From 850ef80139680300e154e90416d132c33e776991 Mon Sep 17 00:00:00 2001
From: Jeremy Dormitzer <jeremydormitzer@lola.com>
Date: Fri, 8 Nov 2019 23:34:45 -0500
Subject: [PATCH] Implement more flexible state management

---
 deps.edn                             |  3 +-
 src/three_playground/core.cljs       | 50 ++++++++++++++++++++--------
 test/three_playground/core_test.cljs |  9 ++++-
 3 files changed, 47 insertions(+), 15 deletions(-)

diff --git a/deps.edn b/deps.edn
index 8a49d9e..d795e19 100644
--- a/deps.edn
+++ b/deps.edn
@@ -1,5 +1,6 @@
 {:deps {org.clojure/clojure {:mvn/version "1.9.0"}
-        org.clojure/clojurescript {:mvn/version "1.10.520"}}
+        org.clojure/clojurescript {:mvn/version "1.10.520"}
+        binaryage/oops {:mvn/version "0.7.0"}}
  :paths ["src" "resources"]
  :aliases {:fig {:extra-deps
                   {com.bhauman/rebel-readline-cljs {:mvn/version "0.1.4"}
diff --git a/src/three_playground/core.cljs b/src/three_playground/core.cljs
index 2488d88..b416ae6 100644
--- a/src/three_playground/core.cljs
+++ b/src/three_playground/core.cljs
@@ -1,6 +1,8 @@
 (ns ^:figwheel-hooks three-playground.core
   (:require
    [goog.dom :as gdom]
+   [goog.object :as obj]
+   [oops.core :refer [oset!+]]
    [three]))
 
 (defn get-app-element []
@@ -24,31 +26,53 @@
     (.setSize renderer (.-innerWidth js/window) (.-innerHeight js/window))
     (.add scene cube)
     (atom {:running true
-           :cube {:rotation {:x 0 :y 0}}
            :renderer renderer
-           :scene scene
-           :camera {:position {:z 5}}
-           :entities {:cube cube
+           :entity-state {:cube {:rotation {:x 0 :y 0}}
+                          :camera {:position {:z 5}}}
+           :entities {:scene scene
+                      :cube cube
                       :camera camera}})))
 
 (defonce app-state (init-state))
 
 (defn update-state [state]
   (-> state
-      (assoc-in [:cube :rotation :x]
-                (+ (get-in state [:cube :rotation :x])
-                   0.01))
-      (assoc-in [:cube :rotation :y]
-                (+ (get-in state [:cube :rotation :y])
+      (assoc-in [:entity-state :cube :rotation :x]
+                (+ (get-in state [:entity-state :cube :rotation :x])
+                   0.03))
+      (assoc-in [:entity-state :cube :rotation :y]
+                (+ (get-in state [:entity-state :cube :rotation :y])
                    0.01))))
 
+(defn map->paths [m]
+  (if (map? m)
+    (vec
+     (mapcat (fn [[k v]]
+               (let [sub (map->paths v)
+                     nested (map #(into [k] %) (filter (comp not empty?) sub))]
+                 (if (seq nested)
+                   nested
+                   [[k]])))
+             m))
+    []))
+
+(defn update-entities! [state]
+  (doseq [[id entity] (:entities state)]
+    (let [target-state (get-in state [:entity-state id])]
+      (when target-state
+        (doseq [path (map->paths target-state)]
+          (let [str-path (map name path)
+                current (apply aget entity str-path)
+                new (get-in target-state path)]
+            (when-not (= current new)
+              (oset!+ entity str-path new))))))))
+
 (defn render [state]
-  (let [{:keys [renderer scene]} state
+  (let [renderer (:renderer state)
+        scene (get-in state [:entities :scene])
         camera (get-in state [:entities :camera])
         cube (get-in state [:entities :cube])]
-    (set! (-> camera (.-position) (.-z)) (get-in state [:camera :position :z]))
-    (set! (-> cube (.-rotation) (.-x)) (get-in state [:cube :rotation :x]))
-    (set! (-> cube (.-rotation) (.-y)) (get-in state [:cube :rotation :y]))
+    (update-entities! state)
     (.render renderer scene camera)))
 
 (defn the-loop []
diff --git a/test/three_playground/core_test.cljs b/test/three_playground/core_test.cljs
index 659b5de..761498c 100644
--- a/test/three_playground/core_test.cljs
+++ b/test/three_playground/core_test.cljs
@@ -1 +1,8 @@
-(ns three-playground.core-test)
+(ns three-playground.core-test
+  (:require [cljs.test :refer-macros [deftest testing is]]
+            [three-playground.core :as core]))
+
+(deftest test-map->paths
+  (testing "Basic case"
+    (is (= (core/map->paths {:foo {:bar 1 :baz 2} :qux 3})
+           [[:foo :bar] [:foo :baz] [:qux]]))))