diff --git a/TODO b/TODO
index 7e30a5c..5f9d36e 100644
--- a/TODO
+++ b/TODO
@@ -36,6 +36,8 @@ code:
* add initial state (x0) to reset state of lp1, ap1, mm1, hs1, ls1, others? all?
* multichannel process (multiple buffers, non interleaved)
* check unused param warning visual studio
+* bw_comb: should also modulate feedback?
+* bw_comb: integer target delay values?
build system:
* make makefiles handle paths with spaces etc
diff --git a/include/bw_comb.h b/include/bw_comb.h
new file mode 100644
index 0000000..056a7ed
--- /dev/null
+++ b/include/bw_comb.h
@@ -0,0 +1,340 @@
+/*
+ * 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 .
+ *
+ * File author: Stefano D'Angelo
+ */
+
+/*!
+ * module_type {{{ dsp }}}
+ * version {{{ 0.4.0 }}}
+ * requires {{{
+ * bw_buf bw_config bw_common bw_delay bw_gain bw_math bw_one_pole
+ * }}}
+ * description {{{
+ * Comb filter / delay effect with feedforward and feedback paths.
+ *
+ * Essentially an implementation of the structure described in
+ *
+ * J. Dattorro, "Effect Design, Part 2: Delay-Line Modulation and Chorus",
+ * J. Audio Eng. Soc., vol. 45, no. 10, pp. 764-788, October 1997.
+ *
+ * Unlike in the original paper, the feedback signal is not subtracted but
+ * rather added to the input.
+ * }}}
+ * changelog {{{
+ *
+ * - Version 0.4.0:
+ *
- First release.
+ *
+ *
+ *
+ * }}}
+ */
+
+#ifndef _BW_COMB_H
+#define _BW_COMB_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include
+
+/*! api {{{
+ * #### bw_comb_coeffs
+ * ```>>> */
+typedef struct _bw_comb_coeffs bw_comb_coeffs;
+/*! <<<```
+ * Coefficients and related.
+ *
+ * ### bw_comb_state
+ * ```>>> */
+typedef struct _bw_comb_state bw_comb_state;
+/*! <<<```
+ * Internal state and related.
+ *
+ * #### bw_comb_init()
+ * ```>>> */
+static inline void bw_comb_init(bw_comb_coeffs *BW_RESTRICT coeffs, float max_delay);
+/*! <<<```
+ * Initializes input parameter values in `coeffs` using `max_delay` (s) as
+ * the maximum delay time.
+ *
+ * #### bw_comb_set_sample_rate()
+ * ```>>> */
+static inline void bw_comb_set_sample_rate(bw_comb_coeffs *BW_RESTRICT coeffs, float sample_rate);
+/*! <<<```
+ * Sets the `sample_rate` (Hz) value in `coeffs`.
+ *
+ * ### bw_delay_mem_req()
+ * ```>>> */
+static inline BW_SIZE_T bw_delay_mem_req(bw_delay_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ * Returns the size, in bytes, of contiguous memory to be supplied to
+ * `bw_delay_mem_set()` using `coeffs`.
+ *
+ * ### bw_delay_mem_set()
+ * ```>>> */
+static inline void bw_delay_mem_set(bw_delay_state *BW_RESTRICT state, void *mem);
+/*! <<<```
+ * Associates the contiguous memory block `mem` to the given `state`.
+ *
+ * #### bw_comb_reset_coeffs()
+ * ```>>> */
+static inline void bw_comb_reset_coeffs(bw_comb_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ * Resets coefficients in `coeffs` to assume their target values.
+ *
+ * #### bw_comb_reset_state()
+ * ```>>> */
+static inline void bw_comb_reset_state(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state);
+/*! <<<```
+ * Resets the given `state` to its initial values using the given `coeffs`.
+ *
+ * #### bw_comb_update_coeffs_ctrl()
+ * ```>>> */
+static inline void bw_comb_update_coeffs_ctrl(bw_comb_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ * Triggers control-rate update of coefficients in `coeffs`.
+ *
+ * #### bw_comb_update_coeffs_audio()
+ * ```>>> */
+static inline void bw_comb_update_coeffs_audio(bw_comb_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ * Triggers audio-rate update of coefficients in `coeffs`.
+ *
+ * #### bw_comb_process1()
+ * ```>>> */
+static inline float bw_comb_process1(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, float x, float x_mod);
+/*! <<<```
+ * Processes one input sample `x` using `coeffs` and the feedforward delay
+ * time modulation term `x_mod` (s), while using and updating `state`.
+ * Returns the corresponding output sample.
+ *
+ * #### bw_comb_process()
+ * ```>>> */
+static inline void bw_comb_process(bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, const float *x, const float *x_mod, float *y, int 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).
+ *
+ * `x_mod` can either be `NULL`, in which case the feedforward delay time is
+ * not modulated, or it points to a buffer whose first `n_samples` contain
+ * values (s) used for modulating the feedforward delay time.
+ *
+ * #### bw_comb_set_delay_ff()
+ * ```>>> */
+static inline void bw_comb_set_delay_ff(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ * Sets the feedforward delay time `value` (s) in `coeffs`.
+ *
+ * Default value: `0.f`.
+ *
+ * #### bw_comb_set_delay_fb()
+ * ```>>> */
+static inline void bw_comb_set_delay_fb(bw_comb_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ * Sets the feedback delay time `value` (s) in `coeffs`.
+ *
+ * Default value: `0.f`.
+ *
+ * #### bw_comb_set_blend()
+ * ```>>> */
+static inline void bw_mm1_set_coeff_blend(bw_mm1_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ * Sets the blend coefficient `value` in `coeffs`.
+ *
+ * Default value: `1.f`.
+ *
+ * #### bw_comb_set_coeff_ff()
+ * ```>>> */
+static inline void bw_mm1_set_coeff_ff(bw_mm1_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ * Sets the feedforward coefficient `value` in `coeffs`.
+ *
+ * Default value: `0.f`.
+ *
+ * #### bw_comb_set_coeff_fb()
+ * ```>>> */
+static inline void bw_mm1_set_coeff_fb(bw_mm1_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ * Sets the feedback coefficient `value` in `coeffs`.
+ *
+ * Default value: `0.f`.
+ * }}} */
+
+/*** 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
+#include
+
+struct _bw_comb_coeffs {
+ // Sub-components
+ bw_delay_coeffs delay_coeffs;
+ bw_gain_coeffs blend_coeffs;
+ bw_gain_coeffs ff_coeffs;
+ bw_gain_coeffs fb_coeffs;
+ bw_one_pole smooth_coeffs;
+ bw_one_pole smooth_delay_ff_state;
+ bw_one_pole smooth_delay_fb_state;
+
+ // Coefficients
+ float fs;
+
+ BW_SIZE_T dfbi;
+ float dfbf;
+
+ // Parameters
+ float delay_ff;
+ float delay_fb;
+};
+
+struct _bw_comb_state {
+ // Sub-components
+ bw_delay_state delay_state;
+};
+
+static inline void bw_comb_init(bw_comb_coeffs *BW_RESTRICT coeffs, float max_delay) {
+ bw_delay_init(&coeffs->delay_coeffs, max_delay);
+ bw_gain_init(&coeffs->blend_coeffs);
+ bw_gain_init(&coeffs->ff_coeffs);
+ bw_gain_init(&coeffs->fb_coeffs);
+ bw_one_pole_init(&coeffs->smooth_coeffs);
+ bw_one_pole_set_tau(&coeffs->smooth_coeffs, 0.005f);
+ bw_gain_set_gain_lin(&coeffs->ff_coeffs, 0.f);
+ bw_gain_set_gain_lin(&coeffs->fb_coeffs, 0.f);
+ coeffs->delay_ff = 0.f;
+ coeffs->delay_fb = 0.f;
+}
+
+static inline void bw_comb_set_sample_rate(bw_comb_coeffs *BW_RESTRICT coeffs, float sample_rate) {
+ bw_delay_set_sample_rate(&coeffs->delay_coeffs, sample_rate);
+ bw_gain_set_sample_rate(&coeffs->blend_coeffs, sample_rate);
+ bw_gain_set_sample_rate(&coeffs->ff_coeffs, sample_rate);
+ bw_gain_set_sample_rate(&coeffs->fb_coeffs, sample_rate);
+ bw_one_pole_set_sample_rate(&coeffs->smooth_coeffs, sample_rate);
+ bw_one_pole_reset_coeffs(&coeffs->smooth_coeffs);
+ coeffs->fs = sample_rate;
+}
+
+static inline BW_SIZE_T bw_delay_mem_req(bw_delay_coeffs *BW_RESTRICT coeffs) {
+ return bw_delay_mem_req(&coeffs->delay_coeffs);
+}
+
+static inline void bw_delay_mem_set(bw_delay_state *BW_RESTRICT state, void *mem) {
+ bw_delay_mem_set(&state->delay_state, mem);
+}
+
+static inline void bw_comb_reset_coeffs(bw_comb_coeffs *BW_RESTRICT coeffs) {
+ bw_delay_reset_coeffs(&coeffs->delay_coeffs);
+ bw_gain_reset_coeffs(&coeffs->blend_coeffs);
+ bw_gain_reset_coeffs(&coeffs->ff_coeffs);
+ bw_gain_reset_coeffs(&coeffs->fb_coeffs);
+ bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_delay_ff_state, coeffs->fs * coeffs->delay_ff);
+ bw_one_pole_reset_state(&coeffs->smooth_coeffs, &coeffs->smooth_delay_fb_state, coeffs->fs * coeffs->delay_fb);
+}
+
+static inline void bw_comb_reset_state(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state) {
+ bw_delay_reset_state(&coeffs->delay_coeffs, &state->delay_state);
+}
+
+static inline void bw_comb_update_coeffs_ctrl(bw_comb_coeffs *BW_RESTRICT coeffs) {
+ bw_gain_update_coeffs_ctrl(&coeffs->blend_coeffs);
+ bw_gain_update_coeffs_ctrl(&coeffs->ff_coeffs);
+ bw_gain_update_coeffs_ctrl(&coeffs->fb_coeffs);
+}
+
+static inline void bw_comb_update_coeffs_audio(bw_comb_coeffs *BW_RESTRICT coeffs) {
+ bw_gain_update_coeffs_audio(&coeffs->blend_coeffs);
+ bw_gain_update_coeffs_audio(&coeffs->ff_coeffs);
+ bw_gain_update_coeffs_audio(&coeffs->fb_coeffs);
+ bw_one_pole_process1(&coeffs->smooth_coeffs, &coeffs->smooth_delay_ff_state, coeffs->fs * coeffs->delay_ff);
+ bw_one_pole_process1(&coeffs->smooth_coeffs, &coeffs->smooth_delay_fb_state, coeffs->fs * coeffs->delay_fb);
+ const BW_SIZE_T len = bw_delay_get_length(&coeffs->delay_coeffs);
+ const float dfb = bw_maxf(bw_one_pole_get_y_z1(&coeffs->smooth_delay_fb_state), 1.f) - 1.f;
+ float dfbif, dfbf;
+ bw_intfracf(dfb, &dfbif, &dfbf);
+ BW_SIZE_T dfbi = (BW_SIZE_T)dfbif;
+ if (dfbi >= len) {
+ dfbi = len;
+ dfbf = 0.f;
+ }
+ coeffs->dfbi = dfbi;
+ coeffs->dfbf = dfbf;
+}
+
+static inline float bw_comb_process1(const bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, float x, float x_mod) {
+ const BW_SIZE_T len = bw_delay_get_length(&coeffs->delay_coeffs);
+ const float dff = bw_maxf(bw_one_pole_get_y_z1(&coeffs->smooth_delay_ff_state) + x_mod, 0.f);
+ float dffif, dfff;
+ bw_intfracf(dff, &dffif, &dfff);
+ BW_SIZE_T dffi = (BW_SIZE_T)dffif;
+ if (dffi >= len) {
+ dffi = len;
+ dfff = 0.f;
+ }
+ const float fb = bw_delay_read(&coeffs->delay_coeffs, &state->delay_state, dfbi, dfbf);
+ const float v = x + fb;
+ bw_delay_write(&coeffs->delay_coeffs, &state->delay_state, v);
+ const float ff = bw_delay_read(&coeffs->delay_coeffs, &state->delay_state, dffi, dfff);
+ return bw_gain_process1(&coeffs->blend_coeffs, v) + bw_gain_process1(&coeffs->ff_coeffs, ff);
+}
+
+static inline void bw_comb_process(bw_comb_coeffs *BW_RESTRICT coeffs, bw_comb_state *BW_RESTRICT state, const float *x, const float *x_mod, float *y, int n_samples) {
+ bw_comb_update_coeffs_ctrl(coeffs);
+ if (x_mod != NULL)
+ for (int i = 0; i < n_samples; i++) {
+ bw_comb_update_coeffs_audio(coeffs);
+ y[i] = bw_comb_process1(coeffs, state, x[i], x_mod[i]);
+ }
+ else
+ for (int i = 0; i < n_samples; i++) {
+ bw_comb_update_coeffs_audio(coeffs);
+ y[i] = bw_comb_process1(coeffs, state, x[i], 0.f);
+ }
+}
+
+static inline void bw_comb_set_delay_ff(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
+ coeffs->delay_ff = value;
+}
+
+static inline void bw_comb_set_delay_fb(bw_comb_coeffs *BW_RESTRICT coeffs, float value) {
+ coeffs->delay_fb = value;
+}
+
+static inline void bw_mm1_set_coeff_blend(bw_mm1_coeffs *BW_RESTRICT coeffs, float value) {
+ bw_gain_set_gain_lin(&coeffs->blend_coeffs, value);
+}
+
+static inline void bw_mm1_set_coeff_ff(bw_mm1_coeffs *BW_RESTRICT coeffs, float value) {
+ bw_gain_set_gain_lin(&coeffs->ff_coeffs, value);
+}
+
+static inline void bw_mm1_set_coeff_fb(bw_mm1_coeffs *BW_RESTRICT coeffs, float value) {
+ bw_gain_set_gain_lin(&coeffs->fb_coeffs, value);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
diff --git a/include/bw_delay.h b/include/bw_delay.h
index 73dd7d7..bc1e52a 100644
--- a/include/bw_delay.h
+++ b/include/bw_delay.h
@@ -23,7 +23,7 @@
* version {{{ 0.4.0 }}}
* requires {{{ bw_buf bw_config bw_common bw_math }}}
* description {{{
- * Interpolated delay line.
+ * Interpolated delay line, not smoothed.
*
* You can either use the usual API for updating coefficients and processing
* signals or you can directly write and read from the delay line which,
@@ -102,7 +102,7 @@ static inline void bw_delay_reset_state(const bw_delay_coeffs *BW_RESTRICT coeff
*
* #### bw_delay_read()
* ```>>> */
-static float bw_delay_read(const bw_delay_coeffs *BW_RESTRICT coeffs, bw_delay_state *BW_RESTRICT state, BW_SIZE_T di, float df);
+static float bw_delay_read(const bw_delay_coeffs *BW_RESTRICT coeffs, const bw_delay_state *BW_RESTRICT state, BW_SIZE_T di, float df);
/*! <<<```
* Returns the interpolated value read from the delay line identified by
* `coeffs` and `state` by applying a delay of `di` + `df` samples.
@@ -135,7 +135,7 @@ static inline float bw_delay_process1(const bw_delay_coeffs *BW_RESTRICT coeffs,
* Processes one input sample `x` using `coeffs`, while using and updating
* `state`. Returns the corresponding output sample.
*
- * #### bw_env_follow_process()
+ * #### bw_delay_process()
* ```>>> */
static inline void bw_delay_process(bw_delay_coeffs *BW_RESTRICT coeffs, bw_delay_state *BW_RESTRICT state, const float *x, float *y, int n_samples);
/*! <<<```
@@ -150,6 +150,12 @@ static inline void bw_delay_set_delay(bw_delay_coeffs *BW_RESTRICT coeffs, float
* Sets the delay time `value` (s) in `coeffs`.
*
* Default value: `0.f`.
+ *
+ * #### bw_delay_get_length()
+ * ```>>> */
+static inline BW_SIZE_T bw_delay_get_length(bw_delay_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ * Returns the length of the delay line in samples.
* }}} */
/*** Implementation ***/
@@ -207,7 +213,7 @@ static inline void bw_delay_reset_state(const bw_delay_coeffs *BW_RESTRICT coeff
state->idx = 0;
}
-static float bw_delay_read(const bw_delay_coeffs *BW_RESTRICT coeffs, bw_delay_state *BW_RESTRICT state, BW_SIZE_T di, float df) {
+static float bw_delay_read(const bw_delay_coeffs *BW_RESTRICT coeffs, const bw_delay_state *BW_RESTRICT state, BW_SIZE_T di, float df) {
const BW_SIZE_T n = (state->idx + (state->idx >= di ? 0 : coeffs->len)) - di;
const BW_SIZE_T p = (n ? n : coeffs->len) - 1;
return state->buf[n] + df * (state->buf[p] - state->buf[n]);
@@ -221,10 +227,9 @@ static void bw_delay_write(const bw_delay_coeffs *BW_RESTRICT coeffs, bw_delay_s
static inline void bw_delay_update_coeffs_ctrl(bw_delay_coeffs *BW_RESTRICT coeffs) {
if (coeffs->delay_changed) {
- const float s = coeffs->delay * coeffs->fs;
- const float f = bw_floorf(s);
- coeffs->di = (BW_SIZE_T)f;
- coeffs->df = s - f;
+ float i;
+ bw_intfracf(coeffs->fs * coeffs->delay, &i, &coeffs->df);
+ coeffs->di = (BW_SIZE_T)i;
coeffs->delay_changed = 0;
}
}
@@ -251,6 +256,10 @@ static inline void bw_delay_set_delay(bw_delay_coeffs *BW_RESTRICT coeffs, float
}
}
+static inline BW_SIZE_T bw_delay_get_length(bw_delay_coeffs *BW_RESTRICT coeffs) {
+ return coeffs->len;
+}
+
#ifdef __cplusplus
}
#endif
diff --git a/include/bw_math.h b/include/bw_math.h
index 67c5996..59f3264 100644
--- a/include/bw_math.h
+++ b/include/bw_math.h
@@ -72,8 +72,8 @@
*
* - Version 0.4.0:
*
- * - Added `bw_ceilf()`, `bw_sinhf_3()`, `bw_coshf_3()`,
- * `bw_asinhf_3()`, and `bw_acoshf_3()`.
+ * - Added `bw_ceilf()`, `bw_intfracf()`, `bw_sinhf_3()`,
+ * `bw_coshf_3()`, `bw_asinhf_3()`, and `bw_acoshf_3()`.
*
*
* - Version 0.3.0:
@@ -241,6 +241,13 @@ static inline float bw_ceilf(float x);
* Returns the smallest integer greater or equal than `x` (i.e., `x` is
* rounded up).
*
+ * #### bw_intfracf()
+ * ```>>> */
+static inline void bw_intfracf(float x, float *i, float *f);
+/*! <<<```
+ * Puts the integer part (floor) of `x` in `i` and the fractional part in
+ * `f`.
+ *
* #### bw_rcpf_2()
* ```>>> */
static inline float bw_rcpf_2(float x);
@@ -576,6 +583,11 @@ static inline float bw_ceilf(float x) {
return t.f + s.f;
}
+static inline void bw_intfracf(float x, float *i, float *f) {
+ *i = bw_floorf(x);
+ *f = x - *i;
+}
+
static inline float bw_rcpf_2(float x) {
_bw_floatint v = {.f = x};
v.i = 0x7ef0e840 - v.i;
diff --git a/include/bw_one_pole.h b/include/bw_one_pole.h
index 25f0704..889b0a5 100644
--- a/include/bw_one_pole.h
+++ b/include/bw_one_pole.h
@@ -129,7 +129,7 @@ static inline float bw_one_pole_process1_asym(const bw_one_pole_coeffs *BW_RESTR
static inline float bw_one_pole_process1_asym_sticky_abs(const bw_one_pole_coeffs *BW_RESTRICT coeffs, bw_one_pole_state *BW_RESTRICT state, float x);
static inline float bw_one_pole_process1_asym_sticky_rel(const bw_one_pole_coeffs *BW_RESTRICT coeffs, bw_one_pole_state *BW_RESTRICT state, float x);
/*! <<<```
- * These function process one input sample `x` using `coeffs`, while using
+ * These functions process one input sample `x` using `coeffs`, while using
* and updating `state`. They return the corresponding output sample.
*
* In particular:
diff --git a/include/bw_wah.h b/include/bw_wah.h
index 4e4b7e4..51965da 100644
--- a/include/bw_wah.h
+++ b/include/bw_wah.h
@@ -21,7 +21,7 @@
/*!
* module_type {{{ dsp }}}
* version {{{ 0.4.0 }}}
- * requires {{{ bw_config bw_common bw_one_pole bw_math bw_svf }}}
+ * requires {{{ bw_config bw_common bw_math bw_one_pole bw_svf }}}
* description {{{
* Wah effect.
*
@@ -33,7 +33,8 @@
*
* - Now specifying `0.f` as initial input value for
* `bw_svf_reset_state()`.
- * - Fixed documentation for `bw_wah_state` and `bw_wah_reset_state()`.
+ * - Fixed documentation for `bw_wah_state`, `bw_wah_reset_state()`,
+ * and `bw_wah_process()`.
*
*
* - Version 0.3.0:
@@ -115,7 +116,7 @@ static inline float bw_wah_process1(const bw_wah_coeffs *BW_RESTRICT coeffs, bw_
* Processes one input sample `x` using `coeffs`, while using and updating
* `state`. Returns the corresponding output sample.
*
- * #### bw_env_follow_process()
+ * #### 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, int n_samples);
/*! <<<```