/* See dg_makegrid.h */
/* Last edited on 2009-05-18 14:16:47 by stolfi */

#include <dg_makegrid.h>
#include <dg_tree.h>
#include <bz_basic.h>
#include <bz_patch.h>
#include <stdio.h>
#include <math.h>
#include <affirm.h>
#include <assert.h>

dg_tree_node_t *dg_make_grid
  ( mdg_dim_t d,
    mdg_cell_index_t k,
    mdg_rank_t r,
    bz_patch_t *b,
    dg_tree_node_t *p,
    mdg_cell_predicate_t *split
  )
  { dg_tree_node_t *n = NULL;
    fprintf(stderr, "+ dg_make_grid  cell = %lld  rank = %d\n", k, r); 
    affirm(r < mdg_MAX_RANK, "max rank exceeded");
    dg_tree_node_t *ch[2];
    if (split(k, r, b, p))
      { dg_tree_node_t *pch[2];  /* Enclosing nodes of children */
        int i;
        /* Node is not a leaf: */
        mdg_axis_t ax = mdg_split_axis(d, r); /* Splitting axis. */
        /* Split Bézier patch: */
        bz_patch_t bzch[2], *bch[2];
        if (b == NULL)
          { bch[0] = bch[1] = NULL; }
        else
          { bzch[0] = bz_patch_new(b->m, b->n, b->g); bch[0] = &(bzch[0]);
            bzch[1] = bz_patch_new(b->m, b->n, b->g); bch[1] = &(bzch[1]);
            bz_patch_split(b, ax, 0.5, bch[0], bch[1]);
          }
        /* Generate subtrees: */
        dg_tree_node_enclose_children(p, pch);
        for (i = 0; i < 2; i++)
          { ch[i] = dg_make_grid(d, 2*k + i, r+1, bch[i], pch[i], split);
            if (b != NULL) { bz_patch_free(bzch[i]); }
          }
        /* If both subtrees are empty, omit cell too: */
        assert((ch[0] != NULL) && (ch[1] != NULL));
        n = dg_tree_node_new(NULL, k);
        for (i = 0; i < 2; i++)
          { n->ch[i] = ch[i];
            if (ch[i] != NULL) 
              { n->nodes += ch[i]->nodes;
                ch[i]->pa = n;
              }
          }
      }
    else
      { /* Node is a leaf: */
        n = dg_tree_node_new(NULL, k);
      }
    fprintf(stderr, "- dg_make_grid  cell = %lld  rank = %d\n", k, r); 
    return n;
  }