public class HeightMap
{

float[][] heightMap;

public HeightMap (String fileName)
{
    int height, width;
    try
    {
        BufferedImage image = ImageIO.read(getClass().getResourceAsStream(fileName));
        heightMap = new float[image.getWidth()][image.getHeight()];
        for (int x = 0; x < image.getHeight(); ++x)
        {
            for (int z = 0; z < image.getWidth(); ++z)
            {
                heightMap[x][z] = new Color(image.getRGB(x, z)).getRed() / 255f;
            }
        }
    }
    catch (IOException e)
    {
        e.printStackTrace();
    }
}