Fixed some issues and improved performance of AndroidAudioService (#348)

* Fixed Android volume buttons not working

* Moved native calls to a separate thread to prevent slowing games (same as iOS)

* Added pendingPlay flag to alleviate the Audio flow in extreme situations (same as iOS)

* Increased the global SoundPool maxStreams setting from 5 to 20

* Added skipPause & skipStop flags to prevent an Android issue (pausing or stopping a music before playing it makes it unplayable)

* Updated Gluon copyright and implemented volume keys management

* Updated Gluon copyright

* Removed volume keys management code (now directly managed by Gluon Substrate)

Author: salmonb

modules/audio/src/main/java/com/gluonhq/attach/audio/impl/AndroidAudioService.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020 Gluon
+ * Copyright (c) 2020, 2023, Gluon
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -37,6 +37,8 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.Optional;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
 import java.util.function.Function;
 import java.util.logging.Logger;
 
@@ -121,10 +123,17 @@ private String copyToPrivateStorageIfNeeded(URL url) throws Exception {
         return file.toAbsolutePath().toString();
     }
 
+    // All native calls are executed in a background thread to not hold the caller thread (which is probably the UI
+    // thread). This prevents games using many sounds to be slowed down by audio calls.
+    private final static ScheduledExecutorService nativeExecutor = Executors.newSingleThreadScheduledExecutor();
+
     private static class AndroidAudio implements Audio {
 
-        private boolean isDisposed = false;
         private final int id;
+        private boolean isDisposed = false;
+        private boolean pendingPlay = false; // flag used by play() to alleviate the Audio flow in extreme situations
+        private boolean skipPause = true; // flag used to skip unnecessary calls to pause(), because calling pause() before play() prevents the music to be played (Android issue)
+        private boolean skipStop = true;  // flag used to skip unnecessary calls to stop(), because calling stop() before play() prevents the music to be played (Android issue)
 
         AndroidAudio(int id) {
             this.id = id;
@@ -135,39 +144,53 @@ public void setLooping(boolean looping) {
             if (isDisposed)
                 return;
 
-            AndroidAudioService.setLooping(id, looping);
+            nativeExecutor.execute(() -> AndroidAudioService.setLooping(id, looping));
         }
 
         @Override
         public void setVolume(double volume) {
             if (isDisposed)
                 return;
 
-            AndroidAudioService.setVolume(id, volume);
+            nativeExecutor.execute(() -> AndroidAudioService.setVolume(id, volume));
         }
 
         @Override
         public void play() {
-            if (isDisposed)
+            // We set pendingPlay to true before the native play() call, and then back to false after that call.
+            // In extreme situations (like observed with SpaceFX with many simultaneous explosions sounds), it can
+            // happen that the game calls play() again even before the previous call has been executed. In that case,
+            // we just drop that second call, as it doesn't make sense to start the same sound twice so closely. And
+            // most important, this improves the performance (the game was noticeably slower when the native iOS sound
+            // system was not alleviate in this way).
+
+            if (isDisposed || pendingPlay)
                 return;
 
-            AndroidAudioService.play(id);
+            pendingPlay = true;
+            nativeExecutor.execute(() -> {
+                AndroidAudioService.play(id);
+                pendingPlay = false;
+            });
+            skipPause = skipStop = false;
         }
 
         @Override
         public void pause() {
-            if (isDisposed)
+            if (isDisposed || skipPause)
                 return;
 
-            AndroidAudioService.pause(id);
+            nativeExecutor.execute(() -> AndroidAudioService.pause(id));
+            skipPause = true;
         }
 
         @Override
         public void stop() {
-            if (isDisposed)
+            if (isDisposed || skipStop)
                 return;
 
-            AndroidAudioService.stop(id);
+            nativeExecutor.execute(() -> AndroidAudioService.stop(id));
+            skipPause = skipStop = true;
         }
 
         @Override
@@ -176,7 +199,7 @@ public void dispose() {
                 return;
 
             isDisposed = true;
-            AndroidAudioService.dispose(id);
+            nativeExecutor.execute(() -> AndroidAudioService.dispose(id));
         }
 
         @Override
@@ -185,7 +208,6 @@ public boolean isDisposed() {
         }
     }
 
-    // native
     private native static int loadSoundImpl(String fullName);
     private native static int loadMusicImpl(String fullName);
 

modules/audio/src/main/native/android/c/audio.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, 2021, Gluon
+ * Copyright (c) 2020, 2023, Gluon
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -41,7 +41,7 @@ static jmethodID jAudioServiceDisposeMethod;
 static void initializeAudioDalvikHandles() {
     jAudioServiceClass = GET_REGISTER_DALVIK_CLASS(jAudioServiceClass, "com/gluonhq/helloandroid/DalvikAudioService");
     ATTACH_DALVIK();
-    jmethodID jAudioServiceInitMethod = (*dalvikEnv)->GetMethodID(dalvikEnv, jAudioServiceClass, "<init>", "()V");
+    jmethodID jAudioServiceInitMethod = (*dalvikEnv)->GetMethodID(dalvikEnv, jAudioServiceClass, "<init>", "(Landroid/app/Activity;)V");
 
     jAudioServiceLoadSoundMethod = (*dalvikEnv)->GetMethodID(dalvikEnv, jAudioServiceClass, "loadSoundImpl", "(Ljava/lang/String;)I");
     jAudioServiceLoadMusicMethod = (*dalvikEnv)->GetMethodID(dalvikEnv, jAudioServiceClass, "loadMusicImpl", "(Ljava/lang/String;)I");
@@ -53,7 +53,8 @@ static void initializeAudioDalvikHandles() {
     jAudioServiceStopMethod = (*dalvikEnv)->GetMethodID(dalvikEnv, jAudioServiceClass, "stop", "(I)V");
     jAudioServiceDisposeMethod = (*dalvikEnv)->GetMethodID(dalvikEnv, jAudioServiceClass, "dispose", "(I)V");
 
-    jobject jObj = (*dalvikEnv)->NewObject(dalvikEnv, jAudioServiceClass, jAudioServiceInitMethod);
+    jobject jActivity = substrateGetActivity();
+    jobject jObj = (*dalvikEnv)->NewObject(dalvikEnv, jAudioServiceClass, jAudioServiceInitMethod, jActivity);
     jDalvikAudioService = (*dalvikEnv)->NewGlobalRef(dalvikEnv, jObj);
 
     DETACH_DALVIK();

modules/audio/src/main/native/android/dalvik/DalvikAudioService.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020, Gluon
+ * Copyright (c) 2020, 2023, Gluon
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -27,6 +27,8 @@
  */
 package com.gluonhq.helloandroid;
 
+import android.app.Activity;
+import android.content.Context;
 import android.media.AudioAttributes;
 import android.media.AudioManager;
 import android.media.MediaPlayer;
@@ -39,11 +41,10 @@
 public class DalvikAudioService {
 
     private DalvikAudio[] cache = new DalvikAudio[10];
-
     private SoundPool pool = null;
 
-    public DalvikAudioService() {
-
+    public DalvikAudioService(Activity activity) {
+        activity.setVolumeControlStream(AudioManager.STREAM_MUSIC);
     }
 
     /**
@@ -108,7 +109,7 @@ private SoundPool createPool() {
         return new SoundPool.Builder()
                 .setAudioAttributes(audioAttributes)
                 // this is arbitrary, but it should be a reasonable amount
-                .setMaxStreams(5)
+                .setMaxStreams(20)
                 .build();
     }