sprite

engine/sprite.go

@@ -0,0 +1,66 @@
+package engine
+
+import (
+	"image"
+
+	"github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/inpututil"
+)
+
+// Sprite combines an Actor with the ability to Draw...
+type Sprite struct {
+	Actor
+	AnimRef
+	Hidden bool
+	ID
+	Src ImageRef
+	ZPos
+
+	vx, vy     float64       // TODO: refactor
+}
+
+func (s *Sprite) Draw(screen *ebiten.Image, geom ebiten.GeoM) {
+	if s.Hidden {
+		return
+	}
+	var op ebiten.DrawImageOptions
+	op.GeoM.Translate(float64(s.Actor.Position.X), float64(s.Actor.Position.Y))
+	op.GeoM.Concat(geom)
+
+	frame := s.Anim().CurrentFrame()
+	src := s.Src.Image()
+	w, _ := src.Size()
+	sx, sy := (frame * s.Actor.Size.X) % w, ((frame * s.Actor.Size.X) / w) * s.Actor.Size.Y
+
+	screen.DrawImage(src.SubImage(image.Rect(sx, sy, sx + s.Actor.Size.X, sy+s.Actor.Size.Y)).(*ebiten.Image), &op)
+}
+
+func (s *Sprite) Scan() []interface{}{
+	return []interface{}{&s.Actor}
+}
+
+func (s *Sprite) Update() error {
+	// TODO: delegate updating to something else
+	if s.Actor.CollidesAt(s.Actor.Position.Add(image.Pt(0, 1))) {
+		// Not falling
+		s.vy = 0
+		if inpututil.IsKeyJustPressed(ebiten.KeySpace) {
+			// Jump?
+			s.vy = -7
+		}
+	} else {
+		// Falling
+		s.vy += gravity
+	}
+	switch {
+	case ebiten.IsKeyPressed(ebiten.KeyLeft):
+		s.vx = -3
+	case ebiten.IsKeyPressed(ebiten.KeyRight):
+		s.vx = 3
+	default:
+		s.vx = 0
+	}
+	s.Actor.MoveX(s.vx, func() { s.vx = 0 })
+	s.Actor.MoveY(s.vy, func() { s.vy = 0 })
+	return s.Anim().Update()
+}