yes

engine/asset.go

@@ -2,9 +2,9 @@ package engine
 
 import (
 	"encoding/gob"
-	"fmt"
 	"image"
 	"io/fs"
+	"log"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
@@ -16,34 +16,34 @@ var (
 	imageCache   = make(map[string]*ebiten.Image)
 )
 
-// AnimRef
+// AnimRef loads AnimDef from an asset and manages an Anim using it.
 type AnimRef struct {
 	Path string
 
 	anim *Anim
 }
 
-func (r *AnimRef) Anim() (*Anim, error) {
+func (r *AnimRef) Anim() *Anim {
 	if r.anim != nil {
-		return r.anim, nil
+		return r.anim
 	}
 	if ad := animDefCache[r.Path]; ad != nil {
 		r.anim = &Anim{Def: ad}
-		return r.anim, nil
+		return r.anim
 	}
 	f, err := AssetFS.Open(r.Path)
 	if err != nil {
-		return nil, fmt.Errorf("open asset: %w", err)
+		log.Fatalf("Couldn't open asset: %v", err)
 	}
 	defer f.Close()
 	dec := gob.NewDecoder(f)
 	ad := &AnimDef{}
 	if err := dec.Decode(ad); err != nil {
-		return nil, fmt.Errorf("decode asset: %w", err)
+		log.Fatalf("Couldn't decode asset: %v", err)
 	}
 	animDefCache[r.Path] = ad
 	r.anim = &Anim{Def: ad}
-	return r.anim, nil
+	return r.anim
 }
 
 // ImageRef loads images from the AssetFS into *ebiten.Image form.
@@ -57,24 +57,24 @@ type ImageRef struct {
 
 // Image returns the image. If it hasn't been loaded yet, it loads.
 // Multiple distinct ImageRefs can use the same path.
-func (r *ImageRef) Image() (*ebiten.Image, error) {
+func (r *ImageRef) Image() *ebiten.Image {
 	if r.image != nil {
-		return r.image, nil
+		return r.image
 	}
 	r.image = imageCache[r.Path]
 	if r.image != nil {
-		return r.image, nil
+		return r.image
 	}
 	f, err := AssetFS.Open(r.Path)
 	if err != nil {
-		return nil, fmt.Errorf("open asset: %w", err)
+		log.Fatalf("Couldn't open asset: %v", err)
 	}
 	defer f.Close()
 	i, _, err := image.Decode(f)
 	if err != nil {
-		return nil, fmt.Errorf("decode asset: %w", err)
+		log.Fatalf("Couldn't decode asset: %v", err)
 	}
 	r.image = ebiten.NewImageFromImage(i)
 	imageCache[r.Path] = r.image
-	return r.image, nil
+	return r.image
 }

engine/tiles.go

@@ -3,7 +3,6 @@ package engine
 import (
 	"encoding/gob"
 	"image"
-	"log"
 
 	"github.com/hajimehoshi/ebiten/v2"
 )
@@ -33,11 +32,7 @@ func (t *Tilemap) Draw(screen *ebiten.Image, geom ebiten.GeoM) {
 			op.GeoM.Concat(geom)
 
 			sx := tile.TileIndex() * t.TileSize
-			im, err := t.Src.Image()
+			src := t.Src.Image().SubImage(image.Rect(sx, 0, sx+t.TileSize, t.TileSize)).(*ebiten.Image)
-			if err != nil {
-				log.Fatalf("Tilemap.Draw loading image: %v", err)
-			}
-			src := im.SubImage(image.Rect(sx, 0, sx+t.TileSize, t.TileSize)).(*ebiten.Image)
 			screen.DrawImage(src, &op)
 		}
 	}
@@ -69,7 +64,9 @@ func (s StaticTile) TileIndex() int { return int(s) }
 
 // AnimatedTile uses an Anim to choose a tile index.
 type AnimatedTile struct {
-	Anim
+	AnimRef
 }
 
-func (a *AnimatedTile) TileIndex() int { return a.CurrentFrame() }
+func (a *AnimatedTile) TileIndex() int { return a.Anim().CurrentFrame() }
+
+func (a *AnimatedTile) Update() error { return a.Anim().Update() }

main.go

@@ -46,29 +46,31 @@ func main() {
 		}
 	}
 
-	tiles[4][5] = &engine.AnimatedTile{
+	/*
-		Anim: engine.Anim{
+		tiles[4][5] = &engine.AnimatedTile{
-			Def: &engine.AnimDef{
+			Anim: engine.Anim{
-				Frames: []engine.AnimFrame{
+				Def: &engine.AnimDef{
-					{Frame: 0, Duration: 16},
+					Frames: []engine.AnimFrame{
-					{Frame: 1, Duration: 16},
+						{Frame: 0, Duration: 16},
-					{Frame: 2, Duration: 16},
+						{Frame: 1, Duration: 16},
+						{Frame: 2, Duration: 16},
+					},
 				},
 			},
-		},
+		}
-	}
+		tiles[6][7] = &engine.AnimatedTile{
-	tiles[6][7] = &engine.AnimatedTile{
+			Anim: engine.Anim{
-		Anim: engine.Anim{
+				Def: &engine.AnimDef{
-			Def: &engine.AnimDef{
+					Frames: []engine.AnimFrame{
-				Frames: []engine.AnimFrame{
+						{Frame: 3, Duration: 12},
-					{Frame: 3, Duration: 12},
+						{Frame: 4, Duration: 12},
-					{Frame: 4, Duration: 12},
+						{Frame: 5, Duration: 12},
-					{Frame: 5, Duration: 12},
+						{Frame: 6, Duration: 12},
-					{Frame: 6, Duration: 12},
+					},
 				},
 			},
-		},
+		}
-	}
+	*/
 
 	game := &engine.Game{
 		ScreenHeight: screenHeight,