Don't destroy ordering information in conv.ConvertObjects

cmd/view-map/main.go

@@ -87,7 +87,7 @@ func main() {
 	env := &env{
 		gameMap: gameMap,
 		set:     mapSet,
-		objects: objects,
+		objects: conv.MapByName(objects),
 		batch:   batch,
 	}
 

cmd/view-set/main.go

@@ -69,7 +69,7 @@ func main() {
 	objects, spritesheet := conv.ConvertObjects(rawObjs)
 	batch := pixel.NewBatch(&pixel.TrianglesData{}, spritesheet)
 
-	env := &env{objects: objects, set: mapSet, batch: batch}
+	env := &env{objects: conv.MapByName(objects), set: mapSet, batch: batch}
 
 	// The main thread now belongs to pixelgl
 	pixelgl.Run(env.run)

internal/conv/object.go

@@ -35,7 +35,17 @@ type Object struct {
 	Sprites []*Sprite
 }
 
-func ConvertObjects(objects []*data.Object) (map[string]*Object, *pixel.PictureData) {
+func MapByName(objects []*Object) map[string]*Object {
+	out := make(map[string]*Object, len(objects))
+
+	for _, obj := range objects {
+		out[obj.Name] = obj
+	}
+
+	return out
+}
+
+func ConvertObjects(objects []*data.Object) ([]*Object, *pixel.PictureData) {
 	// FIXME: this is rather inefficient. It would be better to determine the
 	// maximum size we need for the objects at hand.
 	spritesheet := pixel.MakePictureData(
@@ -47,7 +57,7 @@ func ConvertObjects(objects []*data.Object) (map[string]*Object, *pixel.PictureD
 	yOffset := 0
 	rowMaxY := 0
 
-	out := make(map[string]*Object)
+	out := make([]*Object, 0, len(objects))
 
 	for _, rawObj := range objects {
 		sprites := make([]*Sprite, 0, len(rawObj.Sprites))
@@ -75,7 +85,7 @@ func ConvertObjects(objects []*data.Object) (map[string]*Object, *pixel.PictureD
 			}
 		}
 
-		out[rawObj.Name] = &Object{Name: rawObj.Name, Sprites: sprites}
+		out = append(out, &Object{Name: rawObj.Name, Sprites: sprites})
 	}
 
 	return out, spritesheet