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/*************************************************************************/
/* audio_effect_distortion.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. */
/*************************************************************************/
#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(-2.0*Math_PI*keep_hf_hz.get()/(mix_rate*(float)OVERSAMPLE));
float lpf_c = expf(-2.0 * Math_PI * 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::db2linear(base->pre_gain);
float postgain_f = Math::db2linear(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 = undenormalise(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: {
a = powf(a, 1.0001 - drive_f);
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::instance() {
Ref<AudioEffectDistortionInstance> ins;
ins.instance();
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,WaveShape"), "set_mode", "get_mode");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "pre_gain", PROPERTY_HINT_RANGE, "-60,60,0.01"), "set_pre_gain", "get_pre_gain");
ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "keep_hf_hz", PROPERTY_HINT_RANGE, "1,20500,1"), "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"), "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;
}
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