Walking

terrain/terrain.go

@@ -13,17 +13,21 @@ var (
 )
 
 type Terrain struct {
+	positionX float64
+	positionY float64
 }
 
 func (t *Terrain) DrawTerrain(screen *ebiten.Image) {
 	screenWidth := screen.Bounds().Max.X
 	screenHeight := screen.Bounds().Max.Y
+	offsetX := int(t.positionX) % 64
+	offsetY := int(t.positionY) % 64
 	op := &ebiten.DrawImageOptions{}
-	for i := 0; i <= screenWidth/64; i++ {
-		for j := 0; j <= screenHeight/64; j++ {
+	for i := -1; i <= screenWidth/64+1; i++ {
+		for j := -1; j <= screenHeight/64+1; j++ {
 			// ground
 			op.GeoM.Reset()
-			op.GeoM.Translate(float64(i*64), float64(j*64))
+			op.GeoM.Translate(float64(i*64+offsetX), float64(j*64+offsetY))
 			screen.DrawImage(grassImage.SubImage(image.Rect(32, 160, 32+64, 160+64)).(*ebiten.Image), op)
 		}
 
@@ -37,3 +41,14 @@ func init() {
 	}
 	grassImage = ebiten.NewImageFromImage(img)
 }
+
+func NewTerrain() *Terrain {
+	return &Terrain{
+		positionX: 0,
+		positionY: 0,
+	}
+}
+
+func (t *Terrain) GoDown() {
+	t.positionY += 1
+}