for(int j=margin.wid; j<buf_size.hei - margin.wid; ++j)
    for(int i=margin.hei; i<buf_size.wid - margin.hei; ++i)
    {
        if(pos.x-margin.wid+i > _i*Size && pos.y-margin.hei+j > _j*Size
        && pos.x-margin.wid+i < (_i+1)*Size && pos.y-margin.hei+j < (_j+1)*Size )
        {
            unsigned c = raw_data[ (i + j*(int)buf_size.wid) << 1 ];
            shadows_pixels.setpixel(pos.x+i-margin.wid - _i*Size, pos.y+j-margin.hei - _j*Size, c);
        }
    }