public void setVertices(float x0, float y0, float z0,
                          float x1, float y1, float z1,
                          float x2, float y2, float z2) {
    x_array[0] = x0;
    x_array[1] = x1;
    x_array[2] = x2;

    y_array[0] = y0;
    y_array[1] = y1;
    y_array[2] = y2;

    z_array[0] = z0;
    z_array[1] = z1;
    z_array[2] = z2;
  }