/*
* Brickworks
*
* Copyright (C) 2022, 2023 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
* along with Brickworks. If not, see <http://www.gnu.org/licenses/>.
*
* File author: Stefano D'Angelo
*/
/*!
* module_type {{{ dsp }}}
* version {{{ 1.0.0 }}}
* requires {{{ bw_common bw_math bw_one_pole bw_svf }}}
* description {{{
* Wah effect.
*
* This is a simple digital effect, not an emulation of any analog circuit.
* }}}
* changelog {{{
* <ul>
* <li>Version <strong>1.0.0</strong>:
* <ul>
* <li>Added initial input value to
* <code>bw_wah_reset_state()</code>.</li>
* <li>Added <code>bw_wah_reset_state_multi()</code> and updated C++
* API in this regard.</li>
* <li>Now <code>bw_wah_reset_state()</code> returns the initial output
* value.</li>
* <li>Added overloaded C++ <code>reset()</code> functions taking
* arrays as arguments.</li>
* <li><code>bw_wah_process()</code> and
* <code>bw_wah_process_multi()</code> now use <code>size_t</code>
* to count samples and channels.</li>
* <li>Added more <code>const</code> and <code>BW_RESTRICT</code>
* specifiers to input arguments and implementation.</li>
* <li>Moved C++ code to C header.</li>
* <li>Added overloaded C++ <code>process()</code> function taking
* C-style arrays as arguments.</li>
* <li>Removed usage of reserved identifiers.</li>
* <li>Clearly specified parameter validity ranges.</li>
* <li>Added debugging code.</li>
* </ul>
* </li>
* <li>Version <strong>0.6.0</strong>:
* <ul>
* <li>Removed dependency on bw_config.</li>
* </ul>
* </li>
* <li>Version <strong>0.5.0</strong>:
* <ul>
* <li>Added <code>bw_wah_process_multi()</code>.</li>
* <li>Added C++ wrapper.</li>
* </ul>
* </li>
* <li>Version <strong>0.4.0</strong>:
* <ul>
* <li>Now specifying <code>0.f</code> as initial input value for
* <code>bw_svf_reset_state()</code>.</li>
* <li>Fixed documentation for <code>bw_wah_state</code>,
* <code>bw_wah_reset_state()</code>, and
* <code>bw_wah_process()</code>.</li>
* </ul>
* </li>
* <li>Version <strong>0.3.0</strong>:
* <ul>
* <li>Use bandpass SVF output rather than lowpass.</li>
* </ul>
* </li>
* <li>Version <strong>0.2.0</strong>:
* <ul>
* <li>First release.</li>
* </ul>
* </li>
* </ul>
* }}}
*/
#ifndef BW_WAH_H
#define BW_WAH_H
#include <bw_common.h>
#ifdef __cplusplus
extern "C" {
#endif
/*! api {{{
* #### bw_wah_coeffs
* ```>>> */
typedef struct bw_wah_coeffs bw_wah_coeffs;
/*! <<<```
* Coefficients and related.
*
* #### bw_wah_state
* ```>>> */
typedef struct bw_wah_state bw_wah_state;
/*! <<<```
* Internal state and related.
*
* #### bw_wah_init()
* ```>>> */
static inline void bw_wah_init(
bw_wah_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Initializes input parameter values in `coeffs`.
*
* #### bw_wah_set_sample_rate()
* ```>>> */
static inline void bw_wah_set_sample_rate(
bw_wah_coeffs * BW_RESTRICT coeffs,
float sample_rate);
/*! <<<```
* Sets the `sample_rate` (Hz) value in `coeffs`.
*
* #### bw_wah_reset_coeffs()
* ```>>> */
static inline void bw_wah_reset_coeffs(
bw_wah_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Resets coefficients in `coeffs` to assume their target values.
*
* #### bw_wah_reset_state()
* ```>>> */
static inline float bw_wah_reset_state(
const bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT state,
float x_0);
/*! <<<```
* Resets the given `state` to its initial values using the given `coeffs`
* and the initial input value `x_0`.
*
* Returns the corresponding initial output value.
*
* #### bw_wah_reset_state_multi()
* ```>>> */
static inline void bw_wah_reset_state_multi(
const bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT const * BW_RESTRICT state,
const float * x_0,
float * y_0,
size_t n_channels);
/*! <<<```
* Resets each of the `n_channels` `state`s to its initial values using the
* given `coeffs` and the corresponding initial input value in the `x_0`
* array.
*
* The corresponding initial output values are written into the `y_0` array,
* if not `NULL`.
*
* #### bw_wah_update_coeffs_ctrl()
* ```>>> */
static inline void bw_wah_update_coeffs_ctrl(
bw_wah_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Triggers control-rate update of coefficients in `coeffs`.
*
* #### bw_wah_update_coeffs_audio()
* ```>>> */
static inline void bw_wah_update_coeffs_audio(
bw_wah_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Triggers audio-rate update of coefficients in `coeffs`.
*
* #### bw_wah_process1()
* ```>>> */
static inline float bw_wah_process1(
const bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT state,
float x);
/*! <<<```
* Processes one input sample `x` using `coeffs`, while using and updating
* `state`. Returns the corresponding output sample.
*
* #### bw_wah_process()
* ```>>> */
static inline void bw_wah_process(
bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT state,
const float * x,
float * y,
size_t n_samples);
/*! <<<```
* Processes the first `n_samples` of the input buffer `x` and fills the
* first `n_samples` of the output buffer `y`, while using and updating both
* `coeffs` and `state` (control and audio rate).
*
* #### bw_wah_process_multi()
* ```>>> */
static inline void bw_wah_process_multi(
bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT const * BW_RESTRICT state,
const float * const * x,
float * const * y,
size_t n_channels,
size_t n_samples);
/*! <<<```
* Processes the first `n_samples` of the `n_channels` input buffers `x` and
* fills the first `n_samples` of the `n_channels` output buffers `y`, while
* using and updating both the common `coeffs` and each of the `n_channels`
* `state`s (control and audio rate).
*
* #### bw_wah_set_wah()
* ```>>> */
static inline void bw_wah_set_wah(
bw_wah_coeffs * BW_RESTRICT coeffs,
float value);
/*! <<<```
* Sets the wah pedal position to the given `value` in [`0.f` (low cutoff),
* `1.f` (high cutoff)] in `coeffs`.
*
* Default value: `0.5f`.
*
* #### bw_wah_coeffs_is_valid()
* ```>>> */
static inline char bw_wah_coeffs_is_valid(
const bw_wah_coeffs * BW_RESTRICT coeffs);
/*! <<<```
* Tries to determine whether `coeffs` is valid and returns non-`0` if it
* seems to be the case and `0` if it is certainly not. False positives are
* possible, false negatives are not.
*
* `coeffs` must at least point to a readable memory block of size greater
* than or equal to that of `bw_wah_coeffs`.
*
* #### bw_wah_state_is_valid()
* ```>>> */
static inline char bw_wah_state_is_valid(
const bw_wah_coeffs * BW_RESTRICT coeffs,
const bw_wah_state * BW_RESTRICT state);
/*! <<<```
* Tries to determine whether `state` is valid and returns non-`0` if it
* seems to be the case and `0` if it is certainly not. False positives are
* possible, false negatives are not.
*
* If `coeffs` is not `NULL` extra cross-checks might be performed (`state`
* is supposed to be associated to `coeffs`).
*
* `state` must at least point to a readable memory block of size greater
* than or equal to that of `bw_wah_state`.
* }}} */
#ifdef __cplusplus
}
#endif
/*** 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 <bw_svf.h>
#ifdef __cplusplus
extern "C" {
#endif
#ifdef BW_DEBUG_DEEP
enum bw_wah_coeffs_state {
bw_wah_coeffs_state_invalid,
bw_wah_coeffs_state_init,
bw_wah_coeffs_state_set_sample_rate,
bw_wah_coeffs_state_reset_coeffs
};
#endif
struct bw_wah_coeffs {
#ifdef BW_DEBUG_DEEP
uint32_t hash;
enum bw_wah_coeffs_state state;
uint32_t reset_id;
#endif
// Sub-components
bw_svf_coeffs svf_coeffs;
};
struct bw_wah_state {
#ifdef BW_DEBUG_DEEP
uint32_t hash;
uint32_t coeffs_reset_id;
#endif
// Sub-components
bw_svf_state svf_state;
};
static inline void bw_wah_init(
bw_wah_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != NULL);
bw_svf_init(&coeffs->svf_coeffs);
bw_svf_set_cutoff(&coeffs->svf_coeffs, 600.f);
bw_svf_set_Q(&coeffs->svf_coeffs, 9.f);
#ifdef BW_DEBUG_DEEP
coeffs->hash = bw_hash_sdbm("bw_wah_coeffs");
coeffs->state = bw_wah_coeffs_state_init;
coeffs->reset_id = coeffs->hash + 1;
#endif
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state == bw_wah_coeffs_state_init);
}
static inline void bw_wah_set_sample_rate(
bw_wah_coeffs * BW_RESTRICT coeffs,
float sample_rate) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_init);
BW_ASSERT(bw_is_finite(sample_rate) && sample_rate > 0.f);
bw_svf_set_sample_rate(&coeffs->svf_coeffs, sample_rate);
#ifdef BW_DEBUG_DEEP
coeffs->state = bw_wah_coeffs_state_set_sample_rate;
#endif
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state == bw_wah_coeffs_state_set_sample_rate);
}
static inline void bw_wah_reset_coeffs(
bw_wah_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_set_sample_rate);
bw_svf_reset_coeffs(&coeffs->svf_coeffs);
#ifdef BW_DEBUG_DEEP
coeffs->state = bw_wah_coeffs_state_reset_coeffs;
coeffs->reset_id++;
#endif
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state == bw_wah_coeffs_state_reset_coeffs);
}
static inline float bw_wah_reset_state(
const bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT state,
float x_0) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT(state != NULL);
BW_ASSERT(bw_is_finite(x_0));
float lp, bp, hp;
bw_svf_reset_state(&coeffs->svf_coeffs, &state->svf_state, x_0, &lp, &bp, &hp);
#ifdef BW_DEBUG_DEEP
state->hash = bw_hash_sdbm("bw_wah_state");
state->coeffs_reset_id = coeffs->reset_id;
#endif
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT_DEEP(bw_wah_state_is_valid(coeffs, state));
return 0.f;
}
static inline void bw_wah_reset_state_multi(
const bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT const * BW_RESTRICT state,
const float * x_0,
float * y_0,
size_t n_channels) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT(state != NULL);
BW_ASSERT(x_0 != NULL);
if (y_0 != NULL)
for (size_t i = 0; i < n_channels; i++)
y_0[i] = bw_wah_reset_state(coeffs, state[i], x_0[i]);
else
for (size_t i = 0; i < n_channels; i++)
bw_wah_reset_state(coeffs, state[i], x_0[i]);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT_DEEP(y_0 != NULL ? bw_has_only_finite(y_0, n_channels) : 1);
}
static inline void bw_wah_update_coeffs_ctrl(
bw_wah_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
bw_svf_update_coeffs_ctrl(&coeffs->svf_coeffs);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
}
static inline void bw_wah_update_coeffs_audio(
bw_wah_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
bw_svf_update_coeffs_audio(&coeffs->svf_coeffs);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
}
static inline float bw_wah_process1(
const bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT state,
float x) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT(state != NULL);
BW_ASSERT_DEEP(bw_wah_state_is_valid(coeffs, state));
BW_ASSERT(bw_is_finite(x));
float v_lp, v_hp, v_bp;
bw_svf_process1(&coeffs->svf_coeffs, &state->svf_state, x, &v_lp, &v_bp, &v_hp);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT_DEEP(bw_wah_state_is_valid(coeffs, state));
BW_ASSERT(bw_is_finite(v_bp));
return v_bp;
}
static inline void bw_wah_process(
bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT state,
const float * x,
float * y,
size_t n_samples) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT(state != NULL);
BW_ASSERT_DEEP(bw_wah_state_is_valid(coeffs, state));
BW_ASSERT(x != NULL);
BW_ASSERT_DEEP(bw_has_only_finite(x, n_samples));
BW_ASSERT(y != NULL);
bw_wah_update_coeffs_ctrl(coeffs);
for (size_t i = 0; i < n_samples; i++) {
bw_wah_update_coeffs_audio(coeffs);
y[i] = bw_wah_process1(coeffs, state, x[i]);
}
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT_DEEP(bw_wah_state_is_valid(coeffs, state));
BW_ASSERT_DEEP(bw_has_only_finite(y, n_samples));
}
static inline void bw_wah_process_multi(
bw_wah_coeffs * BW_RESTRICT coeffs,
bw_wah_state * BW_RESTRICT const * BW_RESTRICT state,
const float * const * x,
float * const * y,
size_t n_channels,
size_t n_samples) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
BW_ASSERT(state != NULL);
BW_ASSERT(x != NULL);
BW_ASSERT(y != NULL);
bw_wah_update_coeffs_ctrl(coeffs);
for (size_t i = 0; i < n_samples; i++) {
bw_wah_update_coeffs_audio(coeffs);
for (size_t j = 0; j < n_channels; j++)
y[j][i] = bw_wah_process1(coeffs, state[j], x[j][i]);
}
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_reset_coeffs);
}
static inline void bw_wah_set_wah(
bw_wah_coeffs * BW_RESTRICT coeffs,
float value) {
BW_ASSERT(coeffs != NULL);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_init);
BW_ASSERT(bw_is_finite(value));
BW_ASSERT(value >= 0.f && value <= 1.f);
bw_svf_set_cutoff(&coeffs->svf_coeffs, 400.f + (2e3f - 400.f) * value * value * value);
BW_ASSERT_DEEP(bw_wah_coeffs_is_valid(coeffs));
BW_ASSERT_DEEP(coeffs->state >= bw_wah_coeffs_state_init);
}
static inline char bw_wah_coeffs_is_valid(
const bw_wah_coeffs * BW_RESTRICT coeffs) {
BW_ASSERT(coeffs != NULL);
#ifdef BW_DEBUG_DEEP
if (coeffs->hash != bw_hash_sdbm("bw_wah_coeffs"))
return 0;
if (coeffs->state < bw_wah_coeffs_state_init || coeffs->state > bw_wah_coeffs_state_reset_coeffs)
return 0;
#endif
return bw_svf_coeffs_is_valid(&coeffs->svf_coeffs);
}
static inline char bw_wah_state_is_valid(
const bw_wah_coeffs * BW_RESTRICT coeffs,
const bw_wah_state * BW_RESTRICT state) {
BW_ASSERT(state != NULL);
#ifdef BW_DEBUG_DEEP
if (state->hash != bw_hash_sdbm("bw_wah_state"))
return 0;
if (coeffs != NULL && coeffs->reset_id != state->coeffs_reset_id)
return 0;
#endif
(void)coeffs;
return bw_svf_state_is_valid(&coeffs->svf_coeffs, &state->svf_state);
}
#ifdef __cplusplus
}
#include <array>
namespace Brickworks {
/*** Public C++ API ***/
/*! api_cpp {{{
* ##### Brickworks::Wah
* ```>>> */
template<size_t N_CHANNELS>
class Wah {
public:
Wah();
void setSampleRate(
float sampleRate);
void reset(
float x0 = 0.f,
float * BW_RESTRICT y0 = nullptr);
void reset(
float x0,
std::array<float, N_CHANNELS> * BW_RESTRICT y0);
void reset(
const float * x0,
float * y0 = nullptr);
void reset(
std::array<float, N_CHANNELS> x0,
std::array<float, N_CHANNELS> * BW_RESTRICT y0 = nullptr);
void process(
const float * const * x,
float * const * y,
size_t nSamples);
void process(
std::array<const float *, N_CHANNELS> x,
std::array<float *, N_CHANNELS> y,
size_t nSamples);
void setWah(
float value);
/*! <<<...
* }
* ```
* }}} */
/*** 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. */
private:
bw_wah_coeffs coeffs;
bw_wah_state states[N_CHANNELS];
bw_wah_state * BW_RESTRICT statesP[N_CHANNELS];
};
template<size_t N_CHANNELS>
inline Wah<N_CHANNELS>::Wah() {
bw_wah_init(&coeffs);
for (size_t i = 0; i < N_CHANNELS; i++)
statesP[i] = states + i;
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::setSampleRate(
float sampleRate) {
bw_wah_set_sample_rate(&coeffs, sampleRate);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::reset(
float x0,
float * BW_RESTRICT y0) {
bw_wah_reset_coeffs(&coeffs);
if (y0 != nullptr)
for (size_t i = 0; i < N_CHANNELS; i++)
y0[i] = bw_wah_reset_state(&coeffs, states + i, x0);
else
for (size_t i = 0; i < N_CHANNELS; i++)
bw_wah_reset_state(&coeffs, states + i, x0);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::reset(
float x0,
std::array<float, N_CHANNELS> * BW_RESTRICT y0) {
reset(x0, y0 != nullptr ? y0->data() : nullptr);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::reset(
const float * x0,
float * y0) {
bw_wah_reset_coeffs(&coeffs);
bw_wah_reset_state_multi(&coeffs, statesP, x0, y0, N_CHANNELS);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::reset(
std::array<float, N_CHANNELS> x0,
std::array<float, N_CHANNELS> * BW_RESTRICT y0) {
reset(x0.data(), y0 != nullptr ? y0->data() : nullptr);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::process(
const float * const * x,
float * const * y,
size_t nSamples) {
bw_wah_process_multi(&coeffs, statesP, x, y, N_CHANNELS, nSamples);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::process(
std::array<const float *, N_CHANNELS> x,
std::array<float *, N_CHANNELS> y,
size_t nSamples) {
process(x.data(), y.data(), nSamples);
}
template<size_t N_CHANNELS>
inline void Wah<N_CHANNELS>::setWah(
float value) {
bw_wah_set_wah(&coeffs, value);
}
}
#endif
#endif