contour-creator/src/main.cpp

#include "contour_creator.hh"
#include <gdal/ogr_api.h>
#include "ogrsf_frmts.h"
#include <iostream>
#include <ostream>
#include <vector>
#include <cstdint>
#include <gdal/gdal.h>
#include "gdal/gdal_priv.h"
#include <gdal/gdal_frmts.h>
#include <omp.h>

CellMap produce_cellmap(HeightMap* heightmap, float z)
{
    int length = (heightmap->width-1)*(heightmap->height-1);
    uint8_t *cells = (uint8_t *) CPLMalloc(sizeof(uint8_t)*length);
    for (int i = 0; i<length; i++) {
        int y = i/(heightmap->width-1);
        int x = i%(heightmap->width-1);
        uint8_t result = (heightmap->get_pixel(x,y)>z) + 
        (heightmap->get_pixel(x+1,y)>z)*2 +
        (heightmap->get_pixel(x+1,y+1)>z)*4 +
        (heightmap->get_pixel(x,y+1)>z)*8;
        *(cells + i) = result;
    }
    
    return CellMap(heightmap->width-1, heightmap->height-1, cells, heightmap->reference_system);


}

std::vector<CellMap> vector_cellmap(HeightMap* heightmap, int interval)
{
    int num_contours = (heightmap->max - heightmap->min)/interval;
    std::vector<CellMap> vector_contours;
    omp_set_num_threads(12);

    #pragma omp parallel
    {
        std::vector<CellMap> vec_private;
        #pragma omp for
        for (int i = 1; i <= num_contours; i++) 
        {
            vec_private.push_back(produce_cellmap(heightmap, heightmap->min + interval*i));
        }
        #pragma omp critical
        vector_contours.insert(vector_contours.end(), vec_private.begin(), vec_private.end());

    }
        return vector_contours;
}

void write_output_file(std::vector<CellMap> cellmaps, const char *filepath)
{

    const char *pszDriverName = "ESRI Shapefile";
    GDALDriver *poDriver;

    GDALAllRegister();

    poDriver = GetGDALDriverManager()->GetDriverByName(pszDriverName );
    if( poDriver == NULL )
    {
        printf( "%s driver not available.\n", pszDriverName );
        exit( 1 );
    }

    GDALDataset *poDS;

    poDS = poDriver->Create( filepath, 0, 0, 0, GDT_Unknown, NULL );
    if( poDS == NULL )
    {
        printf( "Creation of output file failed.\n" );
        exit( 1 );
    }

    OGRLayer *poLayer;

    poLayer = poDS->CreateLayer( "contours", &(cellmaps[0]).reference_system, wkbPoint, NULL );
    if( poLayer == NULL )
    {
        printf( "Layer creation failed.\n" );
        exit( 1 );
    }

    OGRFieldDefn oField( "Name", OFTString );

    oField.SetWidth(32);

    if( poLayer->CreateField( &oField ) != OGRERR_NONE )
    {
        printf( "Creating Name field failed.\n" );
        exit( 1 );
    }
    for (int j = 0; j < cellmaps.size(); j++)
    {
        CellMap* cellmap = &cellmaps[j];
        for (int i = 0; i<cellmap->height*cellmap->width; i++) {
            if (*(cellmap->cells + i) != 0 && *(cellmap->cells + i) != 15)
            {
                int x_int = i%cellmap->width;
                int y_int = cellmap->height*cellmap->width - i/cellmap->width;
                double x = double(x_int);
                double y = double(y_int);

                OGRFeature *poFeature;

                poFeature = OGRFeature::CreateFeature( poLayer->GetLayerDefn() );
                poFeature->SetField( "Name", *(cellmap->cells + i) );

                //OGRSpatialReference local;

                //auto poCT = OGRCreateCoordinateTransformation( &local, &cellmap->reference_system );
                
                /*
                if( poCT == NULL || !poCT->Transform( 1, &x, &y ) )
                    printf( "Transformation failed.\n" );
                */
                OGRPoint pt;
                pt.setX( x );
                pt.setY( y );

                poFeature->SetGeometry( &pt );

                if( poLayer->CreateFeature( poFeature ) != OGRERR_NONE )
                {
                    printf( "Failed to create feature in shapefile.\n" );
                    exit( 1 );
                }

                OGRFeature::DestroyFeature( poFeature );
            }
        }
    }

    GDALClose( poDS );
    /*
    OGRDataSourceH datasource = OGR_Dr_CreateDataSource(OGRGetDriverByName("GeoJSON"), "contour.geojson", new char*);
    OGRSpatialReference reference_system = cellmap->reference_system;
    OGRLayerH layer = OGR_DS_CreateLayer(datasource, "contour", &reference_system, wkbLineString25D, new char*);
    
    auto feature = OGR_F_Create(OGR_L_GetLayerDefn(static_cast<OGRLayerH>(layer)));

    OGRGeometryH geometry = OGR_G_CreateGeometry(wkbLineString25D);
    */
}

int main(int argc, const char* argv[])
{
    const char* filepath = argv[1];
    HeightMap map(filepath); 
    
    std::cout << "x: " << map.width << "    y: " << map.height << "\n";
    std::cout << "max: " << map.max << "    min: " << map.min << "\n";
    
    auto cellmap = produce_cellmap(&map, 40);
    /*
    for (int y = 0; y < cellmap.height; y++)
    {
        for (int x = 0; x < cellmap.width; x++)
        {
            if (cellmap.get_cell(x, y) && cellmap.get_cell(x, y)!=15) {
                std::cout << x << ","<< y << "=" << cellmap.get_cell(x, y) << " ";
            }
        }
       //std::cout << "\n";
    }
    */
    
    auto cellmaps = vector_cellmap(&map, 5);
    write_output_file(cellmaps, "out.shp");
}