From d45323cadee9044d8536f7eb9827a43b36e4bdff Mon Sep 17 00:00:00 2001
From: Robert Clarke <clarke.john.robert@gmail.com>
Date: Sun, 12 Feb 2023 03:44:39 -0500
Subject: Everything necessary to register a C++ class with internal state for
 access within Godot

---
 extension/src/Simulation.hpp     | 52 ++++++++++++++++++++++++++++++++++++++++
 extension/src/register_types.cpp | 51 +++++++++++++++++++++++----------------
 2 files changed, 82 insertions(+), 21 deletions(-)
 create mode 100644 extension/src/Simulation.hpp

diff --git a/extension/src/Simulation.hpp b/extension/src/Simulation.hpp
new file mode 100644
index 0000000..6ade846
--- /dev/null
+++ b/extension/src/Simulation.hpp
@@ -0,0 +1,52 @@
+#pragma once
+
+#include <godot_cpp/classes/object.hpp>
+#include <godot_cpp/core/class_db.hpp>
+#include <godot_cpp/variant/utility_functions.hpp>
+#include <vector>
+
+namespace OpenVic2 {
+	class Simulation : public godot::Object {
+		std::vector<size_t> exampleProvinces;
+
+		//BEGIN BOILERPLATE
+		GDCLASS(Simulation, godot::Object);
+		static Simulation* _simulation;
+
+		protected:
+		static void _bind_methods() {
+			godot::ClassDB::bind_method(godot::D_METHOD("conductSimulationStep"), &Simulation::conductSimulationStep);
+			godot::ClassDB::bind_method(godot::D_METHOD("queryProvinceSize"), &Simulation::queryProvinceSize);
+		}
+
+		public:
+		inline static Simulation* get_singleton() { return _simulation; }
+
+		inline Simulation() {
+			ERR_FAIL_COND(_simulation != nullptr);
+			_simulation = this;
+
+			exampleProvinces.resize(10, 1);
+		}
+		inline ~Simulation() {
+			ERR_FAIL_COND(_simulation != this);
+			_simulation = nullptr;
+		}
+		//END BOILERPLATE
+
+		inline void conductSimulationStep() {
+			for (size_t x = 0; x < exampleProvinces.size(); x++) {
+				exampleProvinces[x] += (x + 1);
+			}
+		}
+
+		inline size_t queryProvinceSize(size_t provinceID) {
+			if (provinceID >= exampleProvinces.size()) {
+				return 0;
+			}
+			return exampleProvinces[provinceID];
+		}
+	};
+
+	Simulation* Simulation::_simulation = nullptr;
+}
\ No newline at end of file
diff --git a/extension/src/register_types.cpp b/extension/src/register_types.cpp
index 775e6c3..4b049ce 100644
--- a/extension/src/register_types.cpp
+++ b/extension/src/register_types.cpp
@@ -6,46 +6,55 @@
 #include <godot_cpp/classes/engine.hpp>
 
 #include "TestSingleton.hpp"
+#include "Simulation.hpp"
 
 using namespace godot;
 using namespace OpenVic2;
 
-static TestSingleton *_test_singleton;
+static TestSingleton* _test_singleton;
+static Simulation* _simulation;
 
 void initialize_openvic2_types(ModuleInitializationLevel p_level)
 {
-    if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
-        return;
-    }
+	if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
+		return;
+	}
 
-    ClassDB::register_class<TestSingleton>();
+	ClassDB::register_class<TestSingleton>();
+	_test_singleton = memnew(TestSingleton);
+	Engine::get_singleton()->register_singleton("TestSingleton", TestSingleton::get_singleton());
+
+	ClassDB::register_class<Simulation>();
+	_simulation = memnew(Simulation);
+	Engine::get_singleton()->register_singleton("Simulation", Simulation::get_singleton());
 
-    _test_singleton = memnew(TestSingleton);
-    Engine::get_singleton()->register_singleton("TestSingleton", TestSingleton::get_singleton());
 }
 
 void uninitialize_openvic2_types(ModuleInitializationLevel p_level) {
-    if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
-        return;
-    }
+	if (p_level != MODULE_INITIALIZATION_LEVEL_SCENE) {
+		return;
+	}
+
+	Engine::get_singleton()->unregister_singleton("TestSingleton");
+	memdelete(_test_singleton);
 
-    Engine::get_singleton()->unregister_singleton("TestSingleton");
-    memdelete(_test_singleton);
+	Engine::get_singleton()->unregister_singleton("Simulation");
+	memdelete(_test_singleton);
 }
 
 extern "C"
 {
 
-    // Initialization.
+	// Initialization.
 
-    GDExtensionBool GDE_EXPORT openvic2_library_init(const GDExtensionInterface *p_interface, const GDExtensionClassLibraryPtr p_library, GDExtensionInitialization *r_initialization)
-    {
-        GDExtensionBinding::InitObject init_obj(p_interface, p_library, r_initialization);
+	GDExtensionBool GDE_EXPORT openvic2_library_init(const GDExtensionInterface *p_interface, const GDExtensionClassLibraryPtr p_library, GDExtensionInitialization *r_initialization)
+	{
+		GDExtensionBinding::InitObject init_obj(p_interface, p_library, r_initialization);
 
-        init_obj.register_initializer(initialize_openvic2_types);
-        init_obj.register_terminator(uninitialize_openvic2_types);
-        init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);
+		init_obj.register_initializer(initialize_openvic2_types);
+		init_obj.register_terminator(uninitialize_openvic2_types);
+		init_obj.set_minimum_library_initialization_level(MODULE_INITIALIZATION_LEVEL_SCENE);
 
-        return init_obj.init();
-    }
+		return init_obj.init();
+	}
 }
\ No newline at end of file
-- 
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