virtualx-engine/servers/audio/effects/reverb.cpp
2021-05-04 16:30:23 +02:00

326 lines
8.9 KiB
C++

/*************************************************************************/
/* reverb.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
// Author: Juan Linietsky <reduzio@gmail.com>, (C) 2006
#include "reverb.h"
#include "core/math/math_funcs.h"
#include <math.h>
const float Reverb::comb_tunings[MAX_COMBS] = {
//freeverb comb tunings
0.025306122448979593f,
0.026938775510204082f,
0.028956916099773241f,
0.03074829931972789f,
0.032244897959183672f,
0.03380952380952381f,
0.035306122448979592f,
0.036666666666666667f
};
const float Reverb::allpass_tunings[MAX_ALLPASS] = {
//freeverb allpass tunings
0.0051020408163265302f,
0.007732426303854875f,
0.01f,
0.012607709750566893f
};
void Reverb::process(float *p_src, float *p_dst, int p_frames) {
if (p_frames > INPUT_BUFFER_MAX_SIZE)
p_frames = INPUT_BUFFER_MAX_SIZE;
int predelay_frames = lrint((params.predelay / 1000.0) * params.mix_rate);
if (predelay_frames < 10)
predelay_frames = 10;
if (predelay_frames >= echo_buffer_size)
predelay_frames = echo_buffer_size - 1;
for (int i = 0; i < p_frames; i++) {
if (echo_buffer_pos >= echo_buffer_size)
echo_buffer_pos = 0;
int read_pos = echo_buffer_pos - predelay_frames;
while (read_pos < 0)
read_pos += echo_buffer_size;
float in = undenormalise(echo_buffer[read_pos] * params.predelay_fb + p_src[i]);
echo_buffer[echo_buffer_pos] = in;
input_buffer[i] = in;
p_dst[i] = 0; //take the chance and clear this
echo_buffer_pos++;
}
if (params.hpf > 0) {
float hpaux = expf(-2.0 * Math_PI * params.hpf * 6000 / params.mix_rate);
float hp_a1 = (1.0 + hpaux) / 2.0;
float hp_a2 = -(1.0 + hpaux) / 2.0;
float hp_b1 = hpaux;
for (int i = 0; i < p_frames; i++) {
float in = input_buffer[i];
input_buffer[i] = in * hp_a1 + hpf_h1 * hp_a2 + hpf_h2 * hp_b1;
hpf_h2 = input_buffer[i];
hpf_h1 = in;
}
}
for (int i = 0; i < MAX_COMBS; i++) {
Comb &c = comb[i];
int size_limit = c.size - lrintf((float)c.extra_spread_frames * (1.0 - params.extra_spread));
for (int j = 0; j < p_frames; j++) {
if (c.pos >= size_limit) //reset this now just in case
c.pos = 0;
float out = undenormalise(c.buffer[c.pos] * c.feedback);
out = out * (1.0 - c.damp) + c.damp_h * c.damp; //lowpass
c.damp_h = out;
c.buffer[c.pos] = input_buffer[j] + out;
p_dst[j] += out;
c.pos++;
}
}
static const float allpass_feedback = 0.7;
/* this one works, but the other version is just nicer....
int ap_size_limit[MAX_ALLPASS];
for (int i=0;i<MAX_ALLPASS;i++) {
AllPass &a=allpass[i];
ap_size_limit[i]=a.size-lrintf((float)a.extra_spread_frames*(1.0-params.extra_spread));
}
for (int i=0;i<p_frames;i++) {
float sample=p_dst[i];
float aux,in;
float AllPass*ap;
#define PROCESS_ALLPASS(m_ap) \
ap=&allpass[m_ap]; \
if (ap->pos>=ap_size_limit[m_ap]) \
ap->pos=0; \
aux=undenormalise(ap->buffer[ap->pos]); \
in=sample; \
sample=-in+aux; \
ap->pos++;
PROCESS_ALLPASS(0);
PROCESS_ALLPASS(1);
PROCESS_ALLPASS(2);
PROCESS_ALLPASS(3);
p_dst[i]=sample;
}
*/
for (int i = 0; i < MAX_ALLPASS; i++) {
AllPass &a = allpass[i];
int size_limit = a.size - lrintf((float)a.extra_spread_frames * (1.0 - params.extra_spread));
for (int j = 0; j < p_frames; j++) {
if (a.pos >= size_limit)
a.pos = 0;
float aux = a.buffer[a.pos];
a.buffer[a.pos] = undenormalise(allpass_feedback * aux + p_dst[j]);
p_dst[j] = aux - allpass_feedback * a.buffer[a.pos];
a.pos++;
}
}
static const float wet_scale = 0.6;
for (int i = 0; i < p_frames; i++) {
p_dst[i] = p_dst[i] * params.wet * wet_scale + p_src[i] * params.dry;
}
}
void Reverb::set_room_size(float p_size) {
params.room_size = p_size;
update_parameters();
}
void Reverb::set_damp(float p_damp) {
params.damp = p_damp;
update_parameters();
}
void Reverb::set_wet(float p_wet) {
params.wet = p_wet;
}
void Reverb::set_dry(float p_dry) {
params.dry = p_dry;
}
void Reverb::set_predelay(float p_predelay) {
params.predelay = p_predelay;
}
void Reverb::set_predelay_feedback(float p_predelay_fb) {
params.predelay_fb = p_predelay_fb;
}
void Reverb::set_highpass(float p_frq) {
if (p_frq > 1)
p_frq = 1;
if (p_frq < 0)
p_frq = 0;
params.hpf = p_frq;
}
void Reverb::set_extra_spread(float p_spread) {
params.extra_spread = p_spread;
}
void Reverb::set_mix_rate(float p_mix_rate) {
params.mix_rate = p_mix_rate;
configure_buffers();
}
void Reverb::set_extra_spread_base(float p_sec) {
params.extra_spread_base = p_sec;
configure_buffers();
}
void Reverb::configure_buffers() {
clear_buffers(); //clear if necessary
for (int i = 0; i < MAX_COMBS; i++) {
Comb &c = comb[i];
c.extra_spread_frames = lrint(params.extra_spread_base * params.mix_rate);
int len = lrint(comb_tunings[i] * params.mix_rate) + c.extra_spread_frames;
if (len < 5)
len = 5; //may this happen?
c.buffer = memnew_arr(float, len);
c.pos = 0;
for (int j = 0; j < len; j++)
c.buffer[j] = 0;
c.size = len;
}
for (int i = 0; i < MAX_ALLPASS; i++) {
AllPass &a = allpass[i];
a.extra_spread_frames = lrint(params.extra_spread_base * params.mix_rate);
int len = lrint(allpass_tunings[i] * params.mix_rate) + a.extra_spread_frames;
if (len < 5)
len = 5; //may this happen?
a.buffer = memnew_arr(float, len);
a.pos = 0;
for (int j = 0; j < len; j++)
a.buffer[j] = 0;
a.size = len;
}
echo_buffer_size = (int)(((float)MAX_ECHO_MS / 1000.0) * params.mix_rate + 1.0);
echo_buffer = memnew_arr(float, echo_buffer_size);
for (int i = 0; i < echo_buffer_size; i++) {
echo_buffer[i] = 0;
}
echo_buffer_pos = 0;
}
void Reverb::update_parameters() {
//more freeverb derived constants
static const float room_scale = 0.28f;
static const float room_offset = 0.7f;
for (int i = 0; i < MAX_COMBS; i++) {
Comb &c = comb[i];
c.feedback = room_offset + params.room_size * room_scale;
if (c.feedback < room_offset)
c.feedback = room_offset;
else if (c.feedback > (room_offset + room_scale))
c.feedback = (room_offset + room_scale);
float auxdmp = params.damp / 2.0 + 0.5; //only half the range (0.5 .. 1.0 is enough)
auxdmp *= auxdmp;
c.damp = expf(-2.0 * Math_PI * auxdmp * 10000 / params.mix_rate); // 0 .. 10khz
}
}
void Reverb::clear_buffers() {
if (echo_buffer)
memdelete_arr(echo_buffer);
for (int i = 0; i < MAX_COMBS; i++) {
if (comb[i].buffer)
memdelete_arr(comb[i].buffer);
comb[i].buffer = nullptr;
}
for (int i = 0; i < MAX_ALLPASS; i++) {
if (allpass[i].buffer)
memdelete_arr(allpass[i].buffer);
allpass[i].buffer = nullptr;
}
}
Reverb::Reverb() {
params.room_size = 0.8;
params.damp = 0.5;
params.dry = 1.0;
params.wet = 0.0;
params.mix_rate = 44100;
params.extra_spread_base = 0;
params.extra_spread = 1.0;
params.predelay = 150;
params.predelay_fb = 0.4;
params.hpf = 0;
hpf_h1 = 0;
hpf_h2 = 0;
input_buffer = memnew_arr(float, INPUT_BUFFER_MAX_SIZE);
echo_buffer = nullptr;
configure_buffers();
update_parameters();
}
Reverb::~Reverb() {
memdelete_arr(input_buffer);
clear_buffers();
}