examples: Add comment to explain about files

examples/additive/main.go

@@ -65,6 +65,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
 	if err != nil {
 		log.Fatal(err)

examples/airship/main.go

@@ -52,6 +52,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/alphablending/main.go

@@ -68,6 +68,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
 	if err != nil {
 		log.Fatal(err)

examples/contextlost/main.go

@@ -71,6 +71,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/filter/main.go

@@ -60,13 +60,23 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
-	// Specifying filter on NewImage(FromImage) is just for backward compatibility.
-	// Now specifying filter at DrawImageOptions is recommended.
-	// Specify FilterDefault here, that means to prefer filter specified at DrawImageOptions.
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
 	if err != nil {
 		log.Fatal(err)
 	}
+
+	// Specifying filter on NewImage[FromImage] is just for backward compatibility.
+	// Now specifying filter at DrawImageOptions is recommended.
+	// Specify FilterDefault here, that means to prefer filter specified at DrawImageOptions.
 	ebitenImage, _ = ebiten.NewImageFromImage(img, ebiten.FilterDefault)
 
 	if err := ebiten.Run(update, screenWidth, screenHeight, 1, "Filter (Ebiten Demo)"); err != nil {

examples/flood/main.go

@@ -84,6 +84,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
 	if err != nil {
 		log.Fatal(err)

examples/hsv/main.go

@@ -127,6 +127,15 @@ Inverted:   %s [I]`, hue, saturation, value, msgInverted)
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/hue/main.go

@@ -57,6 +57,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/infinitescroll/main.go

@@ -38,6 +38,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Tile_png))
 	if err != nil {
 		log.Fatal(err)

examples/masking/main.go

@@ -45,6 +45,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/mosaic/main.go

@@ -39,6 +39,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/perspective/main.go

@@ -66,6 +66,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/rotate/main.go

@@ -61,6 +61,15 @@ func update(screen *ebiten.Image) error {
 }
 
 func main() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)

examples/sprites/main.go

@@ -93,6 +93,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
 	if err != nil {
 		log.Fatal(err)

examples/spriteshd/main.go

@@ -95,6 +95,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Ebiten_png))
 	if err != nil {
 		log.Fatal(err)

examples/tiles/main.go

@@ -43,6 +43,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Tiles_png))
 	if err != nil {
 		log.Fatal(err)

examples/ui/main.go

@@ -45,6 +45,15 @@ var (
 )
 
 func init() {
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.UI_png))
 	if err != nil {
 		log.Fatal(err)

examples/windowsize/main.go

@@ -154,6 +154,15 @@ FPS: %0.2f`, x, y, ebiten.CurrentFPS())
 func main() {
 	fmt.Printf("Device scale factor: %0.2f\n", ebiten.DeviceScaleFactor())
 
+	// Decode image from a byte slice instead of a file so that
+	// this example works in any working directory.
+	// If you want to use a file, there are some options:
+	// 1) Use os.Open and pass the file to the image decoder.
+	//    This is a very regular way, but doesn't work on browsers.
+	// 2) Use ebitenutil.OpenFile and pass the file to the image decoder.
+	//    This works even on browsers.
+	// 3) Use ebitenutil.NewImageFromFile to create an ebiten.Image directly from a file.
+	//    This also works on browsers.
 	img, _, err := image.Decode(bytes.NewReader(images.Gophers_jpg))
 	if err != nil {
 		log.Fatal(err)