/*************************************************************************/ /* eq.cpp */ /*************************************************************************/ /* This file is part of: */ /* GODOT ENGINE */ /* https://godotengine.org */ /*************************************************************************/ /* Copyright (c) 2007-2017 Juan Linietsky, Ariel Manzur. */ /* Copyright (c) 2014-2017 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: reduzio@gmail.com (C) 2006 #include "eq.h" #include "error_macros.h" #include "math_funcs.h" #include #define POW2(v) ((v) * (v)) /* Helper */ static int solve_quadratic(double a, double b, double c, double *r1, double *r2) { //solves quadractic and returns number of roots double base = 2 * a; if (base == 0.0f) return 0; double squared = b * b - 4 * a * c; if (squared < 0.0) return 0; squared = sqrt(squared); *r1 = (-b + squared) / base; *r2 = (-b - squared) / base; if (*r1 == *r2) return 1; else return 2; } EQ::BandProcess::BandProcess() { c1 = c2 = c3 = history.a1 = history.a2 = history.a3 = 0; history.b1 = history.b2 = history.b3 = 0; } void EQ::recalculate_band_coefficients() { #define BAND_LOG(m_f) (log((m_f)) / log(2.)) for (int i = 0; i < band.size(); i++) { double octave_size; double frq = band[i].freq; if (i == 0) { octave_size = BAND_LOG(band[1].freq) - BAND_LOG(frq); } else if (i == (band.size() - 1)) { octave_size = BAND_LOG(frq) - BAND_LOG(band[i - 1].freq); } else { double next = BAND_LOG(band[i + 1].freq) - BAND_LOG(frq); double prev = BAND_LOG(frq) - BAND_LOG(band[i - 1].freq); octave_size = (next + prev) / 2.0; } double frq_l = round(frq / pow(2.0, octave_size / 2.0)); double side_gain2 = POW2(Math_SQRT12); double th = 2.0 * Math_PI * frq / mix_rate; double th_l = 2.0 * Math_PI * frq_l / mix_rate; double c2a = side_gain2 * POW2(cos(th)) - 2.0 * side_gain2 * cos(th_l) * cos(th) + side_gain2 - POW2(sin(th_l)); 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)); 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)); //printf("band %i, precoefs = %f,%f,%f\n",i,c2a,c2b,c2c); double r1, r2; //roots int roots = solve_quadratic(c2a, c2b, c2c, &r1, &r2); ERR_CONTINUE(roots == 0); band[i].c1 = 2.0 * ((0.5 - r1) / 2.0); band[i].c2 = 2.0 * r1; band[i].c3 = 2.0 * (0.5 + r1) * cos(th); //printf("band %i, coefs = %f,%f,%f\n",i,(float)bands[i].c1,(float)bands[i].c2,(float)bands[i].c3); } } void EQ::set_preset_band_mode(Preset p_preset) { band.clear(); #define PUSH_BANDS(m_bands) \ for (int i = 0; i < m_bands; i++) { \ Band b; \ b.freq = bands[i]; \ band.push_back(b); \ } switch (p_preset) { case PRESET_6_BANDS: { static const double bands[] = { 32, 100, 320, 1e3, 3200, 10e3 }; PUSH_BANDS(6); } break; case PRESET_8_BANDS: { static const double bands[] = { 32, 72, 192, 512, 1200, 3000, 7500, 16e3 }; PUSH_BANDS(8); } break; case PRESET_10_BANDS: { static const double bands[] = { 31.25, 62.5, 125, 250, 500, 1e3, 2e3, 4e3, 8e3, 16e3 }; PUSH_BANDS(10); } break; case PRESET_21_BANDS: { 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 }; PUSH_BANDS(21); } break; case PRESET_31_BANDS: { 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 }; PUSH_BANDS(31); } break; }; recalculate_band_coefficients(); } int EQ::get_band_count() const { return band.size(); } float EQ::get_band_frequency(int p_band) { ERR_FAIL_INDEX_V(p_band, band.size(), 0); return band[p_band].freq; } void EQ::set_bands(const Vector &p_bands) { band.resize(p_bands.size()); for (int i = 0; i < p_bands.size(); i++) { band[i].freq = p_bands[i]; } recalculate_band_coefficients(); } void EQ::set_mix_rate(float p_mix_rate) { mix_rate = p_mix_rate; recalculate_band_coefficients(); } EQ::BandProcess EQ::get_band_processor(int p_band) const { EQ::BandProcess band_proc; ERR_FAIL_INDEX_V(p_band, band.size(), band_proc); band_proc.c1 = band[p_band].c1; band_proc.c2 = band[p_band].c2; band_proc.c3 = band[p_band].c3; return band_proc; } EQ::EQ() { mix_rate = 44100; } EQ::~EQ() { }