added tuple.hlsl

Author: keptsecret

include/nbl/builtin/hlsl/tuple.hlsl

@@ -0,0 +1,61 @@
+// Copyright (C) 2025 - DevSH Graphics Programming Sp. z O.O.
+// This file is part of the "Nabla Engine".
+// For conditions of distribution and use, see copyright notice in nabla.h
+#ifndef _NBL_BUILTIN_HLSL_TUPLE_INCLUDED_
+#define _NBL_BUILTIN_HLSL_TUPLE_INCLUDED_
+
+#include "nbl/builtin/hlsl/type_traits.hlsl"
+
+namespace nbl
+{
+namespace hlsl
+{
+
+template<typename T0, typename T1=void, typename T2=void> // TODO: in the future use BOOST_PP to make this
+struct tuple
+{
+    T0 t0;
+    T1 t1;
+    T2 t2;
+};
+
+template<uint32_t N, typename Tuple>
+struct tuple_element;
+
+template<typename T0>
+struct tuple<T0,void,void>
+{
+   T0 t0;
+};
+
+template<typename T0, typename T1>
+struct tuple<T0,T1,void>
+{
+   T0 t0;
+   T1 t1;
+};
+// specializations for less and less void elements
+
+// base case
+template<typename Head, typename T1, typename T2>
+struct tuple_element<0,tuple<Head,T1,T2> >
+{
+   using type = Head;
+};
+
+template<typename T0, typename Head, typename T2>
+struct tuple_element<1,tuple<T0,Head,T2> >
+{
+   using type = Head;
+};
+
+template<typename T0, typename T1, typename Head>
+struct tuple_element<2,tuple<T0,T1,Head> >
+{
+   using type = Head;
+};
+
+}
+}
+
+#endif