Merge pull request #431 from JD557/sound-mixer

Add realtime mixing operations
JD557 · Oct 8, 2023 · 46f061d · 46f061d
2 parents 4a8c8d4 + a53faea
commit 46f061d
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Showing 7 changed files with 86 additions and 11 deletions.
diff --git a/backend/js/src/main/scala/eu/joaocosta/minart/backend/JsAudioPlayer.scala b/backend/js/src/main/scala/eu/joaocosta/minart/backend/JsAudioPlayer.scala
@@ -62,4 +62,10 @@ final class JsAudioPlayer() extends LowLevelAudioPlayer {
   def stop(): Unit = playQueue.clear()
 
   def stop(channel: Int): Unit = playQueue.clear(channel)
+
+  def getChannelMix(channel: Int): AudioMix =
+    playQueue.getChannelMix(channel)
+
+  def setChannelMix(mix: AudioMix, channel: Int): Unit =
+    playQueue.setChannelMix(mix, channel)
 }
diff --git a/backend/jvm/src/main/scala/eu/joaocosta/minart/backend/JavaAudioPlayer.scala b/backend/jvm/src/main/scala/eu/joaocosta/minart/backend/JavaAudioPlayer.scala
@@ -67,4 +67,10 @@ final class JavaAudioPlayer() extends LowLevelAudioPlayer {
   def stop(): Unit = playQueue.clear()
 
   def stop(channel: Int): Unit = playQueue.clear(channel)
+
+  def getChannelMix(channel: Int): AudioMix =
+    playQueue.getChannelMix(channel)
+
+  def setChannelMix(mix: AudioMix, channel: Int): Unit =
+    playQueue.setChannelMix(mix, channel)
 }
diff --git a/backend/native/src/main/scala/eu/joaocosta/minart/backend/SdlAudioPlayer.scala b/backend/native/src/main/scala/eu/joaocosta/minart/backend/SdlAudioPlayer.scala
@@ -106,4 +106,10 @@ final class SdlAudioPlayer() extends LowLevelAudioPlayer {
   def stop(channel: Int): Unit = {
     playQueue.clear(channel)
   }
+
+  def getChannelMix(channel: Int): AudioMix =
+    playQueue.getChannelMix(channel)
+
+  def setChannelMix(mix: AudioMix, channel: Int): Unit =
+    playQueue.setChannelMix(mix, channel)
 }
diff --git a/core/shared/src/main/scala/eu/joaocosta/minart/audio/AudioMix.scala b/core/shared/src/main/scala/eu/joaocosta/minart/audio/AudioMix.scala
@@ -0,0 +1,7 @@
+package eu.joaocosta.minart.audio
+
+/**  Definitions of how a channel should be mixed.
+  *
+  *  @param volume the channel volume from 0.0 to 1.0
+  */
+final case class AudioMix(volume: Double = 1.0)
diff --git a/core/shared/src/main/scala/eu/joaocosta/minart/audio/AudioPlayer.scala b/core/shared/src/main/scala/eu/joaocosta/minart/audio/AudioPlayer.scala
@@ -58,6 +58,33 @@ trait AudioPlayer {
     *  @param channel channel to stop
     */
   def stop(channel: Int): Unit
+
+  /** Gets the mixing definitions for a channel.
+    *
+    * @param channel channel to check
+    */
+  def getChannelMix(channel: Int): AudioMix
+
+  /** Sets the mixing definitions for a channel.
+    *
+    * @param mix the new mixing definitions
+    * @param channel channel to update
+    */
+  def setChannelMix(mix: AudioMix, channel: Int): Unit
+
+  /** Updates the mixing definitions for a channel based on the current definitions.
+    *
+    * @param f update function
+    * @param channel channel to update
+    * @return the new audio mix
+    */
+  final def updateChannelMix(f: AudioMix => AudioMix, channel: Int): AudioMix = {
+    val currentMix = getChannelMix(channel)
+    val newMix     = f(currentMix)
+    setChannelMix(newMix, channel)
+    newMix
+  }
+
 }
 
 object AudioPlayer {

diff --git a/core/shared/src/main/scala/eu/joaocosta/minart/audio/AudioQueue.scala b/core/shared/src/main/scala/eu/joaocosta/minart/audio/AudioQueue.scala
@@ -1,7 +1,5 @@
 package eu.joaocosta.minart.audio
 
-import scala.jdk.CollectionConverters.*
-
 /** Internal AudioQueue abstraction.
   *
   *  This is not expected to be used by user code, but it's helpful to implement custom backends
@@ -24,10 +22,11 @@ object AudioQueue {
 
   final class SingleChannelAudioQueue(sampleRate: Int) extends AudioQueue {
     private val valueQueue = scala.collection.mutable.Queue[Double]()
-    private val clipQueue  = new java.util.ArrayDeque[AudioClip]() // Use scala's ArrayDeque on 2.13+
+    private val clipQueue  = scala.collection.mutable.ArrayDeque[AudioClip]()
+    var mix                = AudioMix()
 
     def isEmpty() = synchronized { valueQueue.isEmpty && clipQueue.isEmpty }
-    def size = clipQueue.iterator.asScala.foldLeft(valueQueue.size) { case (acc, clip) =>
+    def size = clipQueue.foldLeft(valueQueue.size) { case (acc, clip) =>
       if (acc == Int.MaxValue || clip.duration.isInfinite) Int.MaxValue
       else {
         val newValue = acc + Sampler.numSamples(clip, sampleRate)
@@ -37,21 +36,21 @@ object AudioQueue {
     }
 
     def enqueue(clip: AudioClip): this.type = synchronized {
-      clipQueue.addLast(clip)
+      clipQueue.append(clip)
       this
     }
     def dequeue(): Double = synchronized {
       if (valueQueue.nonEmpty) {
-        valueQueue.dequeue()
-      } else if (!clipQueue.isEmpty()) {
-        val nextClip = clipQueue.removeFirst()
+        valueQueue.dequeue() * mix.volume
+      } else if (!clipQueue.isEmpty) {
+        val nextClip = clipQueue.removeHead()
         if (nextClip.duration > maxBufferSize) {
           valueQueue ++= Sampler.sampleClip(nextClip.take(maxBufferSize), sampleRate)
-          clipQueue.addFirst(nextClip.drop(maxBufferSize))
+          clipQueue.prepend(nextClip.drop(maxBufferSize))
         } else {
           valueQueue ++= Sampler.sampleClip(nextClip, sampleRate)
         }
-        valueQueue.dequeue()
+        valueQueue.dequeue() * mix.volume
       } else {
         0.0
       }
@@ -65,7 +64,14 @@ object AudioQueue {
   }
 
   final class MultiChannelAudioQueue(sampleRate: Int) extends AudioQueue {
-    private val channels = scala.collection.mutable.Map[Int, AudioQueue]()
+    private val channels = scala.collection.mutable.Map[Int, SingleChannelAudioQueue]()
+
+    private val channelMixes = scala.collection.mutable.Map[Int, AudioMix]()
+    def getChannelMix(channel: Int): AudioMix =
+      channelMixes.getOrElse(channel, AudioMix())
+    def setChannelMix(mix: AudioMix, channel: Int): Unit =
+      channelMixes.update(channel, mix)
+      channels.get(channel).foreach(_.mix = mix)
 
     def isEmpty()              = channels.values.forall(_.isEmpty())
     def isEmpty(channel: Int)  = channels.get(channel).map(_.isEmpty()).getOrElse(true)
@@ -77,6 +83,7 @@ object AudioQueue {
     def enqueue(clip: AudioClip): this.type = enqueue(clip, 0)
     def enqueue(clip: AudioClip, channel: Int): this.type = synchronized {
       val queue = channels.getOrElseUpdate(channel, new SingleChannelAudioQueue(sampleRate))
+      queue.mix = getChannelMix(channel)
       queue.enqueue(clip)
       this
     }

diff --git a/core/shared/src/test/scala/eu/joaocosta/minart/audio/AudioQueueSpec.scala b/core/shared/src/test/scala/eu/joaocosta/minart/audio/AudioQueueSpec.scala
@@ -100,6 +100,22 @@ class AudioQueueSpec extends munit.FunSuite {
     assert(queue.isEmpty() == true)
   }
 
+  test("A multi channel audio queue correctly mixes audio with different mixing definitions") {
+    val clipA = AudioClip(x => x / 4.0, 2.0)
+    val clipB = AudioClip(_ => 0.25, 2.0)
+
+    val queue = new AudioQueue.MultiChannelAudioQueue(1)
+
+    queue.enqueue(clipA, 0)
+    queue.enqueue(clipB, 1)
+    queue.setChannelMix(AudioMix(0.5), 1)
+    assert(queue.size == 2)
+    assert(queue.isEmpty() == false)
+    assert(queue.dequeue() == 0.00 + 0.25 * 0.5)
+    assert(queue.dequeue() == 0.25 + 0.25 * 0.5)
+    assert(queue.isEmpty() == true)
+  }
+
   test("A multi channel audio queue correctly clips audio") {
     val clipA = AudioClip(x => (x * 10) - 5, 2.0)
     val clipB = AudioClip(x => (x * 10) - 5, 1.0)