Create add-joint! multimethod

src/play_clj/core_physics.clj

@@ -11,6 +11,11 @@
 `basic-body` or a `rigid-body`."
   (fn [screen body] (-> screen (u/get-obj :world) class)))
 
+(defmulti add-joint!
+  "Adds the `joint` to the `screen` for physics simulations and returns it. For
+2D physics, `joint` should be a `joint-def`."
+  (fn [screen joint] (-> screen (u/get-obj :world) class)))
+
 (defmulti body-position!
   "Changes the position of the body in `entity`. For 2D physics, the arguments
 should be x, y, and angle, whereas for 3D physics they should be x, y, and z."

src/play_clj/g2d_physics.clj

@@ -103,16 +103,6 @@
   [object k & options]
   `(u/call! ^Joint ~object ~k ~@options))
 
-(defn create-joint!*
-  [screen j-def]
-  (box-2d! screen :create-joint j-def))
-
-(defmacro create-joint!
-  "Returns a [Joint](http://libgdx.badlogicgames.com/nightlies/docs/api/com/badlogic/gdx/physics/box2d/Joint.html)."
-  [screen j-def & options]
-  `(let [object# (create-joint!* ~screen ~j-def)]
-     (u/calls! object# ~@options)))
-
 ; fixtures
 
 (defmacro fixture-def
@@ -220,6 +210,11 @@
   [screen b-def]
   (box-2d! screen :create-body b-def))
 
+(defmethod c/add-joint!
+  World
+  [screen j-def]
+  (box-2d! screen :create-joint j-def))
+
 (defmethod c/physics-listeners
   World
   [screen