Draw entities with a protocol instead of a multi-method

src/play_clj/utils.clj

@@ -1,8 +1,8 @@
 (ns play-clj.utils
   (:require [clojure.string :as s])
-  (:import [com.badlogic.gdx.graphics.g2d NinePatch ParticleEffect
+  (:import [com.badlogic.gdx.graphics.g2d NinePatch ParticleEffect SpriteBatch
             TextureRegion]
-           [com.badlogic.gdx.graphics.g3d ModelInstance]
+           [com.badlogic.gdx.graphics.g3d Environment ModelBatch ModelInstance]
            [com.badlogic.gdx.scenes.scene2d Actor]
            [com.badlogic.gdx.utils Array ArrayMap]))
 
@@ -172,7 +172,53 @@ new object to be created each time a field is set)
   [object k & options]
   `(call! ^ArrayMap ~object ~k ~@options))
 
-; entities
+; entity protocol/records
+
+(defprotocol Entity
+  "Internal use only"
+  (draw-entity! [this batch] "Draws the entity"))
+
+(defrecord TextureEntity [object] Entity
+  (draw-entity! [{:keys [^TextureRegion object x y width height]} batch]
+    (let [x (float (or x 0))
+          y (float (or y 0))
+          width (float (or width (.getRegionWidth object)))
+          height (float (or height (.getRegionHeight object)))]
+      (.draw ^SpriteBatch batch object x y width height))))
+
+(defrecord NinePatchEntity [object] Entity
+  (draw-entity! [{:keys [^NinePatch object x y width height]} batch]
+    (let [x (float (or x 0))
+          y (float (or y 0))
+          width (float (or width (.getTotalWidth object)))
+          height (float (or height (.getTotalHeight object)))]
+      (.draw object ^SpriteBatch batch x y width height))))
+
+(defrecord ParticleEffectEntity [object] Entity
+  (draw-entity! [{:keys [^ParticleEffect object x y delta-time]} batch]
+    (let [x (float (or x 0))
+          y (float (or y 0))
+          delta-time (float delta-time)]
+      (.setPosition object x y)
+      (.draw object ^SpriteBatch batch delta-time))))
+
+(defrecord ActorEntity [object] Entity
+  (draw-entity! [{:keys [^Actor object] :as entity} batch]
+    (doseq [[k v] entity]
+      (case k
+        :x (.setX object v)
+        :y (.setY object v)
+        :width (.setWidth object v)
+        :height (.setHeight object v)
+        nil))
+    (.draw object ^SpriteBatch batch 1)))
+
+(defrecord ModelEntity [object] Entity
+  (draw-entity! [{:keys [^ModelInstance object]}
+                 {:keys [^ModelBatch renderer ^Environment attributes]}]
+    (.render renderer object attributes)))
+
+; create-entity
 
 (defmulti create-entity
   "Internal use only"
@@ -180,20 +226,20 @@ new object to be created each time a field is set)
 
 (defmethod create-entity TextureRegion
   [obj]
-  {:type :texture :object obj})
+  (TextureEntity. obj))
 
 (defmethod create-entity NinePatch
   [obj]
-  {:type :nine-patch :object obj})
+  (NinePatchEntity. obj))
 
 (defmethod create-entity ParticleEffect
   [obj]
-  {:type :particle-effect :object obj})
+  (ParticleEffectEntity. obj))
 
 (defmethod create-entity Actor
   [obj]
-  {:type :actor :object obj})
+  (ActorEntity. obj))
 
 (defmethod create-entity ModelInstance
   [obj]
-  {:type :model :object obj})
+  (ModelEntity. obj))