intersect_edge_2d.h

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/** @file
 *  @author Bram de Greve (bramz@users.sourceforge.net)
 *  @author Tom De Muer (tomdemuer@users.sourceforge.net)
 *
 *  *** BEGIN LICENSE INFORMATION ***
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 *  The contents of this file are subject to the Common Public Attribution License 
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 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
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 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
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 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
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#ifndef LASS_GUARDIAN_OF_INCLUSION_PRIM_IMPL_INTERSECT_EDGE_2D_H
#define LASS_GUARDIAN_OF_INCLUSION_PRIM_IMPL_INTERSECT_EDGE_2D_H

#include "../../num/floating_point_consistency.h"

namespace lass
{
namespace prim
{
namespace impl
{

/** @internal
 */
template <typename Point, typename Vector, typename T> inline
bool intersectEdge2D(const Point& iSupport, const Vector& iDirection, 
                     const Point& iTail, const Point& iHead, 
                     T& oTNear, const T& iMinT)
{
    typedef typename Point::TNumTraits TNumTraits;
    typedef num::Consistent<T> TConsistent;

    LASS_ASSERT(oTNear > iMinT);

    const Vector edge = iHead - iTail;
    const T denominator = perpDot(iDirection, -edge);
    if (denominator != TNumTraits::zero)
    {
        const Vector difference = iTail - iSupport;
        const TConsistent tRay = perpDot(difference, -edge) / denominator;
        const T tEdge = perpDot(iDirection, difference) / denominator;
        if ((tRay > iMinT && tRay < oTNear) && 
            (tEdge >= TNumTraits::zero && tEdge <= TNumTraits::one))
        {
            oTNear = tRay.value();
            LASS_ASSERT(oTNear > iMinT);
            return true;
        }
    }
    return false;
}

}

}

}

#endif

// EOF