Pulling combination matrices

**
 * This restores the matrix transformation at a combination by taking leaf matrix tranformations,    Innverting
 * and storing the changes at the combinations.
 */
static void
comb_mat_restore(struct db_i *dbip, struct rt_comb_internal *UNUSED(comb), union tree *comb_leaf, genptr_t user_ptr1, genptr_t (user_ptr2), genptr_t UNUSED(user_ptr3), genptr_t UNUSED(user_ptr4))
{
    struct directory *dp;
    struct bu_vls *msg = (struct bu_vls *)user_ptr1;
    mat_t inv_mat;
    matp_t mat = (matp_t)user_ptr2;

    RT_CK_DBI(dbip);
    RT_CK_TREE(comb_leaf);

    if ((dp = db_lookup(dbip, comb_leaf->tr_l.tl_name, LOOKUP_NOISY)) == RT_DIR_NULL)
    return;

    /* invert the matrix transformation of the leaf and store new matrix  at comb */
    bn_mat_inverse(inv_mat, &mat);

    /* multiply inverse and store at combination */
    bn_mat_mul2(inv_mat,comb_leaf->tr_l.tl_mat);

    MAT_COPY(&mat,comb_leaf->tr_l.tl_mat);

    comb_restore(dp, dbip, mat);
}


/**
 *@brief
 *comb_restore(): This routine enters a comb restoring the matrix transformation at the combination
 *                calls and calls do_comb_restore() which updates current matrix transformation and moves up tree.
 */
void
comb_restore(struct dbi *dbip,
             struct directory *dp,
             (matp_t mp)
{
    struct rt_db_internal intern;
    struct rt_comb_internal *comb;

    if (dp->d_flags & RT_DIR_SOLID)
        return;
    if (rt_db_get_internal(&intern, dp, dbip, (fastf_t *)NULL, &rt_uniresource) < 0) {
    bu_vls_printf(msg, "Database read error, aborting\n");
    return;
    }
    comb = (struct rt_comb_internal *)intern.idb_ptr;

    if (comb->tree) {
    db_tree_funcleaf(dbip, comb, comb->tree, comb_mat_restore,
             (genptr_t)mp, (genptr_t)NULL, (genptr_t)NULL);
    if (rt_db_put_internal(dp, dbip, &intern, &rt_uniresource) < 0) {
        bu_vls_printf(msg, "Cannot write modified combination (%s) to database\n", dp->d_namep);
        return;
    }
    }
}