ebiten: add SetWindowMousePassthrough and IsWindowMousePassthrough

Closes #2511

examples/mascot/main.go

@@ -142,6 +142,7 @@ func main() {
 	ebiten.SetWindowDecorated(false)
 	ebiten.SetWindowFloating(true)
 	ebiten.SetWindowSize(width, height)
+	ebiten.SetWindowMousePassthrough(true)
 
 	op := &ebiten.RunGameOptions{}
 	op.ScreenTransparent = true

examples/windowsize/main.go

@@ -147,6 +147,7 @@ func (g *game) Update() error {
 	floating := ebiten.IsWindowFloating()
 	resizingMode := ebiten.WindowResizingMode()
 	screenCleared := ebiten.IsScreenClearedEveryFrame()
+	mousePassthrough := ebiten.IsWindowMousePassthrough()
 
 	const d = 16
 	toUpdateWindowSize := false
@@ -267,6 +268,9 @@ func (g *game) Update() error {
 			restore = inpututil.IsKeyJustPressed(ebiten.KeyE)
 		}
 	}
+	if inpututil.IsKeyJustPressed(ebiten.KeyP) {
+		mousePassthrough = !mousePassthrough
+	}
 
 	if toUpdateWindowSize {
 		g.width = screenWidth
@@ -304,6 +308,8 @@ func (g *game) Update() error {
 		ebiten.SetWindowIcon([]image.Image{createRandomIconImage()})
 	}
 
+	ebiten.SetWindowMousePassthrough(mousePassthrough)
+
 	g.count++
 	return nil
 }
@@ -357,6 +363,7 @@ func (g *game) Draw(screen *ebiten.Image) {
 [D] Switch the window decoration (only for desktops)
 [L] Switch the window floating state (only for desktops)
 [W] Switch whether to skip clearing the screen
+[P] Switch whether a mouse cursor passthroughs the window (only for desktops)
 %s
 IsFocused?: %s
 Window Position: (%d, %d)

internal/ui/ui_glfw.go

@@ -84,16 +84,17 @@ type userInterfaceImpl struct {
 	initFullscreenWidthInDIP  int
 	initFullscreenHeightInDIP int
 
-	initFullscreen           bool
-	initCursorMode           CursorMode
-	initWindowDecorated      bool
-	initWindowMonitor        int
-	initWindowPositionXInDIP int
-	initWindowPositionYInDIP int
-	initWindowWidthInDIP     int
-	initWindowHeightInDIP    int
-	initWindowFloating       bool
-	initWindowMaximized      bool
+	initFullscreen             bool
+	initCursorMode             CursorMode
+	initWindowDecorated        bool
+	initWindowMonitor          int
+	initWindowPositionXInDIP   int
+	initWindowPositionYInDIP   int
+	initWindowWidthInDIP       int
+	initWindowHeightInDIP      int
+	initWindowFloating         bool
+	initWindowMaximized        bool
+	initWindowMousePassthrough bool
 
 	// bufferOnceSwapped must be accessed from the main thread.
 	bufferOnceSwapped bool
@@ -525,6 +526,18 @@ func (u *userInterfaceImpl) setInitWindowMaximized(maximized bool) {
 	u.m.Unlock()
 }
 
+func (u *userInterfaceImpl) isInitWindowMousePassthrough() bool {
+	u.m.RLock()
+	defer u.m.RUnlock()
+	return u.initWindowMousePassthrough
+}
+
+func (u *userInterfaceImpl) setInitWindowMousePassthrough(enabled bool) {
+	u.m.Lock()
+	defer u.m.Unlock()
+	u.initWindowMousePassthrough = enabled
+}
+
 func (u *userInterfaceImpl) isWindowClosingHandled() bool {
 	u.m.RLock()
 	v := u.windowClosingHandled
@@ -984,6 +997,12 @@ func (u *userInterfaceImpl) initOnMainThread(options *RunOptions) error {
 	}
 	glfw.WindowHint(glfw.FocusOnShow, focused)
 
+	mousePassthrough := glfw.False
+	if u.isInitWindowMousePassthrough() {
+		mousePassthrough = glfw.True
+	}
+	glfw.WindowHint(glfw.MousePassthrough, mousePassthrough)
+
 	// Set the window visible explicitly or the application freezes on Wayland (#974).
 	if os.Getenv("WAYLAND_DISPLAY") != "" {
 		glfw.WindowHint(glfw.Visible, glfw.True)
@@ -1717,6 +1736,19 @@ func (u *userInterfaceImpl) setOrigWindowPos(x, y int) {
 	u.origWindowPosY = y
 }
 
+// setWindowMousePassthrough must be called from the main thread.
+func (u *userInterfaceImpl) setWindowMousePassthrough(enabled bool) {
+	if microsoftgdk.IsXbox() {
+		return
+	}
+
+	v := glfw.False
+	if enabled {
+		v = glfw.True
+	}
+	u.window.SetAttrib(glfw.MousePassthrough, v)
+}
+
 func IsScreenTransparentAvailable() bool {
 	return true
 }

internal/ui/window.go

@@ -41,6 +41,8 @@ type Window interface {
 	Restore()
 	SetClosingHandled(handled bool)
 	IsClosingHandled() bool
+	SetMousePassthrough(enabled bool)
+	IsMousePassthrough() bool
 }
 
 type nullWindow struct{}
@@ -119,3 +121,10 @@ func (*nullWindow) SetClosingHandled(handled bool) {
 func (*nullWindow) IsClosingHandled() bool {
 	return false
 }
+
+func (*nullWindow) SetMousePassthrough(enabled bool) {
+}
+
+func (*nullWindow) IsMousePassthrough() bool {
+	return false
+}

internal/ui/window_glfw.go

@@ -387,3 +387,36 @@ func (w *glfwWindow) SetClosingHandled(handled bool) {
 func (w *glfwWindow) IsClosingHandled() bool {
 	return w.ui.isWindowClosingHandled()
 }
+
+func (w *glfwWindow) SetMousePassthrough(enabled bool) {
+	if w.ui.isTerminated() {
+		return
+	}
+	if !w.ui.isRunning() {
+		w.ui.setInitWindowMousePassthrough(enabled)
+		return
+	}
+	w.ui.mainThread.Call(func() {
+		if w.ui.isTerminated() {
+			return
+		}
+		w.ui.setWindowMousePassthrough(enabled)
+	})
+}
+
+func (w *glfwWindow) IsMousePassthrough() bool {
+	if w.ui.isTerminated() {
+		return false
+	}
+	if !w.ui.isRunning() {
+		return w.ui.isInitWindowMousePassthrough()
+	}
+	var v bool
+	w.ui.mainThread.Call(func() {
+		if w.ui.isTerminated() {
+			return
+		}
+		v = w.ui.window.GetAttrib(glfw.MousePassthrough) == glfw.True
+	})
+	return v
+}

window.go

@@ -54,7 +54,7 @@ func IsWindowDecorated() bool {
 // The window is decorated by default.
 //
 // SetWindowDecorated works only on desktops.
-// SetWindowDecorated does nothing on other platforms.
+// SetWindowDecorated does nothing if the platform is not a desktop.
 //
 // SetWindowDecorated is concurrent-safe.
 func SetWindowDecorated(decorated bool) {
@@ -99,7 +99,7 @@ func SetWindowResizable(resizable bool) {
 
 // SetWindowTitle sets the title of the window.
 //
-// SetWindowTitle does nothing on browsers or mobiles.
+// SetWindowTitle does nothing if the platform is not a desktop.
 //
 // SetWindowTitle is concurrent-safe.
 func SetWindowTitle(title string) {
@@ -123,7 +123,7 @@ func SetWindowTitle(title string) {
 //
 // As macOS windows don't have icons, SetWindowIcon doesn't work on macOS.
 //
-// SetWindowIcon doesn't work on browsers or mobiles.
+// SetWindowIcon doesn't work if the platform is not a desktop.
 //
 // SetWindowIcon is concurrent-safe.
 func SetWindowIcon(iconImages []image.Image) {
@@ -138,7 +138,7 @@ func SetWindowIcon(iconImages []image.Image) {
 //
 // WindowPosition returns the original window position in fullscreen mode.
 //
-// WindowPosition returns (0, 0) on browsers and mobiles.
+// WindowPosition returns (0, 0) if the platform is not a desktop.
 //
 // WindowPosition is concurrent-safe.
 func WindowPosition() (x, y int) {
@@ -151,7 +151,7 @@ func WindowPosition() (x, y int) {
 //
 // SetWindowPosition sets the original window position in fullscreen mode.
 //
-// SetWindowPosition does nothing on browsers and mobiles.
+// SetWindowPosition does nothing if the platform is not a desktop.
 //
 // SetWindowPosition is concurrent-safe.
 func SetWindowPosition(x, y int) {
@@ -215,7 +215,7 @@ func SetWindowSizeLimits(minw, minh, maxw, maxh int) {
 
 // IsWindowFloating reports whether the window is always shown above all the other windows.
 //
-// IsWindowFloating returns false on browsers and mobiles.
+// IsWindowFloating returns false if the platform is not a desktop.
 //
 // IsWindowFloating is concurrent-safe.
 func IsWindowFloating() bool {
@@ -224,7 +224,7 @@ func IsWindowFloating() bool {
 
 // SetWindowFloating sets the state whether the window is always shown above all the other windows.
 //
-// SetWindowFloating does nothing on browsers or mobiles.
+// SetWindowFloating does nothing if the platform is not a desktop.
 //
 // SetWindowFloating is concurrent-safe.
 func SetWindowFloating(float bool) {
@@ -235,7 +235,7 @@ func SetWindowFloating(float bool) {
 //
 // MaximizeWindow does nothing when the window is not resizable (WindowResizingModeEnabled).
 //
-// MaximizeWindow does nothing on browsers or mobiles.
+// MaximizeWindow does nothing if the platform is not a desktop.
 //
 // MaximizeWindow is concurrent-safe.
 func MaximizeWindow() {
@@ -246,7 +246,7 @@ func MaximizeWindow() {
 //
 // IsWindowMaximized returns false when the window is not resizable (WindowResizingModeEnabled).
 //
-// IsWindowMaximized always returns false on browsers and mobiles.
+// IsWindowMaximized always returns false if the platform is not a desktop.
 //
 // IsWindowMaximized is concurrent-safe.
 func IsWindowMaximized() bool {
@@ -257,7 +257,7 @@ func IsWindowMaximized() bool {
 //
 // If the main loop does not start yet, MinimizeWindow does nothing.
 //
-// MinimizeWindow does nothing on browsers or mobiles.
+// MinimizeWindow does nothing if the platform is not a desktop.
 //
 // MinimizeWindow is concurrent-safe.
 func MinimizeWindow() {
@@ -266,7 +266,7 @@ func MinimizeWindow() {
 
 // IsWindowMinimized reports whether the window is minimized or not.
 //
-// IsWindowMinimized always returns false on browsers and mobiles.
+// IsWindowMinimized always returns false if the platform is not a desktop.
 //
 // IsWindowMinimized is concurrent-safe.
 func IsWindowMinimized() bool {
@@ -289,7 +289,7 @@ func RestoreWindow() {
 // As the window is closed immediately by default,
 // you might want to call SetWindowClosingHandled(true) to prevent the window is automatically closed.
 //
-// IsWindowBeingClosed always returns false on other platforms.
+// IsWindowBeingClosed always returns false if the platform is not a desktop.
 //
 // IsWindowBeingClosed is concurrent-safe.
 func IsWindowBeingClosed() bool {
@@ -304,7 +304,7 @@ func IsWindowBeingClosed() bool {
 // To end the game, you have to return an error value at the Game's Update function.
 //
 // SetWindowClosingHandled works only on desktops.
-// SetWindowClosingHandled does nothing on other platforms.
+// SetWindowClosingHandled does nothing if the platform is not a desktop.
 //
 // SetWindowClosingHandled is concurrent-safe.
 func SetWindowClosingHandled(handled bool) {
@@ -313,9 +313,31 @@ func SetWindowClosingHandled(handled bool) {
 
 // IsWindowClosingHandled reports whether the window closing is handled or not on desktops by SetWindowClosingHandled.
 //
-// IsWindowClosingHandled always returns false on other platforms.
+// IsWindowClosingHandled always returns false if the platform is not a desktop.
 //
 // IsWindowClosingHandled is concurrent-safe.
 func IsWindowClosingHandled() bool {
 	return ui.Get().Window().IsClosingHandled()
 }
+
+// SetWindowMousePassthrough sets whether a mouse cursor passthroughs the window or not on desktops. The default state is false.
+//
+// Even if this is set true, some platforms might requrie a window to be undecorated
+// in order to make the mouse cursor passthrough the window.
+//
+// SetWindowMousePassthrough works only on desktops.
+// SetWindowMousePassthrough does nothing if the platform is not a desktop.
+//
+// SetWindowMousePassthrough is concurrent-safe.
+func SetWindowMousePassthrough(enabled bool) {
+	ui.Get().Window().SetMousePassthrough(enabled)
+}
+
+// IsWindowMousePassthrough reports whether a mouse cursor passthroughs the window or not on desktops.
+//
+// IsWindowMousePassthrough alaywas returns false if the platform is not a desktop.
+//
+// IsWindowMousePassthrough is concurrent-safe.
+func IsWindowMousePassthrough() bool {
+	return ui.Get().Window().IsMousePassthrough()
+}