contour-creator/HeightMap.cpp

#include <gdal/gdal.h>
#include "gdal/gdal_priv.h"
#include <iostream>

#include <stdfloat>

#include "HeightMap.hh"

HeightMap::HeightMap(const char* filepath) 
{
    // Open the file with some gdal nonsense:
    const GDALAccess eAccess = GA_ReadOnly;
    GDALDatasetUniquePtr file;
    GDALAllRegister();
    file = GDALDatasetUniquePtr(GDALDataset::FromHandle(GDALOpen( filepath, eAccess )));
    if( !file )
    {
        std::cout << "Could not open tiff file!"; // handle error
    }
    
    // The heigthmap only has one band
    auto band = file->GetBands()[0];
    // write the attrributes
    this->x_size = band->GetXSize();
    this->y_size = band->GetYSize();
    
    this->data = (float *) CPLMalloc(sizeof(float)*x_size*y_size);
    band->RasterIO( GF_Read, 0, 0, x_size, y_size,
                    this->data, x_size, y_size, GDT_Float32,
                    0, 0 );
    
    band->FlushCache();
}
float HeightMap::get_pixel(int x, int y)
{
    // all the pixels are in an array of floats from left to right, top to bottom
    int offset = ((this->x_size * y) + x);
    return *(this->data + offset);
}