From fc991cab5ca0d3d0e73e4f2aefccc7c3dc15b0ce Mon Sep 17 00:00:00 2001
From: Daniel Cassidy <mail@danielcassidy.me.uk>
Date: Tue, 5 Nov 2019 02:06:50 +0000
Subject: [PATCH] [#1317] Don't ramp volume when set at start of playback
 (#1318)

Closes #1317

## Changes:

- Only apply volume ramp if sound is already playing.
---
 src/engine/Resources/Sound/AudioInstance.ts |  2 +-
 src/spec/WebAudioInstanceSpec.ts            | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/src/engine/Resources/Sound/AudioInstance.ts b/src/engine/Resources/Sound/AudioInstance.ts
index 52075665..122e1eb5 100644
--- a/src/engine/Resources/Sound/AudioInstance.ts
+++ b/src/engine/Resources/Sound/AudioInstance.ts
@@ -193,7 +193,7 @@ export class WebAudioInstance extends AudioInstance {
 
     this._volume = value;
 
-    if (this._volumeNode.gain.setTargetAtTime) {
+    if (this._isPlaying && this._volumeNode.gain.setTargetAtTime) {
       // https://developer.mozilla.org/en-US/docs/Web/API/AudioParam/setTargetAtTime
       // After each .1 seconds timestep, the target value will ~63.2% closer to the target value.
       // This exponential ramp provides a more pleasant trasition in gain
diff --git a/src/spec/WebAudioInstanceSpec.ts b/src/spec/WebAudioInstanceSpec.ts
index eea46de3..414b3bfd 100644
--- a/src/spec/WebAudioInstanceSpec.ts
+++ b/src/spec/WebAudioInstanceSpec.ts
@@ -31,6 +31,12 @@ describe('A webaudio instance', () => {
         setValueAtTime: () => {
           /*empty*/
         }
+      },
+      start: () => {
+        /*empty*/
+      },
+      stop: () => {
+        /*empty*/
       }
     };
 
@@ -51,8 +57,15 @@ describe('A webaudio instance', () => {
     expect(webaudio).toBeDefined();
   });
 
-  it('should use specific settings for volume', () => {
-    webaudio.volume = 1;
+  it('should set volume immediately', () => {
+    webaudio.volume = 0.5;
+    expect(mockGainNode.gain.value).toEqual(0.5);
+    expect(mockGainNode.gain.setTargetAtTime).not.toHaveBeenCalled();
+  });
+
+  it('should ramp volume when set during playback', () => {
+    webaudio.play();
+    webaudio.volume = 0.25;
     expect(mockGainNode.gain.setTargetAtTime).toHaveBeenCalledWith(webaudio.volume, 0, 0.1);
   });
 });
-- 
2.51.2