a7f49ac9a1
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128 lines
4.3 KiB
C++
128 lines
4.3 KiB
C++
/*************************************************************************/
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/* audio_filter_sw.h */
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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) 2007-2020 Juan Linietsky, Ariel Manzur. */
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/* Copyright (c) 2014-2020 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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#ifndef AUDIO_FILTER_SW_H
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#define AUDIO_FILTER_SW_H
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#include "core/math/math_funcs.h"
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class AudioFilterSW {
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public:
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struct Coeffs {
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float a1, a2;
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float b0, b1, b2;
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//bool operator==(const Coeffs &p_rv) { return (FLOATS_EQ(a1,p_rv.a1) && FLOATS_EQ(a2,p_rv.a2) && FLOATS_EQ(b1,p_rv.b1) && FLOATS_EQ(b2,p_rv.b2) && FLOATS_EQ(b0,p_rv.b0) ); }
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Coeffs() { a1 = a2 = b0 = b1 = b2 = 0.0; }
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};
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enum Mode {
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BANDPASS,
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HIGHPASS,
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LOWPASS,
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NOTCH,
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PEAK,
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BANDLIMIT,
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LOWSHELF,
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HIGHSHELF
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};
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class Processor { // simple filter processor
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AudioFilterSW *filter;
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Coeffs coeffs;
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float ha1, ha2, hb1, hb2; //history
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Coeffs incr_coeffs;
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public:
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void set_filter(AudioFilterSW *p_filter, bool p_clear_history = true);
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void process(float *p_samples, int p_amount, int p_stride = 1, bool p_interpolate = false);
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void update_coeffs(int p_interp_buffer_len = 0);
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_ALWAYS_INLINE_ void process_one(float &p_sample);
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_ALWAYS_INLINE_ void process_one_interp(float &p_sample);
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Processor();
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};
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private:
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float cutoff;
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float resonance;
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float gain;
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float sampling_rate;
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int stages;
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Mode mode;
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public:
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float get_response(float p_freq, Coeffs *p_coeffs);
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void set_mode(Mode p_mode);
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void set_cutoff(float p_cutoff);
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void set_resonance(float p_resonance);
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void set_gain(float p_gain);
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void set_sampling_rate(float p_srate);
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void set_stages(int p_stages); //adjust for multiple stages
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void prepare_coefficients(Coeffs *p_coeffs);
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AudioFilterSW();
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};
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/* inline methods */
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void AudioFilterSW::Processor::process_one(float &p_sample) {
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float pre = p_sample;
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p_sample = (p_sample * coeffs.b0 + hb1 * coeffs.b1 + hb2 * coeffs.b2 + ha1 * coeffs.a1 + ha2 * coeffs.a2);
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ha2 = ha1;
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hb2 = hb1;
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hb1 = pre;
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ha1 = p_sample;
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}
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void AudioFilterSW::Processor::process_one_interp(float &p_sample) {
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float pre = p_sample;
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p_sample = (p_sample * coeffs.b0 + hb1 * coeffs.b1 + hb2 * coeffs.b2 + ha1 * coeffs.a1 + ha2 * coeffs.a2);
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ha2 = ha1;
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hb2 = hb1;
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hb1 = pre;
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ha1 = p_sample;
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coeffs.b0 += incr_coeffs.b0;
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coeffs.b1 += incr_coeffs.b1;
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coeffs.b2 += incr_coeffs.b2;
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coeffs.a1 += incr_coeffs.a1;
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coeffs.a2 += incr_coeffs.a2;
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}
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#endif // AUDIO_FILTER_SW_H
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