From 3a65bc0650f84e40abb43453cee04b3e3751efd5 Mon Sep 17 00:00:00 2001
From: Felix Roos <flix91@gmail.com>
Date: Sun, 18 Sep 2022 22:39:40 +0200
Subject: [PATCH] improve adsr

---
 packages/webaudio/webaudio.mjs | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/packages/webaudio/webaudio.mjs b/packages/webaudio/webaudio.mjs
index 39a3591a..5a4c9c2e 100644
--- a/packages/webaudio/webaudio.mjs
+++ b/packages/webaudio/webaudio.mjs
@@ -33,12 +33,17 @@ const getFilter = (type, frequency, Q) => {
 
 const getADSR = (attack, decay, sustain, release, velocity, begin, end) => {
   const gainNode = getAudioContext().createGain();
-  gainNode.gain.setValueAtTime(0, begin);
-  gainNode.gain.linearRampToValueAtTime(velocity, begin + attack); // attack
-  gainNode.gain.linearRampToValueAtTime(sustain * velocity, begin + attack + decay); // sustain start
-  gainNode.gain.setValueAtTime(sustain * velocity, end); // sustain end
-  gainNode.gain.linearRampToValueAtTime(0, end + release); // release
-  // for some reason, using exponential ramping creates little cracklings
+  let t = begin;
+  gainNode.gain.setValueAtTime(0, t);
+  gainNode.gain.exponentialRampToValueAtTime(velocity, (t += attack));
+  const sustainGain = Math.max(sustain * velocity, 0.001);
+  gainNode.gain.exponentialRampToValueAtTime(sustainGain, (t += decay));
+  if (end - begin < attack + decay) {
+    gainNode.gain.cancelAndHoldAtTime(end);
+  } else {
+    gainNode.gain.setValueAtTime(sustainGain, end);
+  }
+  gainNode.gain.exponentialRampToValueAtTime(0.001, end + release); // release
   return gainNode;
 };