sprite stuff

common/sprites/v1/sprite.go

@@ -0,0 +1,133 @@
+package sprites
+
+import (
+	"image"
+
+	"git.vezzani.net/ben/games/common/window/v1"
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+var (
+	updateCount int
+)
+
+func Update() {
+	updateCount++
+}
+
+type animation struct {
+	RowNumber  uint8
+	FrameCount uint8
+	Scale      float32
+}
+
+type subImager interface {
+	image.Image
+	SubImage(r image.Rectangle) image.Image
+}
+
+type Sprite struct {
+	width, height int
+	imgData       subImager
+	animations    map[string]animation
+
+	baseAnim *animation
+}
+
+func (s *Sprite) baseAnimation() animation {
+	if s.baseAnim != nil {
+		return *s.baseAnim
+	}
+
+	for i := range s.animations {
+		if s.animations[i].RowNumber == 0 {
+			a := s.animations[i]
+			s.baseAnim = &a
+			return a
+		}
+	}
+
+	return animation{}
+}
+
+func (s *Sprite) getAnimation(id string) animation {
+	if id == "" {
+		return s.baseAnimation()
+	}
+
+	if anim, ok := s.animations[id]; ok {
+		return anim
+	}
+
+	return s.baseAnimation()
+}
+
+func (s *Sprite) Image(ops imageOptions) image.Image {
+	anim := s.getAnimation(ops.animation)
+
+	xOffset := updateCount % int(anim.FrameCount) * s.width
+	yOffset := int(anim.RowNumber) * s.height
+
+	r := image.Rect(xOffset, yOffset, s.width, s.height).Intersect(s.imgData.Bounds())
+
+	return s.imgData.SubImage(r)
+}
+
+func (s *Sprite) Draw(screen *ebiten.Image, options ...ImageOption) int {
+	ops := imageOptions{
+		scaleX: window.Scale,
+		scaleY: window.Scale,
+	}
+
+	for _, o := range options {
+		o(&ops)
+	}
+
+	geom := ebiten.GeoM{}
+	geom.Translate(ops.x, ops.y)
+	geom.Scale(ops.scaleX, ops.scaleY)
+	geom.Rotate(ops.rotateTheta)
+
+	screen.DrawImage(
+		ebiten.NewImageFromImage(
+			s.Image(ops),
+		),
+		&ebiten.DrawImageOptions{
+			GeoM: geom,
+		},
+	)
+}
+
+type imageOptions struct {
+	x, y           float64
+	scaleX, scaleY float64
+	rotateTheta    float64
+	animation      string
+}
+
+type ImageOption func(options *imageOptions)
+
+func ToScale(x, y float64) ImageOption {
+	return func(o *imageOptions) {
+		o.scaleX *= x
+		o.scaleY *= y
+	}
+}
+
+func Animation(name string) ImageOption {
+	return func(o *imageOptions) {
+		o.animation = name
+	}
+}
+
+func AtPosition(x, y float64) ImageOption {
+	return func(o *imageOptions) {
+		o.x, o.y = x, y
+	}
+}
+
+func Rotate(theta float64) ImageOption {
+	return func(o *imageOptions) {
+		o.rotateTheta = theta
+	}
+}

common/window/v1/window.go

@@ -0,0 +1,5 @@
+package window
+
+var (
+	Scale float64 = 1.0
+)