brep2sdf/code/pre_processing/ParametricSample/Mathematics/Sector2.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/Vector2.h>

// A solid sector is the intersection of a disk and a 2D cone.  The disk
// has center C, radius R, and contains points X for which |X-C| <= R.  The
// 2D cone has vertex C, unit-length axis direction D, angle A in (0,pi)
// measured from D, and contains points X for which
// Dot(D,(X-C)/|X-C|) >= cos(A).  Sector points X satisfy both inequality
// constraints.

namespace gte
{
    template <typename Real>
    class Sector2
    {
    public:
        // Construction and destruction.  The default constructor sets the
        // vertex to (0,0), radius to 1, axis direction to (1,0), and angle
        // to pi, all of which define a disk.
        Sector2()
            :
            vertex(Vector2<Real>::Zero()),
            radius((Real)1),
            direction(Vector2<Real>::Unit(0)),
            angle((Real)GTE_C_PI),
            cosAngle((Real)-1),
            sinAngle((Real)0)
        {
        }

        Sector2(Vector2<Real> const& inVertex, Real inRadius,
            Vector2<Real> const& inDirection, Real inAngle)
            :
            vertex(inVertex),
            radius(inRadius),
            direction(inDirection)
        {
            SetAngle(inAngle);
        }

        // Set the angle and cos(angle) simultaneously.
        void SetAngle(Real inAngle)
        {
            angle = inAngle;
            cosAngle = std::cos(angle);
            sinAngle = std::sin(angle);
        }

        // Test whether P is in the sector. 
        bool Contains(Vector2<Real> const& p) const
        {
            Vector2<Real> diff = p - vertex;
            Real length = Length(diff);
            return length <= radius && Dot(direction, diff) >= length * cosAngle;
        }

        // The cosine and sine of the angle are used in queries, so all o
        // angle, cos(angle), and sin(angle) are stored. If you set 'angle'
        // via the public members, you must set all to be consistent.  You
        // can also call SetAngle(...) to ensure consistency.
        Vector2<Real> vertex;
        Real radius;
        Vector2<Real> direction;
        Real angle, cosAngle, sinAngle;

    public:
        // Comparisons to support sorted containers.
        bool operator==(Sector2 const& sector) const
        {
            return vertex == sector.vertex && radius == sector.radius
                && direction == sector.direction && angle == sector.angle;
        }

        bool operator!=(Sector2 const& sector) const
        {
            return !operator==(sector);
        }

        bool operator< (Sector2 const& sector) const
        {
            if (vertex < sector.vertex)
            {
                return true;
            }

            if (vertex > sector.vertex)
            {
                return false;
            }

            if (radius < sector.radius)
            {
                return true;
            }

            if (radius > sector.radius)
            {
                return false;
            }

            if (direction < sector.direction)
            {
                return true;
            }

            if (direction > sector.direction)
            {
                return false;
            }

            return angle < sector.angle;
        }

        bool operator<=(Sector2 const& sector) const
        {
            return !sector.operator<(*this);
        }

        bool operator> (Sector2 const& sector) const
        {
            return sector.operator<(*this);
        }

        bool operator>=(Sector2 const& sector) const
        {
            return !operator<(sector);
        }
    };
}