native_midi_mac.c

SDL_mixer 是一个基于 SDL 的混音器

/*
    native_midi_mac:  Native Midi support on MacOS for the SDL_mixer library
    Copyright (C) 2001  Max Horn

    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

    Max Horn
    [e-mail]
*/
#include "SDL_config.h"
#include "SDL_endian.h"

#if __MACOS__ || __MACOSX__

#include "native_midi.h"
#include "native_midi_common.h"

#if __MACOSX__
#include <QuickTime/QuickTimeMusic.h>
#else
#include <QuickTimeMusic.h>
#endif

#include <assert.h>
#include <stdlib.h>
#include <string.h>


/* Native Midi song */
struct _NativeMidiSong
{
	Uint32		*tuneSequence;
	Uint32		*tuneHeader;
};

enum
{
	/* number of (32-bit) long words in a note request event */
	kNoteRequestEventLength = ((sizeof(NoteRequest)/sizeof(long)) + 2),

	/* number of (32-bit) long words in a marker event */
	kMarkerEventLength	= 1,

	/* number of (32-bit) long words in a general event, minus its data */
	kGeneralEventLength	= 2
};

#define ERROR_BUF_SIZE			256
#define	BUFFER_INCREMENT		5000

#define REST_IF_NECESSARY()	do {\
			int timeDiff = eventPos->time - lastEventTime;	\
			if(timeDiff)	\
			{	\
				timeDiff = (int)(timeDiff*tick);	\
				qtma_StuffRestEvent(*tunePos, timeDiff);	\
				tunePos++;	\
				lastEventTime = eventPos->time;	\
			}	\
		} while(0)


static Uint32 *BuildTuneSequence(MIDIEvent *evntlist, int ppqn, int part_poly_max[32], int part_to_inst[32], int *numParts);
static Uint32 *BuildTuneHeader(int part_poly_max[32], int part_to_inst[32], int numParts);

/* The global TunePlayer instance */
static TunePlayer	gTunePlayer = NULL;
static int			gInstaceCount = 0;
static Uint32		*gCurrentTuneSequence = NULL;
static char			gErrorBuffer[ERROR_BUF_SIZE] = "";


/* Check whether QuickTime is available */
int native_midi_detect()
{
	/* TODO */
	return 1;
}

NativeMidiSong *native_midi_loadsong(char *midifile)
{
	NativeMidiSong	*song = NULL;
	MIDIEvent		*evntlist = NULL;
	int				part_to_inst[32];
	int				part_poly_max[32];
	int				numParts = 0;
	Uint16			ppqn;
	SDL_RWops		*rw;

	/* Init the arrays */
	memset(part_poly_max,0,sizeof(part_poly_max));
	memset(part_to_inst,-1,sizeof(part_to_inst));
	
	/* Attempt to load the midi file */
	rw = SDL_RWFromFile(midifile, "rb");
	if (rw) {
		evntlist = CreateMIDIEventList(rw, &ppqn);
		SDL_RWclose(rw);
		if (!evntlist)
			goto bail;
	}

	/* Allocate memory for the song struct */
	song = malloc(sizeof(NativeMidiSong));
	if (!song)
		goto bail;

	/* Build a tune sequence from the event list */
	song->tuneSequence = BuildTuneSequence(evntlist, ppqn, part_poly_max, part_to_inst, &numParts);
	if(!song->tuneSequence)
		goto bail;

	/* Now build a tune header from the data we collect above, create
	   all parts as needed and assign them the correct instrument.
	*/
	song->tuneHeader = BuildTuneHeader(part_poly_max, part_to_inst, numParts);
	if(!song->tuneHeader)
		goto bail;
	
	/* Increment the instance count */
	gInstaceCount++;
	if (gTunePlayer == NULL)
		gTunePlayer = OpenDefaultComponent(kTunePlayerComponentType, 0);

	/* Finally, free the event list */
	FreeMIDIEventList(evntlist);
	
	return song;
	
bail:
	if (evntlist)
		FreeMIDIEventList(evntlist);
	
	if (song)
	{
		if(song->tuneSequence)
			free(song->tuneSequence);
		
		if(song->tuneHeader)
			DisposePtr((Ptr)song->tuneHeader);

		free(song);
	}
	
	return NULL;
}

NativeMidiSong *native_midi_loadsong_RW(SDL_RWops *rw)
{
	NativeMidiSong	*song = NULL;
	MIDIEvent		*evntlist = NULL;
	int				part_to_inst[32];
	int				part_poly_max[32];
	int				numParts = 0;
	Uint16			ppqn;

	/* Init the arrays */
	memset(part_poly_max,0,sizeof(part_poly_max));
	memset(part_to_inst,-1,sizeof(part_to_inst));
	
	/* Attempt to load the midi file */
	evntlist = CreateMIDIEventList(rw, &ppqn);
	if (!evntlist)
		goto bail;

	/* Allocate memory for the song struct */
	song = malloc(sizeof(NativeMidiSong));
	if (!song)
		goto bail;

	/* Build a tune sequence from the event list */
	song->tuneSequence = BuildTuneSequence(evntlist, ppqn, part_poly_max, part_to_inst, &numParts);
	if(!song->tuneSequence)
		goto bail;

	/* Now build a tune header from the data we collect above, create
	   all parts as needed and assign them the correct instrument.
	*/
	song->tuneHeader = BuildTuneHeader(part_poly_max, part_to_inst, numParts);
	if(!song->tuneHeader)
		goto bail;
	
	/* Increment the instance count */
	gInstaceCount++;
	if (gTunePlayer == NULL)
		gTunePlayer = OpenDefaultComponent(kTunePlayerComponentType, 0);

	/* Finally, free the event list */
	FreeMIDIEventList(evntlist);
	
	return song;
	
bail:
	if (evntlist)
		FreeMIDIEventList(evntlist);
	
	if (song)
	{
		if(song->tuneSequence)
			free(song->tuneSequence);
		
		if(song->tuneHeader)
			DisposePtr((Ptr)song->tuneHeader);

		free(song);
	}
	
	return NULL;
}

void native_midi_freesong(NativeMidiSong *song)
{
	if(!song || !song->tuneSequence)
		return;

	/* If this is the currently playing song, stop it now */	
	if (song->tuneSequence == gCurrentTuneSequence)
		native_midi_stop();
	
	/* Finally, free the data storage */
	free(song->tuneSequence);
	DisposePtr((Ptr)song->tuneHeader);
	free(song);

	/* Increment the instance count */
	gInstaceCount--;
	if ((gTunePlayer != NULL) && (gInstaceCount == 0))
	{
		CloseComponent(gTunePlayer);
		gTunePlayer = NULL;
	}
}

void native_midi_start(NativeMidiSong *song)
{
	UInt32		queueFlags = 0;
	ComponentResult tpError;
	
	assert (gTunePlayer != NULL);
	
	SDL_PauseAudio(1);
	SDL_UnlockAudio();
    
	/* First, stop the currently playing music */
	native_midi_stop();
	
	/* Set up the queue flags */
	queueFlags = kTuneStartNow;

	/* Set the time scale (units per second), we want milliseconds */
	tpError = TuneSetTimeScale(gTunePlayer, 1000);
	if (tpError != noErr)
	{
		strncpy (gErrorBuffer, "MIDI error during TuneSetTimeScale", ERROR_BUF_SIZE);
		goto done;
	}

	/* Set the header, to tell what instruments are used */
	tpError = TuneSetHeader(gTunePlayer, (UInt32 *)song->tuneHeader);
	if (tpError != noErr)
	{
		strncpy (gErrorBuffer, "MIDI error during TuneSetHeader", ERROR_BUF_SIZE);
		goto done;
	}
	
	/* Have it allocate whatever resources are needed */
	tpError = TunePreroll(gTunePlayer);
	if (tpError != noErr)
	{
		strncpy (gErrorBuffer, "MIDI error during TunePreroll", ERROR_BUF_SIZE);
		goto done;
	}

	/* We want to play at normal volume */
	tpError = TuneSetVolume(gTunePlayer, 0x00010000);
	if (tpError != noErr)
	{
		strncpy (gErrorBuffer, "MIDI error during TuneSetVolume", ERROR_BUF_SIZE);
		goto done;
	}
	
	/* Finally, start playing the full song */
	gCurrentTuneSequence = song->tuneSequence;
	tpError = TuneQueue(gTunePlayer, (UInt32 *)song->tuneSequence, 0x00010000, 0, 0xFFFFFFFF, queueFlags, NULL, 0);
	if (tpError != noErr)
	{
		strncpy (gErrorBuffer, "MIDI error during TuneQueue", ERROR_BUF_SIZE);
		goto done;
	}
    
done:
	SDL_LockAudio();
	SDL_PauseAudio(0);
}

void native_midi_stop()
{
	if (gTunePlayer == NULL)
		return;

	/* Stop music */
	TuneStop(gTunePlayer, 0);
	
	/* Deallocate all instruments */
	TuneUnroll(gTunePlayer);
}

int native_midi_active()
{
	if (gTunePlayer != NULL)
	{
		TuneStatus	ts;

		TuneGetStatus(gTunePlayer,&ts);
		return ts.queueTime != 0;
	}
	else
		return 0;
}

void native_midi_setvolume(int volume)
{
	if (gTunePlayer == NULL)
		return;

	/* QTMA olume may range from 0.0 to 1.0 (in 16.16 fixed point encoding) */
	TuneSetVolume(gTunePlayer, (0x00010000 * volume)/SDL_MIX_MAXVOLUME);
}

char *native_midi_error()
{
	return gErrorBuffer;
}

Uint32 *BuildTuneSequence(MIDIEvent *evntlist, int ppqn, int part_poly_max[32], int part_to_inst[32], int *numParts)
{
	int			part_poly[32];
	int			channel_to_part[16];
	
	int			channel_pan[16];
	int			channel_vol[16];