remove demo game

asset.manager.go

@@ -0,0 +1,87 @@
+package pncdsl
+
+import (
+	"hash/fnv"
+	"image"
+	"image/color"
+	_ "image/jpeg"
+	_ "image/png"
+	"os"
+
+	"github.com/hajimehoshi/ebiten/v2"
+)
+
+type AssetManager = Manager[Asset]
+
+// loadedAssets is the runtime cache for decoded image/audio resources.
+// The Asset structs in the manager remain immutable spec; this is where
+// the actual *ebiten.Image bytes live, lazily decoded on first access.
+type loadedAssets struct {
+	images       map[string]*ebiten.Image
+	placeholders map[string]bool
+	defaultW, defaultH int
+}
+
+func newLoadedAssets(w, h int) *loadedAssets {
+	return &loadedAssets{
+		images:       make(map[string]*ebiten.Image),
+		placeholders: make(map[string]bool),
+		defaultW:     w,
+		defaultH:     h,
+	}
+}
+
+func (la *loadedAssets) image(am *AssetManager, name string) *ebiten.Image {
+	if img, ok := la.images[name]; ok {
+		return img
+	}
+	a, ok := am.Get(name)
+	if !ok {
+		img := placeholderImage(name, la.defaultW, la.defaultH)
+		la.images[name] = img
+		la.placeholders[name] = true
+		return img
+	}
+	img := loadImageFile(a.Path)
+	if img == nil {
+		img = placeholderImage(name, la.defaultW, la.defaultH)
+		la.placeholders[name] = true
+	}
+	la.images[name] = img
+	return img
+}
+
+func (la *loadedAssets) isPlaceholder(name string) bool {
+	_, _ = la.images[name], la.placeholders[name] // ensure populated via image()
+	return la.placeholders[name]
+}
+
+func loadImageFile(path string) *ebiten.Image {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil
+	}
+	defer f.Close()
+	src, _, err := image.Decode(f)
+	if err != nil {
+		return nil
+	}
+	return ebiten.NewImageFromImage(src)
+}
+
+// placeholderImage creates a deterministic colored rectangle for missing
+// assets so the game still runs without art on disk.
+func placeholderImage(seed string, w, h int) *ebiten.Image {
+	img := ebiten.NewImage(w, h)
+	h32 := fnv.New32a()
+	_, _ = h32.Write([]byte(seed))
+	sum := h32.Sum32()
+	c := color.RGBA{
+		R: 60 + uint8(sum&0x7F),
+		G: 60 + uint8((sum>>8)&0x7F),
+		B: 60 + uint8((sum>>16)&0x7F),
+		A: 255,
+	}
+	img.Fill(c)
+	return img
+}