Creation of the RTree Godot Class

Basic defintions, we are going to see if it fits the use case.

src/rectangletree.cpp

@@ -0,0 +1,43 @@
+#include "rectangletree.hpp"
+#include "godot_cpp/core/class_db.hpp"
+#include "godot_cpp/variant/packed_int32_array.hpp"
+#include "godot_cpp/variant/packed_vector2_array.hpp"
+#include "godot_cpp/variant/typed_array.hpp"
+
+RectangleTree::RectangleTree() {}
+
+void RectangleTree::_bind_methods() {
+  ClassDB::bind_method(
+      godot::D_METHOD("add", "min_bound", "max_bound", "polygon_index"),
+      &RectangleTree::add);
+  ClassDB::bind_method(godot::D_METHOD("remove", "point"),
+                       &RectangleTree::remove);
+  ClassDB::bind_method(godot::D_METHOD("query", "point"),
+                       &RectangleTree::query);
+}
+
+void RectangleTree::add(const Vector2 &min_bound, const Vector2 &max_bound,
+                        const int &polygon_index) {
+  // convert into c++ types from godot types
+  Rect rect = Rect(min_bound.x, min_bound.y, max_bound.x, max_bound.y);
+
+  tree.Insert(rect.min, rect.max, polygon_index);
+}
+
+void RectangleTree::remove(const int &polygon_index) {
+  tree.Remove(polygon_index);
+}
+
+PackedInt32Array RectangleTree::query(const Vector2 &point) {
+  Rect rect = Rect(point.x, point.y, point.x, point.y);
+
+  PackedInt32Array return_value;
+  auto callbackLambda = [&return_value](int index) {
+    return_value.push_back(index);
+    return true;
+  };
+
+  tree.Search(rect.min, rect.max, callbackLambda);
+
+  return return_value;
+}