barycenter.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
 *                                                                           *
 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
 *                                                                           *
 * All rights reserved.                                                      *
 *                                                                           *
 * This program is free software; you can redistribute it and/or modify      *
 * it under the terms of the Mozilla Public License Version 2.0 as published *
 * by the Mozilla Foundation; either version 2 of the License, or            *
 * (at your option) any later version.                                       *
 *                                                                           *
 * This program 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              *
 * Mozilla Public License Version 2.0                                        *
 * (https://www.mozilla.org/en-US/MPL/2.0/) for more details.                *
 ****************************************************************************/
 
#ifndef VCL_ALGORITHMS_MESH_STAT_BARYCENTER_H
#define VCL_ALGORITHMS_MESH_STAT_BARYCENTER_H
 
#include <vclib/concepts/mesh.h>
#include <vclib/mesh/requirements.h>
 
namespace vcl {
 
template<MeshConcept MeshType>
typename MeshType::VertexType::CoordType barycenter(const MeshType& m)
{
    using VertexType = MeshType::VertexType;
    using CoordType  = VertexType::CoordType;
 
    CoordType bar;
 
    for (const VertexType& v : m.vertices()) {
        bar += v.coord();
    }
 
    return bar / m.vertexNumber();
}
 
template<MeshConcept MeshType>
typename MeshType::VertexType::CoordType scalarWeightedBarycenter(
    const MeshType& m)
{
    requirePerVertexQuality(m);
 
    using VertexType  = MeshType::VertexType;
    using CoordType   = VertexType::CoordType;
    using QualityType = VertexType::QualityType;
 
    CoordType   bar;
    QualityType weightedSum = 0;
 
    for (const VertexType& v : m.vertices()) {
        bar += v.coord() * v.quality();
        weightedSum += v.quality();
    }
 
    return bar / weightedSum;
}
 
template<FaceMeshConcept MeshType>
typename MeshType::VertexType::CoordType shellBarycenter(const MeshType& m)
{
    using VertexType = MeshType::VertexType;
    using FaceType   = MeshType::FaceType;
    using CoordType  = VertexType::CoordType;
    using ScalarType = CoordType::ScalarType;
 
    CoordType bar;
    bar.setZero();
    ScalarType areaSum = 0;
 
    for (const FaceType& f : m.faces()) {
        ScalarType area = faceArea(f);
        bar += faceBarycenter(f) * area;
        areaSum += area;
    }
 
    return bar / areaSum;
}
 
} // namespace vcl
 
#endif // VCL_ALGORITHMS_MESH_STAT_BARYCENTER_H