fix audio ctx resume

src/app.ts

@@ -90,6 +90,7 @@ export default (opt: {
 		fpsCounter: new FPSCounter(),
 		timeScale: 1,
 		skipTime: false,
+		isHidden: false,
 		numFrames: 0,
 		mousePos: new Vec2(0),
 		mouseDeltaPos: new Vec2(0),
@@ -133,6 +134,10 @@ export default (opt: {
 		return state.dt * state.timeScale
 	}
 
+	function isHidden() {
+		return state.isHidden
+	}
+
 	function time() {
 		return state.time
 	}
@@ -796,8 +801,10 @@ export default (opt: {
 		if (document.visibilityState === "visible") {
 			// prevent a surge of dt when switch back after the tab being hidden for a while
 			state.skipTime = true
+			state.isHidden = false
 			state.events.trigger("show")
 		} else {
+			state.isHidden = true
 			state.events.trigger("hide")
 		}
 	}
@@ -854,6 +861,7 @@ export default (opt: {
 		fps,
 		numFrames,
 		quit,
+		isHidden,
 		setFullscreen,
 		isFullscreen,
 		setCursor,

src/kaboom.ts

@@ -1188,19 +1188,27 @@ export default (gopt: KaboomOpt = {}): KaboomCtx => {
 
 		src.connect(audio.masterNode)
 
-		if (!opt.paused) {
-			// TODO: check debug.paused and tab hidden state
+		function resumeAudioCtx() {
+			if (debug.paused) return
+			if (app.isHidden() && !gopt.backgroundAudio) return
 			audio.ctx.resume()
+		}
+
+		function play() {
+			resumeAudioCtx()
 			el.play()
 		}
 
+		if (!opt.paused) {
+			play()
+		}
+
 		el.onended = () => onEndEvents.trigger()
 
 		return {
 
 			play() {
-				audio.ctx.resume()
-				el.play()
+				play()
 			},
 
 			seek(time: number) {
@@ -1224,8 +1232,7 @@ export default (gopt: KaboomOpt = {}): KaboomCtx => {
 				if (p) {
 					el.pause()
 				} else {
-					audio.ctx.resume()
-					el.play()
+					play()
 				}
 			},
 
@@ -6166,7 +6173,6 @@ export default (gopt: KaboomOpt = {}): KaboomCtx => {
 	function handleErr(err: Error) {
 
 		console.error(err)
-
 		audio.ctx.suspend()
 
 		// TODO: this should only run once