HalfspaceTypes.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Math/UnrealMath.h"
#include "VectorTypes.h"
#include "VectorUtil.h"
 
namespace UE
{
namespace Geometry
{
 
using namespace UE::Math;
 
/*
 * 3D Halfspace stored as parameters to Plane Equation (Normal, Normal.Dot(PointOnPlane))
 * The Normal points "into" the halfspace, ie X is inside if (Normal.Dot(X) - Constant) >= 0
 */
template<typename T>
struct THalfspace3
{
public:
    TVector<T> Normal = TVector<T>::UnitY();
    T Constant = (T)0;
 
    THalfspace3() = default;
 
    THalfspace3(const TVector<T>& PlaneNormalIn, T ConstantIn)
        : Normal(PlaneNormalIn), Constant(ConstantIn) {}
 
    THalfspace3(T NormalX, T NormalY, T NormalZ, T ConstantIn)
        : Normal(NormalX,NormalY,NormalZ), Constant(ConstantIn) {}
 
 
    THalfspace3(const TVector<T>& PlaneNormalIn, const TVector<T>& PlanePoint)
        : Normal(PlaneNormalIn), Constant(Normal.Dot(PlanePoint)) {}
 
    THalfspace3(const TVector<T>& P0, const TVector<T>& P1, const TVector<T>& P2)
    {
        Normal = VectorUtil::Normal(P0, P1, P2);
        Constant = Normal.Dot(P0);
    }
 
 
    bool Contains(const TVector<T>& Point) const
    {
        return (Normal.Dot(Point) - Constant) >= 0;
    }
 
};
 
 
typedef THalfspace3<float> FHalfspace3f;
typedef THalfspace3<double> FHalfspace3d;
 
 
} // end namespace UE::Geometry
} // end namespace UE