playmidi.c

MIDI解码程序(用VC编写)

    {
	/* Unlink chorus link */
	voice[v1].chorus_link = v1;
	voice[v2].chorus_link = v2;
    }
    voice[v1].status = VOICE_FREE;
    voice[v1].temper_instant = 0;
}

static int find_free_voice(void)
{
    int i, nv = voices, lowest;
    int32 lv, v;

    for(i = 0; i < nv; i++)
	if(voice[i].status == VOICE_FREE)
	{
	    if(upper_voices <= i)
		upper_voices = i + 1;
	    return i;
	}

    upper_voices = voices;

    /* Look for the decaying note with the lowest volume */
    lv = 0x7FFFFFFF;
    lowest = -1;
    for(i = 0; i < nv; i++)
    {
	if(voice[i].status & ~(VOICE_ON | VOICE_DIE) &&
	   !(voice[i].sample && voice[i].sample->note_to_use && ISDRUMCHANNEL(voice[i].channel)))
	{
	    v = voice[i].left_mix;
	    if((voice[i].panned==PANNED_MYSTERY) && (voice[i].right_mix>v))
		v = voice[i].right_mix;
	    if(v<lv)
	    {
		lv = v;
		lowest = i;
	    }
	}
    }
    if(lowest != -1 && !prescanning_flag)
    {
	free_voice(lowest);
	ctl_note_event(lowest);
    }
    return lowest;
}

static int find_samples(MidiEvent *e, int *vlist)
{
	int i, j, ch, bank, prog, note, nv;
	SpecialPatch *s;
	Instrument *ip;
	
	ch = e->channel;
	if (channel[ch].special_sample > 0) {
		if ((s = special_patch[channel[ch].special_sample]) == NULL) {
			ctl->cmsg(CMSG_WARNING, VERB_VERBOSE,
					"Strange: Special patch %d is not installed",
					channel[ch].special_sample);
			return 0;
		}
		note = e->a + channel[ch].key_shift + note_key_offset;
		note = (note < 0) ? 0 : ((note > 127) ? 127 : note);
		return select_play_sample(s->sample, s->samples, &note, vlist, e);
	}
	bank = channel[ch].bank;
	if (ISDRUMCHANNEL(ch)) {
		note = e->a & 0x7f;
		instrument_map(channel[ch].mapID, &bank, &note);
		if (! (ip = play_midi_load_instrument(1, bank, note)))
			return 0;	/* No instrument? Then we can't play. */
		/* if (ip->type == INST_GUS && ip->samples != 1)
			ctl->cmsg(CMSG_WARNING, VERB_VERBOSE,
					"Strange: percussion instrument with %d samples!",
					ip->samples); */
		/* "keynum" of SF2, and patch option "note=" */
		if (ip->sample->note_to_use)
			note = ip->sample->note_to_use;
	} else {
		if ((prog = channel[ch].program) == SPECIAL_PROGRAM)
			ip = default_instrument;
		else {
			instrument_map(channel[ch].mapID, &bank, &prog);
			if (! (ip = play_midi_load_instrument(0, bank, prog)))
				return 0;	/* No instrument? Then we can't play. */
		}
		note = ((ip->sample->note_to_use) ? ip->sample->note_to_use : e->a)
				+ channel[ch].key_shift + note_key_offset;
		note = (note < 0) ? 0 : ((note > 127) ? 127 : note);
	}
	nv = select_play_sample(ip->sample, ip->samples, &note, vlist, e);
	/* Replace the sample if the sample is cached. */
	if (! prescanning_flag) {
		if (ip->sample->note_to_use)
			note = MIDI_EVENT_NOTE(e);
		for (i = 0; i < nv; i++) {
			j = vlist[i];
			if (! opt_realtime_playing && allocate_cache_size > 0
					&& ! channel[ch].portamento) {
				voice[j].cache = resamp_cache_fetch(voice[j].sample, note);
				if (voice[j].cache)	/* cache hit */
					voice[j].sample = voice[j].cache->resampled;
			} else
				voice[j].cache = NULL;
		}
	}
	return nv;
}

static int select_play_sample(Sample *splist,
		int nsp, int *note, int *vlist, MidiEvent *e)
{
	int ch = e->channel, kn = e->a & 0x7f, vel = e->b;
	int32 f, fs, ft, fst, fc, fr, cdiff, diff, sample_link;
	int8 tt = channel[ch].temper_type;
	uint8 tp = channel[ch].rpnmap[RPN_ADDR_0003];
	Sample *sp, *spc, *spr;
	int16 sf, sn;
	double ratio;
	int i, j, k, nv, nvc;
	
	if (ISDRUMCHANNEL(ch))
		f = fs = freq_table[*note];
	else {
		if (opt_pure_intonation) {
			if (current_keysig < 8)
				f = freq_table_pureint[current_freq_table][*note];
			else
				f = freq_table_pureint[current_freq_table + 12][*note];
		} else if (opt_temper_control)
			switch (tt) {
			case 0:
				f = freq_table_tuning[tp][*note];
				break;
			case 1:
				if (current_temper_keysig < 8)
					f = freq_table_pytha[
							current_temper_freq_table][*note];
				else
					f = freq_table_pytha[
							current_temper_freq_table + 12][*note];
				break;
			case 2:
				if (current_temper_keysig < 8)
					f = freq_table_meantone[current_temper_freq_table
							+ ((temper_adj) ? 36 : 0)][*note];
				else
					f = freq_table_meantone[current_temper_freq_table
							+ ((temper_adj) ? 24 : 12)][*note];
				break;
			case 3:
				if (current_temper_keysig < 8)
					f = freq_table_pureint[current_temper_freq_table
							+ ((temper_adj) ? 36 : 0)][*note];
				else
					f = freq_table_pureint[current_temper_freq_table
							+ ((temper_adj) ? 24 : 12)][*note];
				break;
			default:	/* user-defined temperament */
				if ((tt -= 0x40) >= 0 && tt < 4) {
					if (current_temper_keysig < 8)
						f = freq_table_user[tt][current_temper_freq_table
								+ ((temper_adj) ? 36 : 0)][*note];
					else
						f = freq_table_user[tt][current_temper_freq_table
								+ ((temper_adj) ? 24 : 12)][*note];
				} else
					f = freq_table[*note];
				break;
			}
		else
			f = freq_table[*note];
		if (! opt_pure_intonation && opt_temper_control
				&& tt == 0 && f != freq_table[*note]) {
			*note = log(f / 440000.0) / log(2) * 12 + 69.5;
			*note = (*note < 0) ? 0 : ((*note > 127) ? 127 : *note);
			fs = freq_table[*note];
		} else
			fs = freq_table[*note];
	}
	nv = 0;
	for (i = 0, sp = splist; i < nsp; i++, sp++) {
		/* GUS/SF2 - Scale Tuning */
		if ((sf = sp->scale_factor) != 1024) {
			sn = sp->scale_freq;
			ratio = pow(2.0, (*note - sn) * (sf - 1024) / 12288.0);
			ft = f * ratio + 0.5, fst = fs * ratio + 0.5;
		} else
			ft = f, fst = fs;
		if (ISDRUMCHANNEL(ch) && channel[ch].drums[kn] != NULL)
			if ((ratio = get_play_note_ratio(ch, kn)) != 1.0)
				ft = ft * ratio + 0.5, fst = fst * ratio + 0.5;
		if (sp->low_freq <= fst && sp->high_freq >= fst
				&& sp->low_vel <= vel && sp->high_vel >= vel
				&& ! (sp->inst_type == INST_SF2
				&& sp->sample_type == SF_SAMPLETYPE_RIGHT)) {
			j = vlist[nv] = find_voice(e);
			voice[j].orig_frequency = ft;
			MYCHECK(voice[j].orig_frequency);
			voice[j].sample = sp;
			voice[j].status = VOICE_ON;
			nv++;
		}
	}
	if (nv == 0) {	/* we must select at least one sample. */
		fr = fc = 0;
		spc = spr = NULL;
		cdiff = 0x7fffffff;
		for (i = 0, sp = splist; i < nsp; i++, sp++) {
			/* GUS/SF2 - Scale Tuning */
			if ((sf = sp->scale_factor) != 1024) {
				sn = sp->scale_freq;
				ratio = pow(2.0, (*note - sn) * (sf - 1024) / 12288.0);
				ft = f * ratio + 0.5, fst = fs * ratio + 0.5;
			} else
				ft = f, fst = fs;
			if (ISDRUMCHANNEL(ch) && channel[ch].drums[kn] != NULL)
				if ((ratio = get_play_note_ratio(ch, kn)) != 1.0)
					ft = ft * ratio + 0.5, fst = fst * ratio + 0.5;
			diff = abs(sp->root_freq - fst);
			if (diff < cdiff) {
				if (sp->inst_type == INST_SF2
						&& sp->sample_type == SF_SAMPLETYPE_RIGHT) {
					fr = ft;	/* reserve */
					spr = sp;	/* reserve */
				} else {
					fc = ft;
					spc = sp;
					cdiff = diff;
				}
			}
		}
		/* If spc is not NULL, a makeshift sample is found. */
		/* Otherwise, it's a lonely right sample, but better than nothing. */
		j = vlist[nv] = find_voice(e);
		voice[j].orig_frequency = (spc) ? fc : fr;
		MYCHECK(voice[j].orig_frequency);
		voice[j].sample = (spc) ? spc : spr;
		voice[j].status = VOICE_ON;
		nv++;
	}
	nvc = nv;
	for (i = 0; i < nvc; i++) {
		spc = voice[vlist[i]].sample;
		/* If it's left sample, there must be right sample. */
		if (spc->inst_type == INST_SF2
				&& spc->sample_type == SF_SAMPLETYPE_LEFT) {
			sample_link = spc->sf_sample_link;
			for (j = 0, sp = splist; j < nsp; j++, sp++)
				if (sp->inst_type == INST_SF2
						&& sp->sample_type == SF_SAMPLETYPE_RIGHT
						&& sp->sf_sample_index == sample_link) {
					/* right sample is found. */
					/* GUS/SF2 - Scale Tuning */
					if ((sf = sp->scale_factor) != 1024) {
						sn = sp->scale_freq;
						ratio = pow(2.0, (*note - sn) * (sf - 1024) / 12288.0);
						ft = f * ratio + 0.5;
					} else
						ft = f;
					if (ISDRUMCHANNEL(ch) && channel[ch].drums[kn] != NULL)
						if ((ratio = get_play_note_ratio(ch, kn)) != 1.0)
							ft = ft * ratio + 0.5;
					k = vlist[nv] = find_voice(e);
					voice[k].orig_frequency = ft;
					MYCHECK(voice[k].orig_frequency);
					voice[k].sample = sp;
					voice[k].status = VOICE_ON;
					nv++;
					break;
				}
		}
	}
	return nv;
}

static double get_play_note_ratio(int ch, int note)
{
	int play_note = channel[ch].drums[note]->play_note;
	int bank = channel[ch].bank;
	ToneBank *dbank;
	int def_play_note;
	
	if (play_note == -1)
		return 1.0;
	instrument_map(channel[ch].mapID, &bank, &note);
	dbank = (drumset[bank]) ? drumset[bank] : drumset[0];
	if ((def_play_note = dbank->tone[note].play_note) == -1)
		return 1.0;
	if (play_note >= def_play_note)
		return bend_coarse[(play_note - def_play_note) & 0x7f];
	else
		return 1 / bend_coarse[(def_play_note - play_note) & 0x7f];
}

/* Only one instance of a note can be playing on a single channel. */
static int find_voice(MidiEvent *e)
{
	int ch = e->channel;
	int note = MIDI_EVENT_NOTE(e);
	int status_check, mono_check;
	AlternateAssign *altassign;
	int i, lowest = -1;
	
	status_check = (opt_overlap_voice_allow)
			? (VOICE_OFF | VOICE_SUSTAINED) : 0xff;
	mono_check = channel[ch].mono;
	altassign = find_altassign(channel[ch].altassign, note);
	for (i = 0; i < upper_voices; i++)
		if (voice[i].status == VOICE_FREE) {
			lowest = i;	/* lower volume */
			break;
		}
	for (i = 0; i < upper_voices; i++)
		if (voice[i].status != VOICE_FREE && voice[i].channel == ch) {
			if ((voice[i].note == note && (voice[i].status & status_check))
			    || mono_check
			    || (altassign && find_altassign(altassign, voice[i].note)))
				kill_note(i);
			else if (voice[i].note == note &&
				 (channel[ch].assign_mode == 0
				  || (channel[ch].assign_mode == 1
				      && voice[i].proximate_flag == 0)))
				kill_note(i);
		}
	for (i = 0; i < upper_voices; i++)
		if (voice[i].channel == ch && voice[i].note == note)
			voice[i].proximate_flag = 0;
	if (lowest != -1)	/* Found a free voice. */
		return lowest;
	if (upper_voices < voices)
		return upper_voices++;
	return reduce_voice();
}

int32 get_note_freq(Sample *sp, int note)
{
	int32 f;
	int16 sf, sn;
	double ratio;
	
	f = freq_table[note];
	/* GUS/SF2 - Scale Tuning */
	if ((sf = sp->scale_factor) != 1024) {
		sn = sp->scale_freq;
		ratio = pow(2.0, (note - sn) * (sf - 1024) / 12288.0);
		f = f * ratio + 0.5;
	}
	return f;
}

static int get_panning(int ch, int note,int v)
{
    int pan;

	if(channel[ch].panning != NO_PANNING) {pan = (int)channel[ch].panning - 64;}
	else {pan = 0;}
	if(ISDRUMCHANNEL(ch) &&
	 channel[ch].drums[note] != NULL &&
	 channel[ch].drums[note]->drum_panning != NO_PANNING) {
		pan += channel[ch].drums[note]->drum_panning;
	} else {
		pan += voice[v].sample->panning;
	}

	if (pan > 127) pan = 127;
	else if (pan < 0) pan = 0;

	return pan;
}

/*! initialize vibrato parameters for a voice. */
static void init_voice_vibrato(int v)
{
	Voice *vp = &(voice[v]);
	int ch = vp->channel, j, nrpn_vib_flag;
	double ratio;

	/* if NRPN vibrato is set, it's believed that there must be vibrato. */
	nrpn_vib_flag = opt_nrpn_vibrato
		&& (channel[ch].vibrato_ratio != 1.0 || channel[ch].vibrato_depth != 0);
	
	/* vibrato sweep */
	vp->vibrato_sweep = vp->sample->vibrato_sweep_increment;
	vp->vibrato_sweep_position = 0;

	/* vibrato rate */
	if (nrpn_vib_flag) {
		if(vp->sample->vibrato_control_ratio == 0) {
			ratio = cnv_Hz_to_vib_ratio(5.0) * channel[ch].vibrato_ratio;
		} else {
			ratio = (double)vp->sample->vibrato_control_ratio * channel[ch].vibrato_ratio;
		}
		if (ratio < 0) {ratio = 0;}
		vp->vibrato_control_ratio = (int)ratio;
	} else {
		vp->vibrato_control_ratio = vp->sample->vibrato_control_ratio;
	}
	
	/* vibrato depth */
	if (nrpn_vib_flag) {
		vp->vibrato_depth = vp->sample->vibrato_depth + channel[ch].vibrato_depth;
		if (vp->vibrato_depth > VIBRATO_DEPTH_MAX) {vp->vibrato_depth = VIBRATO_DEPTH_MAX;}
		else if (vp->vibrato_depth < 1) {vp->vibrato_depth = 1;}
		if (vp->sample->vibrato_depth < 0) {	/* in opposite phase */
			vp->vibrato_depth = -vp->vibrato_depth;
		}
	} else {
		vp->vibrato_depth = vp->sample->vibrato_depth;
	}
	
	/* vibrato delay */
	vp->vibrato_delay = vp->sample->vibrato_delay + channel[ch].vibrato_delay;
	
	/* internal parameters */
	vp->orig_vibrato_control_ratio = vp->vibrato_control_ratio;
	vp->vibrato_control_counter = vp->vibrato_phase = 0;
	for (j = 0; j < VIBRATO_SAMPLE_INCREMENTS; j++) {
		vp->vibrato_sample_increment[j] = 0;
	}
}

/*! initialize panning-delay for a voice. */
static void init_voice_pan_delay(int v)
{
#ifdef ENABLE_PAN_DELAY
	Voice *vp = &(voice[v]);
	int ch = vp->channel;
	double pan_delay_diff; 

	if (vp->pan_delay_buf != NULL) {
		free(vp->pan_delay_buf);
		vp->pan_delay_buf = NULL;
	}
	vp->pan_delay_rpt = 0;
	if (opt_pan_delay && channel[ch].insertion_effect == 0 && !opt_surround_chorus) {
		if (vp->panning == 64) {vp->delay += pan_delay_table[64] * play_mode->rate / 1000;}
		else {
			if(pan_delay_table[vp->panning] > pan_delay_table[127 - vp->panning]) {
				pan_delay_diff = pan_delay_table[vp->panning] - pan_delay_table[127 - vp->panning];
				vp->delay += (pan_delay_table[vp->panning] - pan_delay_diff) * play_mode->rate / 1000;
			} else {
				pan_delay_diff = pan_delay_table[127 - vp->panning] - pan_delay_table[vp->panning];
				vp->delay += (pan_delay_t