/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 1991-2008 OpenCFD Ltd.
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software; you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by the
    Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM; if not, write to the Free Software Foundation,
    Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

Class
    Foam::triangleFuncs

Description
    Various triangle functions.

SourceFiles
    triangleFuncs.C

\*---------------------------------------------------------------------------*/

#ifndef triangleFuncs_H
#define triangleFuncs_H

#include "point.H"
#include "label.H"
#include "scalar.H"
#include "pointField.H"

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

namespace Foam
{

// Forward declaration of classes
class treeBoundBox;

/*---------------------------------------------------------------------------*\
                           Class triangleFuncs Declaration
\*---------------------------------------------------------------------------*/

class triangleFuncs
{

public:

    // Public data types

        //- Enumeration defining nearness classification
        enum proxType
        {
            NONE,
            POINT,
            EDGE
        };


private:

    // Private Member Functions

        //- Helper function for intersect. Sets pt to be anywhere on the edge
        //  between oppositeSidePt and thisSidePt depending on both signs.
        static void setIntersection
        (
            const point& oppositeSidePt,
            const scalar oppositeSign,
            const point& thisSidePt,
            const scalar thisSign,
            const scalar tol,
            point& pt
        );

        //- Helper function.
        static void selectPt
        (
            const bool select0,
            const point& p0,
            const point& p1,
            point& min
        );

public:

    //- Intersect triangle with parallel edges aligned with axis i0.
    //  Returns true (and intersection in pInter) if any of them intersects
    //  triangle. Used in intersectBb.
    static bool intersectAxesBundle
    (
        const point& V0,
        const point& V10,
        const point& V20,
        const label i0,
        const pointField& origin,
        const scalar maxLength,
        point& pInter
    );

    //- Does triangle intersect bounding box.
    static bool intersectBb
    (
        const point& p0,
        const point& p1,
        const point& p2,
        const treeBoundBox& cubeBb
    );

    //- Does triangle intersect plane. Return bool and set intersection segment.
    static bool intersect
    (
        const point& va0,
        const point& va10,
        const point& va20,

        const point& basePoint,
        const vector& normal,

        point& pInter0,
        point& pInter1
    );

    //- Do triangles intersect. Return bool and set intersection segment.
    static bool intersect
    (
        const point& va0,
        const point& va10,
        const point& va20,

        const point& vb0,
        const point& vb10,
        const point& vb20,

        point& pInter0,
        point& pInter1
    );


    //- Classify point on triangle plane w.r.t. triangle edges.
    //  - inside/outside (returned)
    //  - near point (0, 1, 2)
    //  - near edge (0, 1, 2). Note: edges are counted from starting vertex
    //    so e.g. edge 2 is from f[2] to f[0]
    static bool classify
    (
        const point& baseVertex,
        const vector& E0,
        const vector& E1,
        const vector& n,
        const point& pInter,
        const scalar tol,
        label& nearType,
        label& nearLabel
    );

};


// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

} // End namespace Foam

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

#endif

// ************************************************************************* //