public void setLibre(int x, int y) {
   int axe, xtemp, ytemp;
   Case cas;
   xtemp = x;
   ytemp = y * this.nbCasesLignes;
   axe = xtemp + ytemp;
   cas = this.grille.get(axe);
   for (int i = 0; i < cas.getBatiment().getTailleX(); i++) {
     for (int j = 0; j < cas.getBatiment().getTailleY(); j++) {
       xtemp = (x + i);
       ytemp = (y + j) * this.nbCasesLignes;
       axe = xtemp + ytemp;
       cas = this.grille.get(axe);
       cas.setVide();
     }
   }
 }