Add a simple animation manager to util

libs/util/include/psemek/util/animation_manager.hpp

@@ -0,0 +1,80 @@
+#pragma once
+
+#include <vector>
+#include <algorithm>
+#include <cmath>
+
+namespace psemek::util
+{
+
+	template <typename Time, typename Data>
+	struct animation_manager
+	{
+		struct animation
+		{
+			Time time;
+			Time duration;
+			Data data;
+
+			Time position() const
+			{
+				return std::max(Time{0}, std::min(Time{1}, time / duration));
+			}
+
+			Time remaining() const
+			{
+				return duration - time;
+			}
+
+			bool finished() const
+			{
+				return remaining() <= Time{0};
+			}
+		};
+
+		void add(Time duration, Data data)
+		{
+			animations_.push_back(animation{Time{0}, duration, data});
+			std::push_heap(animations_.begin(), animations_.end(), compare{});
+		}
+
+		void update(Time dt)
+		{
+			for (auto & animation : animations_)
+				animation.time += dt;
+
+			while (!animations_.empty() && animations_.front().finished())
+			{
+				std::pop_heap(animations_.begin(), animations_.end(), compare{});
+				animations_.pop_back();
+			}
+		}
+
+		animation const * begin() const
+		{
+			return animations_.data();
+		}
+
+		animation const * end() const
+		{
+			return animations_.data() + animations_.size();
+		}
+
+		std::size_t size() const
+		{
+			return animations_.size();
+		}
+
+	private:
+		std::vector<animation> animations_;
+
+		struct compare
+		{
+			bool operator() (animation const & a1, animation const & a2)
+			{
+				return a1.remaining() > a2.remaining();
+			}
+		};
+	};
+
+}