Graphics: Add DistanceAsSortKey function

include/Nazara/Graphics/Algorithm.inl

@@ -0,0 +1,37 @@
+// Copyright (C) 2020 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Graphics module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Graphics/Algorithm.hpp>
+#include <cmath>
+#include <cstring>
+#include <limits>
+#include <Nazara/Graphics/Debug.hpp>
+
+namespace Nz
+{
+	inline UInt32 DistanceAsSortKey(float distance)
+	{
+#if defined(arm) && \
+    ((defined(__MAVERICK__) && defined(NAZARA_BIG_ENDIAN)) || \
+    (!defined(__SOFTFP__) && !defined(__VFP_FP__) && !defined(__MAVERICK__)))
+#error The following code relies on native-endian IEEE-754 representation, which your platform does not guarantee
+#endif
+
+		static_assert(sizeof(float) == sizeof(UInt32));
+		static_assert(std::numeric_limits<float>::is_iec559);
+
+		if (std::isnan(distance))
+			return std::numeric_limits<UInt32>::max();
+
+		if (std::isinf(distance))
+			return 0;
+
+		UInt32 distanceInt;
+		std::memcpy(&distanceInt, &distance, sizeof(UInt32));
+
+		return ~distanceInt; //< Reverse distance to have back to front
+	}
+}
+
+#include <Nazara/Graphics/DebugOff.hpp>