midi.c

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

   Sets the position of the song pointer.
---------------------------------------------------------------------*/

void MIDI_SetSongTime
(
    uint32_t milliseconds
)

{
    uint32_t mil;
    uint32_t sec;
    uint32_t newtime;

    if (!_MIDI_SongLoaded)
    {
        return;
    }

    MIDI_PauseSong();

    mil = ((milliseconds % 1000) << TIME_PRECISION) / 1000;
    sec = (milliseconds / 1000) << TIME_PRECISION;
    newtime = sec + mil;

    if (newtime < _MIDI_Time)
    {
        _MIDI_ResetTracks();
        MIDI_Reset();
    }

    while (_MIDI_Time < newtime)
    {
        if (_MIDI_ProcessNextTick())
        {
            break;
        }
        if (_MIDI_ActiveTracks == 0)
        {
            _MIDI_ResetTracks();
            if (!_MIDI_Loop)
            {
                return;
            }
            break;
        }
    }

    MIDI_SetVolume(_MIDI_TotalVolume);
    MIDI_ContinueSong();
}


/*---------------------------------------------------------------------
   Function: MIDI_SetSongPosition

   Sets the position of the song pointer.
---------------------------------------------------------------------*/

void MIDI_SetSongPosition
(
    int32_t measure,
    int32_t beat,
    int32_t tick
)

{
    uint32_t pos;

    if (!_MIDI_SongLoaded)
    {
        return;
    }

    MIDI_PauseSong();

    pos = RELATIVE_BEAT(measure, beat, tick);

    if (pos < (uint32_t)RELATIVE_BEAT(_MIDI_Measure, _MIDI_Beat, _MIDI_Tick))
    {
        _MIDI_ResetTracks();
        MIDI_Reset();
    }

    while ((uint32_t)RELATIVE_BEAT(_MIDI_Measure, _MIDI_Beat, _MIDI_Tick) < pos)
    {
        if (_MIDI_ProcessNextTick())
        {
            break;
        }
        if (_MIDI_ActiveTracks == 0)
        {
            _MIDI_ResetTracks();
            if (!_MIDI_Loop)
            {
                return;
            }
            break;
        }
    }

    MIDI_SetVolume(_MIDI_TotalVolume);
    MIDI_ContinueSong();
}


/*---------------------------------------------------------------------
   Function: MIDI_GetSongPosition

   Returns the position of the song pointer in Measures, beats, ticks.
---------------------------------------------------------------------*/

void MIDI_GetSongPosition
(
    songposition *pos
)

{
    uint32_t mil;
    uint32_t sec;

    mil = (_MIDI_Time & ((1 << TIME_PRECISION) - 1)) * 1000;
    sec = _MIDI_Time >> TIME_PRECISION;
    pos->milliseconds = (mil >> TIME_PRECISION) + (sec * 1000);
    pos->tickposition = _MIDI_PositionInTicks;
    pos->measure      = _MIDI_Measure;
    pos->beat         = _MIDI_Beat;
    pos->tick         = _MIDI_Tick;
}


/*---------------------------------------------------------------------
   Function: MIDI_GetSongLength

   Returns the length of the song.
---------------------------------------------------------------------*/

void MIDI_GetSongLength
(
    songposition *pos
)

{
    uint32_t mil;
    uint32_t sec;

    mil = (_MIDI_TotalTime & ((1 << TIME_PRECISION) - 1)) * 1000;
    sec = _MIDI_TotalTime >> TIME_PRECISION;

    pos->milliseconds = (mil >> TIME_PRECISION) + (sec * 1000);
    pos->measure      = _MIDI_TotalMeasures;
    pos->beat         = _MIDI_TotalBeats;
    pos->tick         = _MIDI_TotalTicks;
    pos->tickposition = 0;
}


/*---------------------------------------------------------------------
   Function: MIDI_InitEMIDI

   Sets up the EMIDI
---------------------------------------------------------------------*/

static void _MIDI_InitEMIDI
(
    void
)

{
    int32_t    event;
    int32_t    command;
    int32_t    channel;
    int32_t    length;
    int32_t    IncludeFound;
    track *Track;
    int32_t    tracknum;
    int32_t    type;
    int32_t    c1;
    int32_t    c2;

    type = EMIDI_GeneralMIDI;

    _MIDI_ResetTracks();

    _MIDI_TotalTime     = 0;
    _MIDI_TotalTicks    = 0;
    _MIDI_TotalBeats    = 0;
    _MIDI_TotalMeasures = 0;

    Track = _MIDI_TrackPtr;
    tracknum = 0;
    while ((tracknum < _MIDI_NumTracks) && (Track != NULL))
    {
        _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_ActiveTracks    = 0;
        _MIDI_Context         = -1;

        Track->RunningStatus = 0;
        Track->active        = TRUE;

        Track->EMIDI_ProgramChange = FALSE;
        Track->EMIDI_VolumeChange  = FALSE;
        Track->EMIDI_IncludeTrack  = TRUE;

        memset(Track->context, 0, sizeof(Track->context));

        while (Track->delay > 0)
        {
            _MIDI_AdvanceTick();
            Track->delay--;
        }

        IncludeFound = FALSE;
        while (Track->active)
        {
            GET_NEXT_EVENT(Track, event);

            if (GET_MIDI_COMMAND(event) == MIDI_SPECIAL)
            {
                switch (event)
                {
                case MIDI_SYSEX :
                case MIDI_SYSEX_CONTINUE :
                    _MIDI_SysEx(Track);
                    break;

                case MIDI_META_EVENT :
                    _MIDI_MetaEvent(Track);
                    break;
                }

                if (Track->active)
                {
                    Track->delay = _MIDI_ReadDelta(Track);
                    while (Track->delay > 0)
                    {
                        _MIDI_AdvanceTick();
                        Track->delay--;
                    }
                }

                continue;
            }

            if (event & MIDI_RUNNING_STATUS)
            {
                Track->RunningStatus = event;
            }
            else
            {
                event = Track->RunningStatus;
                Track->pos--;
            }

            channel = GET_MIDI_CHANNEL(event);
            command = GET_MIDI_COMMAND(event);
            length = _MIDI_CommandLengths[ command ];

            if (command == MIDI_CONTROL_CHANGE)
            {
                if (*Track->pos == MIDI_MONO_MODE_ON)
                {
                    length++;
                }
                GET_NEXT_EVENT(Track, c1);
                GET_NEXT_EVENT(Track, c2);
                length -= 2;

                switch (c1)
                {
                case EMIDI_LOOP_START :
                case EMIDI_SONG_LOOP_START :
                    if (c2 == 0)
                    {
                        Track->context[ 0 ].loopcount = EMIDI_INFINITE;
                    }
                    else
                    {
                        Track->context[ 0 ].loopcount = c2;
                    }

                    Track->context[ 0 ].pos              = Track->pos;
                    Track->context[ 0 ].loopstart        = Track->pos;
                    Track->context[ 0 ].RunningStatus    = Track->RunningStatus;
                    Track->context[ 0 ].time             = _MIDI_Time;
                    Track->context[ 0 ].FPSecondsPerTick = _MIDI_FPSecondsPerTick;
                    Track->context[ 0 ].tick             = _MIDI_Tick;
                    Track->context[ 0 ].beat             = _MIDI_Beat;
                    Track->context[ 0 ].measure          = _MIDI_Measure;
                    Track->context[ 0 ].BeatsPerMeasure  = _MIDI_BeatsPerMeasure;
                    Track->context[ 0 ].TicksPerBeat     = _MIDI_TicksPerBeat;
                    Track->context[ 0 ].TimeBase         = _MIDI_TimeBase;
                    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;

                case EMIDI_INCLUDE_TRACK :
                    if (EMIDI_AffectsCurrentCard(c2, type))
                    {
                        //printf( "Include track %d on card %d\n", tracknum, c2 );
                        IncludeFound = TRUE;
                        Track->EMIDI_IncludeTrack = TRUE;
                    }
                    else if (!IncludeFound)
                    {
                        //printf( "Track excluded %d on card %d\n", tracknum, c2 );
                        IncludeFound = TRUE;
                        Track->EMIDI_IncludeTrack = FALSE;
                    }
                    break;

                case EMIDI_EXCLUDE_TRACK :
                    if (EMIDI_AffectsCurrentCard(c2, type))
                    {
                        //printf( "Exclude track %d on card %d\n", tracknum, c2 );
                        Track->EMIDI_IncludeTrack = FALSE;
                    }
                    break;

                case EMIDI_PROGRAM_CHANGE :
                    if (!Track->EMIDI_ProgramChange)
                        //printf( "Program change on track %d\n", tracknum );
                        Track->EMIDI_ProgramChange = TRUE;
                    break;

                case EMIDI_VOLUME_CHANGE :
                    if (!Track->EMIDI_VolumeChange)
                        //printf( "Volume change on track %d\n", tracknum );
                        Track->EMIDI_VolumeChange = TRUE;
                    break;

                case EMIDI_CONTEXT_START :
                    if ((c2 > 0) && (c2 < EMIDI_NUM_CONTEXTS))
                    {
                        Track->context[ c2 ].pos              = Track->pos;
                        Track->context[ c2 ].loopstart        = Track->context[ 0 ].loopstart;
                        Track->context[ c2 ].loopcount        = Track->context[ 0 ].loopcount;
                        Track->context[ c2 ].RunningStatus    = Track->RunningStatus;
                        Track->context[ c2 ].time             = _MIDI_Time;
                        Track->context[ c2 ].FPSecondsPerTick = _MIDI_FPSecondsPerTick;
                        Track->context[ c2 ].tick             = _MIDI_Tick;
                        Track->context[ c2 ].beat             = _MIDI_Beat;
                        Track->context[ c2 ].measure          = _MIDI_Measure;
                        Track->context[ c2 ].BeatsPerMeasure  = _MIDI_BeatsPerMeasure;
                        Track->context[ c2 ].TicksPerBeat     = _MIDI_TicksPerBeat;
                        Track->context[ c2 ].TimeBase         = _MIDI_TimeBase;
                    }
                    break;

                case EMIDI_CONTEXT_END :
                    break;
                }
            }

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

            while (Track->delay > 0)
            {
                _MIDI_AdvanceTick();
                Track->delay--;
            }
        }

        _MIDI_TotalTime = max(_MIDI_TotalTime, _MIDI_Time);
        if (RELATIVE_BEAT(_MIDI_Measure, _MIDI_Beat, _MIDI_Tick) >
                RELATIVE_BEAT(_MIDI_TotalMeasures, _MIDI_TotalBeats,
                              _MIDI_TotalTicks))
        {
            _MIDI_TotalTicks    = _MIDI_Tick;
            _MIDI_TotalBeats    = _MIDI_Beat;
            _MIDI_TotalMeasures = _MIDI_Measure;
        }

        Track++;
        tracknum++;
    }

    _MIDI_ResetTracks();
}


/*---------------------------------------------------------------------
   Function: MIDI_LoadTimbres

   Preloads the timbres on cards that use patch-caching.
---------------------------------------------------------------------*/

void MIDI_LoadTimbres
(
    void
)

{
    int32_t    event;
    int32_t    command;
    int32_t    channel;
    int32_t    length;
    int32_t    Finished;
    track *Track;
    int32_t    tracknum;

    Track = _MIDI_TrackPtr;
    tracknum = 0;
    while ((tracknum < _MIDI_NumTracks) && (Track != NULL))
    {
        Finished = FALSE;
        while (!Finished)
        {
            GET_NEXT_EVENT(Track, event);

            if (GET_MIDI_COMMAND(event) == MIDI_SPECIAL)
            {
                switch (event)
                {
                case MIDI_SYSEX :
                case MIDI_SYSEX_CONTINUE :
                    length = _MIDI_ReadDelta(Track);
                    Track->pos += length;
                    break;

                case MIDI_META_EVENT :
                    GET_NEXT_EVENT(Track, command);
                    GET_NEXT_EVENT(Track, length);

                    if (command == MIDI_END_OF_TRACK)
                    {
                        Finished = TRUE;
                    }

                    Track->pos += length;
                    break;
                }

                if (!Finished)
                {
                    _MIDI_ReadDelta(Track);
                }

                continue;
            }

            if (event & MIDI_RUNNING_STATUS)
            {
                Track->RunningStatus = event;
            }
            else
            {
                event = Track->RunningStatus;
                Track->pos--;
            }

            channel = GET_MIDI_CHANNEL(event);
            command = GET_MIDI_COMMAND(event);
            length = _MIDI_CommandLengths[ command ];

            if (command == MIDI_CONTROL_CHANGE)
            {
                if (*Track->pos == MIDI_MONO_MODE_ON)
                {
                    length++;
                }

                if (*Track->pos == EMIDI_PROGRAM_CHANGE)
                {
                    _MIDI_Funcs->LoadPatch(*(Track->pos + 1));
                }
            }

            if (channel == MIDI_RHYTHM_CHANNEL)
            {
                if (command == MIDI_NOTE_ON)
                {
                    _MIDI_Funcs->LoadPatch(128 + *Track->pos);
                }
            }
            else
            {
                if (command == MIDI_PROGRAM_CHANGE)
                {
                    _MIDI_Funcs->LoadPatch(*Track->pos);
                }
            }
            Track->pos += length;
            _MIDI_ReadDelta(Track);
        }
        Track++;
        tracknum++;
    }

    _MIDI_ResetTracks();
}


void MIDI_UpdateMusic(void)
{
    if (!_MIDI_SongLoaded || !_MIDI_SongActive) return;
    while (_MPU_BuffersWaiting < 4) _MIDI_ServiceRoutine();
}