/* * 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_one_pole bw_math }}} * description {{{ * State variable filter (2nd order, 12 dB/oct) model with separated lowpass, * bandpass, and highpass outputs. * }}} * changelog {{{ * * }}} */ #ifndef _BW_SVF_H #define _BW_SVF_H #ifdef __cplusplus extern "C" { #endif #include /*! api {{{ * #### bw_svf_coeffs * ```>>> */ typedef struct _bw_svf_coeffs bw_svf_coeffs; /*! <<<``` * Coefficients. * * ### bw_svf_state * ```>>> */ typedef struct _bw_svf_state bw_svf_state; /*! <<<``` * State. * * #### bw_svf_init() * ```>>> */ static inline void bw_svf_init(bw_svf_coeffs *BW_RESTRICT coeffs); /*! <<<``` * Initializes `coeffs`. * * #### bw_svf_set_sample_rate() * ```>>> */ static inline void bw_svf_set_sample_rate(bw_svf_coeffs *BW_RESTRICT coeffs, float sample_rate); /*! <<<``` * Sets the `sample_rate` (Hz) value for the given `coeffs`. * * #### bw_svf_reset_state() * ```>>> */ static inline void bw_svf_reset_state(const bw_svf_coeffs *BW_RESTRICT coeffs, bw_svf_state *BW_RESTRICT state); /*! <<<``` * Resets the given `state` to the initial state using the given `coeffs`. * >>> */ static inline void bw_svf_reset_coeffs(bw_svf_coeffs *BW_RESTRICT coeffs); static inline void bw_svf_update_coeffs_ctrl(bw_svf_coeffs *BW_RESTRICT coeffs); static inline void bw_svf_update_coeffs_audio(bw_svf_coeffs *BW_RESTRICT coeffs); static inline void bw_svf_process1(const bw_svf_coeffs *BW_RESTRICT coeffs, bw_svf_state *BW_RESTRICT state, float x, float *y_lp, float *y_bp, float *y_hp); /*! ... * #### bw_svf_process() * ```>>> */ static inline void bw_svf_process(bw_svf_coeffs *BW_RESTRICT coeffs, bw_svf_state *BW_RESTRICT state, const float *x, float *y_lp, float *y_bp, float *y_hp, 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 * buffers `y_lp` (lowpass), `y_bp` (bandpass), and `y_hp` (highpass), if * they are not `NULL`. * >>> */ /*! ... * #### bw_svf_set_cutoff() * ```>>> */ static inline void bw_svf_set_cutoff(bw_svf_coeffs *BW_RESTRICT coeffs, float value); /*! <<<``` * Sets the cutoff frequency to the given `value` (Hz) for the given * `instance`. * * Default value: `1e3f`. * >>> */ /*! ... * #### bw_svf_set_Q() * ```>>> */ static inline void bw_svf_set_Q(bw_svf_coeffs *BW_RESTRICT coeffs, float value); /*! <<<``` * Sets the quality factor to the given `value` (Hz) for the given * `instance`. * * Default value: `0.5f`. * }}} */ /*** Implementation ***/ /* WARNING: This part of the file is not part of the public API. Its content may * change at any time in future versions. Please, do not use it directly. */ #include #include struct _bw_svf_coeffs { // Sub-components bw_one_pole_coeffs smooth_coeffs; bw_one_pole_state smooth_cutoff_state; bw_one_pole_state smooth_Q_state; // Coefficients float t_k; float t; float k; float hp_hp_z1; float hp_bp_z1; float hp_x; // Parameters float cutoff; float Q; }; struct _bw_svf_state { float hp_z1; float lp_z1; float bp_z1; }; static inline void bw_svf_init(bw_svf_coeffs *BW_RESTRICT coeffs) { bw_one_pole_init(&coeffs->smooth_coeffs); bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.005f); bw_one_pole_set_sticky_thresh(&coeffs->smooth_coeffs, 1e-3f); coeffs->cutoff = 1e3f; coeffs->Q = 0.5f; } static inline void bw_svf_set_sample_rate(bw_svf_coeffs *BW_RESTRICT coeffs, float sample_rate) { bw_one_pole_set_sample_rate(&coeffs->smooth_coeffs, sample_rate); bw_one_pole_reset_coeffs(&coeffs->smooth_coeffs); coeffs->t_k = 3.141592653589793f / sample_rate; } static inline void _bw_svf_do_update_coeffs(bw_svf_coeffs *BW_RESTRICT coeffs, char force) { float cutoff_cur = bw_one_pole_get_y_z1(&coeffs->smooth_cutoff_state); float Q_cur = bw_one_pole_get_y_z1(&coeffs->smooth_Q_state); const char cutoff_changed = force || coeffs->cutoff != cutoff_cur; const char Q_changed = force || coeffs->Q != Q_cur; if (cutoff_changed || Q_changed) { if (cutoff_changed) { cutoff_cur = bw_one_pole_process1_sticky_rel(&coeffs->smooth_coeffs, &coeffs->smooth_cutoff_state, coeffs->cutoff); coeffs->t = bw_tanf_3(coeffs->t_k * cutoff_cur); } if (Q_changed) { Q_cur = bw_one_pole_process1_sticky_abs(&coeffs->smooth_coeffs, &coeffs->smooth_Q_state, coeffs->Q); coeffs->k = bw_rcpf_2(Q_cur); } const float kpt = coeffs->k + coeffs->t; coeffs->hp_hp_z1 = coeffs->t * kpt; coeffs->hp_bp_z1 = coeffs->t + kpt; coeffs->hp_x = bw_rcpf_2(1.f + coeffs->hp_hp_z1); } } static inline void bw_svf_reset_coeffs(bw_svf_coeffs *BW_RESTRICT coeffs) { bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_cutoff_state, coeffs->cutoff); bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_Q_state, coeffs->Q); _bw_svf_do_update_coeffs(coeffs, 1); } static inline void bw_svf_reset_state(const bw_svf_coeffs *BW_RESTRICT coeffs, bw_svf_state *BW_RESTRICT state) { state->hp_z1 = 0.f; state->lp_z1 = 0.f; state->bp_z1 = 0.f; } static inline void bw_svf_update_coeffs_ctrl(bw_svf_coeffs *BW_RESTRICT coeffs) { } static inline void bw_svf_update_coeffs_audio(bw_svf_coeffs *BW_RESTRICT coeffs) { _bw_svf_do_update_coeffs(coeffs, 0); } static inline void bw_svf_process1(const bw_svf_coeffs *BW_RESTRICT coeffs, bw_svf_state *BW_RESTRICT state, float x, float *y_lp, float *y_bp, float *y_hp) { *y_hp = coeffs->hp_x * (x - state->lp_z1 + coeffs->hp_bp_z1 * state->bp_z1 - coeffs->hp_hp_z1 * state->hp_z1); *y_bp = state->bp_z1 - coeffs->t * (*y_hp + state->hp_z1); *y_lp = state->lp_z1 - coeffs->t * (*y_bp + state->bp_z1); state->hp_z1 = *y_hp; state->lp_z1 = *y_lp; state->bp_z1 = *y_bp; } static inline void bw_svf_process(bw_svf_coeffs *BW_RESTRICT coeffs, bw_svf_state *BW_RESTRICT state, const float *x, float *y_lp, float *y_bp, float *y_hp, int n_samples) { if (y_lp != NULL) { if (y_bp != NULL) { if (y_hp != NULL) { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); bw_svf_process1(coeffs, state, x[i], y_lp + i, y_bp + i, y_hp + i); } } else { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_lp; bw_svf_process1(coeffs, state, x[i], &v_lp, y_bp + i, y_hp + i); } } } else { if (y_hp != NULL) { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_bp; bw_svf_process1(coeffs, state, x[i], y_lp + i, &v_bp, y_hp + i); } } else { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_bp, v_hp; bw_svf_process1(coeffs, state, x[i], y_lp + i, &v_bp, &v_hp); } } } } else { if (y_bp != NULL) { if (y_hp != NULL) { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_lp; bw_svf_process1(coeffs, state, x[i], &v_lp, y_bp + i, y_hp + i); } } else { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_lp, v_hp; bw_svf_process1(coeffs, state, x[i], &v_lp, y_bp + i, &v_hp); } } } else { if (y_hp != NULL) { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_lp, v_bp; bw_svf_process1(coeffs, state, x[i], &v_lp, &v_bp, y_hp + i); } } else { for (int i = 0; i < n_samples; i++) { bw_svf_update_coeffs_audio(coeffs); float v_lp, v_bp, v_hp; bw_svf_process1(coeffs, state, x[i], &v_lp, &v_bp, &v_hp); } } } } } static inline void bw_svf_set_cutoff(bw_svf_coeffs *BW_RESTRICT coeffs, float value) { coeffs->cutoff = value; } static inline void bw_svf_set_Q(bw_svf_coeffs *BW_RESTRICT coeffs, float value) { coeffs->Q = value; } #ifdef __cplusplus } #endif #endif