From 5df3e0b43ee8ea3914c81086d46a4afaf25a77ee Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 27 Jan 2024 11:19:54 +0200
Subject: [PATCH] Add polymorphism discovery for systems

---
 source/game/director.cpp |  1 +
 source/game/stage.h      | 10 ++++------
 source/game/system.h     |  2 ++
 3 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/source/game/director.cpp b/source/game/director.cpp
index eedc4d5..53c5454 100644
--- a/source/game/director.cpp
+++ b/source/game/director.cpp
@@ -21,6 +21,7 @@ Director::Director(DataFile::Collection &r):
 
 	reflector.get_or_create_class<Entity>();
 	reflector.get_or_create_class<Component>();
+	reflector.get_or_create_class<System>();
 }
 
 // Hide ~unique_ptr<Stage> from the header
diff --git a/source/game/stage.h b/source/game/stage.h
index 0095c76..8e98d76 100644
--- a/source/game/stage.h
+++ b/source/game/stage.h
@@ -86,13 +86,11 @@ inline void Stage::iterate_objects(const F &func)
 template<typename T, typename... Args>
 inline T &Stage::add_system(Args &&... args)
 {
-	// Ensure that a reflected class exists for scheduling
-	reflector.get_or_create_class<T>();
-
-	auto &sys = systems.emplace_back(std::make_unique<T>(*this, std::forward<Args>(args)...));
-	scheduler.add_system(*sys);
+	auto &sys = static_cast<T &>(*systems.emplace_back(std::make_unique<T>(*this, std::forward<Args>(args)...)));
+	reflector.get_or_create_class<T>().template set_polymorphic_base<System>(sys);
+	scheduler.add_system(sys);
 	pending_reschedule = true;
-	return static_cast<T &>(*sys);
+	return sys;
 }
 
 template<typename T>
diff --git a/source/game/system.h b/source/game/system.h
index 4d39e30..2f0f8ba 100644
--- a/source/game/system.h
+++ b/source/game/system.h
@@ -14,6 +14,8 @@ namespace Msp::Game {
 class MSPGAME_API System
 {
 public:
+	using PolymorphicBase = System;
+
 	enum DependencyFlags
 	{
 		NO_DEPENDENCY = 0,
-- 
2.45.2