uidriver/glfw: Enable to call SetWindowDecorated after Run

Fixes #556

examples/windowsize/main.go

@@ -18,7 +18,6 @@ package main
 
 import (
 	"bytes"
-	"flag"
 	"fmt"
 	"image"
 	"image/color"
@@ -34,10 +33,6 @@ import (
 	"github.com/hajimehoshi/ebiten/inpututil"
 )
 
-var (
-	windowDecorated = flag.Bool("windowdecorated", true, "whether the window is decorated")
-)
-
 func init() {
 	rand.Seed(time.Now().UnixNano())
 }
@@ -81,6 +76,7 @@ func update(screen *ebiten.Image) error {
 	cursorVisible := ebiten.IsCursorVisible()
 	vsyncEnabled := ebiten.IsVsyncEnabled()
 	tps := ebiten.MaxTPS()
+	decorated := ebiten.IsWindowDecorated()
 
 	if inpututil.IsKeyJustPressed(ebiten.KeyUp) {
 		screenHeight += d
@@ -138,6 +134,9 @@ func update(screen *ebiten.Image) error {
 			panic("not reached")
 		}
 	}
+	if inpututil.IsKeyJustPressed(ebiten.KeyD) {
+		decorated = !decorated
+	}
 
 	ebiten.SetScreenSize(screenWidth, screenHeight)
 	ebiten.SetScreenScale(screenScale)
@@ -146,6 +145,7 @@ func update(screen *ebiten.Image) error {
 	ebiten.SetCursorVisible(cursorVisible)
 	ebiten.SetVsyncEnabled(vsyncEnabled)
 	ebiten.SetMaxTPS(tps)
+	ebiten.SetWindowDecorated(decorated)
 
 	if inpututil.IsKeyJustPressed(ebiten.KeyI) {
 		ebiten.SetWindowIcon([]image.Image{createRandomIconImage()})
@@ -180,6 +180,7 @@ Press C key to switch the cursor visibility
 Press I key to change the window icon (only for desktops)
 Press V key to switch vsync
 Press T key to switch TPS (ticks per second)
+Press D key to switch the window decoration
 Cursor: (%d, %d)
 TPS: Current: %0.2f / Max: %s
 FPS: %0.2f
@@ -189,8 +190,6 @@ Device Scale Factor: %0.2f`, x, y, ebiten.CurrentTPS(), tpsStr, ebiten.CurrentFP
 }
 
 func main() {
-	flag.Parse()
-
 	fmt.Printf("Device scale factor: %0.2f\n", ebiten.DeviceScaleFactor())
 	w, h := ebiten.ScreenSizeInFullscreen()
 	fmt.Printf("Screen size in fullscreen: %d, %d\n", w, h)
@@ -212,8 +211,6 @@ func main() {
 
 	ebiten.SetWindowIcon([]image.Image{createRandomIconImage()})
 
-	ebiten.SetWindowDecorated(*windowDecorated)
-
 	if err := ebiten.Run(update, initScreenWidth, initScreenHeight, initScreenScale, "Window Size (Ebiten Demo)"); err != nil {
 		log.Fatal(err)
 	}

internal/glfw/glfw_notwindows.go

@@ -94,6 +94,10 @@ func (w *Window) GetAttrib(attrib Hint) int {
 	return w.w.GetAttrib(glfw.Hint(attrib))
 }
 
+func (w *Window) SetAttrib(attrib Hint, value int) {
+	w.w.SetAttrib(glfw.Hint(attrib), value)
+}
+
 func (w *Window) GetCursorPos() (x, y float64) {
 	return w.w.GetCursorPos()
 }

internal/glfw/glfw_windows.go

@@ -114,6 +114,11 @@ func (w *Window) GetAttrib(attrib Hint) int {
 	return int(r)
 }
 
+func (w *Window) SetAttrib(attrib Hint, value int) {
+	glfwDLL.call("glfwSetWindowAttrib", w.w, uintptr(attrib), uintptr(value))
+	panicError()
+}
+
 func (w *Window) GetCursorPos() (x, y float64) {
 	glfwDLL.call("glfwGetCursorPos", w.w, uintptr(unsafe.Pointer(&x)), uintptr(unsafe.Pointer(&y)))
 	panicError()

internal/uidriver/glfw/ui.go

@@ -386,6 +386,7 @@ func (u *UserInterface) SetWindowTitle(title string) {
 	if !u.isRunning() {
 		return
 	}
+	u.title = title
 	_ = u.t.Call(func() error {
 		u.window.SetTitle(title)
 		return nil
@@ -503,19 +504,19 @@ func (u *UserInterface) SetWindowDecorated(decorated bool) {
 		return
 	}
 
-	panic("ui: SetWindowDecorated can't be called after Run so far.")
+	_ = u.t.Call(func() error {
+		v := glfw.False
+		if decorated {
+			v = glfw.True
+		}
+		u.window.SetAttrib(glfw.Decorated, v)
 
-	// TODO: Now SetAttrib doesn't exist on GLFW 3.2. Revisit later (#556).
-	// If SetAttrib exists, the implementation would be:
-	//
-	//     _ = u.t.Call(func() error {
-	//         v := glfw.False
-	//         if decorated {
-	//             v = glfw.True
-	//         }
-	//     })
-	//     u.window.SetAttrib(glfw.Decorated, v)
-	//     return nil
+		// The title can be lost when the decoration is gone. Recover this.
+		if v == glfw.True {
+			u.window.SetTitle(u.title)
+		}
+		return nil
+	})
 }
 
 func (u *UserInterface) IsWindowResizable() bool {
@@ -649,7 +650,7 @@ func (u *UserInterface) run(width, height int, scale float64, title string, cont
 		// currentMonitor returns the monitor for the active window when possible and then the monitor for
 		// the foreground window as fallback. In the current situation, the current window is hidden and
 		// there is not the active window but the foreground window. After showing the current window, the
-		// current window will be the active window. Thus, currentMonitor retuls varies before and after
+		// current window will be the active window. Thus, currentMonitor result varies before and after
 		// showing the window.
 		m := u.currentMonitor()
 		mx, my := m.GetPos()

run.go

@@ -333,8 +333,6 @@ func IsRunnableInBackground() bool {
 // SetWindowDecorated works only on desktops.
 // SetWindowDecorated does nothing on other platforms.
 //
-// SetWindowDecorated panics if SetWindowDecorated is called after Run.
-//
 // SetWindowDecorated is concurrent-safe.
 func SetWindowDecorated(decorated bool) {
 	uiDriver().SetWindowDecorated(decorated)