int curr_base_len = nb;
int next_base_len = 0;
- if ( is_tree_42 || is_tree_31 )
+ if ( true )
+ { // ------------------------------------------------------------------
+ // New algorithm implemented by request of IPAL22856
+ // "2D quadrangle mesher of reduced type works wrong"
+ // http://bugtracker.opencascade.com/show_bug.cgi?id=22856
+
+ // the algorithm is following: all reduces are centred in horizontal
+ // direction and are distributed among all rows
+
+ if (ncol_bot > max_tree42) {
+ is_lin_31 = true;
+ }
+ else {
+ if ((ncol_top/3)*3 == ncol_top ) {
+ is_lin_31 = true;
+ }
+ else {
+ is_lin_42 = true;
+ }
+ }
+
+ const int col_top_size = is_lin_42 ? 2 : 1;
+ const int col_base_size = is_lin_42 ? 4 : 3;
+
+ // Compute nb of "columns" (like in "linear" simple reducing) in all rows
+
+ vector<int> nb_col_by_row;
+
+ int delta_all = nb - nt;
+ int delta_one_col = nrows * 2;
+ int nb_col = delta_all / delta_one_col;
+ int remainder = delta_all - nb_col * delta_one_col;
+ if (remainder > 0) {
+ nb_col++;
+ }
+ if ( nb_col * col_top_size >= nt ) // == "tree" reducing situation
+ {
+ // top row is full (all elements reduced), add "columns" one by one
+ // in rows below until all bottom elements are reduced
+ nb_col = ( nt - 1 ) / col_top_size;
+ nb_col_by_row.resize( nrows, nb_col );
+ int nbrows_not_full = nrows - 1;
+ int cur_top_size = nt - 1;
+ remainder = delta_all - nb_col * delta_one_col;
+ while ( remainder > 0 )
+ {
+ delta_one_col = nbrows_not_full * 2;
+ int nb_col_add = remainder / delta_one_col;
+ cur_top_size += 2 * nb_col_by_row[ nbrows_not_full ];
+ int nb_col_free = cur_top_size / col_top_size - nb_col_by_row[ nbrows_not_full-1 ];
+ if ( nb_col_add > nb_col_free )
+ nb_col_add = nb_col_free;
+ for ( int irow = 0; irow < nbrows_not_full; ++irow )
+ nb_col_by_row[ irow ] += nb_col_add;
+ nbrows_not_full --;
+ remainder -= nb_col_add * delta_one_col;
+ }
+ }
+ else // == "linear" reducing situation
+ {
+ nb_col_by_row.resize( nrows, nb_col );
+ if (remainder > 0)
+ for ( int irow = remainder / 2; irow < nrows; ++irow )
+ nb_col_by_row[ irow ]--;
+ }
+
+ // Make elements
+
+ PReduceFunction reduceFunction = & ( is_lin_42 ? reduce42 : reduce31 );
+
+ const int reduce_grp_size = is_lin_42 ? 4 : 3;
+
+ for (i = 1; i < nr; i++) // layer by layer
+ {
+ nb_col = nb_col_by_row[ i-1 ];
+ int nb_next = curr_base_len - nb_col * 2;
+ if (nb_next < nt) nb_next = nt;
+
+ const double y = uv_el[ i ].normParam;
+
+ if ( i + 1 == nr ) // top
+ {
+ next_base = uv_et;
+ }
+ else
+ {
+ next_base.clear();
+ next_base.resize( nb_next, nullUVPtStruct );
+ next_base.front() = uv_el[i];
+ next_base.back() = uv_er[i];
+
+ // compute normalized param u
+ double du = 1. / ( nb_next - 1 );
+ next_base[0].normParam = 0.;
+ for ( j = 1; j < nb_next; ++j )
+ next_base[j].normParam = next_base[j-1].normParam + du;
+ }
+ uv[ UV_L ].SetCoord( next_base.front().u, next_base.front().v );
+ uv[ UV_R ].SetCoord( next_base.back().u, next_base.back().v );
+
+ int free_left = ( curr_base_len - 1 - nb_col * col_base_size ) / 2;
+ int free_middle = curr_base_len - 1 - nb_col * col_base_size - 2 * free_left;
+
+ // not reduced left elements
+ for (j = 0; j < free_left; j++)
+ {
+ // f (i + 1, j + 1)
+ const SMDS_MeshNode*& Nf = next_base[++next_base_len].node;
+ if ( !Nf )
+ Nf = makeNode( next_base[ next_base_len ], y, quad, uv, myHelper, S );
+
+ myHelper->AddFace(curr_base[ j ].node,
+ curr_base[ j+1 ].node,
+ Nf,
+ next_base[ next_base_len-1 ].node);
+ }
+
+ for (int icol = 1; icol <= nb_col; icol++)
+ {
+ // add "H"
+ reduceFunction( curr_base, next_base, j, next_base_len, quad, uv, y, myHelper, S );
+
+ j += reduce_grp_size;
+
+ // elements in the middle of "columns" added for symmetry
+ if ( free_middle > 0 && ( nb_col % 2 == 0 ) && icol == nb_col / 2 )
+ {
+ for (int imiddle = 1; imiddle <= free_middle; imiddle++) {
+ // f (i + 1, j + imiddle)
+ const SMDS_MeshNode*& Nf = next_base[++next_base_len].node;
+ if ( !Nf )
+ Nf = makeNode( next_base[ next_base_len ], y, quad, uv, myHelper, S );
+
+ myHelper->AddFace(curr_base[ j-1+imiddle ].node,
+ curr_base[ j +imiddle ].node,
+ Nf,
+ next_base[ next_base_len-1 ].node);
+ }
+ j += free_middle;
+ }
+ }
+
+ // not reduced right elements
+ for (; j < curr_base_len-1; j++) {
+ // f (i + 1, j + 1)
+ const SMDS_MeshNode*& Nf = next_base[++next_base_len].node;
+ if ( !Nf )
+ Nf = makeNode( next_base[ next_base_len ], y, quad, uv, myHelper, S );
+
+ myHelper->AddFace(curr_base[ j ].node,
+ curr_base[ j+1 ].node,
+ Nf,
+ next_base[ next_base_len-1 ].node);
+ }
+
+ curr_base_len = next_base_len + 1;
+ next_base_len = 0;
+ curr_base.swap( next_base );
+ }
+
+ }
+ else if ( is_tree_42 || is_tree_31 )
{
// "tree" simple reduce "42": 2->4->8->16->32->...
//
} // end "linear" simple reduce
else {
+ return false;
}
} // end Simple Reduce implementation
