Add webaudio option to System.start

Backends/HTML5/kha/SystemImpl.hx

@@ -460,7 +460,7 @@ class SystemImpl {
 		}
 		// canvas.getContext("2d").scale(transform, transform);
 
-		if (!mobile && kha.audio2.Audio._init()) {
+		if ((!mobile || options.audio.allowMobileWebAudio) && kha.audio2.Audio._init()) {
 			SystemImpl._hasWebAudio = true;
 			kha.audio2.Audio1._init();
 		}

Backends/HTML5/kha/audio2/Audio.hx

@@ -1,14 +1,14 @@
 package kha.audio2;
 
-import js.Syntax;
 import js.Browser;
+import js.Syntax;
 import js.html.URL;
 import js.html.audio.AudioContext;
 import js.html.audio.AudioProcessingEvent;
 import js.html.audio.ScriptProcessorNode;
+import kha.Sound;
 import kha.internal.IntBox;
 import kha.js.AEAudioChannel;
-import kha.Sound;
 
 class Audio {
 	public static var disableGcInteractions = false;
@@ -70,7 +70,7 @@ class Audio {
 
 	public static var samplesPerSecond: Int;
 
-	public static var audioCallback: kha.internal.IntBox->Buffer->Void;
+	public static var audioCallback: (outputBufferLength: IntBox, buffer: Buffer) -> Void;
 
 	static var virtualChannels: Array<VirtualStreamChannel> = [];
 

Sources/kha/System.hx

@@ -2,24 +2,33 @@ package kha;
 
 import kha.WindowOptions;
 
+@:structInit
+private class AudioOptions {
+	/** Allow `audio2.Audio` api initialization on mobile browsers (only for HTML5 target) **/
+	public var allowMobileWebAudio = false;
+}
+
 @:structInit
 class SystemOptions {
-	@:optional public var title: String = "Kha";
-	@:optional public var width: Int = -1;
-	@:optional public var height: Int = -1;
-	@:optional public var window: WindowOptions = null;
-	@:optional public var framebuffer: FramebufferOptions = null;
+	public var title: String = "Kha";
+	public var width: Int = -1;
+	public var height: Int = -1;
+	public var window: WindowOptions = null;
+	public var framebuffer: FramebufferOptions = null;
+	public var audio: AudioOptions = null;
 
 	/**
-	 * Used to provide parameters for System.start
+	 * Used to provide parameters for `System.start`
 	 * @param title The application title is the default window title (unless the window parameter provides a title of its own)
 	 * and is used for various other purposes - for example for save data locations
-	 * @param width Just a shortcut which overwrites window.width if set
-	 * @param height Just a shortcut which overwrites window.height if set
+	 * @param width Just a shortcut which overwrites `window.width` if set
+	 * @param height Just a shortcut which overwrites `window.height` if set
 	 * @param window Optionally provide window options
 	 * @param framebuffer Optionally provide framebuffer options
+	 * @param audio Optionally provide audio options
 	 */
-	public function new(title: String = "Kha", ?width: Int = -1, ?height: Int = -1, window: WindowOptions = null, framebuffer: FramebufferOptions = null) {
+	public function new(title: String = "Kha", ?width: Int = -1, ?height: Int = -1, ?window: WindowOptions, ?framebuffer: FramebufferOptions,
+			?audio: AudioOptions) {
 		this.title = title;
 		this.window = window == null ? {} : window;
 
@@ -44,6 +53,7 @@ class SystemOptions {
 		}
 
 		this.framebuffer = framebuffer == null ? {} : framebuffer;
+		this.audio = audio ?? {};
 	}
 }
 

Sources/kha/audio2/Audio.hx

@@ -1,5 +1,7 @@
 package kha.audio2;
 
+import kha.internal.IntBox;
+
 extern class Audio {
 	/**
 	 * The samples per second natively used by the target system.
@@ -10,8 +12,10 @@ extern class Audio {
 	 * Requests additional audio data.
 	 * Beware: This is called from a separate audio thread on some targets.
 	 * See kha.audio2.Audio1 for sample code.
+	 * This api is disabled on mobile for HTML5 target by default
+	 * and can be enabled in `System.start` options.
 	 */
-	public static var audioCallback: Int->Buffer->Void;
+	public static var audioCallback: (outputBufferLength:IntBox, buffer:Buffer)->Void;
 
 	/**
 	 * Similar to kha.audio1.Audio.stream, but only for hardware accelerated audio playback.