From 4f53537d27a2221ca73e08370ca03c4a13efa007 Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Fri, 23 Jul 2021 23:28:44 +0300
Subject: [PATCH] Support non-default-constructible per-species component types
 in util::ecs

---
 libs/util/include/psemek/util/ecs.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libs/util/include/psemek/util/ecs.hpp b/libs/util/include/psemek/util/ecs.hpp
index d652b1f4..dc0dff52 100644
--- a/libs/util/include/psemek/util/ecs.hpp
+++ b/libs/util/include/psemek/util/ecs.hpp
@@ -53,7 +53,7 @@ namespace psemek::util
 			template <typename Behavior>
 			void apply(Behavior & behavior)
 			{
-				apply_impl(behavior, 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>>{});
 			}
 
 			virtual ~species_base() {}
@@ -65,12 +65,12 @@ namespace psemek::util
 
 		private:
 
-			template <typename Behavior, typename ... Components>
-			void apply_impl(Behavior & behavior, std::tuple<Components...>)
+			template <typename Behavior, typename ... Components, std::size_t ... Is>
+			void apply_impl(Behavior & behavior, std::tuple<Components...> *, std::index_sequence<Is...>)
 			{
 				std::tuple<typename Components::data * ...> cptrs;
 
-				((std::get<typename Components::data *>(cptrs) = get_entity_component<Components>()), ...);
+				((std::get<Is>(cptrs) = get_entity_component<Components>()), ...);
 
 				auto all_nonzero = [](auto * ... ptrs)
 				{