new pinking filter + tiny aesthetic changes

include/bw_phase_gen.h

@@ -149,7 +149,6 @@ struct _bw_phase_gen_coeffs {
 };
 
 struct _bw_phase_gen_state {
-	// State
 	float	phase;
 };
 

include/bw_pink_filt.h

@@ -0,0 +1,135 @@
+/*
+ * Brickworks
+ *
+ * Copyright (C) 2022 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
+ *
+ * File author: Stefano D'Angelo
+ */
+
+/*!
+ *  module_type {{{ dsp }}}
+ *  version {{{ 0.2.0 }}}
+ *  requires {{{ bw_config bw_common }}}
+ *  description {{{
+ *    Pinking filter.
+ *
+ *    ...
+ *  }}}
+ *  changelog {{{
+ *    <ul>
+ *      <li>Version <strong>0.2.0</strong>:
+ *        <ul>
+ *          <li>Refactored API.</li>
+ *        </ul>
+ *      </li>
+ *      <li>Version <strong>0.1.0</strong>:
+ *        <ul>
+ *          <li>First release.</li>
+ *        </ul>
+ *      </li>
+ *    </ul>
+ *  }}}
+ */
+
+#ifndef _BW_PINK_FILT_H
+#define _BW_PINK_FILT_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <bw_common.h>
+
+typedef struct _bw_pink_filt_coeffs bw_pink_filt_coeffs;
+
+/*! api {{{
+ *    #### bw_pink_filt_state
+ *  ```>>> */
+typedef struct _bw_pink_filt_state bw_pink_filt_state;
+/*! <<<```
+ *    State
+ *  >>> */
+
+static inline void bw_pink_filt_set_sample_rate(bw_pink_filt_coeffs *BW_RESTRICT coeffs, float sample_rate);
+
+/*! ...
+ *    #### bw_pink_filt_reset()
+ *  ```>>> */
+static inline void bw_pink_filt_reset_state(const bw_pink_filt_coeffs *BW_RESTRICT coeffs, bw_pink_filt_state *BW_RESTRICT state);
+/*! <<<```
+ *    Resets the given `instance` to its initial state.
+ *  >>> */
+
+static inline float bw_pink_filt_process1(const bw_pink_filt_coeffs *BW_RESTRICT coeffs, bw_pink_filt_state *BW_RESTRICT state, float x);
+
+/*! ...
+ *    #### bw_pink_filt_process()
+ *  ```>>> */
+static inline void bw_pink_filt_process(const bw_pink_filt_coeffs *BW_RESTRICT coeffs, bw_pink_filt_state *BW_RESTRICT state, const float *x, float* y, int n_samples);
+/*! <<<```
+ *    Lets the given `instance` process `n_samples` samples from the input
+ *    buffer `x` and fills the corresponding `n_samples` samples in the output
+ *    buffer `y`.
+ *  }}} */
+
+/*** 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. */
+
+struct _bw_pink_filt_coeffs {
+	// Coefficients
+	float	k;
+};
+
+struct _bw_pink_filt_state {
+	float	s1_z1;
+	float	s2_z1;
+	float	s3_z1;
+	float	s4_z1;
+};
+
+static inline void bw_pink_filt_set_sample_rate(bw_pink_filt_coeffs *BW_RESTRICT coeffs, float sample_rate) {
+	coeffs->k = bw_sqrtf_2(44100.f / sample_rate);
+}
+
+static inline void bw_pink_filt_reset_state(const bw_pink_filt_coeffs *BW_RESTRICT coeffs, bw_pink_filt_state *BW_RESTRICT state) {
+	state->s1_z1 = 0.f;
+	state->s2_z1 = 0.f;
+	state->s3_z1 = 0.f;
+	state->s4_z1 = 0.f;
+}
+
+static inline float bw_pink_filt_process1(const bw_pink_filt_coeffs *BW_RESTRICT coeffs, bw_pink_filt_state *BW_RESTRICT state, float x) {
+	const float s1 = 0.320696754235142f * x + state->s1_z1;
+	state->s1_z1 = 0.999760145116749f * s1 - 0.3204568993518913f * x;
+	const float s2 = 0.2870206617007935f * s1 + state->s2_z1;
+	state->s2_z1 = 0.9974135207366259f * s2 - 0.2844341824374191f * s1;
+	const float s3 = 0.2962862885898576f * s2 + state->s3_z1;
+	state->s3_z1 = 0.9687905029568185f * s3 - 0.265076791546676f * s2;
+	const float s4 = 0.3882183163519794f * s3 + state->s4_z1;
+	state->s4_z1 = 0.6573784623288251f * s4 - 0.04559677868080467 * s3;
+	return coeffs->k * s4;
+}
+
+static inline void bw_pink_filt_process(const bw_pink_filt_coeffs *BW_RESTRICT coeffs, bw_pink_filt_state *BW_RESTRICT state, const float *x, float* y, int n_samples) {
+	for (int i = 0; i < n_samples; i++)
+		y[i] = bw_pink_filt_process1(coeffs, state, x[i]);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

include/bw_slew_lim.h

@@ -167,7 +167,6 @@ struct _bw_slew_lim_coeffs {
 };
 
 struct _bw_slew_lim_state {
-	// State
 	float	y_z1;
 };
 

include/bw_svf.h

@@ -151,7 +151,6 @@ struct _bw_svf_coeffs {
 };
 
 struct _bw_svf_state {
-	// State
 	float	hp_z1;
 	float	lp_z1;
 	float	bp_z1;