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// 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/IntrIntervals.h>
#include <Mathematics/IntrLine2Circle2.h>
#include <Mathematics/Segment.h>
// The queries consider the circle to be a solid (disk).
namespace gte
{
template <typename Real>
class TIQuery<Real, Segment2<Real>, Circle2<Real>>
{
public:
struct Result
{
bool intersect;
};
Result operator()(Segment2<Real> const& segment, Circle2<Real> const& circle)
{
Result result;
FIQuery<Real, Segment2<Real>, Circle2<Real>> scQuery;
result.intersect = scQuery(segment, circle).intersect;
return result;
}
};
template <typename Real>
class FIQuery<Real, Segment2<Real>, Circle2<Real>>
:
public FIQuery<Real, Line2<Real>, Circle2<Real>>
{
public:
struct Result
:
public FIQuery<Real, Line2<Real>, Circle2<Real>>::Result
{
// No additional information to compute.
};
Result operator()(Segment2<Real> const& segment, Circle2<Real> const& circle)
{
Vector2<Real> segOrigin, segDirection;
Real segExtent;
segment.GetCenteredForm(segOrigin, segDirection, segExtent);
Result result;
DoQuery(segOrigin, segDirection, segExtent, circle, result);
for (int i = 0; i < result.numIntersections; ++i)
{
result.point[i] = segOrigin + result.parameter[i] * segDirection;
}
return result;
}
protected:
void DoQuery(Vector2<Real> const& segOrigin,
Vector2<Real> const& segDirection, Real segExtent,
Circle2<Real> const& circle, Result& result)
{
FIQuery<Real, Line2<Real>, Circle2<Real>>::DoQuery(segOrigin,
segDirection, circle, result);
if (result.intersect)
{
// The line containing the segment intersects the disk; the
// t-interval is [t0,t1]. The segment intersects the disk as
// long as [t0,t1] overlaps the segment t-interval
// [-segExtent,+segExtent].
std::array<Real, 2> segInterval = { -segExtent, segExtent };
FIQuery<Real, std::array<Real, 2>, std::array<Real, 2>> iiQuery;
auto iiResult = iiQuery(result.parameter, segInterval);
result.intersect = iiResult.intersect;
result.numIntersections = iiResult.numIntersections;
result.parameter = iiResult.overlap;
}
}
};
}