🚀 go-pugleaf

hi.
    i've got a question about quake II's bsp file format:

typedef struct {
    [...]
     short   _cluster_;
     short   area;
    [...]
    } dleaf_t;

    dleaf_t.cluster probably refers to dvis_t(right?), but where is the
count of the clusters? how many should i use?

// the visibility lump consists of a header with a count, then
// _byte offsets_ for the PVS and PHS of each cluster, then the raw
// compressed bit vectors
typedef struct {
     int   numclusters;
     int   _bitofs_[8][2]; // bitofs[numclusters][2]
    } dvis_t;

    the comments says _byte_ offset but in the struct its called
_bit_ofs....
    the values for dvis_t.bitofs are rather high (40k), so i think it's a
_bit_ offset. (right?)

    the _compressed bit vectors_ are probably the same as the visibility
list from quake I bsp. (right?)

    BUT:    what is PHS and PVS?? how do i use these variables?
    perhaps there are more than one dvis_t, so dleaf_t.cluster refers to a
whole struct?

thx for readin this....
    NukE