diff --git a/README.md b/README.md
index b6c2239..04ddfd6 100644
--- a/README.md
+++ b/README.md
@@ -6,9 +6,8 @@ You can find information and documentation [on the official web page](https://ww
 
 ## Subfolders
 
-* examples: a synth and an effect example in VST3 and Web Audio formats;
-* include: header files;
-* src: source files.
+* examples: synth and an effect examples in VST3 and Web Audio formats;
+* include: header files.
 
 ## Legal
 
@@ -20,6 +19,8 @@ All the code in the repo is released under GPLv3. See the LICENSE file. Alternat
 
 The file examples/common/vst3/plugin.cpp contains code from sse2neon (https://github.com/DLTcollab/sse2neon/), which was released under the MIT license. Details in said file.
 
+The file include/bw\_math.h contains code derived from https://dangelo.audio/code/omega.h, which was released under the ISC license. Details in said file.
+
 The file include/bw\_rand.h contains code from https://nullprogram.com/blog/2017/09/21/, which was released into the public domain by its author.
 
 VST is a registered trademark of Steinberg Media Technologies GmbH.
diff --git a/include/bw_env_follow.h b/include/bw_env_follow.h
index 237afd5..a16cca9 100644
--- a/include/bw_env_follow.h
+++ b/include/bw_env_follow.h
@@ -24,9 +24,6 @@
  *  description {{{
  *    Envelope follower made of a full-wave rectifier followed by
  *    [bw_one_pole](bw_one_pole) one-pole filter (6 dB/oct).
- *
- *    Unlike other dsp modules, you can directly access the parameters of the
- *    internal one-pole filter via the `bw_env_follow_get_one_pole()` function.
  *  }}}
  *  changelog {{{
  *    <ul>
@@ -58,54 +55,93 @@ extern "C" {
  *  ```>>> */
 typedef struct _bw_env_follow_coeffs bw_env_follow_coeffs;
 /*! <<<```
- *    Coefficients.
+ *    Coefficients and input parameter values.
  *
- *    ### bw_env_follow_state
- *  >>> */
+ *    #### bw_env_follow_state
+ *  ```>>> */
 typedef struct _bw_env_follow_state bw_env_follow_state;
 /*! <<<```
- *    State.
+ *    Internal state and output parameter values.
  *
  *    #### bw_env_follow_init()
  *  ```>>> */
 static inline void bw_env_follow_init(bw_env_follow_coeffs *BW_RESTRICT coeffs);
 /*! <<<```
- *    Initializes `coeffs`.
+ *    Initializes input parameter values in `coeffs`.
  *
  *    #### bw_env_follow_set_sample_rate()
  *  ```>>> */
 static inline void bw_env_follow_set_sample_rate(bw_env_follow_coeffs *BW_RESTRICT coeffs, float sample_rate);
 /*! <<<```
- *    Sets the `sample_rate` (Hz) value for the given `coeffs`.
+ *    Sets the `sample_rate` (Hz) value in `coeffs`.
  *
- *    #### bw_one_pole_reset_state()
+ *    #### bw_env_follow_reset_coeffs()
+ *  ```>>> */
+static inline void bw_env_follow_reset_coeffs(bw_env_follow_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Resets coefficients in `coeffs` to assume their target values.
+ *
+ *    #### bw_env_follow_reset_state()
  *  ```>>> */
 static inline void bw_env_follow_reset_state(const bw_env_follow_coeffs *BW_RESTRICT coeffs, bw_env_follow_state *BW_RESTRICT state);
 /*! <<<```
- *    Resets the given `state` to the initial state using the given `coeffs`.
- *  >>> */
-
-static inline void bw_env_follow_reset_coeffs(bw_env_follow_coeffs *BW_RESTRICT coeffs);
-
+ *    Resets the given `state` to its initial values using the given `coeffs`.
+ *
+ *    #### bw_env_follow_update_coeffs_ctrl()
+ *  ```>>> */
 static inline void bw_env_follow_update_coeffs_ctrl(bw_env_follow_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Triggers control-rate update of coefficients in `coeffs`.
+ *
+ *    #### bw_env_follow_update_coeffs_audio()
+ *  ```>>> */
 static inline void bw_env_follow_update_coeffs_audio(bw_env_follow_coeffs *BW_RESTRICT coeffs);
-
+/*! <<<```
+ *    Triggers audio-rate update of coefficients in `coeffs`.
+ *
+ *    #### bw_env_follow_process1()
+ *  ```>>> */
 static inline float bw_env_follow_process1(const bw_env_follow_coeffs *BW_RESTRICT coeffs, bw_env_follow_state *BW_RESTRICT state, float x);
-
-/*! ...
+/*! <<<```
+ *    Processes one input sample `x` using `coeffs` and updating `state` (audio
+ *    rate only). Returns the corresponding output sample.
+ *
  *    #### bw_env_follow_process()
  *  ```>>> */
 static inline void bw_env_follow_process(bw_env_follow_coeffs *BW_RESTRICT coeffs, bw_env_follow_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`.
- *  }}} */
-
+ *    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).
+ *
+ *    `y` may be `NULL`.
+ *
+ *    #### bw_env_follow_set_attack_tau()
+ *  ```>>> */
 static inline void bw_env_follow_set_attack_tau(bw_env_follow_coeffs *BW_RESTRICT coeffs, float value);
+/*! <<<```
+ *    Sets the upgoing (attack)
+ *    <a href="https://en.wikipedia.org/wiki/Time_constant" target="_blank">time
+ *    constant</a> in `coeffs` of the one-pole filter to `value` (s).
+ *
+ *    Default value: `0.f`.
+ *
+ *    #### bw_env_follow_set_release_tau()
+ *  ```>>> */
 static inline void bw_env_follow_set_release_tau(bw_env_follow_coeffs *BW_RESTRICT coeffs, float value);
-
+/*! <<<```
+ *    Sets the downgoing (release)
+ *    <a href="https://en.wikipedia.org/wiki/Time_constant" target="_blank">time
+ *    constant</a> in `coeffs` of the one-pole filter to `value` (s).
+ *
+ *    Default value: `0.f`.
+ *
+ *    #### bw_env_follow_get_y_z1()
+ *  ```>>> */
 static inline float bw_env_follow_get_y_z1(const bw_env_follow_state *BW_RESTRICT state);
+/*! <<<```
+ *    Returns the last output sample stored in `state`.
+ *  }}} */
 
 /*** Implementation ***/
 
@@ -155,7 +191,7 @@ static inline float bw_env_follow_process1(const bw_env_follow_coeffs *BW_RESTRI
 
 static inline void bw_env_follow_process(bw_env_follow_coeffs *BW_RESTRICT coeffs, bw_env_follow_state *BW_RESTRICT state, const float *x, float *y, int n_samples) {
 	bw_env_follow_update_coeffs_ctrl(coeffs);
-	if (y)
+	if (y != NULL)
 		for (int i = 0; i < n_samples; i++) {
 			bw_env_follow_update_coeffs_audio(coeffs);
 			y[i] = bw_env_follow_process1(coeffs, state, x[i]);
diff --git a/include/bw_env_gen.h b/include/bw_env_gen.h
index e412b31..39fe4c9 100644
--- a/include/bw_env_gen.h
+++ b/include/bw_env_gen.h
@@ -24,7 +24,7 @@
  *  description {{{
  *    Linear ADSR envelope generator.
  *
- *    * In the off state (gate off and possible previous release phase ended),
+ *    * In the off phase (gate off and possible previous release phase ended),
  *      the output is `0.f`;
  *    * in the attack phase the output increases from `0.f` to `1.f`;
  *    * in the decay phase the output decreases from `1.f` to the given sustain
@@ -67,13 +67,13 @@ extern "C" {
  *  ```>>> */
 typedef struct _bw_env_gen_coeffs bw_env_gen_coeffs;
 /*! <<<```
- *    Coefficients.
+ *    Coefficients and input parameter values.
  *
- *    ### bw_env_gen_state
+ *    #### bw_env_gen_state
  *  ```>>> */
 typedef struct _bw_env_gen_state bw_env_gen_state;
 /*! <<<```
- *    State.
+ *    Internal state and output parameter values.
  *
  *    #### bw_env_gen_phase
  *  ```>>> */
@@ -85,113 +85,128 @@ typedef enum {
 	bw_env_gen_phase_release
 } bw_env_gen_phase;
 /*! <<<```
- *    Phase:
- *     * `bw_env_gen_phase_off`: ...
- *     * `bw_env_gen_phase_attack`: ...
- *     * `bw_env_gen_phase_decay`: ...
- *     * `bw_env_gen_phase_sustain`: ...
- *     * `bw_env_gen_phase_release`: ...
+ *    Envelope generator phase:
+ *     * `bw_env_gen_phase_off`: off phase;
+ *     * `bw_env_gen_phase_attack`: attack phase;
+ *     * `bw_env_gen_phase_decay`: decay phase;
+ *     * `bw_env_gen_phase_sustain`: sustain phase;
+ *     * `bw_env_gen_phase_release`: release phase.
  *
  *    #### bw_env_gen_init()
  *  ```>>> */
 static inline void bw_env_gen_init(bw_env_gen_coeffs *BW_RESTRICT coeffs);
 /*! <<<```
- *    Initializes `coeffs`.
+ *    Initializes input parameter values in `coeffs`.
  *
  *    #### bw_env_gen_set_sample_rate()
  *  ```>>> */
 static inline void bw_env_gen_set_sample_rate(bw_env_gen_coeffs *BW_RESTRICT coeffs, float sample_rate);
 /*! <<<```
- *    Sets the `sample_rate` (Hz) value for the given `instance`.
+ *    Sets the `sample_rate` (Hz) value in `coeffs`.
+ *
+ *    #### bw_env_gen_reset_coeffs()
+ *  ```>>> */
+static inline void bw_env_gen_reset_coeffs(bw_env_gen_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Resets coefficients in `coeffs` to assume their target values.
  *
  *    #### bw_env_gen_reset_state()
  *  ```>>> */
 static inline void bw_env_gen_reset_state(const bw_env_gen_coeffs *BW_RESTRICT coeffs, bw_env_gen_state *BW_RESTRICT state);
 /*! <<<```
- *    Resets the given `state` to the initial state using the given `coeffs`.
- *  >>> */
-
-static inline void bw_env_gen_reset_coeffs(bw_env_gen_coeffs *BW_RESTRICT coeffs);
-
+ *    Resets the given `state` to its initial values using the given `coeffs`.
+ *
+ *    #### bw_env_gen_update_coeffs_ctrl()
+ *  ```>>> */
 static inline void bw_env_gen_update_coeffs_ctrl(bw_env_gen_coeffs *BW_RESTRICT coeffs);
+/*! <<<```
+ *    Triggers control-rate update of coefficients in `coeffs`.
+ *
+ *    #### bw_env_gen_update_coeffs_audio()
+ *  ```>>> */
 static inline void bw_env_gen_update_coeffs_audio(bw_env_gen_coeffs *BW_RESTRICT coeffs);
-
+/*! <<<```
+ *    Triggers audio-rate update of coefficients in `coeffs`.
+ *
+ *    #### bw_env_gen_update_state_ctrl()
+ *  ```>>> */
 static inline void bw_env_gen_update_state_ctrl(const bw_env_gen_coeffs *BW_RESTRICT coeffs, bw_env_gen_state *BW_RESTRICT state);
-
+/*! <<<```
+ *    Triggers control-rate update of the internal `state` using `coeffs`.
+ *
+ *    #### bw_env_gen_process1()
+ *  ```>>> */
 static inline float bw_env_gen_process1(const bw_env_gen_coeffs *BW_RESTRICT coeffs, bw_env_gen_state *BW_RESTRICT state);
-
-/*! ...
+/*! <<<```
+ *    Generates and returns one sample using `coeffs` and updating `state`
+ *    (audio rate only).
+ *
  *    #### bw_env_gen_process()
  *  ```>>> */
 static inline void bw_env_gen_process(bw_env_gen_coeffs *BW_RESTRICT coeffs, bw_env_gen_state *BW_RESTRICT state, float* y, int n_samples);
 /*! <<<```
- *    Lets the given `instance` generate `n_samples` samples and puts them in
- *    the output buffer `y`.
- *  >>> */
-
-/*! ...
+ *    Generates and fills the first `n_samples` of the output buffer `y`, while
+ *    using and updating both `coeffs` and `state` (control and audio rate).
+ *
+ *    `y` may be `NULL`.
+ *
  *    #### bw_env_gen_set_gate()
  *  ```>>> */
 static inline void bw_env_gen_set_gate(bw_env_gen_coeffs *BW_RESTRICT coeffs, char value);
 /*! <<<```
- *    Sets the input gate to be either off (`0`) or on (non-`0`) for the given
- *    `instance`.
+ *    Sets the input gate to be either off (`0`) or on (non-`0`) in `coeffs`.
  *
  *    Default value: `0` (off).
- *  >>> */
-
-/*! ...
+ *
  *    #### bw_env_gen_set_attack()
  *  ```>>> */
 static inline void bw_env_gen_set_attack(bw_env_gen_coeffs *BW_RESTRICT coeffs, float value);
 /*! <<<```
- *    Sets the attack time to `value` (s) for the given `instance`.
+ *    Sets the attack time to `value` (s) in `coeffs`.
  *
  *    `value` must be smaller than `1e9f`.
  *
  *    Default value: `0.f`.
- *  >>> */
-
-/*! ...
+ *
  *    #### bw_env_gen_set_decay()
  *  ```>>> */
 static inline void bw_env_gen_set_decay(bw_env_gen_coeffs *BW_RESTRICT coeffs, float value);
 /*! <<<```
- *    Sets the decay time to `value` (s) for the given `instance`.
+ *    Sets the decay time to `value` (s) in `coeffs`.
  *
  *    `value` must be smaller than `1e9f`.
  *
  *    Default value: `0.f`.
- *  >>> */
-
-/*! ...
+ *
  *    #### bw_env_gen_set_sustain()
  *  ```>>> */
 static inline void bw_env_gen_set_sustain(bw_env_gen_coeffs *BW_RESTRICT coeffs, float value);
 /*! <<<```
- *    Sets the sustain level to `value` for the given `instance`.
+ *    Sets the sustain level to `value` in `coeffs`.
  *
  *    Default value: `1.f`.
- *  >>> */
-
-/*! ...
+ *
  *    #### bw_env_gen_set_release()
  *  ```>>> */
 static inline void bw_env_gen_set_release(bw_env_gen_coeffs *BW_RESTRICT coeffs, float value);
 /*! <<<```
- *    Sets the release time to `value` (s) for the given `instance`.
+ *    Sets the release time to `value` (s) in `coeffs`.
  *
  *    `value` must be smaller than `1e9f`.
  *
  *    Default value: `0.f`.
- *  >>> */
-
-/*! ...
+ *
  *    #### bw_env_gen_get_phase()
  *  ```>>> */
 static inline bw_env_gen_phase bw_env_gen_get_phase(bw_env_gen_state *state);
 /*! <<<```
- *    ...
+ *    Returns the current envelope generator phase as stored in `state`.
+ *
+ *    #### bw_env_gen_get_y_z1()
+ *  ```>>> */
+static inline float bw_env_gen_get_y_z1(bw_env_gen_state *state);
+/*! <<<```
+ *    Returns the last output sample stored in `state`.
  *  }}} */
 
 static inline float bw_env_gen_get_y_z1(bw_env_gen_state *state);