From 237616490ffe8a2ace1b3dc52c79d9e42da9582f Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Tue, 27 Feb 2018 11:48:14 -0500
Subject: [PATCH 1/4] Add tempo property to rendered target

---
 src/sprites/rendered-target.js | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/sprites/rendered-target.js b/src/sprites/rendered-target.js
index ae02b72bd..538cc576f 100644
--- a/src/sprites/rendered-target.js
+++ b/src/sprites/rendered-target.js
@@ -116,6 +116,12 @@ class RenderedTarget extends Target {
          * @type {!string}
          */
         this.rotationStyle = RenderedTarget.ROTATION_STYLE_ALL_AROUND;
+
+        /**
+         * Current tempo (used by the music extension)
+         * @type {number}
+         */
+        this.tempo = 60;
     }
 
     /**

From 7e5e43fbe16b41363a94ab7b471c8daf2561d0cb Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Tue, 27 Feb 2018 11:48:23 -0500
Subject: [PATCH 2/4] Load tempo from sb2

---
 src/serialization/sb2.js | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/serialization/sb2.js b/src/serialization/sb2.js
index 1102c005e..ada14f5f5 100644
--- a/src/serialization/sb2.js
+++ b/src/serialization/sb2.js
@@ -320,6 +320,9 @@ const parseScratchObject = function (object, runtime, extensions, topLevel) {
             target.rotationStyle = RenderedTarget.ROTATION_STYLE_ALL_AROUND;
         }
     }
+    if (object.hasOwnProperty('tempoBPM')) {
+        target.tempo = object.tempoBPM;
+    }
 
     target.isStage = topLevel;
 

From db795abfbc0b4e9594b9e92790c55c7ae762016a Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Tue, 27 Feb 2018 11:48:49 -0500
Subject: [PATCH 3/4] Use tempo stored in stage

---
 src/extensions/scratch3_music/index.js | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/extensions/scratch3_music/index.js b/src/extensions/scratch3_music/index.js
index 386c2c4a6..2c7e59b36 100644
--- a/src/extensions/scratch3_music/index.js
+++ b/src/extensions/scratch3_music/index.js
@@ -43,13 +43,6 @@ class Scratch3MusicBlocks {
          */
         this.runtime = runtime;
 
-        /**
-         * The current tempo in beats per minute. The tempo is a global property of the project,
-         * not a property of each sprite, so it is not stored in the MusicState object.
-         * @type {number}
-         */
-        this.tempo = 60;
-
         /**
          * The number of drum and instrument sounds currently being played simultaneously.
          * @type {number}
@@ -759,7 +752,7 @@ class Scratch3MusicBlocks {
      * @private
      */
     _beatsToSec (beats) {
-        return (60 / this.tempo) * beats;
+        return (60 / this.getTempo()) * beats;
     }
 
     /**
@@ -829,7 +822,7 @@ class Scratch3MusicBlocks {
      */
     changeTempo (args) {
         const change = Cast.toNumber(args.TEMPO);
-        const tempo = change + this.tempo;
+        const tempo = change + this.getTempo();
         this._updateTempo(tempo);
     }
 
@@ -840,7 +833,10 @@ class Scratch3MusicBlocks {
      */
     _updateTempo (tempo) {
         tempo = MathUtil.clamp(tempo, Scratch3MusicBlocks.TEMPO_RANGE.min, Scratch3MusicBlocks.TEMPO_RANGE.max);
-        this.tempo = tempo;
+        const stage = this.runtime.getTargetForStage();
+        if (stage) {
+            stage.tempo = tempo;
+        }
     }
 
     /**
@@ -848,7 +844,11 @@ class Scratch3MusicBlocks {
      * @return {number} - the current tempo, in beats per minute.
      */
     getTempo () {
-        return this.tempo;
+        const stage = this.runtime.getTargetForStage();
+        if (stage) {
+            return stage.tempo;
+        }
+        return 60;
     }
 }
 

From a0525542fc5dabc7e816cf1ff69e86b5704196df Mon Sep 17 00:00:00 2001
From: Eric Rosenbaum <eric.rosenbaum@gmail.com>
Date: Tue, 27 Feb 2018 15:38:34 -0500
Subject: [PATCH 4/4] Stub runtime to fix unit test

---
 test/unit/extension_music.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/test/unit/extension_music.js b/test/unit/extension_music.js
index 93106297f..ad35b29a8 100644
--- a/test/unit/extension_music.js
+++ b/test/unit/extension_music.js
@@ -1,8 +1,11 @@
 const test = require('tap').test;
 const Music = require('../../src/extensions/scratch3_music/index.js');
-const runtime = Object.create(null);
 
-const blocks = new Music(runtime);
+const fakeRuntime = {
+    getTargetForStage: () => ({tempo: 60})
+};
+
+const blocks = new Music(fakeRuntime);
 
 const util = {
     stackFrame: Object.create(null),