RasterToMesh.h

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// SPDX-FileCopyrightText: Copyright (c) OpenGeoSys Community (opengeosys.org)
// SPDX-License-Identifier: BSD-3-Clause
 
#pragma once
 
#include "GeoLib/Raster.h"
#include "MeshLib/MeshEnums.h"
#include "MeshLib/Properties.h"
 
class vtkImageData;  // For conversion from Image to QuadMesh
 
namespace MeshLib
{
 
class Mesh;
class Node;
class Element;
template <typename T>
class PropertyVector;
}  // namespace MeshLib
 
namespace MeshToolsLib
{

class RasterToMesh
{
public:
    static std::unique_ptr<MeshLib::Mesh> convert(
        GeoLib::Raster const& raster,
        MeshLib::MeshElemType elem_type,
        MeshLib::UseIntensityAs intensity_type,
        std::string const& array_name = "Colour");

    static std::unique_ptr<MeshLib::Mesh> convert(
        vtkImageData* img,
        const double origin[3],
        const double scalingFactor,
        MeshLib::MeshElemType elem_type,
        MeshLib::UseIntensityAs intensity_type,
        std::string const& array_name = "Colour");

    static std::unique_ptr<MeshLib::Mesh> convert(
        const double* const img,
        GeoLib::RasterHeader const& header,
        MeshLib::MeshElemType elem_type,
        MeshLib::UseIntensityAs intensity_type,
        std::string const& array_name = "Colour");
 
private:
    template <typename T>
    static void fillPropertyVector(MeshLib::PropertyVector<T>& prop_vec,
                                   double const* const img,
                                   GeoLib::RasterHeader const& header,
                                   MeshLib::MeshElemType elem_type)
    {
        // each pixel is represented by two cells for triangles and prisms
        bool const two_elements_per_cell =
            (elem_type == MeshLib::MeshElemType::TRIANGLE) ||
            (elem_type == MeshLib::MeshElemType::PRISM);
        std::size_t const elements_per_cell = two_elements_per_cell ? 2 : 1;
 
        // The iterator is filled below without growing prop_vec again.
        auto out = MeshLib::extend(
            prop_vec,
            header.n_depth * header.n_cols * header.n_rows * elements_per_cell);
 
        for (std::size_t k = 0; k < header.n_depth; k++)
        {
            std::size_t const layer_idx = (k * header.n_rows * header.n_cols);
            for (std::size_t i = 0; i < header.n_cols; i++)
            {
                std::size_t idx(i * header.n_rows + layer_idx);
                for (std::size_t j = 0; j < header.n_rows; j++)
                {
                    auto val(static_cast<T>(img[idx + j]));
                    *out++ = val;
                    if (two_elements_per_cell)
                    {
                        *out++ = val;
                    }
                }
            }
        }
    }
};
 
}  // namespace MeshToolsLib