From 9aef5746d8060799df3c8521affda03b1d064c0f Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Tue, 21 Feb 2023 02:06:38 +0900
Subject: [PATCH] tmp

---
 internal/ui/ui_mobile.go | 22 ++++++++++++++++------
 run.go                   |  6 +++---
 2 files changed, 19 insertions(+), 9 deletions(-)

diff --git a/internal/ui/ui_mobile.go b/internal/ui/ui_mobile.go
index 998c1cfa0..2ff3dcb25 100644
--- a/internal/ui/ui_mobile.go
+++ b/internal/ui/ui_mobile.go
@@ -22,6 +22,7 @@ import (
 	"runtime/debug"
 	"sync"
 	"sync/atomic"
+	"time"
 	"unicode"
 
 	"golang.org/x/mobile/app"
@@ -54,6 +55,7 @@ var (
 func init() {
 	theUI.userInterfaceImpl = userInterfaceImpl{
 		foreground:           1,
+		runnableOnUnfocused:  0, // This is 0 for backward compatibility during v2 (#2576).
 		graphicsDriverInitCh: make(chan struct{}),
 		errCh:                make(chan error),
 
@@ -73,7 +75,8 @@ func (u *userInterfaceImpl) Update() error {
 	default:
 	}
 
-	if !u.IsFocused() {
+	if !u.IsFocused() && !u.IsRunnableOnUnfocused() {
+		time.Sleep(time.Second / 60)
 		return nil
 	}
 
@@ -101,8 +104,9 @@ type userInterfaceImpl struct {
 	outsideWidth  float64
 	outsideHeight float64
 
-	foreground int32
-	errCh      chan error
+	foreground          int32
+	runnableOnUnfocused int32
+	errCh               chan error
 
 	// Used for gomobile-build
 	gbuildWidthPx   int
@@ -232,9 +236,11 @@ func (u *userInterfaceImpl) SetForeground(foreground bool) error {
 
 	if foreground {
 		return hooks.ResumeAudio()
-	} else {
+	}
+	if !u.IsRunnableOnUnfocused() {
 		return hooks.SuspendAudio()
 	}
+	return nil
 }
 
 func (u *userInterfaceImpl) Run(game Game, options *RunOptions) error {
@@ -395,11 +401,15 @@ func (u *userInterfaceImpl) IsFocused() bool {
 }
 
 func (u *userInterfaceImpl) IsRunnableOnUnfocused() bool {
-	return false
+	return atomic.LoadInt32(&u.runnableOnUnfocused) != 0
 }
 
 func (u *userInterfaceImpl) SetRunnableOnUnfocused(runnableOnUnfocused bool) {
-	// Do nothing
+	var v int32
+	if runnableOnUnfocused {
+		v = 1
+	}
+	atomic.StoreInt32(&u.runnableOnUnfocused, v)
 }
 
 func (u *userInterfaceImpl) SetFPSMode(mode FPSModeType) {
diff --git a/run.go b/run.go
index 98bf929fd..2a0dd7cf0 100644
--- a/run.go
+++ b/run.go
@@ -428,13 +428,13 @@ func IsRunnableOnUnfocused() bool {
 // SetRunnableOnUnfocused sets the state if the game runs even in background.
 //
 // If the given value is true, the game runs even in background e.g. when losing focus.
-// The initial state is true.
+// The initial state is true on desktops, and false on mobiles.
+// For mobiles, in addition to SetRunnableOnUnfocused, you might require some permission settings
+// not to pause audio when the application goes to background.
 //
 // Known issue: On browsers, even if the state is on, the game doesn't run in background tabs.
 // This is because browsers throttles background tabs not to often update.
 //
-// SetRunnableOnUnfocused does nothing on mobiles so far.
-//
 // SetRunnableOnUnfocused is concurrent-safe.
 func SetRunnableOnUnfocused(runnableOnUnfocused bool) {
 	ui.Get().SetRunnableOnUnfocused(runnableOnUnfocused)