barycentric.C

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    Copyright (C) 2020 OpenCFD Ltd.
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License
    This file is part of OpenFOAM.
 
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#include "barycentric.H"
#include "Random.H"
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
static inline Foam::barycentric barycentric01Impl
(
    Foam::scalar s,
    Foam::scalar t,
    Foam::scalar u
)
{
    // Transform the random point in the unit cube to a random point in the
    // unit tet by means of a series of reflections. See
    // <http://vcg.isti.cnr.it/jgt/tetra.htm> for details.
 
    if (s + t > 1)
    {
        s = 1 - s;
        t = 1 - t;
    }
 
    if (s + t + u > 1)
    {
        Foam::scalar temp = u;
 
        if (t + u > 1)
        {
            u = 1 - s - t;
            t = 1 - temp;
        }
        else
        {
            u = s + t + u - 1;
            s = 1 - t - temp;
        }
    }
 
    return Foam::barycentric(1 - s - t - u, s, t, u);
}
 
 
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
Foam::barycentric Foam::barycentric01(Random& rndGen)
{
    const scalar s(rndGen.sample01<scalar>());
    const scalar t(rndGen.sample01<scalar>());
    const scalar u(rndGen.sample01<scalar>());
 
    return barycentric01Impl(s, t, u);
}
 
 
// ************************************************************************* //