godot/servers/audio/effects/audio_effect_distortion.cpp
Rémi Verschelde d95794ec8a
One Copyright Update to rule them all
As many open source projects have started doing it, we're removing the
current year from the copyright notice, so that we don't need to bump
it every year.

It seems like only the first year of publication is technically
relevant for copyright notices, and even that seems to be something
that many companies stopped listing altogether (in a version controlled
codebase, the commits are a much better source of date of publication
than a hardcoded copyright statement).

We also now list Godot Engine contributors first as we're collectively
the current maintainers of the project, and we clarify that the
"exclusive" copyright of the co-founders covers the timespan before
opensourcing (their further contributions are included as part of Godot
Engine contributors).

Also fixed "cf." Frenchism - it's meant as "refer to / see".
2023-01-05 13:25:55 +01:00

182 lines
7.0 KiB
C++

/**************************************************************************/
/* audio_effect_distortion.cpp */
/**************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
/* */
/* 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. */
/**************************************************************************/
#include "audio_effect_distortion.h"
#include "core/math/math_funcs.h"
#include "servers/audio_server.h"
void AudioEffectDistortionInstance::process(const AudioFrame *p_src_frames, AudioFrame *p_dst_frames, int p_frame_count) {
const float *src = (const float *)p_src_frames;
float *dst = (float *)p_dst_frames;
//float lpf_c=expf(-Math_TAU*keep_hf_hz.get()/(mix_rate*(float)OVERSAMPLE));
float lpf_c = expf(-Math_TAU * base->keep_hf_hz / (AudioServer::get_singleton()->get_mix_rate()));
float lpf_ic = 1.0 - lpf_c;
float drive_f = base->drive;
float pregain_f = Math::db_to_linear(base->pre_gain);
float postgain_f = Math::db_to_linear(base->post_gain);
float atan_mult = pow(10, drive_f * drive_f * 3.0) - 1.0 + 0.001;
float atan_div = 1.0 / (atanf(atan_mult) * (1.0 + drive_f * 8));
float lofi_mult = powf(2.0, 2.0 + (1.0 - drive_f) * 14); //goes from 16 to 2 bits
for (int i = 0; i < p_frame_count * 2; i++) {
float out = undenormalize(src[i] * lpf_ic + lpf_c * h[i & 1]);
h[i & 1] = out;
float a = out;
float ha = src[i] - out; //high freqs
a *= pregain_f;
switch (base->mode) {
case AudioEffectDistortion::MODE_CLIP: {
float a_sign = a < 0 ? -1.0f : 1.0f;
a = powf(abs(a), 1.0001 - drive_f) * a_sign;
if (a > 1.0) {
a = 1.0;
} else if (a < (-1.0)) {
a = -1.0;
}
} break;
case AudioEffectDistortion::MODE_ATAN: {
a = atanf(a * atan_mult) * atan_div;
} break;
case AudioEffectDistortion::MODE_LOFI: {
a = floorf(a * lofi_mult + 0.5) / lofi_mult;
} break;
case AudioEffectDistortion::MODE_OVERDRIVE: {
const double x = a * 0.686306;
const double z = 1 + exp(sqrt(fabs(x)) * -0.75);
a = (expf(x) - expf(-x * z)) / (expf(x) + expf(-x));
} break;
case AudioEffectDistortion::MODE_WAVESHAPE: {
float x = a;
float k = 2 * drive_f / (1.00001 - drive_f);
a = (1.0 + k) * x / (1.0 + k * fabsf(x));
} break;
}
dst[i] = a * postgain_f + ha;
}
}
Ref<AudioEffectInstance> AudioEffectDistortion::instantiate() {
Ref<AudioEffectDistortionInstance> ins;
ins.instantiate();
ins->base = Ref<AudioEffectDistortion>(this);
ins->h[0] = 0;
ins->h[1] = 0;
return ins;
}
void AudioEffectDistortion::set_mode(Mode p_mode) {
mode = p_mode;
}
AudioEffectDistortion::Mode AudioEffectDistortion::get_mode() const {
return mode;
}
void AudioEffectDistortion::set_pre_gain(float p_pre_gain) {
pre_gain = p_pre_gain;
}
float AudioEffectDistortion::get_pre_gain() const {
return pre_gain;
}
void AudioEffectDistortion::set_keep_hf_hz(float p_keep_hf_hz) {
keep_hf_hz = p_keep_hf_hz;
}
float AudioEffectDistortion::get_keep_hf_hz() const {
return keep_hf_hz;
}
void AudioEffectDistortion::set_drive(float p_drive) {
drive = p_drive;
}
float AudioEffectDistortion::get_drive() const {
return drive;
}
void AudioEffectDistortion::set_post_gain(float p_post_gain) {
post_gain = p_post_gain;
}
float AudioEffectDistortion::get_post_gain() const {
return post_gain;
}
void AudioEffectDistortion::_bind_methods() {
ClassDB::bind_method(D_METHOD("set_mode", "mode"), &AudioEffectDistortion::set_mode);
ClassDB::bind_method(D_METHOD("get_mode"), &AudioEffectDistortion::get_mode);
ClassDB::bind_method(D_METHOD("set_pre_gain", "pre_gain"), &AudioEffectDistortion::set_pre_gain);
ClassDB::bind_method(D_METHOD("get_pre_gain"), &AudioEffectDistortion::get_pre_gain);
ClassDB::bind_method(D_METHOD("set_keep_hf_hz", "keep_hf_hz"), &AudioEffectDistortion::set_keep_hf_hz);
ClassDB::bind_method(D_METHOD("get_keep_hf_hz"), &AudioEffectDistortion::get_keep_hf_hz);
ClassDB::bind_method(D_METHOD("set_drive", "drive"), &AudioEffectDistortion::set_drive);
ClassDB::bind_method(D_METHOD("get_drive"), &AudioEffectDistortion::get_drive);
ClassDB::bind_method(D_METHOD("set_post_gain", "post_gain"), &AudioEffectDistortion::set_post_gain);
ClassDB::bind_method(D_METHOD("get_post_gain"), &AudioEffectDistortion::get_post_gain);
ADD_PROPERTY(PropertyInfo(Variant::INT, "mode", PROPERTY_HINT_ENUM, "Clip,ATan,LoFi,Overdrive,Wave Shape"), "set_mode", "get_mode");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "pre_gain", PROPERTY_HINT_RANGE, "-60,60,0.01,suffix:dB"), "set_pre_gain", "get_pre_gain");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "keep_hf_hz", PROPERTY_HINT_RANGE, "1,20500,1,suffix:Hz"), "set_keep_hf_hz", "get_keep_hf_hz");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "drive", PROPERTY_HINT_RANGE, "0,1,0.01"), "set_drive", "get_drive");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "post_gain", PROPERTY_HINT_RANGE, "-80,24,0.01,suffix:dB"), "set_post_gain", "get_post_gain");
BIND_ENUM_CONSTANT(MODE_CLIP);
BIND_ENUM_CONSTANT(MODE_ATAN);
BIND_ENUM_CONSTANT(MODE_LOFI);
BIND_ENUM_CONSTANT(MODE_OVERDRIVE);
BIND_ENUM_CONSTANT(MODE_WAVESHAPE);
}
AudioEffectDistortion::AudioEffectDistortion() {
mode = MODE_CLIP;
pre_gain = 0;
post_gain = 0;
keep_hf_hz = 16000;
drive = 0;
}