example: Use SourceRect (#277)

examples/airship/main.go

@@ -133,43 +133,35 @@ func updateGroundImage(ground *ebiten.Image) {
 	ground.DrawImage(repeatedGophersImage, op)
 }
 
-type groundParts struct {
+func scaleForLine(h int, x int) float64 {
-	image *ebiten.Image
+	x = h - x
-}
+	return 200*((-float64(x)+50)/(float64(x)+50)+1) - 200*((-float64(h)+50)/(float64(h)+50)+1)
-
-func (g *groundParts) Len() int {
-	_, h := g.image.Size()
-	return h
-}
-
-func (g *groundParts) Src(i int) (int, int, int, int) {
-	w, _ := g.image.Size()
-	return 0, i, w, i + 1
-}
-
-func (g *groundParts) scaleForLine(x float64) float64 {
-	_, h := g.image.Size()
-	x = float64(h) - x
-	return 200*((-x+50)/(x+50)+1) - 200*((-float64(h)+50)/(float64(h)+50)+1)
-}
-
-func (g *groundParts) Dst(i int) (int, int, int, int) {
-	w, _ := g.image.Size()
-	r := g.scaleForLine(float64(i))
-	j1 := g.scaleForLine(float64(i))
-	j2 := g.scaleForLine(float64(i + 1))
-	return -int(r), int(j1), w + int(r), int(math.Ceil(j2))
 }
 
 func drawGroundImage(screen *ebiten.Image, ground *ebiten.Image) {
-	w, _ := ground.Size()
+	w, h := ground.Size()
 	op := &ebiten.DrawImageOptions{}
-	op.GeoM.Translate(-float64(w)/2, 0)
+	for i := 0; i < h; i++ {
-	op.GeoM.Rotate(-1 * float64(thePlayer.lean) / maxLean * math.Pi / 8)
+		op.GeoM.Reset()
-	op.GeoM.Translate(float64(w)/2, 0)
+		// TODO: Refactoring
-	op.GeoM.Translate(float64(screenWidth-w)/2, screenHeight/3)
+		r := scaleForLine(h, i)
-	op.ImageParts = &groundParts{ground}
+		j1 := scaleForLine(h, i)
-	screen.DrawImage(ground, op)
+		j2 := scaleForLine(h, i+1)
+		dx0, dy0, dx1, dy1 := -int(r), int(j1), w+int(r), int(math.Ceil(j2))
+		sw := float64(dx1-dx0) / float64(w)
+		sh := float64(dy1 - dy0)
+		op.GeoM.Scale(sw, sh)
+		op.GeoM.Translate(float64(dx0), float64(dy0))
+
+		op.GeoM.Translate(-float64(w)/2, 0)
+		op.GeoM.Rotate(-1 * float64(thePlayer.lean) / maxLean * math.Pi / 8)
+		op.GeoM.Translate(float64(w)/2, 0)
+		op.GeoM.Translate(float64(screenWidth-w)/2, screenHeight/3)
+
+		p := image.Rect(0, i, w, i+1)
+		op.SourceRect = &p
+		screen.DrawImage(ground, op)
+	}
 	op = &ebiten.DrawImageOptions{}
 	op.GeoM.Translate(-float64(w)/2, 0)
 	op.GeoM.Rotate(-1 * float64(thePlayer.lean) / maxLean * math.Pi / 8)

examples/alphablending/main.go

@@ -35,26 +35,6 @@ var (
 	ebitenImage *ebiten.Image
 )
 
-type imageParts struct {
-	diff float64
-}
-
-func (p *imageParts) Src(i int) (int, int, int, int) {
-	w, h := ebitenImage.Size()
-	return 0, 0, w, h
-}
-
-func (p *imageParts) Dst(i int) (int, int, int, int) {
-	x := int(float64(i%10)*p.diff + 15)
-	y := int(float64(i/10)*p.diff + 20)
-	w, h := ebitenImage.Size()
-	return x, y, x + w, y + h
-}
-
-func (p *imageParts) Len() int {
-	return 10 * 10
-}
-
 func update(screen *ebiten.Image) error {
 	count++
 	count %= ebiten.FPS * 10
@@ -71,10 +51,13 @@ func update(screen *ebiten.Image) error {
 	screen.Fill(color.NRGBA{0x00, 0x00, 0x80, 0xff})
 	op := &ebiten.DrawImageOptions{}
 	op.ColorM.Scale(1.0, 1.0, 1.0, 0.5)
-	op.ImageParts = &imageParts{
+	for i := 0; i < 10*10; i++ {
-		diff: diff,
+		op.GeoM.Reset()
+		x := float64(i%10)*diff + 15
+		y := float64(i/10)*diff + 20
+		op.GeoM.Translate(x, y)
+		screen.DrawImage(ebitenImage, op)
 	}
-	screen.DrawImage(ebitenImage, op)
 	return nil
 }
 

examples/blocks/blocks/piece.go

@@ -17,6 +17,8 @@
 package blocks
 
 import (
+	"image"
+
 	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/ebitenutil"
 )
@@ -146,41 +148,29 @@ var Pieces = map[BlockType]*Piece{
 	},
 }
 
-const blockWidth = 10
+const (
-const blockHeight = 10
+	blockWidth     = 10
-const fieldBlockNumX = 10
+	blockHeight    = 10
-const fieldBlockNumY = 20
+	fieldBlockNumX = 10
-
+	fieldBlockNumY = 20
-type blocksImageParts [][]BlockType
+)
-
-func (b blocksImageParts) Len() int {
-	return len(b) * len(b[0])
-}
-
-func (b blocksImageParts) Dst(i int) (x0, y0, x1, y1 int) {
-	i, j := i%len(b), i/len(b)
-	x := i * blockWidth
-	y := j * blockHeight
-	return x, y, x + blockWidth, y + blockHeight
-}
-
-func (b blocksImageParts) Src(i int) (x0, y0, x1, y1 int) {
-	i, j := i%len(b), i/len(b)
-	block := b[i][j]
-	if block == BlockTypeNone {
-		return 0, 0, 0, 0
-	}
-	x := (int(block) - 1) * blockWidth
-	return x, 0, x + blockWidth, blockHeight
-}
 
 func drawBlocks(r *ebiten.Image, blocks [][]BlockType, x, y int, clr ebiten.ColorM) {
-	op := &ebiten.DrawImageOptions{
+	op := &ebiten.DrawImageOptions{}
-		ImageParts: blocksImageParts(blocks),
+	for j := 0; j < len(blocks[0]); j++ {
-		ColorM:     clr,
+		for i := 0; i < len(blocks); i++ {
+			op.GeoM.Reset()
+			op.GeoM.Translate(float64(i*blockWidth+x), float64(j*blockHeight+y))
+			block := blocks[i][j]
+			if block == BlockTypeNone {
+				continue
+			}
+			x := (int(block) - 1) * blockWidth
+			p := image.Rect(x, 0, x+blockWidth, blockHeight)
+			op.SourceRect = &p
+			r.DrawImage(imageBlocks, op)
+		}
 	}
-	op.GeoM.Translate(float64(x), float64(y))
-	r.DrawImage(imageBlocks, op)
 }
 
 func (p *Piece) InitialPosition() (int, int) {

examples/blocks/blocks/titlescene.go

@@ -34,40 +34,12 @@ func init() {
 	}
 }
 
-type titleImageParts struct {
-	image *ebiten.Image
-	count int
-}
-
-func (t *titleImageParts) Len() int {
-	w, h := t.image.Size()
-	return (ScreenWidth/w + 1) * (ScreenHeight/h + 2)
-}
-
-func (t *titleImageParts) Dst(i int) (x0, y0, x1, y1 int) {
-	w, h := t.image.Size()
-	i, j := i%(ScreenWidth/w+1), i/(ScreenWidth/w+1)-1
-	dx := (-t.count / 4) % w
-	dy := (t.count / 4) % h
-	dstX := i*w + dx
-	dstY := j*h + dy
-	return dstX, dstY, dstX + w, dstY + h
-}
-
-func (t *titleImageParts) Src(i int) (x0, y0, x1, y1 int) {
-	w, h := t.image.Size()
-	return 0, 0, w, h
-}
-
 type TitleScene struct {
 	count int
-	parts *titleImageParts
 }
 
 func NewTitleScene() *TitleScene {
-	return &TitleScene{
+	return &TitleScene{}
-		parts: &titleImageParts{imageBackground, 0},
-	}
 }
 
 func anyGamepadAbstractButtonPressed(i *Input) bool {
@@ -117,10 +89,17 @@ func (s *TitleScene) Draw(r *ebiten.Image) {
 }
 
 func (s *TitleScene) drawTitleBackground(r *ebiten.Image, c int) {
-	s.parts.count = c
+	w, h := imageBackground.Size()
-	r.DrawImage(imageBackground, &ebiten.DrawImageOptions{
+	op := &ebiten.DrawImageOptions{}
-		ImageParts: s.parts,
+	for i := 0; i < (ScreenWidth/w+1)*(ScreenHeight/h+2); i++ {
-	})
+		op.GeoM.Reset()
+		dx := (-c / 4) % w
+		dy := (c / 4) % h
+		dstX := (i%(ScreenWidth/w+1))*w + dx
+		dstY := (i/(ScreenWidth/w+1)-1)*h + dy
+		op.GeoM.Translate(float64(dstX), float64(dstY))
+		r.DrawImage(imageBackground, op)
+	}
 }
 
 func drawLogo(r *ebiten.Image, str string) {

examples/keyboard/main.go

@@ -70,25 +70,6 @@ var keyNames = map[ebiten.Key]string{
 	ebiten.KeyAlt:     "Alt",
 }
 
-type pressedKeysParts []string
-
-func (p pressedKeysParts) Len() int {
-	return len(p)
-}
-
-func (p pressedKeysParts) Dst(i int) (x0, y0, x1, y1 int) {
-	k := p[i]
-	r, ok := keyboard.KeyRect(k)
-	if !ok {
-		return 0, 0, 0, 0
-	}
-	return r.Min.X, r.Min.Y, r.Max.X, r.Max.Y
-}
-
-func (p pressedKeysParts) Src(i int) (x0, y0, x1, y1 int) {
-	return p.Dst(i)
-}
-
 func update(screen *ebiten.Image) error {
 	if ebiten.IsRunningSlowly() {
 		return nil
@@ -121,11 +102,18 @@ func update(screen *ebiten.Image) error {
 		}
 	}
 
-	op = &ebiten.DrawImageOptions{
+	op = &ebiten.DrawImageOptions{}
-		ImageParts: pressedKeysParts(pressed),
+	for _, p := range pressed {
+		op.GeoM.Reset()
+		r, ok := keyboard.KeyRect(p)
+		if !ok {
+			continue
+		}
+		op.GeoM.Translate(float64(r.Min.X), float64(r.Min.Y))
+		op.GeoM.Translate(offsetX, offsetY)
+		op.SourceRect = &r
+		screen.DrawImage(keyboardImage, op)
 	}
-	op.GeoM.Translate(offsetX, offsetY)
-	screen.DrawImage(keyboardImage, op)
 
 	return nil
 }

examples/perspective/main.go

@@ -17,6 +17,7 @@
 package main
 
 import (
+	"image"
 	_ "image/jpeg"
 	"log"
 
@@ -33,39 +34,25 @@ var (
 	gophersImage *ebiten.Image
 )
 
-type parts struct {
-	image *ebiten.Image
-}
-
-func (p parts) Len() int {
-	_, h := p.image.Size()
-	return h
-}
-
-func (p parts) Dst(i int) (x0, y0, x1, y1 int) {
-	w, h := p.image.Size()
-	width := w + i*3/4
-	x := ((h - i) * 3 / 4) / 2
-	return x, i, x + width, i + 1
-}
-
-func (p parts) Src(i int) (x0, y0, x1, y1 int) {
-	w, _ := p.image.Size()
-	return 0, i, w, i + 1
-}
-
 func update(screen *ebiten.Image) error {
 	if ebiten.IsRunningSlowly() {
 		return nil
 	}
-	op := &ebiten.DrawImageOptions{
+	op := &ebiten.DrawImageOptions{}
-		ImageParts: &parts{gophersImage},
-	}
 	w, h := gophersImage.Size()
-	maxWidth := float64(w) + float64(h)*0.75
+	for i := 0; i < h; i++ {
-	op.GeoM.Translate(-maxWidth/2, -float64(h)/2)
+		op.GeoM.Reset()
-	op.GeoM.Translate(screenWidth/2, screenHeight/2)
+		width := w + i*3/4
-	screen.DrawImage(gophersImage, op)
+		x := ((h - i) * 3 / 4) / 2
+		op.GeoM.Scale(float64(width)/float64(w), 1)
+		op.GeoM.Translate(float64(x), float64(i))
+		maxWidth := float64(w) + float64(h)*3/4
+		op.GeoM.Translate(-maxWidth/2, -float64(h)/2)
+		op.GeoM.Translate(screenWidth/2, screenHeight/2)
+		p := image.Rect(0, i, w, i+1)
+		op.SourceRect = &p
+		screen.DrawImage(gophersImage, op)
+	}
 	return nil
 }