void Terrain::move (float xMove) {
    if (xMove < 0) return;

    if (_startTerrain) {
        
        if (xMove > 0 && _gapSize < 5) 
            _increaseGapTimer += xMove;
        
        if (_increaseGapTimer > _increaseGapInterval) {
            _increaseGapTimer = 0;
            _gapSize += 1;
        }
    }
    
    this->setPositionX(this->getPositionX() - xMove);
    
   auto  block = _blocks.at(0);  
   if (_position.x + block->getWidth() < 0) {
      auto firstBlock = _blocks.at(0);
      _blocks.erase(0);
      _blocks.pushBack(firstBlock);
      _position.x +=  block->getWidth();
      
      float width_cnt = this->getWidth() - block->getWidth() - ( _blocks.at(0))->getWidth();
      this->initBlock(block);
      this->addBlocks(width_cnt);
    }
}