From e959c275fd6915b9562801e2f04de4143b08cd1a Mon Sep 17 00:00:00 2001
From: Felix Roos <flix91@gmail.com>
Date: Sat, 16 Sep 2023 01:14:14 +0200
Subject: [PATCH] add fanchor

---
 packages/core/controls.mjs         |  1 +
 packages/superdough/helpers.mjs    | 18 +++++++++++++++---
 packages/superdough/superdough.mjs | 18 +++++++++++++++++-
 3 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/packages/core/controls.mjs b/packages/core/controls.mjs
index ce52d670..58c4efa1 100644
--- a/packages/core/controls.mjs
+++ b/packages/core/controls.mjs
@@ -586,6 +586,7 @@ const generic_params = [
    */
   ['bprelease', 'bpr'],
   ['ftype'],
+  ['fanchor'],
   /**
    * Applies the cutoff frequency of the **h**igh-**p**ass **f**ilter.
    *
diff --git a/packages/superdough/helpers.mjs b/packages/superdough/helpers.mjs
index c15bdb83..92f670d9 100644
--- a/packages/superdough/helpers.mjs
+++ b/packages/superdough/helpers.mjs
@@ -78,7 +78,20 @@ export const getParamADSR = (param, attack, decay, sustain, release, min, max, b
   param.linearRampToValueAtTime(min, end + Math.max(release, 0.1));
 };
 
-export function createFilter(context, type, frequency, Q, attack, decay, sustain, release, fenv, start, end) {
+export function createFilter(
+  context,
+  type,
+  frequency,
+  Q,
+  attack,
+  decay,
+  sustain,
+  release,
+  fenv,
+  start,
+  end,
+  fanchor = 0.5,
+) {
   const filter = context.createBiquadFilter();
   filter.type = type;
   filter.Q.value = Q;
@@ -86,8 +99,7 @@ export function createFilter(context, type, frequency, Q, attack, decay, sustain
 
   // Apply ADSR to filter frequency
   if (fenv !== 0) {
-    const anchor = 0.5;
-    const offset = fenv * anchor;
+    const offset = fenv * fanchor;
 
     const min = clamp(2 ** -offset * frequency, 0, 20000);
     const max = clamp(2 ** (fenv - offset) * frequency, 0, 20000);
diff --git a/packages/superdough/superdough.mjs b/packages/superdough/superdough.mjs
index 601ab9e0..289e8d97 100644
--- a/packages/superdough/superdough.mjs
+++ b/packages/superdough/superdough.mjs
@@ -179,6 +179,7 @@ export const superdough = async (value, deadline, hapDuration) => {
     gain = 0.8,
     // filters
     ftype = '12db',
+    fanchor = 0.5,
     // low pass
     cutoff,
     lpenv,
@@ -270,6 +271,7 @@ export const superdough = async (value, deadline, hapDuration) => {
         lpenv,
         t,
         t + hapDuration,
+        fanchor,
       );
     chain.push(lp());
     if (ftype === '24db') {
@@ -291,6 +293,7 @@ export const superdough = async (value, deadline, hapDuration) => {
         hpenv,
         t,
         t + hapDuration,
+        fanchor,
       );
     chain.push(hp());
     if (ftype === '24db') {
@@ -300,7 +303,20 @@ export const superdough = async (value, deadline, hapDuration) => {
 
   if (bandf !== undefined) {
     let bp = () =>
-      createFilter(ac, 'bandpass', bandf, bandq, bpattack, bpdecay, bpsustain, bprelease, bpenv, t, t + hapDuration);
+      createFilter(
+        ac,
+        'bandpass',
+        bandf,
+        bandq,
+        bpattack,
+        bpdecay,
+        bpsustain,
+        bprelease,
+        bpenv,
+        t,
+        t + hapDuration,
+        fanchor,
+      );
     chain.push(bp());
     if (ftype === '24db') {
       chain.push(bp());