441 lines
13 KiB
C++
441 lines
13 KiB
C++
/*
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* Brickworks
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*
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* Copyright (C) 2022-2024 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 {{{ 1.1.0 }}}
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* requires {{{ bw_common }}}
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* description {{{
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* Post-filter to decolorate oscillator waveshapers when antialiasing is on.
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*
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* This <a href="https://en.wikipedia.org/wiki/Linear_time-invariant_system"
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* target="_blank">linear time-invariant filter</a> can be added in series of
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* oscillator waveshapers that use PolyBLEP antialiasing
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* (i.e., [bw_osc_saw](bw_osc_saw), [bw_osc_pulse](bw_osc_pulse),
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* [bw_osc_tri](bw_osc_tri)) to compensate for high-frequency attenuation.
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* }}}
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* changelog {{{
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* <ul>
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* <li>Version <strong>1.1.0</strong>:
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* <ul>
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* <li>Now using <code>BW_NULL</code> and
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* <code>BW_CXX_NO_ARRAY</code>.</li>
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* </ul>
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* </li>
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* <li>Version <strong>1.0.0</strong>:
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* <ul>
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* <li>Added initial input value to
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* <code>bw_osc_filt_reset_state()</code>.</li>
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* <li>Added <code>bw_osc_filt_reset_state_multi()</code> and updated C++
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* API in this regard.</li>
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* <li>Now <code>bw_osc_filt_reset_state()</code> returns the initial
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* output value.</li>
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* <li>Added overloaded C++ <code>reset()</code> functions taking
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* arrays as arguments.</li>
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* <li><code>bw_osc_filt_process()</code> and
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* <code>bw_osc_filt_process_multi()</code> now use
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* <code>size_t</code> to count samples and channels.</li>
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* <li>Added more <code>const</code> and <code>BW_RESTRICT</code>
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* specifiers to input arguments and implementation.</li>
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* <li>Moved C++ code to C header.</li>
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* <li>Added overloaded C++ <code>process()</code> function taking
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* C-style arrays as arguments.</li>
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* <li>Changed implementation topology to use less memory.</li>
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* <li>Removed usage of reserved identifiers.</li>
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* <li>Added debugging 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_filt_process_multi()</code>.</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>0.2.0</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_FILT_H
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#define BW_OSC_FILT_H
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#include <bw_common.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/*! api {{{
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* #### bw_osc_filt_state
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* ```>>> */
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typedef struct bw_osc_filt_state bw_osc_filt_state;
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/*! <<<```
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* Internal state and related.
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*
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* #### bw_osc_filt_reset()
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* ```>>> */
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static inline float bw_osc_filt_reset_state(
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bw_osc_filt_state * BW_RESTRICT state,
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float x_0);
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/*! <<<```
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* Resets the given `state` to its initial values using the given initial
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* input value `x_0`.
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*
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* Returns the corresponding initial output value.
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*
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* #### bw_osc_filt_reset_state_multi()
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* ```>>> */
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static inline void bw_osc_filt_reset_state_multi(
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bw_osc_filt_state * BW_RESTRICT const * BW_RESTRICT state,
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const float * x_0,
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float * y_0,
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size_t n_channels);
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/*! <<<```
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* Resets each of the `n_channels` `state`s to its initial values using the
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* corresponding initial input value in the `x_0` array.
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*
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* The corresponding initial output values are written into the `y_0` array,
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* if not `BW_NULL`.
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*
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* #### bw_osc_filt_process1()
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* ```>>> */
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static inline float bw_osc_filt_process1(
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bw_osc_filt_state * BW_RESTRICT state,
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float x);
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/*! <<<```
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* Processes one input sample `x` using and updating `state`. Returns the
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* corresponding output sample.
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*
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* #### bw_osc_filt_process()
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* ```>>> */
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static inline void bw_osc_filt_process(
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bw_osc_filt_state * BW_RESTRICT state,
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const float * x,
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float * y,
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size_t n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the input buffer `x` and fills the
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* first `n_samples` of the output buffer `y`, while using and updating
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* `state`.
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*
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* #### bw_osc_filt_process_multi()
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* ```>>> */
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static inline void bw_osc_filt_process_multi(
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bw_osc_filt_state * BW_RESTRICT const * BW_RESTRICT state,
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const float * const * x,
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float * const * y,
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size_t n_channels,
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size_t n_samples);
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/*! <<<```
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* Processes the first `n_samples` of the `n_channels` input buffers `x` and
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* fills the first `n_samples` of the `n_channels` output buffers `y`, while
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* using and updating each of the `n_channels` `state`s.
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*
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* #### bw_osc_filt_state_is_valid()
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* ```>>> */
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static inline char bw_osc_filt_state_is_valid(
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const bw_osc_filt_state * BW_RESTRICT state);
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/*! <<<```
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* Tries to determine whether `state` is valid and returns non-`0` if it
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* seems to be the case and `0` if it is certainly not. False positives are
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* possible, false negatives are not.
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*
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* `state` must at least point to a readable memory block of size greater
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* than or equal to that of `bw_osc_filt_state`.
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* }}} */
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#ifdef __cplusplus
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}
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#endif
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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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#ifdef __cplusplus
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extern "C" {
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#endif
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struct bw_osc_filt_state {
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#ifdef BW_DEBUG_DEEP
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uint32_t hash;
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#endif
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// States
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float z1;
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};
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static inline float bw_osc_filt_reset_state(
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bw_osc_filt_state * BW_RESTRICT state,
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float x_0) {
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BW_ASSERT(state != BW_NULL);
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BW_ASSERT(bw_is_finite(x_0));
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state->z1 = 0.f;
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const float y = x_0;
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#ifdef BW_DEBUG_DEEP
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state->hash = bw_hash_sdbm("bw_osc_filt_state");
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#endif
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BW_ASSERT_DEEP(bw_osc_filt_state_is_valid(state));
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BW_ASSERT(bw_is_finite(y));
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return y;
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}
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static inline void bw_osc_filt_reset_state_multi(
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bw_osc_filt_state * BW_RESTRICT const * BW_RESTRICT state,
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const float * x_0,
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float * y_0,
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size_t n_channels) {
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BW_ASSERT(state != BW_NULL);
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#ifndef BW_NO_DEBUG
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for (size_t i = 0; i < n_channels; i++)
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for (size_t j = i + 1; j < n_channels; j++)
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BW_ASSERT(state[i] != state[j]);
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#endif
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BW_ASSERT(x_0 != BW_NULL);
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if (y_0 != BW_NULL)
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for (size_t i = 0; i < n_channels; i++)
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y_0[i] = bw_osc_filt_reset_state(state[i], x_0[i]);
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else
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for (size_t i = 0; i < n_channels; i++)
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bw_osc_filt_reset_state(state[i], x_0[i]);
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BW_ASSERT_DEEP(y_0 != BW_NULL ? bw_has_only_finite(y_0, n_channels) : 1);
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}
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static inline float bw_osc_filt_process1(
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bw_osc_filt_state * BW_RESTRICT state,
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float x) {
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BW_ASSERT(state != BW_NULL);
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BW_ASSERT_DEEP(bw_osc_filt_state_is_valid(state));
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BW_ASSERT(bw_is_finite(x));
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const float y = 1.371308261611209f * x + state->z1;
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state->z1 = 0.08785458027104826f * x - 4.591628418822578e-1f * y;
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BW_ASSERT_DEEP(bw_osc_filt_state_is_valid(state));
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BW_ASSERT(bw_is_finite(y));
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return y;
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}
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static inline void bw_osc_filt_process(
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bw_osc_filt_state * BW_RESTRICT state,
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const float * x,
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float * y,
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size_t n_samples) {
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BW_ASSERT(state != BW_NULL);
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BW_ASSERT_DEEP(bw_osc_filt_state_is_valid(state));
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BW_ASSERT(x != BW_NULL);
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BW_ASSERT_DEEP(bw_has_only_finite(x, n_samples));
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BW_ASSERT(y != BW_NULL);
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for (size_t i = 0; i < n_samples; i++)
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y[i] = bw_osc_filt_process1(state, x[i]);
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BW_ASSERT_DEEP(bw_osc_filt_state_is_valid(state));
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BW_ASSERT_DEEP(bw_has_only_finite(y, n_samples));
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}
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static inline void bw_osc_filt_process_multi(
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bw_osc_filt_state * BW_RESTRICT const * BW_RESTRICT state,
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const float * const * x,
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float * const * y,
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size_t n_channels,
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size_t n_samples) {
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BW_ASSERT(state != BW_NULL);
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#ifndef BW_NO_DEBUG
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for (size_t i = 0; i < n_channels; i++)
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for (size_t j = i + 1; j < n_channels; j++)
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BW_ASSERT(state[i] != state[j]);
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#endif
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BW_ASSERT(x != BW_NULL);
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BW_ASSERT(y != BW_NULL);
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#ifndef BW_NO_DEBUG
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for (size_t i = 0; i < n_channels; i++)
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for (size_t j = i + 1; j < n_channels; j++)
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BW_ASSERT(y[i] != y[j]);
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#endif
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for (size_t i = 0; i < n_channels; i++)
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bw_osc_filt_process(state[i], x[i], y[i], n_samples);
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}
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static inline char bw_osc_filt_state_is_valid(
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const bw_osc_filt_state * BW_RESTRICT state) {
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BW_ASSERT(state != BW_NULL);
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#ifdef BW_DEBUG_DEEP
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if (state->hash != bw_hash_sdbm("bw_osc_filt_state"))
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return 0;
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#endif
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return bw_is_finite(state->z1);
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}
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#ifdef __cplusplus
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}
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#ifndef BW_CXX_NO_ARRAY
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# include <array>
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#endif
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namespace Brickworks {
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/*** Public C++ API ***/
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/*! api_cpp {{{
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* ##### Brickworks::OscFilt
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* ```>>> */
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template<size_t N_CHANNELS>
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class OscFilt {
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public:
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OscFilt();
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void reset(
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float x0 = 0.f,
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float * BW_RESTRICT y0 = nullptr);
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#ifndef BW_CXX_NO_ARRAY
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void reset(
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float x0,
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std::array<float, N_CHANNELS> * BW_RESTRICT y0);
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#endif
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void reset(
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const float * x0,
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float * y0 = nullptr);
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#ifndef BW_CXX_NO_ARRAY
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void reset(
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std::array<float, N_CHANNELS> x0,
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std::array<float, N_CHANNELS> * BW_RESTRICT y0 = nullptr);
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#endif
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void process(
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const float * const * x,
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float * const * y,
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size_t nSamples);
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#ifndef BW_CXX_NO_ARRAY
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void process(
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std::array<const float *, N_CHANNELS> x,
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std::array<float *, N_CHANNELS> y,
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size_t nSamples);
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#endif
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/*! <<<...
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* }
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* ```
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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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private:
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bw_osc_filt_state states[N_CHANNELS];
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bw_osc_filt_state * BW_RESTRICT statesP[N_CHANNELS];
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};
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template<size_t N_CHANNELS>
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inline OscFilt<N_CHANNELS>::OscFilt() {
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for (size_t i = 0; i < N_CHANNELS; i++)
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statesP[i] = states + i;
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}
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template<size_t N_CHANNELS>
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inline void OscFilt<N_CHANNELS>::reset(
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float x0,
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float * BW_RESTRICT y0) {
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if (y0 != nullptr)
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for (size_t i = 0; i < N_CHANNELS; i++)
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y0[i] = bw_osc_filt_reset_state(states + i, x0);
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else
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for (size_t i = 0; i < N_CHANNELS; i++)
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bw_osc_filt_reset_state(states + i, x0);
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}
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#ifndef BW_CXX_NO_ARRAY
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template<size_t N_CHANNELS>
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inline void OscFilt<N_CHANNELS>::reset(
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float x0,
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std::array<float, N_CHANNELS> * BW_RESTRICT y0) {
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reset(x0, y0 != nullptr ? y0->data() : nullptr);
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}
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#endif
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template<size_t N_CHANNELS>
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inline void OscFilt<N_CHANNELS>::reset(
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const float * x0,
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float * y0) {
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bw_osc_filt_reset_state_multi(statesP, x0, y0, N_CHANNELS);
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}
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#ifndef BW_CXX_NO_ARRAY
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template<size_t N_CHANNELS>
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inline void OscFilt<N_CHANNELS>::reset(
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std::array<float, N_CHANNELS> x0,
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std::array<float, N_CHANNELS> * BW_RESTRICT y0) {
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reset(x0.data(), y0 != nullptr ? y0->data() : nullptr);
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}
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#endif
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template<size_t N_CHANNELS>
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inline void OscFilt<N_CHANNELS>::process(
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const float * const * x,
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float * const * y,
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size_t nSamples) {
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bw_osc_filt_process_multi(statesP, x, y, N_CHANNELS, nSamples);
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}
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#ifndef BW_CXX_NO_ARRAY
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template<size_t N_CHANNELS>
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inline void OscFilt<N_CHANNELS>::process(
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std::array<const float *, N_CHANNELS> x,
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std::array<float *, N_CHANNELS> y,
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size_t nSamples) {
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process(x.data(), y.data(), nSamples);
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}
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#endif
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}
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#endif
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#endif
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