ui: Add IsCursorVisible (#377)

examples/windowsize/main.go

@@ -43,6 +43,7 @@ var (
 		ebiten.KeyS:     0,
 		ebiten.KeyF:     0,
 		ebiten.KeyB:     0,
+		ebiten.KeyC:     0,
 	}
 	count = 0
 )
@@ -60,6 +61,7 @@ func update(screen *ebiten.Image) error {
 	screenWidth, screenHeight := screen.Size()
 	fullscreen := ebiten.IsFullscreen()
 	runnableInBackground := ebiten.IsRunnableInBackground()
+	cursorVisible := ebiten.IsCursorVisible()
 
 	if keyStates[ebiten.KeyUp] == 1 {
 		screenHeight += d
@@ -86,7 +88,7 @@ func update(screen *ebiten.Image) error {
 		case 2:
 			screenScale = 1
 		default:
-			panic("not reach")
+			panic("not reached")
 		}
 	}
 	if keyStates[ebiten.KeyF] == 1 {
@@ -95,10 +97,14 @@ func update(screen *ebiten.Image) error {
 	if keyStates[ebiten.KeyB] == 1 {
 		runnableInBackground = !runnableInBackground
 	}
+	if keyStates[ebiten.KeyC] == 1 {
+		cursorVisible = !cursorVisible
+	}
 	ebiten.SetScreenSize(screenWidth, screenHeight)
 	ebiten.SetScreenScale(screenScale)
 	ebiten.SetFullscreen(fullscreen)
 	ebiten.SetRunnableInBackground(runnableInBackground)
+	ebiten.SetCursorVisibility(cursorVisible)
 
 	count++
 
@@ -119,8 +125,9 @@ func update(screen *ebiten.Image) error {
 	x, y := ebiten.CursorPosition()
 	msg := fmt.Sprintf(`Press arrow keys to change the window size
 Press S key to change the window scale
-Press F key to change the fullscreen state
-Press B key to change the run-in-background state
+Press F key to switch the fullscreen state
+Press B key to switch the run-in-background state
+Press C key to switch the cursor visibility
 Cursor: (%d, %d)
 FPS: %0.2f`, x, y, ebiten.CurrentFPS())
 	ebitenutil.DebugPrint(screen, msg)

internal/ui/ui_glfw.go

@@ -45,6 +45,7 @@ type userInterface struct {
 	origPosX             int
 	origPosY             int
 	initFullscreen       bool
+	initCursorVisible    bool
 	runnableInBackground bool
 	m                    sync.Mutex
 }
@@ -81,6 +82,13 @@ func initialize() error {
 	currentUI.funcs = make(chan func())
 
 	currentUI.window.MakeContextCurrent()
+
+	mode := glfw.CursorNormal
+	if !currentUI.isInitCursorVisible() {
+		mode = glfw.CursorHidden
+	}
+	currentUI.window.SetInputMode(glfw.CursorMode, mode)
+
 	return nil
 }
 
@@ -134,6 +142,19 @@ func (u *userInterface) setInitFullscreen(initFullscreen bool) {
 	u.m.Unlock()
 }
 
+func (u *userInterface) isInitCursorVisible() bool {
+	u.m.Lock()
+	v := u.initCursorVisible
+	u.m.Unlock()
+	return v
+}
+
+func (u *userInterface) setInitCursorVisible(visible bool) {
+	u.m.Lock()
+	u.initCursorVisible = visible
+	u.m.Unlock()
+}
+
 func (u *userInterface) isRunnableInBackground() bool {
 	u.m.Lock()
 	v := u.runnableInBackground
@@ -269,18 +290,33 @@ func adjustCursorPosition(x, y int) (int, int) {
 	return x - int(ox/s), y - int(oy/s)
 }
 
+func IsCursorVisible() bool {
+	u := currentUI
+	if !u.isRunning() {
+		return u.isInitCursorVisible()
+	}
+	v := false
+	_ = currentUI.runOnMainThread(func() error {
+		v = currentUI.window.GetInputMode(glfw.CursorMode) == glfw.CursorNormal
+		return nil
+	})
+	return v
+}
+
 func SetCursorVisibility(visible bool) {
-	// This can be called before Run: change the state asyncly.
-	go func() {
-		_ = currentUI.runOnMainThread(func() error {
-			c := glfw.CursorNormal
-			if !visible {
-				c = glfw.CursorHidden
-			}
-			currentUI.window.SetInputMode(glfw.CursorMode, c)
-			return nil
-		})
-	}()
+	u := currentUI
+	if !u.isRunning() {
+		u.setInitCursorVisible(visible)
+		return
+	}
+	_ = currentUI.runOnMainThread(func() error {
+		c := glfw.CursorNormal
+		if !visible {
+			c = glfw.CursorHidden
+		}
+		currentUI.window.SetInputMode(glfw.CursorMode, c)
+		return nil
+	})
 }
 
 func Run(width, height int, scale float64, title string, g GraphicsContext) error {
@@ -502,7 +538,12 @@ func (u *userInterface) setScreenSize(width, height int, scale float64, fullscre
 	// SwapInterval is affected by the current monitor of the window.
 	// This needs to be called at least after SetMonitor.
 	// Without SwapInterval after SetMonitor, vsynch doesn't work (#375).
+	//
+	// TODO: (#405) If triple buffering is needed, SwapInterval(0) should be called,
+	// but is this correct? If glfw.SwapInterval(0) and the driver doesn't support triple
+	// buffering, what will happen?
 	glfw.SwapInterval(1)
+
 	// TODO: Rename this variable?
 	u.sizeChanged = true
 	return true

internal/ui/ui_js.go

@@ -84,6 +84,11 @@ func adjustCursorPosition(x, y int) (int, int) {
 	return x, y
 }
 
+func IsCursorVisible() bool {
+	// The initial value is an empty string, so don't compare with "auto" here.
+	return canvas.Get("style").Get("cursor").String() != "none"
+}
+
 func SetCursorVisibility(visibility bool) {
 	if visibility {
 		canvas.Get("style").Set("cursor", "auto")

internal/ui/ui_mobile.go

@@ -114,6 +114,10 @@ func adjustCursorPosition(x, y int) (int, int) {
 	return x, y
 }
 
+func IsCursorVisible() bool {
+	return false
+}
+
 func SetCursorVisibility(visibility bool) {
 	// Do nothing
 }

run.go

@@ -179,8 +179,20 @@ func ScreenScale() float64 {
 	return ui.ScreenScale()
 }
 
+// IsCursorVisible returns a boolean value indicating whether
+// the cursor is visible or not.
+//
+// IsCursorVisible always returns false on mobiles.
+//
+// This function is concurrent-safe.
+func IsCursorVisible() bool {
+	return ui.IsCursorVisible()
+}
+
 // SetCursorVisibility changes the state of cursor visiblity.
 //
+// SetCursorVisibility does nothing on mobiles.
+//
 // This function is concurrent-safe.
 func SetCursorVisibility(visible bool) {
 	ui.SetCursorVisibility(visible)
@@ -205,7 +217,7 @@ func IsFullscreen() bool {
 // On browsers, the game screen is resized to fit with the body element (client) size.
 // Additionally, the game screen is automatically resized when the body element is resized.
 //
-// SetFullscreen doesn't work on mobiles.
+// SetFullscreen does nothing on mobiles.
 //
 // This function is concurrent-safe.
 func SetFullscreen(fullscreen bool) {
@@ -227,7 +239,7 @@ func IsRunnableInBackground() bool {
 // 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.
 //
-// SetRunnableInBackground doesn't work on mobiles so far.
+// SetRunnableInBackground does nothing on mobiles so far.
 //
 // This function is concurrent-safe.
 func SetRunnableInBackground(runnableInBackground bool) {