float player_bottom = player.get_y() + player.get_height();
float tiles_bottom = tiles.get_y() + tiles.get_height();
float player_right = player.get_x() + player.get_width();
float tiles_right = tiles.get_x() + tiles.get_width();

float b_collision = tiles_bottom - player.get_y();
float t_collision = player_bottom - tiles.get_y();
float l_collision = player_right - tiles.get_x();
float r_collision = tiles_right - player.get_x();

if (t_collision < b_collision && t_collision < l_collision && t_collision < r_collision )
{                           
//Top collision
}
if (b_collision < t_collision && b_collision < l_collision && b_collision < r_collision)                        
{
//bottom collision
}
if (l_collision < r_collision && l_collision < t_collision && l_collision < b_collision)
{
//Left collision
}
if (r_collision < l_collision && r_collision < t_collision && r_collision < b_collision )
{
//Right collision
}