brep2sdf/code/pre_processing/ParametricSample/Mathematics/Circle3.h

// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2021
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
// https://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// Version: 4.0.2019.08.13

#pragma once

#include <Mathematics/Vector3.h>

// The circle is the intersection of the sphere |X-C|^2 = r^2 and the
// plane Dot(N,X-C) = 0, where C is the circle center, r is the radius,
// and N is a unit-length plane normal.

namespace gte
{
    template <typename Real>
    class Circle3
    {
    public:

        // Construction and destruction.  The default constructor sets center
        // to (0,0,0), normal to (0,0,1), and radius to 1.
        Circle3()
            :
            center(Vector3<Real>::Zero()),
            normal(Vector3<Real>::Unit(2)),
            radius((Real)1)
        {
        }

        Circle3(Vector3<Real> const& inCenter, Vector3<Real> const& inNormal, Real inRadius)
            :
            center(inCenter),
            normal(inNormal),
            radius(inRadius)
        {
        }

        // Public member access.
        Vector3<Real> center, normal;
        Real radius;

    public:
        // Comparisons to support sorted containers.
        bool operator==(Circle3 const& circle) const
        {
            return center == circle.center
                && normal == circle.normal
                && radius == circle.radius;
        }

        bool operator!=(Circle3 const& circle) const
        {
            return !operator==(circle);
        }

        bool operator< (Circle3 const& circle) const
        {
            if (center < circle.center)
            {
                return true;
            }

            if (center > circle.center)
            {
                return false;
            }

            if (normal < circle.normal)
            {
                return true;
            }

            if (normal > circle.normal)
            {
                return false;
            }

            return radius < circle.radius;
        }

        bool operator<=(Circle3 const& circle) const
        {
            return !circle.operator<(*this);
        }

        bool operator> (Circle3 const& circle) const
        {
            return circle.operator<(*this);
        }

        bool operator>=(Circle3 const& circle) const
        {
            return !operator<(circle);
        }
    };
}