perm filename PAGE11[00,BGB] blob
sn#046243 filedate 1973-06-05 generic text, type T, neo UTF8
~F8DATA STRUCTURE: TYPE BITS.
Each node has a word reserved for a boolean vector of 36
values, or bits. The first eighteen bits are called the type bits
and are individually named as follows:
_____________________________________________________________________
for 0 WESBIT westward vector.
vectors 1 SOUBIT southward vector.
only 2 EASBIT eastward vector.
3 NORBIT northward vector.
_____________________________________________________________________
4 NFUSE NTIME polygon fusion.
5 NFISS NTIME polygon fission.
for 6 NEXCT NTIME polygon exact match.
polygons
only 7 PFUSE PTIME polygon fusion.
8 PFISS PTIME polygon fission.
9 PEXCT PTIME polygon exact match.
_____________________________________________________________________
10 HOLBIT Hole polygon bit.
modify 11 ARCBIT Arc vector bit.
_____________________________________________________________________
12 SBIT Shape node bit.
13 VBIT Vertex node bit.
14 PBIT Polygon node bit.
kind
15 LBIT Level node bit.
16 IBIT Image node bit.
17 FBIT Film node bit.
_____________________________________________________________________
The first four bits WESBIT, SOUBIT, EASBIT and NORBIT apply
only to vectors and indicate the direction of the vector. The next
six bits NFUSE, NFISS, NEXCT, PFUSE, PFISS, PEXCT are set by the
polygon compare routine to indicate the kind of time mating found;
where N and P mean negative time or postive time linkage; fusion
means that the given polygon and another polygon fuse to form the
time polygon, two into one; fission means the given polygon splits,
one into two; and exact means that the given polygon matchs one for
one with its time polygon.
The next two bits HOLBIT and ARCBIT indicate distinguished
polygons and vectors respectively. Only one of the last six bits:
SBIT, VBIT, PBIT, LBIT, IBIT and FBIT may be on in a node. These
bits indicate the node's type.
~I1973,800;F8- 11 -