITE;
        }
        else
        {
            loopcount = c2;
        }

        if (c1 == EMIDI_SONG_LOOP_START)
        {
            trackptr = _MIDI_TrackPtr;
            tracknum = _MIDI_NumTracks;
        }
        else
        {
            trackptr = Track;
            tracknum = 1;
        }

        while (tracknum > 0)
        {
            trackptr->context[ 0 ].loopcount        = loopcount;
            trackptr->context[ 0 ].pos              = trackptr->pos;
            trackptr->context[ 0 ].loopstart        = trackptr->pos;
            trackptr->context[ 0 ].RunningStatus    = trackptr->RunningStatus;
            trackptr->context[ 0 ].active           = trackptr->active;
            trackptr->context[ 0 ].delay            = trackptr->delay;
            trackptr->context[ 0 ].time             = _MIDI_Time;
            trackptr->context[ 0 ].FPSecondsPerTick = _MIDI_FPSecondsPerTick;
            trackptr->context[ 0 ].tick             = _MIDI_Tick;
            trackptr->context[ 0 ].beat             = _MIDI_Beat;
            trackptr->context[ 0 ].measure          = _MIDI_Measure;
            trackptr->context[ 0 ].BeatsPerMeasure  = _MIDI_BeatsPerMeasure;
            trackptr->context[ 0 ].TicksPerBeat     = _MIDI_TicksPerBeat;
            trackptr->context[ 0 ].TimeBase         = _MIDI_TimeBase;
            trackptr++;
            tracknum--;
        }
        break;

    case EMIDI_LOOP_END :
    case EMIDI_SONG_LOOP_END :
        if ((c2 != EMIDI_END_LOOP_VALUE) ||
                (Track->context[ 0 ].loopstart == NULL) ||
                (Track->context[ 0 ].loopcount == 0))
        {
            break;
        }

        if (c1 == EMIDI_SONG_LOOP_END)
        {
            trackptr = _MIDI_TrackPtr;
            tracknum = _MIDI_NumTracks;
            _MIDI_ActiveTracks = 0;
        }
        else
        {
            trackptr = Track;
            tracknum = 1;
            _MIDI_ActiveTracks--;
        }

        while (tracknum > 0)
        {
            if (trackptr->context[ 0 ].loopcount != EMIDI_INFINITE)
            {
                trackptr->context[ 0 ].loopcount--;
            }

            trackptr->pos           = trackptr->context[ 0 ].loopstart;
            trackptr->RunningStatus = trackptr->context[ 0 ].RunningStatus;
            trackptr->delay         = trackptr->context[ 0 ].delay;
            trackptr->active        = trackptr->context[ 0 ].active;
            if (trackptr->active)
            {
                _MIDI_ActiveTracks++;
            }

            if (!TimeSet)
            {
                _MIDI_Time             = trackptr->context[ 0 ].time;
                _MIDI_FPSecondsPerTick = trackptr->context[ 0 ].FPSecondsPerTick;
                _MIDI_Tick             = trackptr->context[ 0 ].tick;
                _MIDI_Beat             = trackptr->context[ 0 ].beat;
                _MIDI_Measure          = trackptr->context[ 0 ].measure;
                _MIDI_BeatsPerMeasure  = trackptr->context[ 0 ].BeatsPerMeasure;
                _MIDI_TicksPerBeat     = trackptr->context[ 0 ].TicksPerBeat;
                _MIDI_TimeBase         = trackptr->context[ 0 ].TimeBase;
                TimeSet = TRUE;
            }

            trackptr++;
            tracknum--;
        }
        break;