About TGS neighbor traversable conditions ambiguity

[Acuno41]

Hello,
Thanks for the great work !
As I was using the traversable ground segmentation, I came across the neighbor traversable conditions code lines in below and i cant quite understand the skipping conditions.
I would be very grateful if you explain how should we check neighbors ? and what should their reject and acceptance criterias ?
Because it looks like if field set visited true once it wont be checked again. an so on.

Best regards.

TRAVEL/include/travel/tgs.hpp

Lines 923 to 940 in 17a0bdd

	if (tgf_in[n_i.row][n_i.col][n_i.tri].depth >=0){
	continue;
	}
	if (tgf_in[n_i.row][n_i.col][n_i.tri].is_visited) {
	if (!tgf_in[n_i.row][n_i.col][n_i.tri].need_recheck){
	continue;
	} else {
	if (tgf_in[n_i.row][n_i.col][n_i.tri].check_life <= 0){
	continue;
	}
	}
	continue;
	} else {
	if (tgf_in[n_i.row][n_i.col][n_i.tri].node_type != GROUND) {
	continue;
	}
	}

TRAVEL/include/travel/tgs.hpp

Lines 948 to 953 in 17a0bdd

	if(tgf_in[n_i.row][n_i.col][n_i.tri].check_life > 0) {
	tgf_in[n_i.row][n_i.col][n_i.tri].check_life -=1;
	tgf_in[n_i.row][n_i.col][n_i.tri].need_recheck = true;
	} else {
	tgf_in[n_i.row][n_i.col][n_i.tri].need_recheck = false;
	}