public void push(State state) {
   ModelMatrixElement prev = (ModelMatrixElement) getNextInStack();
   if (prev != null) {
     matrix.set(prev.matrix);
   }
 }
 /** Multiplies this element by the given matrix. */
 public void multElt(Mat4f matrix) {
   temp.set(this.matrix);
   this.matrix.mul(temp, matrix);
 }
 public ModelMatrixElement() {
   matrix = new Mat4f();
   matrix.makeIdent();
 }
 /** Sets this element to the identity matrix. */
 public void makeEltIdent() {
   matrix.makeIdent();
 }