From c3999d708fb61f9a5c8052a31ee63833bfb683e2 Mon Sep 17 00:00:00 2001
From: Lynix <lynix680@gmail.com>
Date: Mon, 18 Oct 2021 16:46:03 +0200
Subject: [PATCH] Graphics: Add DistanceAsSortKey function

---
 include/Nazara/Graphics/Algorithm.hpp         | 19 ++++++++++
 include/Nazara/Graphics/Algorithm.inl         | 37 +++++++++++++++++++
 include/Nazara/Graphics/RenderSpriteChain.inl | 16 ++------
 include/Nazara/Graphics/RenderSubmesh.inl     | 16 ++------
 src/Nazara/Graphics/AlgorithmGraphics.cpp     | 10 +++++
 5 files changed, 72 insertions(+), 26 deletions(-)
 create mode 100644 include/Nazara/Graphics/Algorithm.hpp
 create mode 100644 include/Nazara/Graphics/Algorithm.inl
 create mode 100644 src/Nazara/Graphics/AlgorithmGraphics.cpp

diff --git a/include/Nazara/Graphics/Algorithm.hpp b/include/Nazara/Graphics/Algorithm.hpp
new file mode 100644
index 000000000..3bd996b50
--- /dev/null
+++ b/include/Nazara/Graphics/Algorithm.hpp
@@ -0,0 +1,19 @@
+// 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
+
+#pragma once
+
+#ifndef NAZARA_ALGORITHM_GRAPHICS_HPP
+#define NAZARA_ALGORITHM_GRAPHICS_HPP
+
+#include <Nazara/Prerequisites.hpp>
+
+namespace Nz
+{
+	inline UInt32 DistanceAsSortKey(float distance);
+}
+
+#include <Nazara/Graphics/Algorithm.inl>
+
+#endif
diff --git a/include/Nazara/Graphics/Algorithm.inl b/include/Nazara/Graphics/Algorithm.inl
new file mode 100644
index 000000000..22eee99a8
--- /dev/null
+++ b/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>
diff --git a/include/Nazara/Graphics/RenderSpriteChain.inl b/include/Nazara/Graphics/RenderSpriteChain.inl
index 5576967a6..b124f6f2d 100644
--- a/include/Nazara/Graphics/RenderSpriteChain.inl
+++ b/include/Nazara/Graphics/RenderSpriteChain.inl
@@ -3,6 +3,7 @@
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
 #include <Nazara/Graphics/RenderSpriteChain.hpp>
+#include <Nazara/Graphics/Algorithm.hpp>
 #include <Nazara/Graphics/Debug.hpp>
 
 namespace Nz
@@ -32,19 +33,8 @@ namespace Nz
 		{
 			UInt64 matFlags = 1;
 
-#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));
-
-			float distanceNear = frustum.GetPlane(Nz::FrustumPlane::Near).Distance(m_worldInstance.GetWorldMatrix().GetTranslation());
-			UInt32 distanceInt;
-			std::memcpy(&distanceInt, &distanceNear, sizeof(UInt32));
-
-			UInt64 distance = static_cast<UInt64>(~distanceInt); //< Reverse distance to have back to front
+			float distanceNear = frustum.GetPlane(FrustumPlane::Near).Distance(m_worldInstance.GetWorldMatrix().GetTranslation());
+			UInt64 distance = DistanceAsSortKey(distanceNear);
 
 			// Transparent RQ index:
 			// - Layer (8bits)
diff --git a/include/Nazara/Graphics/RenderSubmesh.inl b/include/Nazara/Graphics/RenderSubmesh.inl
index 860793541..92e6451a5 100644
--- a/include/Nazara/Graphics/RenderSubmesh.inl
+++ b/include/Nazara/Graphics/RenderSubmesh.inl
@@ -3,6 +3,7 @@
 // For conditions of distribution and use, see copyright notice in Config.hpp
 
 #include <Nazara/Graphics/RenderSubmesh.hpp>
+#include <Nazara/Graphics/Algorithm.hpp>
 #include <Nazara/Graphics/Debug.hpp>
 
 namespace Nz
@@ -31,19 +32,8 @@ namespace Nz
 		{
 			UInt64 matFlags = 1;
 
-#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));
-
-			float distanceNear = frustum.GetPlane(Nz::FrustumPlane::Near).Distance(m_worldInstance.GetWorldMatrix().GetTranslation());
-			UInt32 distanceInt;
-			std::memcpy(&distanceInt, &distanceNear, sizeof(UInt32));
-
-			UInt64 distance = ~distanceInt; //< Reverse distance to have back to front
+			float distanceNear = frustum.GetPlane(FrustumPlane::Near).Distance(m_worldInstance.GetWorldMatrix().GetTranslation());
+			UInt64 distance = DistanceAsSortKey(distanceNear);
 
 			// Transparent RQ index:
 			// - Layer (8bits)
diff --git a/src/Nazara/Graphics/AlgorithmGraphics.cpp b/src/Nazara/Graphics/AlgorithmGraphics.cpp
new file mode 100644
index 000000000..421dd7e74
--- /dev/null
+++ b/src/Nazara/Graphics/AlgorithmGraphics.cpp
@@ -0,0 +1,10 @@
+// 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 <Nazara/Graphics/Debug.hpp>
+
+namespace Nz
+{
+}