From ec8616a51513229f06f77216d2c4bd771091980d Mon Sep 17 00:00:00 2001
From: Raphael Forment <raphael.forment@gmail.com>
Date: Mon, 4 Sep 2023 04:56:45 +0200
Subject: [PATCH] Envelope filter and filter order

---
 packages/superdough/helpers.mjs    | 14 ++++++++--
 packages/superdough/superdough.mjs | 44 ++++++++++++++++++++++++++----
 2 files changed, 49 insertions(+), 9 deletions(-)

diff --git a/packages/superdough/helpers.mjs b/packages/superdough/helpers.mjs
index 07e2b121..9ce197e1 100644
--- a/packages/superdough/helpers.mjs
+++ b/packages/superdough/helpers.mjs
@@ -66,10 +66,18 @@ export const getADSR = (attack, decay, sustain, release, velocity, begin, end) =
   return gainNode;
 };
 
-export const getFilter = (type, frequency, Q) => {
-  const filter = getAudioContext().createBiquadFilter();
+export function createFilter(context, type, frequency, Q, curve, to, over, t) {
+  const filter = context.createBiquadFilter();
   filter.type = type;
   filter.frequency.value = frequency;
   filter.Q.value = Q;
+
+  if (to !== null && over !== null) {
+    if (curve === 'lin') {
+      filter.frequency.linearRampToValueAtTime(to, t + over);
+    } else {
+      filter.frequency.exponentialRampToValueAtTime(to, t + over);
+    }
+  }
   return filter;
-};
+}
diff --git a/packages/superdough/superdough.mjs b/packages/superdough/superdough.mjs
index af22355f..cf3c231e 100644
--- a/packages/superdough/superdough.mjs
+++ b/packages/superdough/superdough.mjs
@@ -9,7 +9,7 @@ import './reverb.mjs';
 import './vowel.mjs';
 import { clamp } from './util.mjs';
 import workletsUrl from './worklets.mjs?url';
-import { getFilter, gainNode } from './helpers.mjs';
+import { createFilter, gainNode } from './helpers.mjs';
 import { map } from 'nanostores';
 import { logger } from './logger.mjs';
 
@@ -177,6 +177,11 @@ export const superdough = async (value, deadline, hapDuration) => {
     bank,
     source,
     gain = 0.8,
+    // filters
+    order = 12,
+    to,
+    filtenv = 'lin',
+    over,
     // low pass
     cutoff,
     resonance = 1,
@@ -239,11 +244,37 @@ export const superdough = async (value, deadline, hapDuration) => {
   // gain stage
   chain.push(gainNode(gain));
 
-  // filters
-  cutoff !== undefined && chain.push(getFilter('lowpass', cutoff, resonance));
-  hcutoff !== undefined && chain.push(getFilter('highpass', hcutoff, hresonance));
-  bandf !== undefined && chain.push(getFilter('bandpass', bandf, bandq));
-  vowel !== undefined && chain.push(ac.createVowelFilter(vowel));
+  if (cutoff !== undefined) {
+    const filter1 = createFilter(ac, 'lowpass', cutoff, resonance, filtenv, to || cutoff, over || hapDuration, t);
+    chain.push(filter1);
+    if (order === 24) {
+      const filter2 = createFilter(ac, 'lowpass', cutoff, resonance, filtenv, to || cutoff, over || hapDuration, t);
+      chain.push(filter2);
+    }
+  }
+
+  if (hcutoff !== undefined) {
+    const filter1 = createFilter(ac, 'highpass', hcutoff, hresonance, filtenv, to || hcutoff, over || hapDuration, t);
+    chain.push(filter1);
+    if (order === 24) {
+      const filter2 = createFilter(ac, 'highpass', hcutoff, hresonance, filtenv, to || hcutoff, over || hapDuration, t);
+      chain.push(filter2);
+    }
+  }
+
+  if (bandf !== undefined) {
+    const filter1 = createFilter(ac, 'bandpass', bandf, bandq, filtenv, to || bandf, over || hapDuration, t);
+    chain.push(filter1);
+    if (order === 24) {
+      const filter2 = createFilter(ac, 'bandpass', bandf, bandq, filtenv, to || bandf, over || hapDuration, t);
+      chain.push(filter2);
+    }
+  }
+
+  if (vowel !== undefined) {
+    const vowelFilter = ac.createVowelFilter(vowel);
+    chain.push(vowelFilter);
+  }
 
   // effects
   coarse !== undefined && chain.push(getWorklet(ac, 'coarse-processor', { coarse }));
@@ -282,6 +313,7 @@ export const superdough = async (value, deadline, hapDuration) => {
     analyserSend = effectSend(post, analyserNode, analyze);
   }
 
+  console.log(chain);
   // connect chain elements together
   chain.slice(1).reduce((last, current) => last.connect(current), chain[0]);