godot/servers/audio/effects/reverb.cpp
Rémi Verschelde a7f49ac9a1 Update copyright statements to 2020
Happy new year to the wonderful Godot community!

We're starting a new decade with a well-established, non-profit, free
and open source game engine, and tons of further improvements in the
pipeline from hundreds of contributors.

Godot will keep getting better, and we're looking forward to all the
games that the community will keep developing and releasing with it.
2020-01-01 11:16:22 +01:00

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/*************************************************************************/
/* reverb.cpp */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2020 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 = 0;
}
for (int i = 0; i < MAX_ALLPASS; i++) {
if (allpass[i].buffer)
memdelete_arr(allpass[i].buffer);
allpass[i].buffer = 0;
}
}
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 = 0;
configure_buffers();
update_parameters();
}
Reverb::~Reverb() {
memdelete_arr(input_buffer);
clear_buffers();
}