initial commit, 4.5 stable

thirdparty/jolt_physics/Jolt/Geometry/MortonCode.h

@@ -0,0 +1,40 @@
+// Jolt Physics Library (https://github.com/jrouwe/JoltPhysics)
+// SPDX-FileCopyrightText: 2021 Jorrit Rouwe
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#include <Jolt/Geometry/AABox.h>
+
+JPH_NAMESPACE_BEGIN
+
+class MortonCode
+{
+public:
+	/// First converts a floating point value in the range [0, 1] to a 10 bit fixed point integer.
+	/// Then expands a 10-bit integer into 30 bits by inserting 2 zeros after each bit.
+	static uint32 sExpandBits(float inV)
+	{
+		JPH_ASSERT(inV >= 0.0f && inV <= 1.0f);
+		uint32 v = uint32(inV * 1023.0f + 0.5f);
+		JPH_ASSERT(v < 1024);
+		v = (v * 0x00010001u) & 0xFF0000FFu;
+		v = (v * 0x00000101u) & 0x0F00F00Fu;
+		v = (v * 0x00000011u) & 0xC30C30C3u;
+		v = (v * 0x00000005u) & 0x49249249u;
+		return v;
+	}
+
+	/// Calculate the morton code for inVector, given that all vectors lie in inVectorBounds
+	static uint32 sGetMortonCode(Vec3Arg inVector, const AABox &inVectorBounds)
+	{
+		// Convert to 10 bit fixed point
+		Vec3 scaled = (inVector - inVectorBounds.mMin) / inVectorBounds.GetSize();
+		uint x = sExpandBits(scaled.GetX());
+		uint y = sExpandBits(scaled.GetY());
+		uint z = sExpandBits(scaled.GetZ());
+		return (x << 2) + (y << 1) + z;
+	}
+};
+
+JPH_NAMESPACE_END