examples: Add error checks

examples/alphablending/main.go

@@ -64,7 +64,9 @@ func update(screen *ebiten.Image) error {
 		diff = float64(480-count) * 0.2
 	}
 
-	screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff})
+	if err := screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff}); err != nil {
+		return err
+	}
 	op := &ebiten.DrawImageOptions{}
 	op.ColorM.Scale(1.0, 1.0, 1.0, 0.5)
 	op.ImageParts = &imageParts{

examples/audio/main.go

@@ -44,13 +44,17 @@ func init() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	playerBarImage.Fill(&color.RGBA{0x80, 0x80, 0x80, 0xff})
+	if err := playerBarImage.Fill(&color.RGBA{0x80, 0x80, 0x80, 0xff}); err != nil {
+		log.Fatal(err)
+	}
 
 	playerCurrentImage, err = ebiten.NewImage(4, 10, ebiten.FilterNearest)
 	if err != nil {
 		log.Fatal(err)
 	}
-	playerCurrentImage.Fill(&color.RGBA{0xff, 0xff, 0xff, 0xff})
+	if err := playerCurrentImage.Fill(&color.RGBA{0xff, 0xff, 0xff, 0xff}); err != nil {
+		log.Fatal(err)
+	}
 }
 
 type Player struct {
@@ -193,7 +197,9 @@ func update(screen *ebiten.Image) error {
 	op := &ebiten.DrawImageOptions{}
 	x, y, w, h := playerBarRect()
 	op.GeoM.Translate(float64(x), float64(y))
-	screen.DrawImage(playerBarImage, op)
+	if err := screen.DrawImage(playerBarImage, op); err != nil {
+		return err
+	}
 	currentTimeStr := "00:00"
 	if musicPlayer != nil {
 		c := musicPlayer.audioPlayer.Current()
@@ -209,7 +215,9 @@ func update(screen *ebiten.Image) error {
 		cy := y - (ch-h)/2
 		op := &ebiten.DrawImageOptions{}
 		op.GeoM.Translate(float64(cx), float64(cy))
-		screen.DrawImage(playerCurrentImage, op)
+		if err := screen.DrawImage(playerCurrentImage, op); err != nil {
+			return err
+		}
 	}
 
 	msg := fmt.Sprintf(`FPS: %0.2f
@@ -220,7 +228,9 @@ Press Z or X to change volume of the music
 	if musicPlayer == nil {
 		msg += "\nNow Loading..."
 	}
-	ebitenutil.DebugPrint(screen, msg)
+	if err := ebitenutil.DebugPrint(screen, msg); err != nil {
+		return err
+	}
 	if err := audioContext.Update(); err != nil {
 		return err
 	}
@@ -273,7 +283,10 @@ func main() {
 		}
 		close(musicCh)
 		// TODO: Is this goroutine-safe?
-		p.Play()
+		if err := p.Play(); err != nil {
+			log.Fatal(err)
+			return
+		}
 	}()
 	if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Audio (Ebiten Demo)"); err != nil {
 		log.Fatal(err)

examples/blocks/blocks/game.go

@@ -42,12 +42,16 @@ func NewGame() *Game {
 
 func (game *Game) Update(r *ebiten.Image) error {
 	game.input.Update()
-	game.sceneManager.Update(&GameState{
+	if err := game.sceneManager.Update(&GameState{
 		SceneManager: game.sceneManager,
 		Input:        &game.input,
-	})
+	}); err != nil {
+		return err
+	}
 	if !ebiten.IsRunningSlowly() {
-		game.sceneManager.Draw(r)
+		if err := game.sceneManager.Draw(r); err != nil {
+			return err
+		}
 	}
 	return nil
 }

examples/blocks/blocks/gamepadscene.go

@@ -76,7 +76,9 @@ func (s *GamepadScene) Update(state *GameState) error {
 }
 
 func (s *GamepadScene) Draw(screen *ebiten.Image) error {
-	screen.Fill(color.Black)
+	if err := screen.Fill(color.Black); err != nil {
+		return err
+	}
 
 	if s.buttonStates == nil {
 		return nil

examples/blocks/blocks/gamescene.go

@@ -74,7 +74,9 @@ func init() {
 	if err != nil {
 		panic(err)
 	}
-	imageEmpty.Fill(color.White)
+	if err := imageEmpty.Fill(color.White); err != nil {
+		panic(err)
+	}
 	// Background
 	imageGameBG, _, err = ebitenutil.NewImageFromFile("_resources/images/gophers.jpg", ebiten.FilterLinear)
 	if err != nil {
@@ -121,7 +123,9 @@ func init() {
 	if err != nil {
 		panic(err)
 	}
-	imageGameover.Fill(color.NRGBA{0x00, 0x00, 0x00, 0x80})
+	if err := imageGameover.Fill(color.NRGBA{0x00, 0x00, 0x00, 0x80}); err != nil {
+		panic(err)
+	}
 	y = (ScreenHeight - blockHeight) / 2
 	if err := drawTextWithShadowCenter(imageGameover, "GAME OVER", 0, y, 1, color.White, ScreenWidth); err != nil {
 		panic(err)
@@ -248,7 +252,9 @@ func (s *GameScene) addScore(lines int) {
 }
 
 func (s *GameScene) Update(state *GameState) error {
-	s.field.Update()
+	if err := s.field.Update(); err != nil {
+		return err
+	}
 
 	if s.gameover {
 		// TODO: Gamepad key?
@@ -392,7 +398,9 @@ func (s *GameScene) Draw(r *ebiten.Image) error {
 	}
 
 	if s.gameover {
-		r.DrawImage(imageGameover, nil)
+		if err := r.DrawImage(imageGameover, nil); err != nil {
+			return err
+		}
 	}
 
 	return nil

examples/blocks/blocks/scenemanager.go

@@ -72,12 +72,16 @@ func (s *SceneManager) Draw(r *ebiten.Image) error {
 	if s.transitionCount == -1 {
 		return s.current.Draw(r)
 	}
-	transitionFrom.Clear()
+	if err := transitionFrom.Clear(); err != nil {
+		return err
+	}
 	if err := s.current.Draw(transitionFrom); err != nil {
 		return err
 	}
 
-	transitionTo.Clear()
+	if err := transitionTo.Clear(); err != nil {
+		return err
+	}
 	if err := s.next.Draw(transitionTo); err != nil {
 		return err
 	}

examples/blocks/main.go

@@ -33,7 +33,9 @@ func main() {
 		if err != nil {
 			log.Fatal(err)
 		}
-		pprof.StartCPUProfile(f)
+		if err := pprof.StartCPUProfile(f); err != nil {
+			log.Fatal(err)
+		}
 		defer pprof.StopCPUProfile()
 	}
 

examples/font/main.go

@@ -52,7 +52,9 @@ func parseFont() error {
 	if err != nil {
 		return err
 	}
-	defer f.Close()
+	defer func() {
+		_ = f.Close()
+	}()
 	b, err := ioutil.ReadAll(f)
 	if err != nil {
 		return err

examples/gamepad/main.go

@@ -54,7 +54,9 @@ func update(screen *ebiten.Image) error {
   Pressed Buttons: {{.Buttons}}`
 	str = strings.Replace(str, "{{.Axes}}", strings.Join(axes, "\n    "), -1)
 	str = strings.Replace(str, "{{.Buttons}}", strings.Join(pressedButtons, ", "), -1)
-	ebitenutil.DebugPrint(screen, str)
+	if err := ebitenutil.DebugPrint(screen, str); err != nil {
+		return err
+	}
 	return nil
 }
 

examples/keyboard/main.go

@@ -84,7 +84,9 @@ func update(screen *ebiten.Image) error {
 	op := &ebiten.DrawImageOptions{}
 	op.GeoM.Translate(offsetX, offsetY)
 	op.ColorM.Scale(0.5, 0.5, 0.5, 1)
-	screen.DrawImage(keyboardImage, op)
+	if err := screen.DrawImage(keyboardImage, op); err != nil {
+		return err
+	}
 
 	pressed := []string{}
 	for i := 0; i <= 9; i++ {
@@ -112,7 +114,9 @@ func update(screen *ebiten.Image) error {
 		ImageParts: pressedKeysParts(pressed),
 	}
 	op.GeoM.Translate(offsetX, offsetY)
-	screen.DrawImage(keyboardImage, op)
+	if err := screen.DrawImage(keyboardImage, op); err != nil {
+		return err
+	}
 
 	return nil
 }

examples/life/main.go

@@ -179,7 +179,9 @@ var (
 func update(screen *ebiten.Image) error {
 	world.Progress()
 	world.DrawImage(noiseImage)
-	screen.ReplacePixels(noiseImage.Pix)
+	if err := screen.ReplacePixels(noiseImage.Pix); err != nil {
+		return err
+	}
 	return nil
 }
 

examples/mosaic/main.go

@@ -37,10 +37,14 @@ var (
 func update(screen *ebiten.Image) error {
 	op := &ebiten.DrawImageOptions{}
 	op.GeoM.Scale(1.0/mosaicRatio, 1.0/mosaicRatio)
-	gophersRenderTarget.DrawImage(gophersImage, op)
+	if err := gophersRenderTarget.DrawImage(gophersImage, op); err != nil {
+		return err
+	}
 	op = &ebiten.DrawImageOptions{}
 	op.GeoM.Scale(mosaicRatio, mosaicRatio)
-	screen.DrawImage(gophersRenderTarget, op)
+	if err := screen.DrawImage(gophersRenderTarget, op); err != nil {
+		return err
+	}
 	return nil
 }
 

examples/noise/main.go

@@ -56,8 +56,12 @@ func update(screen *ebiten.Image) error {
 		noiseImage.Pix[4*i+2] = uint8(x >> 8)
 		noiseImage.Pix[4*i+3] = 0xff
 	}
-	screen.ReplacePixels(noiseImage.Pix)
+	if err := screen.ReplacePixels(noiseImage.Pix); err != nil {
-	ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %f", ebiten.CurrentFPS()))
+		return err
+	}
+	if err := ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %f", ebiten.CurrentFPS())); err != nil {
+		return err
+	}
 	return nil
 }
 

examples/paint/main.go

@@ -105,7 +105,9 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	canvasImage.Fill(color.White)
+	if err := canvasImage.Fill(color.White); err != nil {
+		log.Fatal(err)
+	}
 
 	if err := ebiten.Run(update, screenWidth, screenHeight, 2, "Paint (Ebiten Demo)"); err != nil {
 		log.Fatal(err)

examples/pcm/main.go

@@ -129,7 +129,9 @@ func addNote() error {
 	if err != nil {
 		return err
 	}
-	p.Play()
+	if err := p.Play(); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -142,7 +144,9 @@ func update(screen *ebiten.Image) error {
 			return err
 		}
 	}
-	ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS()))
+	if err := ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS())); err != nil {
+		return err
+	}
 	if err := audioContext.Update(); err != nil {
 		return err
 	}

examples/perspective/main.go

@@ -60,7 +60,9 @@ func update(screen *ebiten.Image) error {
 	maxWidth := float64(w) + float64(h)*0.75
 	op.GeoM.Translate(-maxWidth/2, -float64(h)/2)
 	op.GeoM.Translate(screenWidth/2, screenHeight/2)
-	screen.DrawImage(gophersImage, op)
+	if err := screen.DrawImage(gophersImage, op); err != nil {
+		return err
+	}
 	return nil
 }
 

examples/piano/main.go

@@ -89,7 +89,9 @@ func addNote(freq float64, vol float64) error {
 		if err != nil {
 			return err
 		}
-		p.Play()
+		if err := p.Play(); err != nil {
+			return err
+		}
 		return nil
 	}
 	length := len(pcm) * baseFreq / f
@@ -110,7 +112,9 @@ func addNote(freq float64, vol float64) error {
 	if err != nil {
 		return err
 	}
-	p.Play()
+	if err := p.Play(); err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -161,7 +165,9 @@ func init() {
 	if err != nil {
 		panic(err)
 	}
-	imageEmpty.Fill(color.White)
+	if err := imageEmpty.Fill(color.White); err != nil {
+		panic(err)
+	}
 	imagePiano, err = ebiten.NewImage(screenWidth, screenHeight, ebiten.FilterNearest)
 	if err != nil {
 		panic(err)
@@ -177,8 +183,12 @@ func init() {
 		op.GeoM.Scale(float64(width-1)/float64(w), float64(height)/float64(h))
 		op.GeoM.Translate(float64(x), float64(y))
 		op.ColorM.Scale(1, 1, 1, 1)
-		imagePiano.DrawImage(imageEmpty, op)
+		if err := imagePiano.DrawImage(imageEmpty, op); err != nil {
-		common.ArcadeFont.DrawText(imagePiano, k, x+8, y+height-16, 1, color.Black)
+			panic(err)
+		}
+		if err := common.ArcadeFont.DrawText(imagePiano, k, x+8, y+height-16, 1, color.Black); err != nil {
+			panic(err)
+		}
 	}
 
 	blackKeys := []string{"Q", "W", "", "R", "T", "", "U", "I", "O"}
@@ -193,8 +203,12 @@ func init() {
 		op.GeoM.Scale(float64(width-1)/float64(w), float64(height)/float64(h))
 		op.GeoM.Translate(float64(x), float64(y))
 		op.ColorM.Scale(0, 0, 0, 1)
-		imagePiano.DrawImage(imageEmpty, op)
+		if err := imagePiano.DrawImage(imageEmpty, op); err != nil {
-		common.ArcadeFont.DrawText(imagePiano, k, x+8, y+height-16, 1, color.White)
+			panic(err)
+		}
+		if err := common.ArcadeFont.DrawText(imagePiano, k, x+8, y+height-16, 1, color.White); err != nil {
+			panic(err)
+		}
 	}
 }
 
@@ -209,10 +223,16 @@ func update(screen *ebiten.Image) error {
 		}
 	}
 
-	screen.Fill(color.RGBA{0x80, 0x80, 0xc0, 0xff})
+	if err := screen.Fill(color.RGBA{0x80, 0x80, 0xc0, 0xff}); err != nil {
-	screen.DrawImage(imagePiano, nil)
+		return err
+	}
+	if err := screen.DrawImage(imagePiano, nil); err != nil {
+		return err
+	}
 
-	ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS()))
+	if err := ebitenutil.DebugPrint(screen, fmt.Sprintf("FPS: %0.2f", ebiten.CurrentFPS())); err != nil {
+		return err
+	}
 
 	if err := audioContext.Update(); err != nil {
 		return err

examples/sinewave/main.go

@@ -98,7 +98,9 @@ func update(screen *ebiten.Image) error {
 		}
 	}
 	msg := fmt.Sprintf("FPS: %0.2f\nThis is an example using infinite audio stream.", ebiten.CurrentFPS())
-	ebitenutil.DebugPrint(screen, msg)
+	if err := ebitenutil.DebugPrint(screen, msg); err != nil {
+		return err
+	}
 	if err := audioContext.Update(); err != nil {
 		return err
 	}

examples/windowsize/main.go

@@ -84,7 +84,9 @@ func update(screen *ebiten.Image) error {
 	ebiten.SetScreenSize(screenWidth, screenHeight)
 	ebiten.SetScreenScale(screenScale)
 
-	screen.Fill(color.RGBA{0x80, 0x80, 0xc0, 0xff})
+	if err := screen.Fill(color.RGBA{0x80, 0x80, 0xc0, 0xff}); err != nil {
+		return err
+	}
 	w, h := gophersImage.Size()
 	w2, h2 := screen.Size()
 	op := &ebiten.DrawImageOptions{}
@@ -98,7 +100,9 @@ func update(screen *ebiten.Image) error {
 Press S key to change the window scale
 Cursor: (%d, %d)
 FPS: %0.2f`, x, y, ebiten.CurrentFPS())
-	ebitenutil.DebugPrint(screen, msg)
+	if err := ebitenutil.DebugPrint(screen, msg); err != nil {
+		return err
+	}
 	return nil
 }