Scener

engine/asset.go

@@ -55,6 +55,7 @@ type ImageRef struct {
 
 // Image returns the image. If it hasn't been loaded yet, it loads.
 // Multiple distinct ImageRefs can use the same path.
+// TODO: adopt Loader?
 func (r *ImageRef) Image() *ebiten.Image {
 	if r.image != nil {
 		return r.image
@@ -78,6 +79,7 @@ func (r *ImageRef) Image() *ebiten.Image {
 }
 
 // SceneRef loads a gzipped, gob-encoded Scene from the asset FS.
+// After Load, Scene is usable.
 type SceneRef struct {
 	Path string
 
@@ -101,17 +103,12 @@ 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 sc.Load()
+	return nil
 }
 
-// Implement Scener by forwarding all the other calls to r.scene
-
-func (r SceneRef) Draw(screen *ebiten.Image, opts ebiten.DrawImageOptions) {
-	r.scene.Draw(screen, opts)
-}
-func (r SceneRef) DrawOrder() float64  { return r.scene.DrawOrder() }
-func (r SceneRef) Ident() string       { return r.scene.Ident() }
-func (r SceneRef) Prepare(g *Game)     { r.scene.Prepare(g) }
-func (r SceneRef) Scan() []interface{} { return r.scene.Scan() }
-func (r SceneRef) Update() error       { return r.scene.Update() }
+// Scene returns the loaded scene, or nil if not yet loaded.
+func (r SceneRef) Scene() *Scene { return r.scene }

engine/camera.go

@@ -84,7 +84,7 @@ func (c *Camera) Draw(screen *ebiten.Image, opts ebiten.DrawImageOptions) {
 	comm.Concat(opts.GeoM)
 
 	// Draw everything.
-	for _, i := range c.Scene.Components {
+	for _, i := range c.Scene.Scan() {
 		if d, ok := i.(Drawer); ok {
 			pf := 1.0
 			if s, ok := i.(ParallaxScaler); ok {
@@ -106,5 +106,5 @@ func (c *Camera) Update() error { return c.Scene.Update() }
 // Scan returns the only child (c.Scene).
 func (c *Camera) Scan() []interface{} { return []interface{}{c.Scene} }
 
-// Prepare grabs a copy of game.
+// Prepare grabs a copy of game (needed for screen dimensions)
 func (c *Camera) Prepare(game *Game) { c.game = game }

engine/game.go

@@ -14,19 +14,19 @@ func init() {
 type Game struct {
 	ScreenWidth  int
 	ScreenHeight int
-	Scene        *Scene
+	Scener
 
 	componentsByID map[string]interface{}
 }
 
 // Draw draws the entire thing, with default draw options.
 func (g *Game) Draw(screen *ebiten.Image) {
-	g.Scene.Draw(screen, ebiten.DrawImageOptions{})
+	g.Scene().Draw(screen, ebiten.DrawImageOptions{})
 }
 
 // Update updates the current scene.
 func (g *Game) Update() error {
-	return g.Scene.Update()
+	return g.Scene().Update()
 }
 
 // Layout returns the configured screen width/height.
@@ -86,10 +86,10 @@ func Walk(c interface{}, v func(interface{}) error) error {
 	return nil
 }
 
-// PrepareToRun builds the component database (using Walk) and then calls
-// Prepare on every Preparer. You must call PrepareToRun before passing to
-// ebiten.RunGame.
-func (g *Game) PrepareToRun() {
+// Prepare builds the component database (using Walk) and then calls
+// Prepare on every Preparer. You must call Prepare before any calls
+// to Component.
+func (g *Game) Prepare() {
 	g.componentsByID = make(map[string]interface{})
 	Walk(g, func(c interface{}) error {
 		g.RegisterComponent(c)

engine/interface.go

@@ -18,7 +18,7 @@ type Drawer interface {
 	Draw(screen *ebiten.Image, opts ebiten.DrawImageOptions)
 }
 
-// DrawOrderer is used to reorder layers.
+// DrawOrderer components can provide a number for determining draw order.
 type DrawOrderer interface {
 	DrawOrder() float64
 }
@@ -55,16 +55,10 @@ type Scanner interface {
 	Scan() []interface{}
 }
 
-// Scener components do everything that a Scene can. The other implementation
-// is SceneRef.
+// Scener components are a scene (Scene or SceneRef).
 type Scener interface {
-	Drawer
-	DrawOrderer
-	Identifier
 	Loader
-	Prepper
-	Scanner
-	Updater
+	Scene() *Scene
 }
 
 // Updater components can update themselves. Update is called repeatedly.

engine/scene.go

@@ -10,7 +10,16 @@ import (
 )
 
 // Ensure Scene satisfies Scener.
-var _ Scener = &Scene{}
+var (
+	_ Drawer      = &Scene{}
+	_ DrawOrderer = &Scene{}
+	_ Identifier  = &Scene{}
+	_ Loader      = &Scene{}
+	_ Scanner     = &Scene{}
+	_ Scener      = &Scene{}
+	_ Prepper     = &Scene{}
+	_ Updater     = &Scene{}
+)
 
 func init() {
 	gob.Register(Scene{})
@@ -73,6 +82,9 @@ func (s *Scene) sortByDrawOrder() {
 // Scan returns all immediate subcomponents.
 func (s *Scene) Scan() []interface{} { return s.Components }
 
+// Scene returns itself.
+func (s *Scene) Scene() *Scene { return s }
+
 // Update calls Update on all Updater components.
 func (s *Scene) Update() error {
 	if s.Disabled {

main.go

@@ -102,7 +102,7 @@ func main() {
 	game := &engine.Game{
 		ScreenHeight: 240,
 		ScreenWidth:  320,
-		Scene: &engine.Scene{
+		Scener: &engine.Scene{
 			ID: "root",
 			Components: []interface{}{
 				&engine.GobDumper{
@@ -116,7 +116,7 @@ func main() {
 			},
 		},
 	}
-	game.PrepareToRun()
+	game.Prepare()
 
 	if err := ebiten.RunGame(game); err != nil {
 		log.Fatalf("Game error: %v", err)