298 lines
10 KiB
C
298 lines
10 KiB
C
/*
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* Brickworks
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*
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* Copyright (C) 2022, 2023 Orastron Srl unipersonale
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*
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* Brickworks is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 3 of the License.
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*
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* Brickworks is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with Brickworks. If not, see <http://www.gnu.org/licenses/>.
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*
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* File author: Stefano D'Angelo
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*/
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/*!
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* module_type {{{ dsp }}}
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* version {{{ 1.0.0 }}}
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* requires {{{ bw_common bw_math bw_one_pole }}}
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* description {{{
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* Triangle oscillator waveshaper with variable slope (increasing time over
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* period) and PolyBLEP antialiasing.
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*
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* It turns a normalized phase signal, such as that geneated by
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* [bw\_phase\_gen](bw_phase_gen), into a triangle wave.
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* }}}
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* changelog {{{
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* <ul>
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* <li>Version <strong>1.0.0</strong>:
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* <ul>
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* <li>Now using <code>size_t</code> instead of
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* <code>BW_SIZE_T</code>.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.6.0</strong>:
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* <ul>
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* <li>Removed dependency on bw_config.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.5.0</strong>:
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* <ul>
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* <li>Added <code>bw_osc_pulse_process_multi()</code>.</li>
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* <li>Fixed typo in <code>bw_osc_tri_process1\*()</code>
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* documentation.</li>
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* <li>Added C++ wrapper.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.4.0</strong>:
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* <ul>
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* <li>Fixed unused parameter warnings.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.2.0</strong>:
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* <ul>
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* <li>Refactored API.</li>
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* </ul>
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* </li>
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* <li>Version <strong>0.1.0</strong>:
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* <ul>
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* <li>First release.</li>
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* </ul>
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* </li>
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* </ul>
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* }}}
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*/
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#ifndef _BW_OSC_TRI_H
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#define _BW_OSC_TRI_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <bw_common.h>
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/*! api {{{
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* #### bw_osc_tri_coeffs
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* ```>>> */
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typedef struct _bw_osc_tri_coeffs bw_osc_tri_coeffs;
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/*! <<<```
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* Coefficients and related.
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*
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* #### bw_osc_tri_init()
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* ```>>> */
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static inline void bw_osc_tri_init(bw_osc_tri_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Initializes input parameter values in `coeffs`.
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*
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* #### bw_osc_tri_set_sample_rate()
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* ```>>> */
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static inline void bw_osc_tri_set_sample_rate(bw_osc_tri_coeffs *BW_RESTRICT coeffs, float sample_rate);
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/*! <<<```
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* Sets the `sample_rate` (Hz) value in `coeffs`.
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*
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* #### bw_osc_tri_reset_coeffs()
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* ```>>> */
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static inline void bw_osc_tri_reset_coeffs(bw_osc_tri_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Resets coefficients in `coeffs` to assume their target values.
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*
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* #### bw_osc_tri_update_coeffs_ctrl()
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* ```>>> */
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static inline void bw_osc_tri_update_coeffs_ctrl(bw_osc_tri_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Triggers control-rate update of coefficients in `coeffs`.
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*
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* #### bw_osc_tri_update_coeffs_audio()
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* ```>>> */
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static inline void bw_osc_tri_update_coeffs_audio(bw_osc_tri_coeffs *BW_RESTRICT coeffs);
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/*! <<<```
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* Triggers audio-rate update of coefficients in `coeffs`.
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*
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* #### bw_osc_tri_process1\*()
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* ```>>> */
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static inline float bw_osc_tri_process1(const bw_osc_tri_coeffs *BW_RESTRICT coeffs, float x);
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static inline float bw_osc_tri_process1_antialias(const bw_osc_tri_coeffs *BW_RESTRICT coeffs, float x, float x_phase_inc);
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/*! <<<```
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* These function process one input sample `x`, indicating the normalized
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* phase, using `coeffs`. They return the corresponding output sample.
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*
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* In particular:
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* * `bw_osc_tri_process1()` assumes that antialiasing is disabled;
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* * `bw_osc_tri_process1_antialias()` assumes that antialiasing is enabled
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* and requires the corresponding phase increment value to be passed via
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* `x_phase_inc`.
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*
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* #### bw_osc_tri_process()
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* ```>>> */
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static inline void bw_osc_tri_process(bw_osc_tri_coeffs *BW_RESTRICT coeffs, const float *x, const float *x_phase_inc, float *y, int n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the input buffer `x`, containing the
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* normalized phase signal, and fills the first `n_samples` of the output
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* buffer `y`, while using and updating `coeffs`.
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*
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* If antialiasing is enabled, `x_phase_inc` must contain phase increment
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* values, otherwise it is ignored and can be `NULL`.
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*
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* #### bw_osc_tri_process_multi()
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* ```>>> */
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static inline void bw_osc_tri_process_multi(bw_osc_tri_coeffs *BW_RESTRICT coeffs, const float **x, const float **x_phase_inc, float **y, int n_channels, int n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the `n_channels` input buffers `x`,
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* containing the normalized phase signals, and fills the first `n_samples`
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* of the `n_channels` output buffers `y`, while using and updating the
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* common `coeffs` (control and audio rate).
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*
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* If antialiasing is enabled, `x_phase_inc` must contain `n_channels`
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* buffers of phase increment values, otherwise it is ignored and can be
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* `NULL`.
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*
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* #### bw_osc_tri_set_antialiasing()
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* ```>>> */
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static inline void bw_osc_tri_set_antialiasing(bw_osc_tri_coeffs *BW_RESTRICT coeffs, char value);
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/*! <<<```
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* Sets whether the antialiasing is on (`value` non-`0`) or off (`0`) in
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* `coeffs`.
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*
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* Default value: `0` (off).
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*
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* #### bw_osc_tri_set_slope()
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* ```>>> */
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static inline void bw_osc_tri_set_slope(bw_osc_tri_coeffs *BW_RESTRICT coeffs, float value);
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/*! <<<```
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* Sets the slope (increasing time over period) to `value` (range [`0.001f`,
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* `0.999f`]) in `coeffs`.
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*
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* Default value: `0.5f`.
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* }}} */
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/*** Implementation ***/
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/* WARNING: This part of the file is not part of the public API. Its content may
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* change at any time in future versions. Please, do not use it directly. */
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#include <bw_math.h>
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#include <bw_one_pole.h>
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struct _bw_osc_tri_coeffs {
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// Sub-components
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bw_one_pole_coeffs smooth_coeffs;
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bw_one_pole_state smooth_state;
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// Parameters
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char antialiasing;
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float slope;
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};
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static inline void bw_osc_tri_init(bw_osc_tri_coeffs *BW_RESTRICT coeffs) {
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bw_one_pole_init(&coeffs->smooth_coeffs);
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bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.005f);
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coeffs->antialiasing = 0;
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coeffs->slope = 0.5f;
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}
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static inline void bw_osc_tri_set_sample_rate(bw_osc_tri_coeffs *BW_RESTRICT coeffs, float sample_rate) {
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bw_one_pole_set_sample_rate(&coeffs->smooth_coeffs, sample_rate);
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bw_one_pole_reset_coeffs(&coeffs->smooth_coeffs);
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}
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static inline void bw_osc_tri_reset_coeffs(bw_osc_tri_coeffs *BW_RESTRICT coeffs) {
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bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_state, coeffs->slope);
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}
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static inline void bw_osc_tri_update_coeffs_ctrl(bw_osc_tri_coeffs *BW_RESTRICT coeffs) {
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(void)coeffs;
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}
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static inline void bw_osc_tri_update_coeffs_audio(bw_osc_tri_coeffs *BW_RESTRICT coeffs) {
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bw_one_pole_process1(&coeffs->smooth_coeffs, &coeffs->smooth_state, coeffs->slope);
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}
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static inline float bw_osc_tri_process1(const bw_osc_tri_coeffs *BW_RESTRICT coeffs, float x) {
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const float slope = bw_one_pole_get_y_z1(&coeffs->smooth_state);
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const float phase_d = x + x;
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return x < slope ? (phase_d - slope) * bw_rcpf(slope) : (1.f + slope - phase_d) * bw_rcpf(1.f - slope);
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}
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// PolyBLAMP residual based on Parzen window (4th-order B-spline), one-sided (x in [0, 2])
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static inline float _bw_osc_tri_blamp_diff(float x) {
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return x < 1.f
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? x * (x * ((0.05f * x - 0.1666666666666667f) * x * x + 0.6666666666666666f) - 1.0f) + 0.4666666666666667f
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: x * (x * (x * ((0.1666666666666667f - 0.01666666666666667f * x) * x - 0.6666666666666666f) + 1.333333333333333f) - 1.333333333333333f) + 0.5333333333333333f;
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}
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static inline float bw_osc_tri_process1_antialias(const bw_osc_tri_coeffs *BW_RESTRICT coeffs, float x, float x_phase_inc) {
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const float slope = bw_one_pole_get_y_z1(&coeffs->smooth_state);
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const float s_1_p_pw = 1.f + slope;
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const float s_1_m_pw = 1.f - slope;
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const float phase_d = x + x;
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float v = x < slope ? (phase_d - slope) * bw_rcpf(slope) : (s_1_p_pw - phase_d) * bw_rcpf(s_1_m_pw);
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if (x_phase_inc != 0.f) {
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const float phase_inc_2 = x_phase_inc + x_phase_inc;
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const float phase_inc_rcp = bw_rcpf(x_phase_inc);
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const float pw_m_phase = slope - x;
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const float phase_2 = bw_copysignf(0.5f, pw_m_phase) + 0.5f - pw_m_phase;
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const float s_1_m_phase = 1.f - x;
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const float s_1_m_phase_2 = 1.f - phase_2;
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float blamp = 0.f;
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if (s_1_m_phase_2 < phase_inc_2)
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blamp += _bw_osc_tri_blamp_diff(s_1_m_phase_2 * phase_inc_rcp);
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if (s_1_m_phase < phase_inc_2)
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blamp -= _bw_osc_tri_blamp_diff(s_1_m_phase * phase_inc_rcp);
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if (x < phase_inc_2)
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blamp -= _bw_osc_tri_blamp_diff(x * phase_inc_rcp);
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if (phase_2 < phase_inc_2)
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blamp += _bw_osc_tri_blamp_diff(phase_2 * phase_inc_rcp);
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v -= bw_rcpf(slope * s_1_m_pw) * bw_absf(x_phase_inc) * blamp;
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}
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return v;
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}
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static inline void bw_osc_tri_process(bw_osc_tri_coeffs *BW_RESTRICT coeffs, const float *x, const float *x_phase_inc, float *y, int n_samples) {
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if (coeffs->antialiasing)
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for (int i = 0; i < n_samples; i++) {
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bw_osc_tri_update_coeffs_audio(coeffs);
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y[i] = bw_osc_tri_process1_antialias(coeffs, x[i], x_phase_inc[i]);
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}
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else
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for (int i = 0; i < n_samples; i++) {
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bw_osc_tri_update_coeffs_audio(coeffs);
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y[i] = bw_osc_tri_process1(coeffs, x[i]);
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}
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}
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static inline void bw_osc_tri_process_multi(bw_osc_tri_coeffs *BW_RESTRICT coeffs, const float **x, const float **x_phase_inc, float **y, int n_channels, int n_samples) {
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if (coeffs->antialiasing)
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for (int i = 0; i < n_samples; i++) {
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bw_osc_tri_update_coeffs_audio(coeffs);
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for (int j = 0; j < n_channels; j++)
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y[j][i] = bw_osc_tri_process1_antialias(coeffs, x[j][i], x_phase_inc[j][i]);
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}
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else
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for (int i = 0; i < n_samples; i++) {
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bw_osc_tri_update_coeffs_audio(coeffs);
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for (int j = 0; j < n_channels; j++)
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y[j][i] = bw_osc_tri_process1(coeffs, x[j][i]);
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}
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}
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static inline void bw_osc_tri_set_antialiasing(bw_osc_tri_coeffs *BW_RESTRICT coeffs, char value) {
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coeffs->antialiasing = value;
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}
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static inline void bw_osc_tri_set_slope(bw_osc_tri_coeffs *BW_RESTRICT coeffs, float value) {
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coeffs->slope = value;
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}
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#ifdef __cplusplus
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}
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#endif
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#endif
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