implement grid and heightmap with lambert shading

src/node.h

@@ -188,6 +188,18 @@ public:
                 return static_cast<T*>(found);
         return nullptr;
     }
+    template<class T = Node> std::shared_ptr<T> find_ref(const char* ids)
+    {
+        uint16_t id = const_hash(ids);
+        for (auto& c : m_children)
+        {
+            if (c->m_nodeID == id)
+                return std::static_pointer_cast<T>(c);
+            else if (auto found = c->find_ref(ids))
+                return std::static_pointer_cast<T>(found);
+        }
+        return nullptr;
+    }
     template<class T> T* add_child()
     {
         auto* n = new T;