CapsuleTypes.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Math/UnrealMath.h"
#include "VectorTypes.h"
#include "SegmentTypes.h"
#include "BoxTypes.h"
#include "OrientedBoxTypes.h"
 
 
namespace UE 
{
namespace Geometry 
{
 
using namespace UE::Math;
 
/*
 * 3D Capsule stored as Line Segment and Radius
 */
template<typename T>
struct TCapsule3
{
public:
    TSegment3<T> Segment;
    T Radius = (T)0;
 
    TCapsule3() = default;
 
    TCapsule3(const TSegment3<T>& SegmentIn, T RadiusIn)
        : Segment(SegmentIn), Radius(RadiusIn) {}
 
    TCapsule3(const TVector<T>& StartPoint, const TVector<T>& EndPoint, T RadiusIn)
        : Segment(StartPoint, EndPoint), Radius(RadiusIn) {}
 
 
    const TVector<T>& Center() const
    {
        return Segment.Center;
    }
 
    const TVector<T>& Direction() const
    {
        return Segment.Direction;
    }
 
    T Length() const
    {
        return (T)2 * Segment.Extent;
    }
 
    T Extent() const
    {
        return Segment.Extent;
    }
 
    T Volume() const
    {
        return Volume(Radius, Segment.Extent);
    }
 
    TAxisAlignedBox3<T> GetBounds() const
    {
        return Segment.GetBounds(Radius);
    }
 
    TOrientedBox3<T> GetOrientedBounds() const
    {
        return TOrientedBox3<T>(
            TFrame3<T>(Segment.Center, Segment.Direction),
            TVector<T>(Radius, Radius, Segment.Extent));
    }
 
    bool Contains(const TVector<T>& Point) const
    {
        T DistSqr = Segment.DistanceSquared(Point);
        return DistSqr <= Radius * Radius;
    }
 
 
    inline T DistanceSquared(const TVector<T>& Point) const
    {
        const T PosDistance = TMathUtil<T>::Max(SignedDistance(Point), (T)0);
        return PosDistance * PosDistance;
    }
 
    inline T SignedDistance(const TVector<T>& Point) const
    {
        T SqrDist = Segment.DistanceSquared(Point);
        return TMathUtil<T>::Sqrt(SqrDist) - Radius;
    }
 
    //
    // Sphere utility functions
    //
 
    static T Volume(T Radius, T Extent)
    {
        T PiRadSqr = TMathUtil<T>::Pi * Radius * Radius;
        return 
            (PiRadSqr * ((T)2 * Extent)) +              // cylinder vol = (pi*r^2)*length
            ((T)(4.0 / 3.0) * PiRadSqr * Radius);
    }
 
 
};
 
 
typedef TCapsule3<float> FCapsule3f;
typedef TCapsule3<double> FCapsule3d;
 
 
} // end namespace UE::Geometry
} // end namespace UE