1 files changed, 49 insertions, 0 deletions
diff --git a/lib/sorting.h b/lib/sorting.h
new file mode 100644
index 0000000..777de00
--- /dev/null
+++ b/lib/sorting.h
@@ -0,0 +1,49 @@
+#pragma once
+
+#include <glm/fwd.hpp>
+#include <type_traits>
+
+template<typename T> struct PtrSorter {
+	bool
+	operator()(const T & a, const T & b) const
+	{
+		return *a < *b;
+	}
+};
+
+template<typename T, auto M> struct PtrMemberSorter : public PtrSorter<T> {
+	using MT = std::decay_t<decltype((*T {}).*M)>;
+	using is_transparent = MT;
+
+	using PtrSorter<T>::operator();
+
+	bool
+	operator()(const MT & a, const T & b) const
+	{
+		return a < (*b).*M;
+	}
+
+	bool
+	operator()(const T & a, const MT & b) const
+	{
+		return (*a).*M < b;
+	}
+};
+
+struct CompareBy {
+	glm::length_t index;
+
+	template<typename T>
+	auto
+	operator()(const T & a, const T & b) const
+	{
+		return get(a) < get(b);
+	}
+
+	template<typename T>
+	auto
+	get(const T & a) const
+	{
+		return a[index];
+	}
+};