From 2482a8c224bfa455d21b0188eea2884db75cfdae Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Tue, 16 Aug 2022 10:14:21 +0300
Subject: [PATCH] Support adding arbitrary arguments to ECS behavior call

---
 libs/util/include/psemek/util/ecs.hpp | 36 +++++++++++++--------------
 1 file changed, 18 insertions(+), 18 deletions(-)

diff --git a/libs/util/include/psemek/util/ecs.hpp b/libs/util/include/psemek/util/ecs.hpp
index 1f2a69c8..41270b44 100644
--- a/libs/util/include/psemek/util/ecs.hpp
+++ b/libs/util/include/psemek/util/ecs.hpp
@@ -85,10 +85,10 @@ namespace psemek::util
 
 			virtual bool entity_active(entity_handle h) const = 0;
 
-			template <typename Behavior>
-			void apply(Behavior & behavior)
+			template <typename Behavior, typename ... Args>
+			void apply(Behavior & behavior, Args const & ... args)
 			{
-				apply_impl(behavior, static_cast<typename Behavior::component_types *>(nullptr), std::make_index_sequence<std::tuple_size_v<typename Behavior::component_types>>{});
+				apply_impl(behavior, static_cast<typename Behavior::component_types *>(nullptr), std::make_index_sequence<std::tuple_size_v<typename Behavior::component_types>>{}, args...);
 			}
 
 			virtual ~species_base() {}
@@ -102,8 +102,8 @@ namespace psemek::util
 			std::string name_;
 			species_handle id_;
 
-			template <typename Behavior, typename ... Components, std::size_t ... Is>
-			void apply_impl(Behavior & behavior, std::tuple<Components...> *, std::index_sequence<Is...>)
+			template <typename Behavior, typename ... Components, std::size_t ... Is, typename ... Args>
+			void apply_impl(Behavior & behavior, std::tuple<Components...> *, std::index_sequence<Is...>, Args const & ... args)
 			{
 				std::tuple<typename Components::data * ...> cptrs;
 
@@ -123,13 +123,13 @@ namespace psemek::util
 
 				auto visit = [&](auto * ... ptrs)
 				{
-					if constexpr (std::is_invocable_v<Behavior, typename Components::data & ..., typename Behavior::context const &>)
+					if constexpr (std::is_invocable_v<Behavior, typename Components::data & ..., typename Behavior::context const &, Args const & ...>)
 					{
-						behavior(*ptrs..., ctx);
+						behavior(*ptrs..., ctx, args...);
 					}
 					else
 					{
-						behavior(*ptrs...);
+						behavior(*ptrs..., args...);
 					}
 				};
 
@@ -460,11 +460,11 @@ namespace psemek::util
 		template <typename Component>
 		typename Component::data const * get_if(entity_handle entity) const;
 
-		template <typename Behavior>
-		void apply(Behavior && behavior);
+		template <typename Behavior, typename ... Args>
+		void apply(Behavior && behavior, Args const & ... args);
 
-		template <typename Behavior>
-		void apply(Behavior && behavior, species_handle species);
+		template <typename Behavior, typename ... Args>
+		void apply(Behavior && behavior, species_handle species, Args const & ... args);
 
 	private:
 		std::vector<std::unique_ptr<ecs_detail::species_base>> species_;
@@ -560,17 +560,17 @@ namespace psemek::util
 		return const_cast<typename Component::data const *>(const_cast<ecs *>(this)->get_if<Component>(entity));
 	}
 
-	template <typename Behavior>
-	void ecs::apply(Behavior && behavior)
+	template <typename Behavior, typename ... Args>
+	void ecs::apply(Behavior && behavior, Args const & ... args)
 	{
 		for (auto & s : species_)
-			s->apply(behavior);
+			s->apply(behavior, args...);
 	}
 
-	template <typename Behavior>
-	void ecs::apply(Behavior && behavior, species_handle species)
+	template <typename Behavior, typename ... Args>
+	void ecs::apply(Behavior && behavior, species_handle species, Args const & ... args)
 	{
-		species_[species.value]->apply(behavior);
+		species_[species.value]->apply(behavior, args...);
 	}
 
 }