new bw_ppm module + using it in synth simple example

examples/synth_simple/src/bw_example_synth_simple.c

@@ -33,7 +33,7 @@
 #include <bw_svf.h>
 #include <bw_env_gen.h>
 #include <bw_gain.h>
-#include <bw_env_follow.h>
+#include <bw_ppm.h>
 #include <bw_buf.h>
 
 enum {
@@ -63,8 +63,8 @@ struct _bw_example_synth_simple {
 	bw_env_gen_coeffs	env_gen_coeffs;
 	bw_env_gen_state	env_gen_state;
 	bw_gain_coeffs		gain_coeffs;
-	bw_env_follow_coeffs	env_follow_coeffs;
+	bw_ppm_coeffs		ppm_coeffs;
-	bw_env_follow_state	env_follow_state;
+	bw_ppm_state		ppm_state;
 
 	// Parameters
 	float			params[p_n];
@@ -87,10 +87,9 @@ bw_example_synth_simple bw_example_synth_simple_new() {
 	bw_svf_init(&instance->svf_coeffs);
 	bw_env_gen_init(&instance->env_gen_coeffs);
 	bw_gain_init(&instance->gain_coeffs);
-	bw_env_follow_init(&instance->env_follow_coeffs);
+	bw_ppm_init(&instance->ppm_coeffs);
 	
 	bw_osc_pulse_set_antialiasing(&instance->osc_pulse_coeffs, 1);
-	bw_env_follow_set_release_tau(&instance->env_follow_coeffs, 1.f);
 	
 	instance->rand_state = 0xbaddecaf600dfeed;
 
@@ -107,7 +106,7 @@ void bw_example_synth_simple_set_sample_rate(bw_example_synth_simple instance, f
 	bw_svf_set_sample_rate(&instance->svf_coeffs, sample_rate);
 	bw_env_gen_set_sample_rate(&instance->env_gen_coeffs, sample_rate);
 	bw_gain_set_sample_rate(&instance->gain_coeffs, sample_rate);
-	bw_env_follow_set_sample_rate(&instance->env_follow_coeffs, sample_rate);
+	bw_ppm_set_sample_rate(&instance->ppm_coeffs, sample_rate);
 }
 
 void bw_example_synth_simple_reset(bw_example_synth_simple instance) {
@@ -120,8 +119,8 @@ void bw_example_synth_simple_reset(bw_example_synth_simple instance) {
 	bw_env_gen_reset_coeffs(&instance->env_gen_coeffs);
 	bw_env_gen_reset_state(&instance->env_gen_coeffs, &instance->env_gen_state);
 	bw_gain_reset_coeffs(&instance->gain_coeffs);
-	bw_env_follow_reset_coeffs(&instance->env_follow_coeffs);
+	bw_ppm_reset_coeffs(&instance->ppm_coeffs);
-	bw_env_follow_reset_state(&instance->env_follow_coeffs, &instance->env_follow_state);
+	bw_ppm_reset_state(&instance->ppm_coeffs, &instance->ppm_state);
 	instance->note = -1;
 }
 
@@ -143,7 +142,7 @@ void bw_example_synth_simple_process(bw_example_synth_simple instance, const flo
 		bw_env_gen_process(&instance->env_gen_coeffs, &instance->env_gen_state, instance->buf, n);
 		bw_buf_mul(out, out, instance->buf, n);
 		bw_gain_process(&instance->gain_coeffs, out, out, n);
-		bw_env_follow_process(&instance->env_follow_coeffs, &instance->env_follow_state, out, NULL, n);
+		bw_ppm_process(&instance->ppm_coeffs, &instance->ppm_state, out, NULL, n);
 	}
 }
 
@@ -183,7 +182,10 @@ void bw_example_synth_simple_set_parameter(bw_example_synth_simple instance, int
 }
 
 float bw_example_synth_simple_get_parameter(bw_example_synth_simple instance, int index) {
-	return index < p_n ? instance->params[index] : bw_clipf(bw_env_follow_get_y_z1(&instance->env_follow_state), 0.f, 1.f);
+	if (index < p_n)
+		return instance->params[index];
+	const float v = bw_ppm_get_y_z1(&instance->ppm_state);
+	return v < -200.f ? 0.f : bw_clipf(0.01666666666666666f * v + 1.f, 0.f, 1.f);
 }
 
 void bw_example_synth_simple_note_on(bw_example_synth_simple instance, char note, char velocity) {

include/bw_ppm.h

@@ -0,0 +1,210 @@
+/*
+ * Brickworks
+ *
+ * Copyright (C) 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 {{{ 0.2.0 }}}
+ *  requires {{{ bw_config bw_common bw_env_follow bw_math bw_one_pole }}}
+ *  description {{{
+ *    Digital peak programme meter with adjustable integration time constant.
+ *
+ *    An integration time constant of `0.f` results in true-peak metering, while
+ *    values between `0.f` and `0.006f` give quasi-peak metering behavior.
+ *  }}}
+ *  changelog {{{
+ *    <ul>
+ *      <li>Version <strong>0.3.0</strong>:
+ *        <ul>
+ *          <li>First release.</li>
+ *        </ul>
+ *      </li>
+ *    </ul>
+ *  }}}
+ */
+
+#ifndef _BW_PPM_H
+#define _BW_PPM_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <bw_common.h>
+
+/*! api {{{
+ *    #### bw_ppm_coeffs
+ *  ```>>> */
+typedef struct _bw_ppm_coeffs bw_ppm_coeffs;
+/*! <<<```
+ *    Coefficients and related.
+ *
+ *    #### bw_ppm_state
+ *  ```>>> */
+typedef struct _bw_ppm_state bw_ppm_state;
+/*! <<<```
+ *    Internal state and related.
+ *
+ *    #### bw_ppm_init()
+ *  ```>>> */
+static inline void bw_ppm_init(bw_ppm_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Initializes input parameter values in `coeffs`.
+ *
+ *    #### bw_ppm_set_sample_rate()
+ *  ```>>> */
+static inline void bw_ppm_set_sample_rate(bw_ppm_coeffs *BW_RESTRICT coeffs, float sample_rate);
+/*! <<<```
+ *    Sets the `sample_rate` (Hz) value in `coeffs`.
+ *
+ *    #### bw_ppm_reset_coeffs()
+ *  ```>>> */
+static inline void bw_ppm_reset_coeffs(bw_ppm_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Resets coefficients in `coeffs` to assume their target values.
+ *
+ *    #### bw_ppm_reset_state()
+ *  ```>>> */
+static inline void bw_ppm_reset_state(const bw_ppm_coeffs *BW_RESTRICT coeffs, bw_ppm_state *BW_RESTRICT state);
+/*! <<<```
+ *    Resets the given `state` to its initial values using the given `coeffs`.
+ *
+ *    #### bw_ppm_update_coeffs_ctrl()
+ *  ```>>> */
+static inline void bw_ppm_update_coeffs_ctrl(bw_ppm_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Triggers control-rate update of coefficients in `coeffs`.
+ *
+ *    #### bw_ppm_update_coeffs_audio()
+ *  ```>>> */
+static inline void bw_ppm_update_coeffs_audio(bw_ppm_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Triggers audio-rate update of coefficients in `coeffs`.
+ *
+ *    #### bw_ppm_process1()
+ *  ```>>> */
+static inline float bw_ppm_process1(const bw_ppm_coeffs *BW_RESTRICT coeffs, bw_ppm_state *BW_RESTRICT state, float x);
+/*! <<<```
+ *    Processes one input sample `x` using `coeffs`, while using and updating
+ *    `state`. Returns the corresponding output sample.
+ *
+ *    #### bw_ppm_process()
+ *  ```>>> */
+static inline void bw_ppm_process(bw_ppm_coeffs *BW_RESTRICT coeffs, bw_ppm_state *BW_RESTRICT state, const float *x, 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).
+ *
+ *    Output sample values are in dBFS.
+ *
+ *    `y` may be `NULL`.
+ *
+ *    #### bw_ppm_set_integration_time()
+ *  ```>>> */
+static inline void bw_ppm_set_integration_tau(bw_ppm_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ *    Sets the upgoing (integration) time constant in `coeffs` to `value` (s).
+ *
+ *    Default value: `0.f`.
+ *
+ *    #### bw_ppm_get_y_z1()
+ *  ```>>> */
+static inline float bw_ppm_get_y_z1(const bw_ppm_state *BW_RESTRICT state);
+/*! <<<```
+ *    Returns the last output sample as stored in `state`.
+ *  }}} */
+
+/*** 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_env_follow.h>
+
+struct _bw_ppm_coeffs {
+	// Sub-components
+	bw_env_follow_coeffs	env_follow_coeffs;
+};
+
+struct _bw_ppm_state {
+	bw_env_follow_state	env_follow_state;
+	float			y_z1;
+};
+
+static inline void bw_ppm_init(bw_ppm_coeffs *BW_RESTRICT coeffs) {
+	bw_env_follow_init(&coeffs->env_follow_coeffs);
+	bw_env_follow_set_release_tau(&coeffs->env_follow_coeffs, 0.738300619235528f);
+}
+
+static inline void bw_ppm_set_sample_rate(bw_ppm_coeffs *BW_RESTRICT coeffs, float sample_rate) {
+	bw_env_follow_set_sample_rate(&coeffs->env_follow_coeffs, sample_rate);
+}
+
+static inline void bw_ppm_reset_coeffs(bw_ppm_coeffs *BW_RESTRICT coeffs) {
+	bw_env_follow_reset_coeffs(&coeffs->env_follow_coeffs);
+}
+
+static inline void bw_ppm_reset_state(const bw_ppm_coeffs *BW_RESTRICT coeffs, bw_ppm_state *BW_RESTRICT state) {
+	bw_env_follow_reset_state(&coeffs->env_follow_coeffs, &state->env_follow_state);
+	state->y_z1 = -INFINITY;
+}
+
+static inline void bw_ppm_update_coeffs_ctrl(bw_ppm_coeffs *BW_RESTRICT coeffs) {
+	bw_env_follow_update_coeffs_ctrl(&coeffs->env_follow_coeffs);
+}
+
+static inline void bw_ppm_update_coeffs_audio(bw_ppm_coeffs *BW_RESTRICT coeffs) {
+	bw_env_follow_update_coeffs_audio(&coeffs->env_follow_coeffs);
+}
+
+static inline float bw_ppm_process1(const bw_ppm_coeffs *BW_RESTRICT coeffs, bw_ppm_state *BW_RESTRICT state, float x) {
+	const float yl = bw_env_follow_process1(&coeffs->env_follow_coeffs, &state->env_follow_state, x);
+	const float y = yl > 0.f ? bw_lin2dBf_3(yl) : -INFINITY;
+	state->y_z1 = y;
+	return y;
+}
+
+static inline void bw_ppm_process(bw_ppm_coeffs *BW_RESTRICT coeffs, bw_ppm_state *BW_RESTRICT state, const float *x, float *y, int n_samples) {
+	bw_ppm_update_coeffs_ctrl(coeffs);
+	if (y != NULL)
+		for (int i = 0; i < n_samples; i++) {
+			bw_ppm_update_coeffs_audio(coeffs);
+			y[i] = bw_ppm_process1(coeffs, state, x[i]);
+		}
+	else
+		for (int i = 0; i < n_samples; i++) {
+			bw_ppm_update_coeffs_audio(coeffs);
+			bw_ppm_process1(coeffs, state, x[i]);
+		}
+}
+
+static inline void bw_ppm_set_integration_tau(bw_ppm_coeffs *BW_RESTRICT coeffs, float value) {
+	bw_env_follow_set_attack_tau(&coeffs->env_follow_coeffs, value);
+}
+
+static inline float bw_ppm_get_y_z1(const bw_ppm_state *BW_RESTRICT state) {
+	return state->y_z1;
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif