Core/ApplicationBase: Add support for updaters with intervals

include/Nazara/Core/ApplicationUpdater.inl

@@ -13,9 +13,59 @@ namespace Nz
 	}
 
 	template<typename F>
-	void ApplicationUpdaterFunctor<F>::Update(Time elapsedTime)
+	Time ApplicationUpdaterFunctor<F>::Update(Time elapsedTime)
 	{
-		m_functor(elapsedTime);
+		if constexpr (std::is_invocable_v<F, Time>)
+			return TriggerFunctor(elapsedTime);
+		else if constexpr (std::is_invocable_v<F>)
+			return TriggerFunctor();
+		else
+			static_assert(AlwaysFalse<F>(), "updater functor must be callable with a Time or nothing");
+	}
+
+	template<typename F>
+	template<typename... Args>
+	Time ApplicationUpdaterFunctor<F>::TriggerFunctor(Args&&... args)
+	{
+		if constexpr (std::is_same_v<std::invoke_result_t<F, Args...>, Time>)
+			return m_functor(std::forward<Args>(args)...);
+		else if constexpr (std::is_same_v<std::invoke_result_t<F, Args...>, void>)
+		{
+			m_functor(std::forward<Args>(args)...);
+			return Time::Zero();
+		}
+		else
+			static_assert(AlwaysFalse<F>(), "updater functor must either return Time or void");
+	}
+
+
+	template<typename F, bool FixedInterval>
+	ApplicationUpdaterFunctorWithInterval<F, FixedInterval>::ApplicationUpdaterFunctorWithInterval(F functor, Time interval) :
+	m_interval(interval),
+	m_functor(std::move(functor))
+	{
+	}
+
+	template<typename F, bool FixedInterval>
+	Time ApplicationUpdaterFunctorWithInterval<F, FixedInterval>::Update(Time elapsedTime)
+	{
+		if constexpr (std::is_invocable_v<F, Time>)
+		{
+			if constexpr (FixedInterval)
+				m_functor(m_interval);
+			else
+				m_functor(elapsedTime);
+		}
+		else
+		{
+			static_assert(std::is_invocable_v<F>, "updater functor must be callable with a Time or nothing");
+			m_functor();
+		}
+
+		if constexpr (FixedInterval)
+			return -m_interval;
+		else
+			return m_interval;
 	}
 }