From 500005811c44621cd69718d355d224a427732f5a Mon Sep 17 00:00:00 2001
From: Matthew Stratford <hi@mstratford.net>
Date: Tue, 27 Oct 2020 22:15:44 +0000
Subject: [PATCH] Fix fader fidgeting volume jumps. Fixes #40

---
 src/mixer/audio.ts | 4 ++++
 src/mixer/state.ts | 9 ++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/mixer/audio.ts b/src/mixer/audio.ts
index 37bbbe2..a29b716 100644
--- a/src/mixer/audio.ts
+++ b/src/mixer/audio.ts
@@ -125,6 +125,10 @@ class Player extends ((PlayerEmitter as unknown) as { new (): EventEmitter }) {
     }
   }
 
+  getVolume() {
+    return this.volume;
+  }
+
   setVolume(val: number) {
     this.volume = val;
     this._applyVolume();
diff --git a/src/mixer/state.ts b/src/mixer/state.ts
index 9c4cf08..421e02e 100644
--- a/src/mixer/state.ts
+++ b/src/mixer/state.ts
@@ -666,7 +666,14 @@ export const setVolume = (
   const state = getState().mixer.players[player];
 
   const currentLevel = state.volume;
-  const currentGain = state.gain;
+  let currentGain = state.gain;
+
+  // If we can, use the engine's 'real' volume gain.
+  // This helps when we've interupted a previous fade, so the state gain won't be correct.
+  if (typeof audioEngine.players[player] !== "undefined") {
+    currentGain = audioEngine.players[player]!.getVolume();
+  }
+
   const volumeTween = new Between(currentLevel, uiLevel)
     .time(FADE_TIME_SECONDS * 1000)
     .on("update", (val: number) => {