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[Andreas Fabri <>]

Hello,

At least on Windows if you read a binary ply file you must open the stream in binary mode.

Can you try    std::ifstream ifs(fn, std::ios::binary);

Best,

Andreas

On 10/21/2021 1:20 AM, Yaoyu Hu ( via cgal-discuss Mailing List) wrote:

Hi,

I am trying to read a binary PLY file as CGAL::Point_set_3 but I can't get it right.

I am using CGAL 5.3.

I suppose there is not a dedicated example showing how to read a PLY file as Point_set_3 that has properties. For my PLY file, there are point normal and color stored. The code I tried to read it as CGAL::Point_set_3 is as follows:

=== Code begins. ===

typedef CGAL::Exact_predicates_inexact_constructions_kernel Kernel_t;
typedef Kernel_t::Point_3  Point_t;
typedef Kernel_t::Vector_3 Vector_t;
typedef std::array< unsigned char, 3 > Color_t;

typedef CGAL::Point_set_3<Point_t> PointSet_t;

typedef PointSet_t::Point_map PS_PointMap_t;
typedef PointSet_t::Vector_map PS_NormalMap_t;
typedef PointSet_t::Property_map<Color_t> PS_ColorMap_t;

PointSet_t sr::read_ply_as_point_set( const std::string& fn ) {
    std::ifstream ifs(fn);

    PointSet_t point_set;

    // Default color.
    const Color_t color_black { { 0, 0, 0 } };

    // The color map.
    PS_ColorMap_t color;
    bool success = false;
    boost::tie( color, success ) =
        point_set.add_property_map<Color_t>("color", color_black);
    assert (success);

    // Read PLY.
    CGAL::read_PLY_with_properties(
            ifs,
            point_set.index_back_inserter(),
            CGAL::make_ply_point_reader( PS_PointMap_t() ),
            CGAL::make_ply_normal_reader( PS_NormalMap_t() ),
            std::make_tuple( PS_ColorMap_t(), CGAL::Construct_array(), 
                             CGAL::PLY_property<unsigned char>("red"),
                             CGAL::PLY_property<unsigned char>("green"),
                             CGAL::PLY_property<unsigned char>("blue") ) ) )

    return point_set;
}

=== Code ends. ===

The codes that I am not sure about are the lines of CGAL::make_ply_point_reader() and CGAL::make_ply_normal_reader(), they are probably wrong but I don't know how to get it right.

Thanks!

Yaoyu

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-- 
Andreas Fabri, PhD
Chief Officer, GeometryFactory
Editor, The CGAL Project