From 819abbfa7a10abf43757365db7c2f52f0b58535f Mon Sep 17 00:00:00 2001
From: Felix Roos <flix91@gmail.com>
Date: Wed, 21 Sep 2022 22:25:35 +0200
Subject: [PATCH] fix sample slicing + unit + nudge

---
 packages/webaudio/webaudio.mjs | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/packages/webaudio/webaudio.mjs b/packages/webaudio/webaudio.mjs
index b1568ea7..4e597c2a 100644
--- a/packages/webaudio/webaudio.mjs
+++ b/packages/webaudio/webaudio.mjs
@@ -187,6 +187,8 @@ Pattern.prototype.out = function () {
         begin = 0,
         end = 1,
         vowel,
+        unit,
+        nudge = 0, // TODO: is this in seconds?
       } = hap.value;
       const { velocity = 1 } = hap.context;
       gain *= velocity; // legacy fix for velocity
@@ -253,17 +255,22 @@ Pattern.prototype.out = function () {
           console.warn('no buffer source');
           return;
         }
+        // TODO: cut, loop
         bufferSource.playbackRate.value = Math.abs(speed) * bufferSource.playbackRate.value;
-        // TODO: nudge, unit, cut, loop
-        let duration = soundfont || clip ? hapDuration : bufferSource.buffer.duration;
-        // let duration = bufferSource.buffer.duration;
-        const offset = begin * duration;
-        duration = ((end - begin) * duration) / Math.abs(speed);
-        if (soundfont || clip) {
-          bufferSource.start(t, offset); // duration does not work here for some reason
-        } else {
-          bufferSource.start(t, offset, duration);
+        if (unit === 'c') {
+          // are there other units?
+          bufferSource.playbackRate.value = bufferSource.playbackRate.value * bufferSource.buffer.duration;
         }
+        let duration = soundfont || clip ? hapDuration : bufferSource.buffer.duration / bufferSource.playbackRate.value;
+        // "The computation of the offset into the sound is performed using the sound buffer's natural sample rate,
+        // rather than the current playback rate, so even if the sound is playing at twice its normal speed,
+        // the midway point through a 10-second audio buffer is still 5."
+        const offset = begin * duration * bufferSource.playbackRate.value;
+        duration = (end - begin) * duration;
+        t += nudge;
+
+        bufferSource.start(t, offset);
+
         chain.push(bufferSource);
         if (soundfont || clip) {
           const env = ac.createGain();