Intersector1.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    Intersector1.h  ported from WildMagic5
=============================================================================*/
 
#pragma once
 
#include "Math/UnrealMath.h"
#include "VectorTypes.h"
#include "BoxTypes.h"
 
namespace UE
{
namespace Geometry
{
 
template<typename RealType>
class TIntersector1
{
private:
    TInterval1<RealType> Intersections;
 
public:
    TInterval1<RealType> U;
    TInterval1<RealType> V;
 
    int NumIntersections = 0;
 
    TIntersector1(RealType u0, RealType u1, RealType v0, RealType v1) : Intersections(0,0), U(u0, u1), V(v0, v1)
    {
        check(u0 <= u1);
        check(v0 <= v1);
    }
 
    TIntersector1(const TInterval1<RealType>& u, const TInterval1<RealType>& v) : Intersections(0, 0), U(u), V(v)
    {
    }
 
    bool Test() const
    {
        return U.Min <= V.Max && U.Max >= V.Min;
    }
 
    RealType GetIntersection(int i)
    {
        return i == 0 ? Intersections.Min : Intersections.Max;
    }
 
    bool Find()
    {
        if ((U.Max < V.Min) || (U.Min > V.Max))
        {
            NumIntersections = 0;
        }
        else if (U.Max > V.Min) 
        {
            if (U.Min < V.Max) 
            {
                NumIntersections = 2;
                Intersections.Min = (U.Min < V.Min ? V.Min : U.Min);
                Intersections.Max = (U.Max > V.Max ? V.Max : U.Max);
                if (Intersections.Min == Intersections.Max) 
                {
                    NumIntersections = 1;
                }
            }
            else 
            {
                // U.Min == V.Max
                NumIntersections = 1;
                Intersections.Min = U.Min;
            }
        }
        else 
        {
            // U.Max == V.Min
            NumIntersections = 1;
            Intersections.Min = U.Max;
        }
 
        return NumIntersections > 0;
    }
 
};
 
typedef TIntersector1<double> FIntersector1d;
typedef TIntersector1<float> FIntersector1f;
 
} // end namespace UE::Geometry
} // end namespace UE