driver: Remove UI.Loop and add UI.RunWithoutMainLoop

internal/driver/ui.go

@@ -39,8 +39,8 @@ type UI interface {
 	IsVsyncEnabled() bool
 	IsWindowDecorated() bool
 	IsWindowResizable() bool
-	Loop(ch <-chan error) error
+	Run(width, height int, scale float64, title string, context UIContext, graphics Graphics) error
-	Run(width, height int, scale float64, title string, context UIContext, mainloop bool, graphics Graphics) error
+	RunWithoutMainLoop(width, height int, scale float64, title string, context UIContext, graphics Graphics) <-chan error
 	ScreenPadding() (x0, y0, x1, y1 float64)
 	ScreenScale() float64
 	ScreenSizeInFullscreen() (int, int)

internal/uidriver/glfw/ui.go

@@ -170,7 +170,7 @@ func getCachedMonitor(wx, wy int) (*cachedMonitor, bool) {
 	return nil, false
 }
 
-func (u *UserInterface) Loop(ch <-chan error) error {
+func (u *UserInterface) mainThreadLoop(ch <-chan error) error {
 	u.setRunning(true)
 	if err := mainthread.Loop(ch); err != nil {
 		return err
@@ -555,7 +555,26 @@ func (u *UserInterface) DeviceScaleFactor() float64 {
 	return f
 }
 
-func (u *UserInterface) Run(width, height int, scale float64, title string, context driver.UIContext, mainloop bool, graphics driver.Graphics) error {
+func (u *UserInterface) Run(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) error {
+	ch := make(chan error)
+	go func() {
+		defer close(ch)
+		if err := u.run(width, height, scale, title, context, graphics); err != nil {
+			ch <- err
+		}
+	}()
+
+	if err := u.mainThreadLoop(ch); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (u *UserInterface) RunWithoutMainLoop(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) <-chan error {
+	panic("glfw: RunWithoutMainLoop is not implemented")
+}
+
+func (u *UserInterface) run(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) error {
 	_ = mainthread.Run(func() error {
 		u.graphics = graphics
 

internal/uidriver/js/ui.go

@@ -384,11 +384,7 @@ func init() {
 	}))
 }
 
-func (u *UserInterface) Loop(ch <-chan error) error {
+func (u *UserInterface) Run(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) error {
-	return <-ch
-}
-
-func (u *UserInterface) Run(width, height int, scale float64, title string, context driver.UIContext, mainloop bool, graphics driver.Graphics) error {
 	document.Set("title", title)
 	u.setScreenSize(width, height, scale, u.fullscreen)
 	canvas.Call("focus")
@@ -407,6 +403,10 @@ func (u *UserInterface) Run(width, height int, scale float64, title string, cont
 	return nil
 }
 
+func (u *UserInterface) RunWithoutMainLoop(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) <-chan error {
+	panic("js: RunWithoutMainLoop is not implemented")
+}
+
 func (u *UserInterface) setScreenSize(width, height int, scale float64, fullscreen bool) bool {
 	if u.width == width && u.height == height &&
 		u.scale == scale && fullscreen == u.fullscreen {

internal/uidriver/mobile/ui.go

@@ -153,7 +153,29 @@ func (u *UserInterface) appMain(a app.App) {
 	}
 }
 
-func (u *UserInterface) Run(width, height int, scale float64, title string, context driver.UIContext, mainloop bool, graphics driver.Graphics) error {
+func (u *UserInterface) Run(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) error {
+	go func() {
+		if err := u.run(width, height, scale, title, context, graphics, true); err != nil {
+			// As mobile apps never ends, Loop can't return. Just panic here.
+			panic(err)
+		}
+	}()
+	app.Main(u.appMain)
+	return nil
+}
+
+func (u *UserInterface) RunWithoutMainLoop(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics) <-chan error {
+	ch := make(chan error)
+	go func() {
+		defer close(ch)
+		if err := u.run(width, height, scale, title, context, graphics, false); err != nil {
+			ch <- err
+		}
+	}()
+	return ch
+}
+
+func (u *UserInterface) run(width, height int, scale float64, title string, context driver.UIContext, graphics driver.Graphics, mainloop bool) error {
 	if graphics != opengl.Get() {
 		panic("ui: graphics driver must be OpenGL")
 	}
@@ -182,17 +204,6 @@ func (u *UserInterface) Run(width, height int, scale float64, title string, cont
 	}
 }
 
-// Loop runs the main routine for gomobile-build.
-func (u *UserInterface) Loop(ch <-chan error) error {
-	go func() {
-		// As mobile apps never ends, Loop can't return. Just panic here.
-		err := <-ch
-		panic(err)
-	}()
-	app.Main(u.appMain)
-	return nil
-}
-
 func (u *UserInterface) updateSize(context driver.UIContext) {
 	width, height := 0, 0
 	actualScale := 0.0

run.go

@@ -90,21 +90,6 @@ func IsRunningSlowly() bool {
 
 var theUIContext atomic.Value
 
-func run(width, height int, scale float64, title string, context *uiContext, mainloop bool) error {
-	atomic.StoreInt32(&isRunning, 1)
-	// On GopherJS, run returns immediately.
-	if !web.IsGopherJS() {
-		defer atomic.StoreInt32(&isRunning, 0)
-	}
-	if err := uiDriver().Run(width, height, scale, title, context, mainloop, graphicsDriver()); err != nil {
-		if err == driver.RegularTermination {
-			return nil
-		}
-		return err
-	}
-	return nil
-}
-
 // Run runs the game.
 // f is a function which is called at every frame.
 // The argument (*Image) is the render target that represents the screen.
@@ -143,21 +128,22 @@ func run(width, height int, scale float64, title string, context *uiContext, mai
 func Run(f func(*Image) error, width, height int, scale float64, title string) error {
 	f = (&imageDumper{f: f}).update
 
-	ch := make(chan error)
+	c := newUIContext(f)
-	go func() {
+	theUIContext.Store(c)
-		defer close(ch)
 
-		g := newUIContext(f)
+	atomic.StoreInt32(&isRunning, 1)
-		theUIContext.Store(g)
+	// On GopherJS, run returns immediately.
-		if err := run(width, height, scale, title, g, true); err != nil {
+	if !web.IsGopherJS() {
-			ch <- err
+		defer atomic.StoreInt32(&isRunning, 0)
-			return
+	}
+
+	if err := uiDriver().Run(width, height, scale, title, c, graphicsDriver()); err != nil {
+		if err == driver.RegularTermination {
+			return nil
 		}
-	}()
-	// TODO: Use context in Go 1.7?
-	if err := uiDriver().Loop(ch); err != nil {
 		return err
 	}
+
 	return nil
 }
 
@@ -169,18 +155,11 @@ func Run(f func(*Image) error, width, height int, scale float64, title string) e
 func RunWithoutMainLoop(f func(*Image) error, width, height int, scale float64, title string) <-chan error {
 	f = (&imageDumper{f: f}).update
 
-	ch := make(chan error)
+	c := newUIContext(f)
-	go func() {
+	theUIContext.Store(c)
-		defer close(ch)
 
-		g := newUIContext(f)
+	atomic.StoreInt32(&isRunning, 1)
-		theUIContext.Store(g)
+	return uiDriver().RunWithoutMainLoop(width, height, scale, title, c, graphicsDriver())
-		if err := run(width, height, scale, title, g, false); err != nil {
-			ch <- err
-			return
-		}
-	}()
-	return ch
 }
 
 // ScreenSizeInFullscreen returns the size in device-independent pixels when the game is fullscreen.