mix.c

MIDI解码程序(用VC编写)

/*
    TiMidity++ -- MIDI to WAVE converter and player
    Copyright (C) 1999-2002 Masanao Izumo <[e-mail]>
    Copyright (C) 1995 Tuukka Toivonen <[e-mail]>

    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

    mix.c
*/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */
#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include "timidity.h"
#include "common.h"
#include "instrum.h"
#include "playmidi.h"
#include "output.h"
#include "controls.h"
#include "tables.h"
#include "resample.h"
#include "mix.h"

#ifdef SMOOTH_MIXING
#ifdef LOOKUP_HACK
/* u2l: 0..255 -> -32256..32256
 * shift 3 bit: -> within MAX_AMP_VALUE
 */
#define FROM_FINAL_VOLUME(a) (_u2l[(uint8) ~(a)] >> 3)
#else
#define FROM_FINAL_VOLUME(a) (a)
#endif
#endif

#define OFFSET_MAX (0x3FFFFFFFL)

#if OPT_MODE != 0
#define VOICE_LPF
#endif

typedef int32 mix_t;

#ifdef LOOKUP_HACK
#define MIXATION(a) *lp++ += mixup[(a << 8) | (uint8) s]
#else
#define MIXATION(a) *lp++ += (a) * s
#endif

#define DELAYED_MIXATION(a) *lp++ += pan_delay_buf[pan_delay_spt];	\
	if (++pan_delay_spt == PAN_DELAY_BUF_MAX) {pan_delay_spt = 0;}	\
	pan_delay_buf[pan_delay_wpt] = (a) * s;	\
	if (++pan_delay_wpt == PAN_DELAY_BUF_MAX) {pan_delay_wpt = 0;}

void mix_voice(int32 *, int, int32);
static inline int do_voice_filter(int, resample_t*, mix_t*, int32);
static inline void recalc_voice_resonance(int);
static inline void recalc_voice_fc(int);
static inline void ramp_out(mix_t *, int32 *, int, int32);
static inline void mix_mono_signal(mix_t *, int32 *, int, int);
static inline void mix_mono(mix_t *, int32 *, int, int);
static inline void mix_mystery_signal(mix_t *, int32 *, int, int);
static inline void mix_mystery(mix_t *, int32 *, int, int);
static inline void mix_center_signal(mix_t *, int32 *, int, int);
static inline void mix_center(mix_t *, int32 *, int, int);
static inline void mix_single_signal(mix_t *, int32 *, int, int);
static inline void mix_single(mix_t *, int32 *, int, int);
static inline int update_signal(int);
static inline int update_envelope(int);
int recompute_envelope(int);
static inline int update_modulation_envelope(int);
int apply_modulation_envelope(int);
int recompute_modulation_envelope(int);
static inline void voice_ran_out(int);
static inline int next_stage(int);
static inline int modenv_next_stage(int);
static inline void update_tremolo(int);
int apply_envelope_to_amp(int);
#ifdef SMOOTH_MIXING
static inline void compute_mix_smoothing(Voice *);
#endif

int min_sustain_time = 5000;

static mix_t filter_buffer[AUDIO_BUFFER_SIZE];

/**************** interface function ****************/
void mix_voice(int32 *buf, int v, int32 c)
{
	Voice *vp = voice + v;
	resample_t *sp;

	if (vp->status == VOICE_DIE) {
		if (c >= MAX_DIE_TIME)
			c = MAX_DIE_TIME;
		sp = resample_voice(v, &c);
		if (do_voice_filter(v, sp, filter_buffer, c)) {sp = filter_buffer;}
		if (c > 0)
			ramp_out(sp, buf, v, c);
		free_voice(v);
	} else {
		vp->delay_counter = c;
		if (vp->delay) {
			if (c < vp->delay) {
				vp->delay -= c;
				if (vp->tremolo_phase_increment)
					update_tremolo(v);
				if (opt_modulation_envelope && vp->sample->modes & MODES_ENVELOPE)
					update_modulation_envelope(v);
				return;
			}
			if (play_mode->encoding & PE_MONO)
				buf += vp->delay;
			else
				buf += vp->delay * 2;
			c -= vp->delay;
			vp->delay = 0;
		}
		sp = resample_voice(v, &c);
		if (do_voice_filter(v, sp, filter_buffer, c)) {sp = filter_buffer;}

		if (play_mode->encoding & PE_MONO) {
			/* Mono output. */
			if (vp->envelope_increment || vp->tremolo_phase_increment)
				mix_mono_signal(sp, buf, v, c);
			else
				mix_mono(sp, buf, v, c);
		} else {
			if (vp->panned == PANNED_MYSTERY) {
				if (vp->envelope_increment || vp->tremolo_phase_increment)
					mix_mystery_signal(sp, buf, v, c);
				else
					mix_mystery(sp, buf, v, c);
			} else if (vp->panned == PANNED_CENTER) {
				if (vp->envelope_increment || vp->tremolo_phase_increment)
					mix_center_signal(sp, buf, v, c);
				else
					mix_center(sp, buf, v, c);
			} else {
				/* It's either full left or full right. In either case,
				 * every other sample is 0. Just get the offset right:
				 */
				if (vp->panned == PANNED_RIGHT)
					buf++;
				if (vp->envelope_increment || vp->tremolo_phase_increment)
					mix_single_signal(sp, buf, v, c);
				else
					mix_single(sp, buf, v, c);
			}
		}
	}
}

/* return 1 if filter is enabled. */
static inline int do_voice_filter(int v, resample_t *sp, mix_t *lp, int32 count)
{
	FilterCoefficients *fc = &(voice[v].fc);
	int32 i, f, q, p, b0, b1, b2, b3, b4, t1, t2, x;
	
	if (fc->type == 1) {	/* copy with applying Chamberlin's lowpass filter. */
		recalc_voice_resonance(v);
		recalc_voice_fc(v);
		f = fc->f, q = fc->q, b0 = fc->b0, b1 = fc->b1, b2 = fc->b2;
		for(i = 0; i < count; i++) {
			b0 = b0 + imuldiv24(b2, f);
			b1 = sp[i] - b0 - imuldiv24(b2, q);
			b2 = imuldiv24(b1, f) + b2;
			lp[i] = b0;
		}
		fc->b0 = b0, fc->b1 = b1, fc->b2 = b2;
		return 1;
	} else if(fc->type == 2) {	/* copy with applying Moog lowpass VCF. */
		recalc_voice_resonance(v);
		recalc_voice_fc(v);
		f = fc->f, q = fc->q, p = fc->p, b0 = fc->b0, b1 = fc->b1,
			b2 = fc->b2, b3 = fc->b3, b4 = fc->b4;
		for(i = 0; i < count; i++) {
			x = sp[i] - imuldiv24(q, b4);	/* feedback */
			t1 = b1;  b1 = imuldiv24(x + b0, p) - imuldiv24(b1, f);
			t2 = b2;  b2 = imuldiv24(b1 + t1, p) - imuldiv24(b2, f);
			t1 = b3;  b3 = imuldiv24(b2 + t2, p) - imuldiv24(b3, f);
			lp[i] = b4 = imuldiv24(b3 + t1, p) - imuldiv24(b4, f);
			b0 = x;
		}
		fc->b0 = b0, fc->b1 = b1, fc->b2 = b2, fc->b3 = b3, fc->b4 = b4;
		return 1;
	} else {
		return 0;
	}
}

#define MOOG_RESONANCE_MAX 0.897638f

static inline void recalc_voice_resonance(int v)
{
	double q;
	FilterCoefficients *fc = &(voice[v].fc);
	
	if (fc->reso_dB != fc->last_reso_dB || fc->q == 0) {
		fc->last_reso_dB = fc->reso_dB;
		if(fc->type == 1) {
			q = 1.0 / chamberlin_filter_db_to_q_table[(int)(fc->reso_dB * 4)];
			fc->q = TIM_FSCALE(q, 24);
			if(fc->q <= 0) {fc->q = 1;}	/* must never be 0. */
		} else if(fc->type == 2) {
			fc->reso_lin = fc->reso_dB * MOOG_RESONANCE_MAX / 20.0f;
			if (fc->reso_lin > MOOG_RESONANCE_MAX) {fc->reso_lin = MOOG_RESONANCE_MAX;}
			else if(fc->reso_lin < 0) {fc->reso_lin = 0;}
		}
		fc->last_freq = -1;
	}
}

static inline void recalc_voice_fc(int v)
{
	double f, p, q, fr;
	FilterCoefficients *fc = &(voice[v].fc);

	if (fc->freq != fc->last_freq) {
		if(fc->type == 1) {
			f = 2.0 * sin(M_PI * (double)fc->freq / (double)play_mode->rate);
			fc->f = TIM_FSCALE(f, 24);
		} else if(fc->type == 2) {
			fr = 2.0 * (double)fc->freq / (double)play_mode->rate;
			q = 1.0 - fr;
			p = fr + 0.8 * fr * q;
			f = p + p - 1.0;
			q = fc->reso_lin * (1.0 + 0.5 * q * (1.0 - q + 5.6 * q * q));
			fc->f = TIM_FSCALE(f, 24);
			fc->p = TIM_FSCALE(p, 24);
			fc->q = TIM_FSCALE(q, 24);
		}
		fc->last_freq = fc->freq;
	}
}

/* Ramp a note out in c samples */
static inline void ramp_out(mix_t *sp, int32 *lp, int v, int32 c)
{
	/* should be final_volume_t, but uint8 gives trouble. */
	int32 left, right, li, ri, i;
	/* silly warning about uninitialized s */
	mix_t s = 0;
#ifdef ENABLE_PAN_DELAY
	Voice *vp = &voice[v];
	int32 pan_delay_wpt = vp->pan_delay_wpt, *pan_delay_buf = vp->pan_delay_buf,
		pan_delay_spt = vp->pan_delay_spt;
#endif

	left = voice[v].left_mix;
	li = -(left / c);
	if (! li)
		li = -1;
#if 0
	printf("Ramping out: left=%d, c=%d, li=%d\n", left, c, li);
#endif
	if (! (play_mode->encoding & PE_MONO)) {
		if (voice[v].panned == PANNED_MYSTERY) {
#ifdef ENABLE_PAN_DELAY
			right = voice[v].right_mix;
			ri = -(right / c);
			if(vp->pan_delay_rpt == 0) {
				for (i = 0; i < c; i++) {
					left += li;
					if (left < 0)
						left = 0;
					right += ri;
					if (right < 0)
						right = 0;
					s = *sp++;
					MIXATION(left);
					MIXATION(right);
				}
			} else if(vp->panning < 64) {
				for (i = 0; i < c; i++) {
					left += li;
					if (left < 0)
						left = 0;
					right += ri;
					if (right < 0)
						right = 0;
					s = *sp++;
					MIXATION(left);
					DELAYED_MIXATION(right);
				}
			} else {
				for (i = 0; i < c; i++) {
					left += li;
					if (left < 0)
						left = 0;
					right += ri;
					if (right < 0)
						right = 0;
					s = *sp++;
					DELAYED_MIXATION(left);
					MIXATION(right);
				}
			}
			vp->pan_delay_wpt = pan_delay_wpt;
			vp->pan_delay_spt = pan_delay_spt;
#else
			right = voice[v].right_mix;
			ri = -(right / c);
			for (i = 0; i < c; i++) {
				left += li;
				if (left < 0)
					left = 0;
				right += ri;
				if (right < 0)
					right = 0;
				s = *sp++;
				MIXATION(left);
				MIXATION(right);
			}
#endif /* ENABLE_PAN_DELAY */
		} else if (voice[v].panned == PANNED_CENTER)
			for (i = 0; i < c; i++) {
				left += li;
				if (left < 0)
					return;
				s = *sp++;
				MIXATION(left);
				MIXATION(left);
			}
		else if (voice[v].panned == PANNED_LEFT)
			for (i = 0; i < c; i++) {
				left += li;
				if (left < 0)
					return;
				s = *sp++;
				MIXATION(left);
				lp++;
			}
		else if (voice[v].panned == PANNED_RIGHT)
			for (i = 0; i < c; i++) {
				left += li;
				if (left < 0)
					return;
				s = *sp++;
				lp++;
				MIXATION(left);
			}
	} else
		/* Mono output. */
		for (i = 0; i < c; i++) {
			left += li;
			if (left < 0)
				return;
			s = *sp++;
			MIXATION(left);
		}
}

static inline void mix_mono_signal(
		mix_t *sp, int32 *lp, int v, int count)
{
	Voice *vp = voice + v;
	final_volume_t left = vp->left_mix;
	int cc, i;
	mix_t s;
#ifdef SMOOTH_MIXING
	int32 linear_left;
#endif
	
	if (! (cc = vp->control_counter)) {
		cc = control_ratio;
		if (update_signal(v))
			/* Envelope ran out */
			return;
		left = vp->left_mix;
	}
#ifdef SMOOTH_MIXING
	compute_mix_smoothing(vp);
#endif
	while (count)
		if (cc < count) {
			count -= cc;
#ifdef SMOOTH_MIXING
			linear_left = FROM_FINAL_VOLUME(left);
			if (vp->left_mix_offset) {
				linear_left += vp->left_mix_offset;
				if (linear_left > MAX_AMP_VALUE) {
					linear_left = MAX_AMP_VALUE;
					vp->left_mix_offset = 0;
				}
				left = FINAL_VOLUME(linear_left);
			}
			for (i = 0; vp->left_mix_offset && i < cc; i++) {
				s = *sp++;
				MIXATION(left);
				vp->left_mix_offset += vp->left_mix_inc;
				linear_left += vp->left_mix_inc;
				if (linear_left > MAX_AMP_VALUE) {
					linear_left = MAX_AMP_VALUE;
					vp->left_mix_offset = 0;
				}
				left = FINAL_VOLUME(linear_left);
			}
			vp->old_left_mix = linear_left;
			cc -= i;
#endif
			for (i = 0; i < cc; i++) {
				s = *sp++;
				MIXATION(left);
			}
			cc = control_ratio;
			if (update_signal(v))
				/* Envelope ran out */
				return;
			left = vp->left_mix;
#ifdef SMOOTH_MIXING
			compute_mix_smoothing(vp);
#endif
		} else {
			vp->control_counter = cc - count;
#ifdef SMOOTH_MIXING
			linear_left = FROM_FINAL_VOLUME(left);
			if (vp->left_mix_offset) {
				linear_left += vp->left_mix_offset;
				if (linear_left > MAX_AMP_VALUE) {
					linear_left = MAX_AMP_VALUE;
					vp->left_mix_offset = 0;
				}
				left = FINAL_VOLUME(linear_left);
			}
			for (i = 0; vp->left_mix_offset && i < count; i++) {
				s = *sp++;
				MIXATION(left);
				vp->left_mix_offset += vp->left_mix_inc;
				linear_left += vp->left_mix_inc;
				if (linear_left > MAX_AMP_VALUE) {
					linear_left = MAX_AMP_VALUE;
					vp->left_mix_offset = 0;
				}
				left = FINAL_VOLUME(linear_left);
			}
			vp->old_left_mix = linear_left;
			count -= i;
#endif
			for (i = 0; i < count; i++) {
				s = *sp++;
				MIXATION(left);
			}
			return;
		}
}

static inline void mix_mono(mix_t *sp, int32 *lp, int v, int count)
{
	final_volume_t left = voice[v].left_mix;
	mix_t s;
	int i;
#ifdef SMOOTH_MIXING
	Voice *vp = voice + v;
	int32 linear_left;
#endif
	
#ifdef SMOOTH_MIXING
	compute_mix_smoothing(vp);
	linear_left = FROM_FINAL_VOLUME(left);
	if (vp->left_mix_offset) {
		linear_left += vp->left_mix_offset;
		if (linear_left > MAX_AMP_VALUE) {
			linear_left = MAX_AMP_VALUE;
			vp->left_mix_offset = 0;
		}
		left = FINAL_VOLUME(linear_left);
	}
	for (i = 0; vp->left_mix_offset && i < count; i++) {
		s = *sp++;
		MIXATION(left);
		MIXATION(left);
		vp->left_mix_offset += vp->left_mix_inc;
		linear_left += vp->left_mix_inc;
		if (linear_left > MAX_AMP_VALUE) {
			linear_left = MAX_AMP_VALUE;
			vp->left_mix_offset = 0;
		}
		left = FINAL_VOLUME(linear_left);
	}
	vp->old_left_mix = linear_left;
	count -= i;