GteIntrSegment2OrientedBox2.h

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// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2017
// Distributed under the Boost Software License, Version 1.0.
// http://www.boost.org/LICENSE_1_0.txt
// http://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// File Version: 3.0.0 (2016/06/19)

#pragma once

#include <Mathematics/GteOrientedBox.h>
#include <Mathematics/GteIntrSegment2AlignedBox2.h>

// The queries consider the box to be a solid.
//
// The test-intersection queries use the method of separating axes.  The
// find-intersection queries use parametric clipping against the four edges of
// the box.

namespace gte
{

template <typename Real>
class TIQuery<Real, Segment2<Real>, OrientedBox2<Real>>
    :
    public TIQuery<Real, Segment2<Real>, AlignedBox2<Real>>
{
public:
    struct Result
        :
        public TIQuery<Real, Segment2<Real>, AlignedBox2<Real>>::Result
    {
        // No additional information to compute.
    };

    Result operator()(Segment2<Real> const& segment,
        OrientedBox2<Real> const& box);
};

template <typename Real>
class FIQuery<Real, Segment2<Real>, OrientedBox2<Real>>
    :
    public FIQuery<Real, Segment2<Real>, AlignedBox2<Real>>
{
public:
    struct Result
        :
        public FIQuery<Real, Segment2<Real>, AlignedBox2<Real>>::Result
    {
        // The base class parameter[] values are t-values for the
        // segment parameterization (1-t)*p[0] + t*p[1], where t in [0,1].
        // The values in this class are s-values for the centered form
        // C + s * D, where s in [-e,e] and e is the extent of the segment.
        std::array<Real, 2> cdeParameter;
    };

    Result operator()(Segment2<Real> const& segment,
        OrientedBox2<Real> const& box);
};


template <typename Real>
typename TIQuery<Real, Segment2<Real>, OrientedBox2<Real>>::Result
TIQuery<Real, Segment2<Real>, OrientedBox2<Real>>::operator()(
    Segment2<Real> const& segment, OrientedBox2<Real> const& box)
{
    // Transform the segment to the oriented-box coordinate system.
    Vector2<Real> tmpOrigin, tmpDirection;
    Real segExtent;
    segment.GetCenteredForm(tmpOrigin, tmpDirection, segExtent);
    Vector2<Real> diff = tmpOrigin - box.center;
    Vector2<Real> segOrigin
    {
        Dot(diff, box.axis[0]),
        Dot(diff, box.axis[1])
    };
    Vector2<Real> segDirection
    {
        Dot(tmpDirection, box.axis[0]),
        Dot(tmpDirection, box.axis[1])
    };

    Result result;
    this->DoQuery(segOrigin, segDirection, segExtent, box.extent, result);
    return result;
}

template <typename Real>
typename FIQuery<Real, Segment2<Real>, OrientedBox2<Real>>::Result
FIQuery<Real, Segment2<Real>, OrientedBox2<Real>>::operator()(
    Segment2<Real> const& segment, OrientedBox2<Real> const& box)
{
    // Transform the segment to the oriented-box coordinate system.
    Vector2<Real> tmpOrigin, tmpDirection;
    Real segExtent;
    segment.GetCenteredForm(tmpOrigin, tmpDirection, segExtent);
    Vector2<Real> diff = tmpOrigin - box.center;
    Vector2<Real> segOrigin
    {
        Dot(diff, box.axis[0]),
        Dot(diff, box.axis[1])
    };
    Vector2<Real> segDirection
    {
        Dot(tmpDirection, box.axis[0]),
        Dot(tmpDirection, box.axis[1])
    };

    Result result;
    this->DoQuery(segOrigin, segDirection, segExtent, box.extent, result);
    for (int i = 0; i < result.numIntersections; ++i)
    {
        // Compute the segment in the aligned-box coordinate system and then
        // translate it back to the original coordinates using the box cener.
        result.point[i] = box.center + (segOrigin + result.parameter[i] * segDirection);
        result.cdeParameter[i] = result.parameter[i];

        // Convert the parameters from the centered form to the endpoint form.
        result.parameter[i] = (result.parameter[i] / segExtent + (Real)1) * (Real)0.5;
    }
    return result;
}


}