internal/ui: refactoring

internal/ui/ui_glfw.go

@@ -1071,95 +1071,102 @@ func (u *userInterfaceImpl) loopGame() error {
 		u.window.Destroy()
 		glfw.Terminate()
 	})
-
 	for {
-		var unfocused bool
-
-		// On Windows, the focusing state might be always false (#987).
-		// On Windows, even if a window is in another workspace, vsync seems to work.
-		// Then let's assume the window is always 'focused' as a workaround.
-		if runtime.GOOS != "windows" {
-			unfocused = u.window.GetAttrib(glfw.Focused) == glfw.False
-		}
-
-		var t1, t2 time.Time
-
-		if unfocused {
-			t1 = time.Now()
-		}
-
-		var outsideWidth, outsideHeight float64
-		var deviceScaleFactor float64
-		var err error
-		if u.mainThread.Call(func() {
-			outsideWidth, outsideHeight, err = u.update()
-			deviceScaleFactor = u.deviceScaleFactor(u.currentMonitor())
-		}); err != nil {
+		if err := u.updateGame(); err != nil {
 			return err
 		}
-
-		if err := u.context.updateFrame(u.graphicsDriver, outsideWidth, outsideHeight, deviceScaleFactor, u); err != nil {
-			return err
-		}
-
-		// Create icon images in a different goroutine (#1478).
-		// In the fullscreen mode, SetIcon fails (#1578).
-		if imgs := u.getIconImages(); len(imgs) > 0 && !u.isFullscreen() {
-			u.setIconImages(nil)
-
-			// Convert the icons in the different goroutine, as (*ebiten.Image).At cannot be invoked
-			// from this goroutine. At works only in between BeginFrame and EndFrame.
-			go func() {
-				newImgs := make([]image.Image, len(imgs))
-				for i, img := range imgs {
-					// TODO: If img is not *ebiten.Image, this converting is not necessary.
-					// However, this package cannot refer *ebiten.Image due to the package
-					// dependencies.
-
-					b := img.Bounds()
-					rgba := image.NewRGBA(b)
-					for j := b.Min.Y; j < b.Max.Y; j++ {
-						for i := b.Min.X; i < b.Max.X; i++ {
-							rgba.Set(i, j, img.At(i, j))
-						}
-					}
-					newImgs[i] = rgba
-				}
-
-				u.mainThread.Call(func() {
-					// In the fullscreen mode, reset the icon images and try again later.
-					if u.isFullscreen() {
-						u.setIconImages(imgs)
-						return
-					}
-					u.window.SetIcon(newImgs)
-				})
-			}()
-		}
-
-		// swapBuffers also checks IsGL, so this condition is redundant.
-		// However, (*thread).Call is not good for performance due to channels.
-		// Let's avoid this whenever possible (#1367).
-		if u.graphicsDriver.IsGL() {
-			u.mainThread.Call(u.swapBuffers)
-		}
-
-		if unfocused {
-			t2 = time.Now()
-		}
-
-		// When a window is not focused, SwapBuffers might return immediately and CPU might be busy.
-		// Mitigate this by sleeping (#982).
-		if unfocused {
-			d := t2.Sub(t1)
-			const wait = time.Second / 60
-			if d < wait {
-				time.Sleep(wait - d)
-			}
-		}
 	}
 }
 
+func (u *userInterfaceImpl) updateGame() error {
+	var unfocused bool
+
+	// On Windows, the focusing state might be always false (#987).
+	// On Windows, even if a window is in another workspace, vsync seems to work.
+	// Then let's assume the window is always 'focused' as a workaround.
+	if runtime.GOOS != "windows" {
+		unfocused = u.window.GetAttrib(glfw.Focused) == glfw.False
+	}
+
+	var t1, t2 time.Time
+
+	if unfocused {
+		t1 = time.Now()
+	}
+
+	var outsideWidth, outsideHeight float64
+	var deviceScaleFactor float64
+	var err error
+	if u.mainThread.Call(func() {
+		outsideWidth, outsideHeight, err = u.update()
+		deviceScaleFactor = u.deviceScaleFactor(u.currentMonitor())
+	}); err != nil {
+		return err
+	}
+
+	if err := u.context.updateFrame(u.graphicsDriver, outsideWidth, outsideHeight, deviceScaleFactor, u); err != nil {
+		return err
+	}
+
+	// Create icon images in a different goroutine (#1478).
+	// In the fullscreen mode, SetIcon fails (#1578).
+	if imgs := u.getIconImages(); len(imgs) > 0 && !u.isFullscreen() {
+		u.setIconImages(nil)
+
+		// Convert the icons in the different goroutine, as (*ebiten.Image).At cannot be invoked
+		// from this goroutine. At works only in between BeginFrame and EndFrame.
+		go func() {
+			newImgs := make([]image.Image, len(imgs))
+			for i, img := range imgs {
+				// TODO: If img is not *ebiten.Image, this converting is not necessary.
+				// However, this package cannot refer *ebiten.Image due to the package
+				// dependencies.
+
+				b := img.Bounds()
+				rgba := image.NewRGBA(b)
+				for j := b.Min.Y; j < b.Max.Y; j++ {
+					for i := b.Min.X; i < b.Max.X; i++ {
+						rgba.Set(i, j, img.At(i, j))
+					}
+				}
+				newImgs[i] = rgba
+			}
+
+			u.mainThread.Call(func() {
+				// In the fullscreen mode, reset the icon images and try again later.
+				if u.isFullscreen() {
+					u.setIconImages(imgs)
+					return
+				}
+				u.window.SetIcon(newImgs)
+			})
+		}()
+	}
+
+	// swapBuffers also checks IsGL, so this condition is redundant.
+	// However, (*thread).Call is not good for performance due to channels.
+	// Let's avoid this whenever possible (#1367).
+	if u.graphicsDriver.IsGL() {
+		u.mainThread.Call(u.swapBuffers)
+	}
+
+	if unfocused {
+		t2 = time.Now()
+	}
+
+	// When a window is not focused, SwapBuffers might return immediately and CPU might be busy.
+	// Mitigate this by sleeping (#982).
+	if unfocused {
+		d := t2.Sub(t1)
+		const wait = time.Second / 60
+		if d < wait {
+			time.Sleep(wait - d)
+		}
+	}
+
+	return nil
+}
+
 // swapBuffers must be called from the main thread.
 func (u *userInterfaceImpl) swapBuffers() {
 	if u.graphicsDriver.IsGL() {