fix bug

engine/asset.go

@@ -99,8 +99,7 @@ type SceneRef struct {
 	scene *Scene // not exported for gob reasons
 }
 
-// Load loads the scene from the file and then calls Load
-// on the freshly-loaded Scene.
+// Load loads the scene from the file.
 func (r *SceneRef) Load() error {
 	f, err := AssetFS.Open(r.Path)
 	if err != nil {
@@ -116,9 +115,6 @@ func (r *SceneRef) Load() error {
 	if err := gob.NewDecoder(gz).Decode(sc); err != nil {
 		return err
 	}
-	if err := sc.Load(); err != nil {
-		return err
-	}
 	r.scene = sc
 	return nil
 }

engine/game.go

@@ -61,7 +61,7 @@ func (g *Game) UnregisterComponent(c interface{}) {
 func (g *Game) Component(id string) interface{} { return g.componentsByID[id] }
 
 // Scan implements Scanner.
-func (g *Game) Scan() []interface{} { return []interface{}{g.Scene} }
+func (g *Game) Scan() []interface{} { return []interface{}{g.Scener} }
 
 // Walk calls v with every component reachable from c via Scan, recursively,
 // for as long as visit returns nil.
@@ -81,17 +81,29 @@ func Walk(c interface{}, v func(interface{}) error) error {
 	return nil
 }
 
+// Load calls Load on all Loaders reachable via Scan (using Walk).
+// It stops on the first error.
+func (g *Game) Load() error {
+	return Walk(g.Scener, func(c interface{}) error {
+		l, ok := c.(Loader)
+		if !ok {
+			return nil
+		}
+		return l.Load()
+	})
+}
+
 // Prepare builds the component database (using Walk) and then calls
 // Prepare on every Preparer. You must call Prepare before any calls
 // to Component. You may call Prepare again (e.g. as an alternative to
 // fastidiously calling RegisterComponent/UnregisterComponent).
 func (g *Game) Prepare() {
 	g.componentsByID = make(map[string]interface{})
-	Walk(g, func(c interface{}) error {
+	Walk(g.Scener, func(c interface{}) error {
 		g.RegisterComponent(c)
 		return nil
 	})
-	Walk(g, func(c interface{}) error {
+	Walk(g.Scener, func(c interface{}) error {
 		if p, ok := c.(Prepper); ok {
 			p.Prepare(g)
 		}

engine/interface.go

@@ -70,7 +70,6 @@ type Scener interface {
 	Drawer
 	DrawOrderer
 	Identifier
-	Loader
 	Prepper
 	Scanner
 	Updater

engine/scene.go

@@ -39,20 +39,6 @@ func (s *Scene) Draw(screen *ebiten.Image, opts ebiten.DrawImageOptions) {
 	}
 }
 
-// Load loads any subcomponents that need loading.
-func (s *Scene) Load() error {
-	for _, i := range s.Components {
-		l, ok := i.(Loader)
-		if !ok {
-			continue
-		}
-		if err := l.Load(); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
 // Prepare does an initial Z-order sort.
 func (s *Scene) Prepare(game *Game) { s.sortByDrawOrder() }
 

main.go

@@ -43,6 +43,9 @@ func main() {
 	tiles := make(map[image.Point]engine.Tile)
 	for j, row := range denseTiles {
 		for i, tile := range row {
+			if tile == nil {
+				continue
+			}
 			tiles[image.Pt(i, j)] = tile
 		}
 	}