point_sampler.h

/*****************************************************************************
 * VCLib                                                                     *
 * Visual Computing Library                                                  *
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 * Copyright(C) 2021-2025                                                    *
 * Visual Computing Lab                                                      *
 * ISTI - Italian National Research Council                                  *
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 * 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_SPACE_COMPLEX_SAMPLER_POINT_SAMPLER_H
#define VCL_SPACE_COMPLEX_SAMPLER_POINT_SAMPLER_H
 
#include <vclib/algorithms/core/polygon.h>
#include <vclib/concepts/mesh/elements/edge.h>
#include <vclib/concepts/mesh/elements/face.h>
#include <vclib/concepts/mesh/elements/vertex.h>
#include <vclib/concepts/space/sampler.h>
 
namespace vcl {
 
template<PointConcept PointT = Point3d>
class PointSampler
{
    std::vector<PointT> mSamples;
 
public:
    using PointType     = PointT;
    using ScalarType    = PointT::ScalarType;
    using ConstIterator = std::vector<PointT>::const_iterator;
 
    PointSampler() = default;
 
    const std::vector<PointT>& samples() const { return mSamples; }
 
    const PointT& sample(uint i) const { return mSamples[i]; }
 
    std::size_t size() const { return mSamples.size(); }
 
    void clear() { mSamples.clear(); }
 
    void reserve(uint n) { mSamples.reserve(n); }
 
    void resize(uint n) { mSamples.resize(n); }
 
    void add(const PointT& p) { mSamples.push_back(p); }
 
    void set(uint i, const PointT& p) { mSamples[i] = p; }
 
    template<VertexConcept VertexType>
    void add(const VertexType& v)
    {
        mSamples.push_back(v.coord());
    }
 
    template<VertexConcept VertexType>
    void set(uint i, const VertexType& v)
    {
        mSamples[i] = v.coord();
    }
 
    template<EdgeConcept EdgeType>
    void add(const EdgeType& e, double u = 0.5)
    {
        mSamples.push_back(
            (e.vertex(0).coord() * (1 - u)) + (e.vertex(1).coord() * u));
    }
 
    template<EdgeConcept EdgeType>
    void set(uint i, const EdgeType& e, double u = 0.5)
    {
        mSamples[i] =
            (e.vertex(0).coord() * (1 - u)) + (e.vertex(1).coord() * u);
    }
 
    template<FaceConcept FaceType>
    void add(const FaceType& f)
    {
        mSamples.push_back(faceBarycenter(f));
    }
 
    template<FaceConcept FaceType>
    void set(uint i, const FaceType& f)
    {
        mSamples[i] = faceBarycenter(f);
    }
 
    template<FaceConcept FaceType>
    void add(const FaceType& f, const std::vector<ScalarType>& barCoords)
    {
        assert(f.vertexNumber() <= barCoords.size());
 
        PointT p;
        for (uint i = 0; i < f.vertexNumber(); i++)
            p += f.vertex(i)->coord() * barCoords[i];
 
        mSamples.push_back(p);
    }
 
    template<FaceConcept FaceType>
    void set(
        uint                           i,
        const FaceType&                f,
        const std::vector<ScalarType>& barCoords)
    {
        assert(f.vertexNumber() <= barCoords.size());
 
        PointT p;
        for (uint i = 0; i < f.vertexNumber(); i++)
            p += f.vertex(i)->coord() * barCoords[i];
 
        mSamples[i] = p;
    }
 
    template<FaceConcept FaceType>
    void add(const FaceType& f, const PointT& barCoords)
    {
        static_assert(FaceType::NV == 3 || FaceType::NV == -1);
        if constexpr (FaceType::NV == -1) {
            assert(f.vertexNumber() == 3);
        }
 
        PointT p = triangleBarycentricCoordinatePoint(f, barCoords);
 
        mSamples.push_back(p);
    }
 
    template<FaceConcept FaceType>
    void set(uint i, const FaceType& f, const PointT& barCoords)
    {
        static_assert(FaceType::NV == 3 || FaceType::NV == -1);
        if constexpr (FaceType::NV == -1) {
            assert(f.vertexNumber() == 3);
        }
 
        PointT p = triangleBarycentricCoordinatePoint(f, barCoords);
 
        mSamples[i] = p;
    }
 
    ConstIterator begin() const { return mSamples.begin(); }
 
    ConstIterator end() const { return mSamples.end(); }
};
 
} // namespace vcl
 
#endif // VCL_SPACE_COMPLEX_SAMPLER_POINT_SAMPLER_H