ebiten: refactoring: remove imageDumperGame

This enables passing the user's Game to internal/ui without wrapping.

This is necessary to check whether the user's Game implements an
optional function or not.

Updates #2046

gameforui.go

@@ -79,6 +79,7 @@ type gameForUI struct {
 	offscreen    *Image
 	screen       *Image
 	screenShader *Shader
+	imageDumper  imageDumper
 }
 
 func newGameForUI(game Game) *gameForUI {
@@ -129,11 +130,21 @@ func (g *gameForUI) Layout(outsideWidth, outsideHeight int) (int, int) {
 }
 
 func (g *gameForUI) Update() error {
-	return g.game.Update()
+	if err := g.game.Update(); err != nil {
+		return err
+	}
+	if err := g.imageDumper.update(); err != nil {
+		return err
+	}
+	return nil
 }
 
-func (g *gameForUI) DrawOffscreen() {
+func (g *gameForUI) DrawOffscreen() error {
 	g.game.Draw(g.offscreen)
+	if err := g.imageDumper.dump(g.offscreen); err != nil {
+		return err
+	}
+	return nil
 }
 
 func (g *gameForUI) DrawScreen() {

imagedumper_mobile.go

@@ -18,11 +18,11 @@
 package ebiten
 
 type imageDumper struct {
-	g Game
 }
 
 func (i *imageDumper) update() error {
-	return i.g.Update()
+	// Do nothing
+	return nil
 }
 
 func (i *imageDumper) dump(screen *Image) error {

imagedumper_notmobile.go

@@ -57,8 +57,6 @@ func dumpInternalImages() error {
 }
 
 type imageDumper struct {
-	g Game
-
 	keyState map[Key]int
 
 	hasScreenshotKey bool
@@ -93,10 +91,6 @@ func (i *imageDumper) update() error {
 		return i.err
 	}
 
-	if err := i.g.Update(); err != nil {
-		return err
-	}
-
 	// If keyState is nil, all values are not initialized.
 	if i.keyState == nil {
 		i.keyState = map[Key]int{}

internal/ui/context.go

@@ -38,7 +38,7 @@ type Game interface {
 	NewScreenImage(width, height int) *Image
 	Layout(outsideWidth, outsideHeight int) (int, int)
 	Update() error
-	DrawOffscreen()
+	DrawOffscreen() error
 	DrawScreen()
 	ScreenScaleAndOffsets() (scale, offsetX, offsetY float64)
 }
@@ -143,14 +143,16 @@ func (c *context) updateFrameImpl(graphicsDriver graphicsdriver.Graphics, update
 	}
 
 	// Draw the game.
-	c.drawGame(graphicsDriver)
+	if err := c.drawGame(graphicsDriver); err != nil {
+		return err
+	}
 
 	// All the vertices data are consumed at the end of the frame, and the data backend can be
 	// available after that. Until then, lock the vertices backend.
 	return nil
 }
 
-func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) {
+func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) error {
 	if c.offscreen.volatile != theGlobalState.isScreenClearedEveryFrame() {
 		w, h := c.offscreen.width, c.offscreen.height
 		c.offscreen.MarkDisposed()
@@ -163,7 +165,9 @@ func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) {
 	if theGlobalState.isScreenClearedEveryFrame() {
 		c.offscreen.clear()
 	}
-	c.game.DrawOffscreen()
+	if err := c.game.DrawOffscreen(); err != nil {
+		return err
+	}
 
 	if graphicsDriver.NeedsClearingScreen() {
 		// This clear is needed for fullscreen mode or some mobile platforms (#622).
@@ -171,6 +175,7 @@ func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) {
 	}
 
 	c.game.DrawScreen()
+	return nil
 }
 
 func (c *context) layoutGame(outsideWidth, outsideHeight float64, deviceScaleFactor float64) (int, int) {

run.go

@@ -143,35 +143,6 @@ func IsScreenFilterEnabled() bool {
 	return isScreenFilterEnabled()
 }
 
-type imageDumperGame struct {
-	game Game
-	d    *imageDumper
-	err  error
-}
-
-func (i *imageDumperGame) Update() error {
-	if i.err != nil {
-		return i.err
-	}
-	if i.d == nil {
-		i.d = &imageDumper{g: i.game}
-	}
-	return i.d.update()
-}
-
-func (i *imageDumperGame) Draw(screen *Image) {
-	if i.err != nil {
-		return
-	}
-
-	i.game.Draw(screen)
-	i.err = i.d.dump(screen)
-}
-
-func (i *imageDumperGame) Layout(outsideWidth, outsideHeight int) (screenWidth, screenHeight int) {
-	return i.game.Layout(outsideWidth, outsideHeight)
-}
-
 // Termination is a special error which indicates Game termination without error.
 var Termination = ui.RegularTermination
 
@@ -206,9 +177,7 @@ func RunGame(game Game) error {
 	defer atomic.StoreInt32(&isRunGameEnded_, 1)
 
 	initializeWindowPositionIfNeeded(WindowSize())
-	g := newGameForUI(&imageDumperGame{
+	g := newGameForUI(game)
-		game: game,
-	})
 	if err := ui.Get().Run(g); err != nil {
 		if errors.Is(err, Termination) {
 			return nil