triangle_3d.inl

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/** @file
 *  @author Bram de Greve (bramz@users.sourceforge.net)
 *  @author Tom De Muer (tomdemuer@users.sourceforge.net)
 *
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 *  The contents of this file are subject to the Common Public Attribution License 
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 *  with Exhibit B.
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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.
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 *  *** END LICENSE INFORMATION ***
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#ifndef LASS_GUARDIAN_OF_INCLUSION_PRIM_SIMPLE_TRIANGLE_3D_INL
#define LASS_GUARDIAN_OF_INCLUSION_PRIM_SIMPLE_TRIANGLE_3D_INL

#include "prim_common.h"
#include "triangle_3d.h"

namespace lass
{
namespace prim
{

/** constructs an empty triangle.
 *  all vertices are (0, 0) and thus equal.
 */
template <typename T>
Triangle3D<T>::Triangle3D()
{
}



/** Constructs a triangle through three points in positive sequence.
 */
template <typename T>
Triangle3D<T>::Triangle3D(const TPoint& iA, const TPoint& iB, const TPoint& iC)
{
    vertices_[0] = iA;
    vertices_[1] = iB;
    vertices_[2] = iC;
}



/** @copydoc SimplePolygon3D::operator[]
 */
template <typename T>
const typename Triangle3D<T>::TPoint&
Triangle3D<T>::operator[](int iIndexOfVertex) const
{
    LASS_ASSERT(isInRange(iIndexOfVertex));
    return vertices_[iIndexOfVertex];
}



/** @copydoc SimplePolygon3D::operator[]
 */
template <typename T>
typename Triangle3D<T>::TPoint&
Triangle3D<T>::operator[](int iIndexOfVertex)
{
    LASS_ASSERT(isInRange(iIndexOfVertex));
    return vertices_[iIndexOfVertex];
}



/** @copydoc SimplePolygon3D::at
 */
template <typename T>
const typename Triangle3D<T>::TPoint&
Triangle3D<T>::at(int iIndexOfVertex) const
{
    const int i = num::mod(iIndexOfVertex, static_cast<unsigned>(size_));
    LASS_ASSERT(isInRange(i));
    return vertices_[i];
}



/** @copydoc SimplePolygon3D::at
 */
template <typename T>
typename Triangle3D<T>::TPoint&
Triangle3D<T>::at(int iIndexOfVertex)
{
    const int i = num::mod(iIndexOfVertex, static_cast<unsigned>(size_));
    LASS_ASSERT(isInRange(i));
    return vertices_[i];
}



/** @copydoc SimplePolygon3D::edge
 */
template <typename T>
const typename Triangle3D<T>::TLineSegment
Triangle3D<T>::edge(int iIndexOfTailVertex) const
{
    return TLineSegment(at(iIndexOfTailVertex), at(iIndexOfTailVertex + 1));
}



/** @copydoc SimplePolygon3D::vector
 */
template <typename T>
const typename Triangle3D<T>::TVector
Triangle3D<T>::vector(int iIndexOfTailVertex) const
{
    return at(iIndexOfTailVertex + 1) - at(iIndexOfTailVertex);
}



/** @copydoc SimplePolygon3D::plane
 */
template <typename T>
const typename Triangle3D<T>::TPlane
Triangle3D<T>::plane() const
{
    return TPlane(vertices_[0], vertices_[1], vertices_[2]);
}



/** @copydoc SimplePolygon3D::isEmpty
 *  @par Triangle specific:
 *      if all vertices are equal, we assume the triangle is empty
 */
template <typename T>
const bool Triangle3D<T>::isEmpty() const
{
    return vertices_[0] == vertices_[1] && vertices_[0] == vertices_[2];
}



/** @copydoc SimplePolygon3D::size
 */
template <typename T>
const int Triangle3D<T>::size() const
{
    return size_;
}



/** returns squared area of triangle to avoid the square root.
 *  @return num::sqr(area()) but faster :)
 */
template <typename T>
const typename Triangle3D<T>::TValue
Triangle3D<T>::squaredArea() const
{
    LASS_ASSERT(size_ == 3);
    return cross(vertices_[1] - vertices_[0], vertices_[2] - vertices_[0]).squaredNorm() / 4;
}



/** @copydoc SimplePolygon3D::area
 */
template <typename T>
const typename Triangle3D<T>::TValue
Triangle3D<T>::area() const
{
    return num::sqrt(squaredArea());
}



/** @copydoc SimplePolygon3D::perimeter
 */
template <typename T>
const typename Triangle3D<T>::TValue
Triangle3D<T>::perimeter() const
{
    return distance(vertices_[0], vertices_[1]) +
           distance(vertices_[1], vertices_[2]) +
           distance(vertices_[2], vertices_[0]);
}



/** @copydoc SimplePolygon3D::vertexCentroid
 */
template <typename T>
const typename Triangle3D<T>::TPointH
Triangle3D<T>::vertexCentroid() const
{
    TPointH result = vertices_[0] + vertices_[1] + vertices_[2];
    return result;
}



/** @copydoc SimplePolygon3D::surfaceCentroid
 */
template <typename T> inline
const typename Triangle3D<T>::TPointH
Triangle3D<T>::surfaceCentroid() const
{
    return vertexCentroid();
}



/** @copydoc SimplePolygon3D::isSimple
 *  @par Triangle specific:
 *      A triangle is always simple
 */
template <typename T>
const bool Triangle3D<T>::isSimple() const
{
    return true;
}



/** @copydoc SimplePolygon3D::isConvex
 *  @par Triangle specific:
 *      A triangle is always convex
 */
template <typename T>
const bool Triangle3D<T>::isConvex() const
{
    return true;
}



/** @copydoc SimplePolygon3D::isReflex
 *  @par Triangle specific:
 *  A triangle never has reflex vertices
 */
template <typename T>
const bool Triangle3D<T>::isReflex(int iIndexOfVertex) const
{
    return false;
}



// --- private -------------------------------------------------------------------------------------

/** return if index of vertex is in range of the std::vector
 */
template <typename T>
const bool Triangle3D<T>::isInRange(int iIndexOfVertex) const
{
    return iIndexOfVertex >= 0 && iIndexOfVertex < size_;
}



// --- free ----------------------------------------------------------------------------------------

/** @relates lass::prim::Triangle3D
 */
template <typename T>
io::XmlOStream& operator<<(io::XmlOStream& ioOStream, const Triangle3D<T>& iTriangle)
{
    LASS_ENFORCE_STREAM(ioOStream) << "<Triangle3D>\n";
    for (unsigned i = 0; i < 3; ++i)
    {
        ioOStream << "<vertex id='" << i << "'>" << iTriangle[i] << "</vertex>\n";
    }
    ioOStream << "</Triangle3D>\n";
    return ioOStream;
}



/** @relates lass::prim::Triangle3D
 */
template <typename T>
std::ostream& operator<<(std::ostream& ioOStream, const Triangle3D<T>& iTriangle)
{
    LASS_ENFORCE_STREAM(ioOStream) 
        << "{" << iTriangle[0] << ", " << iTriangle[1] << ", " << iTriangle[2] << "}";
    return ioOStream;
}



}

}

#endif

// EOF