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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: 4.0.2021.05.06
#pragma once
#include <Mathematics/IntrIntervals.h>
#include <Mathematics/IntrLine2Triangle2.h>
#include <Mathematics/Segment.h>
// The queries consider the triangle to be a solid.
namespace gte
{
template <typename Real>
class TIQuery<Real, Segment2<Real>, Triangle2<Real>>
{
public:
struct Result
{
Result()
:
intersect(false)
{
}
bool intersect;
};
Result operator()(Segment2<Real> const& segment, Triangle2<Real> const& triangle)
{
Result result{};
FIQuery<Real, Segment2<Real>, Triangle2<Real>> stQuery;
result.intersect = stQuery(segment, triangle).intersect;
return result;
}
};
template <typename Real>
class FIQuery <Real, Segment2<Real>, Triangle2<Real>>
:
public FIQuery<Real, Line2<Real>, Triangle2<Real>>
{
public:
struct Result
:
public FIQuery<Real, Line2<Real>, Triangle2<Real>>::Result
{
// No additional information to compute.
};
Result operator()(Segment2<Real> const& segment, Triangle2<Real> const& triangle)
{
Vector2<Real> segOrigin, segDirection;
Real segExtent;
segment.GetCenteredForm(segOrigin, segDirection, segExtent);
Result result{};
DoQuery(segOrigin, segDirection, segExtent, triangle, result);
if (result.numIntersections == 2)
{
result.point[0] = segOrigin + result.parameter[0] * segDirection;
result.point[1] = segOrigin + result.parameter[1] * segDirection;
}
else if (result.numIntersections == 1)
{
result.point[0] = segOrigin + result.parameter[0] * segDirection;
result.point[1] = result.point[0];
}
// else: result set to no-intersection in DoQuery(...)
return result;
}
protected:
void DoQuery(Vector2<Real> const& segOrigin,
Vector2<Real> const& segDirection, Real segExtent,
Triangle2<Real> const& triangle, Result& result)
{
FIQuery<Real, Line2<Real>, Triangle2<Real>>::DoQuery(segOrigin,
segDirection, triangle, result);
if (result.intersect)
{
// The line containing the segment intersects the triangle;
// the t-interval is [t0,t1]. The segment intersects the
// triangle 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);
if (iiResult.intersect)
{
result.numIntersections = iiResult.numIntersections;
result.parameter = iiResult.overlap;
}
else
{
// Set the state to no-intersection.
result = Result{};
}
}
}
};
}