204 lines
6.5 KiB
C++
204 lines
6.5 KiB
C++
/*************************************************************************/
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/* eq.cpp */
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/*************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/*************************************************************************/
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/* Copyright (c) 2007-2021 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2021 Godot Engine contributors (cf. AUTHORS.md). */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/*************************************************************************/
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// Author: reduzio@gmail.com (C) 2006
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#include "eq.h"
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#include "core/error/error_macros.h"
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#include "core/math/math_funcs.h"
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#include <math.h>
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#define POW2(v) ((v) * (v))
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/* Helper */
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static int solve_quadratic(double a, double b, double c, double *r1, double *r2) {
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//solves quadractic and returns number of roots
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double base = 2 * a;
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if (base == 0.0f) {
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return 0;
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}
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double squared = b * b - 4 * a * c;
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if (squared < 0.0) {
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return 0;
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}
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squared = sqrt(squared);
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*r1 = (-b + squared) / base;
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*r2 = (-b - squared) / base;
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if (*r1 == *r2) {
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return 1;
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} else {
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return 2;
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}
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}
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EQ::BandProcess::BandProcess() {
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c1 = c2 = c3 = history.a1 = history.a2 = history.a3 = 0;
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history.b1 = history.b2 = history.b3 = 0;
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}
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void EQ::recalculate_band_coefficients() {
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#define BAND_LOG(m_f) (log((m_f)) / log(2.))
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for (int i = 0; i < band.size(); i++) {
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double octave_size;
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double frq = band[i].freq;
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if (i == 0) {
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octave_size = BAND_LOG(band[1].freq) - BAND_LOG(frq);
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} else if (i == (band.size() - 1)) {
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octave_size = BAND_LOG(frq) - BAND_LOG(band[i - 1].freq);
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} else {
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double next = BAND_LOG(band[i + 1].freq) - BAND_LOG(frq);
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double prev = BAND_LOG(frq) - BAND_LOG(band[i - 1].freq);
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octave_size = (next + prev) / 2.0;
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}
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double frq_l = round(frq / pow(2.0, octave_size / 2.0));
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double side_gain2 = POW2(Math_SQRT12);
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double th = Math_TAU * frq / mix_rate;
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double th_l = Math_TAU * frq_l / mix_rate;
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double c2a = side_gain2 * POW2(cos(th)) - 2.0 * side_gain2 * cos(th_l) * cos(th) + side_gain2 - POW2(sin(th_l));
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double c2b = 2.0 * side_gain2 * POW2(cos(th_l)) + side_gain2 * POW2(cos(th)) - 2.0 * side_gain2 * cos(th_l) * cos(th) - side_gain2 + POW2(sin(th_l));
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double c2c = 0.25 * side_gain2 * POW2(cos(th)) - 0.5 * side_gain2 * cos(th_l) * cos(th) + 0.25 * side_gain2 - 0.25 * POW2(sin(th_l));
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//printf("band %i, precoefs = %f,%f,%f\n",i,c2a,c2b,c2c);
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// Default initializing to silence compiler warning about potential uninitialized use.
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// Both variables are properly set in _solve_quadratic before use, or we continue if roots == 0.
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double r1 = 0, r2 = 0; //roots
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int roots = solve_quadratic(c2a, c2b, c2c, &r1, &r2);
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ERR_CONTINUE(roots == 0);
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band.write[i].c1 = 2.0 * ((0.5 - r1) / 2.0);
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band.write[i].c2 = 2.0 * r1;
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band.write[i].c3 = 2.0 * (0.5 + r1) * cos(th);
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//printf("band %i, coefs = %f,%f,%f\n",i,(float)bands[i].c1,(float)bands[i].c2,(float)bands[i].c3);
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}
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}
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void EQ::set_preset_band_mode(Preset p_preset) {
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band.clear();
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#define PUSH_BANDS(m_bands) \
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for (int i = 0; i < m_bands; i++) { \
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Band b; \
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b.freq = bands[i]; \
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b.c1 = b.c2 = b.c3 = 0; \
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band.push_back(b); \
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}
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switch (p_preset) {
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case PRESET_6_BANDS: {
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static const double bands[] = { 32, 100, 320, 1e3, 3200, 10e3 };
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PUSH_BANDS(6);
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} break;
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case PRESET_8_BANDS: {
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static const double bands[] = { 32, 72, 192, 512, 1200, 3000, 7500, 16e3 };
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PUSH_BANDS(8);
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} break;
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case PRESET_10_BANDS: {
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static const double bands[] = { 31.25, 62.5, 125, 250, 500, 1e3, 2e3, 4e3, 8e3, 16e3 };
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PUSH_BANDS(10);
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} break;
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case PRESET_21_BANDS: {
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static const double bands[] = { 22, 32, 44, 63, 90, 125, 175, 250, 350, 500, 700, 1e3, 1400, 2e3, 2800, 4e3, 5600, 8e3, 11e3, 16e3, 22e3 };
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PUSH_BANDS(21);
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} break;
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case PRESET_31_BANDS: {
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static const double bands[] = { 20, 25, 31.5, 40, 50, 63, 80, 100, 125, 160, 200, 250, 315, 400, 500, 630, 800, 1e3, 1250, 1600, 2e3, 2500, 3150, 4e3, 5e3, 6300, 8e3, 10e3, 12500, 16e3, 20e3 };
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PUSH_BANDS(31);
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} break;
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};
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recalculate_band_coefficients();
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}
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int EQ::get_band_count() const {
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return band.size();
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}
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float EQ::get_band_frequency(int p_band) {
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ERR_FAIL_INDEX_V(p_band, band.size(), 0);
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return band[p_band].freq;
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}
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void EQ::set_bands(const Vector<float> &p_bands) {
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band.resize(p_bands.size());
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for (int i = 0; i < p_bands.size(); i++) {
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band.write[i].freq = p_bands[i];
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}
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recalculate_band_coefficients();
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}
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void EQ::set_mix_rate(float p_mix_rate) {
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mix_rate = p_mix_rate;
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recalculate_band_coefficients();
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}
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EQ::BandProcess EQ::get_band_processor(int p_band) const {
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EQ::BandProcess band_proc;
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ERR_FAIL_INDEX_V(p_band, band.size(), band_proc);
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band_proc.c1 = band[p_band].c1;
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band_proc.c2 = band[p_band].c2;
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band_proc.c3 = band[p_band].c3;
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return band_proc;
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}
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EQ::EQ() {
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mix_rate = 44100;
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}
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EQ::~EQ() {
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}
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