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