/* * Brickworks * * Copyright (C) 2022 Orastron Srl unipersonale * * Brickworks is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, version 3 of the License. * * Brickworks is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * * File author: Stefano D'Angelo */ /*! * module_type {{{ dsp }}} * version {{{ 0.2.0 }}} * requires {{{ bw_config bw_common bw_math }}} * description {{{ * One-pole (6 dB/oct) lowpass filter with unitary DC gain, separate attack * and decay time constants, and sticky target-reach threshold. * }}} * changelog {{{ * * }}} */ #ifndef _BW_ONE_POLE_H #define _BW_ONE_POLE_H #ifdef __cplusplus extern "C" { #endif /*! api {{{ * #### bw_one_pole * ```>>> */ typedef struct _bw_one_pole bw_one_pole; /*! <<<``` * Instance object. * >>> */ /*! ... * #### bw_one_pole_sticky_mode * ```>>> */ typedef enum { bw_one_pole_sticky_mode_abs, bw_one_pole_sticky_mode_rel } bw_one_pole_sticky_mode; /*! <<<``` * Distance metrics for sticky behavior: * * `bw_one_pole_sticky_mode_abs`: absolute difference (|`out` - `in`|); * * `bw_one_pole_sticky_mode_rel`: relative difference with respect to * input (|`out` - `in`| / |`in`|); * >>> */ /*! ... * #### bw_one_pole_init() * ```>>> */ void bw_one_pole_init(bw_one_pole *instance); /*! <<<``` * Initializes the `instance` object. * >>> */ /*! ... * #### bw_one_pole_set_sample_rate() * ```>>> */ void bw_one_pole_set_sample_rate(bw_one_pole *instance, float sample_rate); /*! <<<``` * Sets the `sample_rate` (Hz) value for the given `instance`. * >>> */ /*! ... * #### bw_one_pole_reset() * ```>>> */ void bw_one_pole_reset(bw_one_pole *instance); /*! <<<``` * Resets the given `instance` to its initial state. * >>> */ /*! ... * #### bw_one_pole_process() * ```>>> */ void bw_one_pole_process(bw_one_pole *instance, const float* x, float* y, int n_samples); /*! <<<``` * Lets the given `instance` process `n_samples` samples from the input * buffer `x` and fills the corresponding `n_samples` samples in the output * buffer `y`. * >>> */ /*! ... * #### bw_one_pole_set_init_val() * ```>>> */ void bw_one_pole_set_init_val(bw_one_pole *instance, float value); /*! <<<``` * Sets the initial/quiescent `value` for the given `instance`. * * In practice, when processing the first buffer after a reset, the past * input and output are both assumed to have virtually been constant and of * the specified `value`. * * Default value: `0.f`. * >>> */ /*! ... * #### bw_one_pole_set_cutoff() * ```>>> */ void bw_one_pole_set_cutoff(bw_one_pole *instance, float value); /*! <<<``` * Sets both the upgoing (attack) and downgoing (decay) cutoff frequency to * the given `value` (Hz) for the given `instance`. * * This is equivalent to calling both `bw_one_pole_set_cutoff_up()` and * `bw_one_pole_set_cutoff_down()` with same `instance` and `value` or * calling `bw_one_pole_set_tau()` with same `instance` and * value = 1 / (2 * pi * `value`) (net of numerical errors). * * Default value: `INFINITY`. * >>> */ /*! ... * #### bw_one_pole_set_cutoff_up() * ```>>> */ void bw_one_pole_set_cutoff_up(bw_one_pole *instance, float value); /*! <<<``` * Sets the upgoing (attack) cutoff frequency to the given `value` (Hz) for * the given `instance`. * * This is equivalent to calling `bw_one_pole_set_tau_up()` with same * `instance` and value = 1 / (2 * pi * `value`) (net of numerical errors). * * Default value: `INFINITY`. * >>> */ /*! ... * #### bw_one_pole_set_cutoff_down() * ```>>> */ void bw_one_pole_set_cutoff_down(bw_one_pole *instance, float value); /*! <<<``` * Sets the downgoing (attack) cutoff frequency to the given `value` (Hz) * for the given `instance`. * * This is equivalent to calling `bw_one_pole_set_tau_down()` with same * `instance` and value = 1 / (2 * pi * `value`) (net of numerical errors). * * Default value: `INFINITY`. * >>> */ /*! ... * #### bw_one_pole_set_tau() * ```>>> */ void bw_one_pole_set_tau(bw_one_pole *instance, float value); /*! <<<``` * Sets both the upgoing (attack) and downgoing (decay) time constant to the * given `value` (s) for the given `instance`. * * This is equivalent to calling both `bw_one_pole_set_tau_up()` and * `bw_one_pole_set_tau_down()` with same `instance` and `value` or calling * `bw_one_pole_set_cutoff()` with same `instance` and * value = 1 / (2 * pi * `value`) (net of numerical errors). * * Default value: `0.f`. * >>> */ /*! ... * #### bw_one_pole_set_tau_up() * ```>>> */ void bw_one_pole_set_tau_up(bw_one_pole *instance, float value); /*! <<<``` * Sets the upgoing (attack) time constant to the given `value` (s) for the * given `instance`. * * This is equivalent to calling `bw_one_pole_set_cutoff_up()` with same * `instance` and value = 1 / (2 * pi * `value`) (net of numerical errors). * * Default value: `0.f`. * >>> */ /*! ... * #### bw_one_pole_set_tau_down() * ```>>> */ void bw_one_pole_set_tau_down(bw_one_pole *instance, float value); /*! <<<``` * Sets the downgoing (decay) time constant to the given `value` (s) for the * given `instance`. * * This is equivalent to calling `bw_one_pole_set_cutoff_down()` with same * `instance` and value = 1 / (2 * pi * `value`) (net of numerical errors). * * Default value: `0.f`. * >>> */ /*! ... * #### bw_one_pole_set_sticky_thresh() * ```>>> */ void bw_one_pole_set_sticky_thresh(bw_one_pole *instance, float value); /*! <<<``` * Sets the target-reach threshold specified by `value` for the given * `instance`. * * When the difference between the output and the input would fall under such * threshold according to the current distance metric (see * `bw_one_pole_set_sticky_mode()`), the output is forcefully set to be equal * to the input value. * * Default value: `0.f`. * >>> */ /*! ... * #### bw_one_pole_set_sticky_mode() * ```>>> */ void bw_one_pole_set_sticky_mode(bw_one_pole *instance, bw_one_pole_sticky_mode value); /*! <<<``` * Sets the current distance metric for sticky behavior. * }}} */ /* WARNING: the internal definition of this struct is not part of the public * API. Its content may change at any time in future versions. Please, do not * access its members directly. */ struct _bw_one_pole { // Coefficients float Ttm2pi; float mA1u; float mA1d; float st2; // Parameters float init_val; float cutoff_up; float cutoff_down; float sticky_thresh; bw_one_pole_sticky_mode sticky_mode; int param_changed; // State char first_run; float x_z1; float y_z1; }; #ifdef __cplusplus } #endif #endif