#pragma once

#include "glm/glm.hpp"
#include <memory>

// Hash function for Eigen matrix and vector.
// The code is from `hash_combine` function of the Boost library. See
// http://www.boost.org/doc/libs/1_55_0/doc/html/hash/reference.html#boost.hash_combine .

template<glm::length_t L, typename T, glm::qualifier Q>
struct std::hash<glm::vec<L, T, Q>>
{
	auto operator() (const glm::vec<L, T, Q>& key) const
	{
		auto seed = std::size_t{};

		for (glm::length_t i{}; i != L; ++i)
		{
			seed ^= std::hash<T>{}(key[i]) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
		}

		return seed;
	}
};