perm filename WINGS.NEW[GEM,BGB] blob
sn#049887 filedate 1973-06-21 generic text, type T, neo UTF8
COMMENT ⊗ VALID 00015 PAGES
RECORD PAGE DESCRIPTION
00001 00001
00004 00002 TITLE WINGS - THE WINGED EDGE SUBROUTINES - JULY 1972.
00005 00003 SUBR(MKWORLD)-----------------------------------------------------
00007 00004 SUBR(MKCAMERA) ---------------------------------------------------
00009 00005 SUBR(MKB)BODY OR WORLD OR 0 --------------------------------------
00011 00006 SUBR(MKF)BODY ----------------------------------------------------
00013 00007 SUBR(KLF)B,FNEW --------------------------------------------------
00015 00008 SUBR(WING)E1,E2---------------------------------------------------
00017 00009 SUBR(LINKED)Q1,Q2 ------------------------------------------------
00020 00010 INTERN ERIGHT,ELEFT-----------------------------------------------
00022 00011 SUBR(ECW)FEV,FV --------------------------------------------------
00024 00012 SUBR(OTHER)E,Q----------------------------------------------------
00026 00013 SUBR(BGET)BFEVY --------------------------------------------------
00028 00014 SUBR(BDET)B ------------------------------------------------------
00030 00015 SUBR(VCW)EDGE,FACE -----------------------------------------------
00033 ENDMK
⊗;
TITLE WINGS - THE WINGED EDGE SUBROUTINES - JULY 1972.
EXTERN MKNODE,KLNODE,UNIVERSE
INTERN BTOTAL,FTOTAL,ETOTAL,VTOTAL
DECLARE{BTOTAL,FTOTAL,ETOTAL,VTOTAL}
DECLARE{WORLD}
INTERN WORLD ;FOR THE LOU PAUL KLUDGE.
SUBR(MKWORLD)-----------------------------------------------------
BEGIN MKWORLD; MAKE A WORLD NODE.
SETQ(WORLD,{MKNODE,[PBIT+$WORLD]})
CW. 1,1↔CCW. 1,1 ;EMPTY BODY RING.
CALL(MKFRAME) ;WORLD FRAME OF REFERENCE.
LAC 2,WORLD
FRAME. 1,2
CALL(BATT,WORLD,UNIVERSE) ;PLACE WORLD IN UNIVERSE.
LAC 1,WORLD
POP0J
BEND MKWORLD; BGB 12 MARCH 1973 ----------------------------------
SUBR(MKWINDOW) ---------------------------------------------------
BEGIN MKWINDOW; MAKE A WINDOW NODE.
SETQ(WINDOW#,{MKNODE,[PBIT+$WINDOW]})
LAC[3.5]↔DAC -1(1) ;MAG
LAC[XWD -=511,=511]↔DAC 1(1) ;XWD XL,,XH
LAC[XWD -=384,=384]↔DAC 2(1) ;XWD YL,,YH
CALL(BATT,WINDOW,UNIVERSE)
LAC 1,WINDOW
POP0J
BEND MKWINDOW; BGB 12 MARCH 1973 ---------------------------------
SUBR(MKFRAME)-----------------------------------------------------
BEGIN MKFRAME; MAKE A FRAME OF REFERENCE NODE.
CALL(MKNODE,[1.0])
SLACI(<1.0>)
DAC IX(1)
DAC JY(1)
DAC KZ(1)
POP0J
BEND MKFRAME; BGB 13 MARCH 1973 ----------------------------------
SUBR(MKCAMERA) ---------------------------------------------------
BEGIN MKCAMERA; MAKE A CAMERA NODE.
SETQ(CAMERA#,{MKNODE,[PBIT+$CAMERA]})
;DEFAULT PHYSICAL RASTER SIZE.
DEFINE MM{3.2808E-3}
LAC[0.1739109E-1]↔DAC 1(1) ;PDX.
LAC[0.1314883E-1]↔DAC 2(1) ;PDY.
LAC[0.4101E-1]↔DAC 3(1) ;FOCAL
;DEFAULT LOCIGAL RASTER SIZE.
LACI =144↔DAP 1(1) ;LDX
LACI =108↔DAP 2(1) ;LDY
LACI =100000↔DAP 3(1) ;LDZ
LAC[-339.57]↔DAC -3(1) ;SCALEX
LAC[-336.84]↔DAC -2(1) ;SCALEY
LAC[4101.00]↔DAC -1(1) ;SCALEZ
;CAMERA LOCUS AND ORIENTATION.
CALL(MKFRAME)
LAC[16.0]↔DAC ZWC(1) ;16 FEET ABOVE XY PLANE.
LAC 2,CAMERA↔FRAME. 1,2
CALL(BATT,CAMERA,UNIVERSE)
LAC 1,CAMERA
POP0J
BEND MKCAMERA; BGB 12 MARCH 1973 ---------------------------------
SUBR(MKB)BODY OR WORLD OR 0 --------------------------------------
BEGIN MKB; MAKE BODY IN WORLD Q OR WORLD OF Q.
AOS BTOTAL↔CALL(MKNODE,{[BBIT+PBIT+$BODY]}) ;CREATE NODE.
DIP 1,1↔DAC 1,1(1)↔DAC 1,2(1)↔DAC 1,3(1) ;FEV - RINGS.
SKIPN 3,ARG1↔LAC 3,WORLD
TESTZ 3,BBIT↔CCW 3,3↔CW 2,3 ;GET WORLD.
CW. 1,3↔CCW. 3,1↔CCW. 1,2↔CW. 2,1 ;WORLD RINGIN.
CDR 1,1↔POP1J ;RETURN BNEW.
BEND;1/14/73------------------------------------------------------
SUBR(KLB)BNEW-----------------------------------------------------
BEGIN KLB; KILL A BODY NODE.
B←1 ↔ X←2 ↔ Y←3
LAC B,ARG1
CW X,B↔CCW Y,B ;DELETE FROM ALBODY RING.
CW. X,Y↔CCW. Y,X
CALL(KLNODE,B)
SOS BTOTAL↔POP1J
BEND;1/13/73------------------------------------------------------
SUBR(KLBFEV)Q-----------------------------------------------------
BEGIN KLBFEV
ACCUMULATORS{B,F,E,V}
LAC B,ARG1
SETQ(B,{BGET,B})
L1: PFACE F,B↔CAME F,B↔GO[CALL KLF,B,F↔GO L1]
L2: PED E,B↔CAME E,B↔GO[CALL KLE,B,E↔GO L2]
L3: PVT V,B↔CAME V,B↔GO[CALL KLV,B,V↔GO L3]
CALL KLB,B
POP1J
BEND;1/13/73------------------------------------------------------
SUBR(MKF)BODY ----------------------------------------------------
BEGIN MKF; MAKE FACE NODE.
Q←1 ↔ X←2 ↔ B←3
AOS FTOTAL↔CALL(MKNODE,{[FBIT+$FACE]}) ;FACE NODE.
PUSH P,X↔PUSH P,B
LAC B,ARG3↔NFACE X,B↔PFACE. Q,X
NFACE. Q,B↔PFACE. B,Q↔NFACE. X,Q ;RINGIN.
POP P,B↔POP P,X↔POP1J
BEND MKF; BGB 1/13/73 --------------------------------------------
SUBR(MKE)BODY ----------------------------------------------------
BEGIN MKE; MAKE EDGE NODE.
Q←1 ↔ X←2 ↔ B←3
AOS ETOTAL↔CALL(MKNODE,{[EBIT+$EDGE]}) ;EDGE NODE.
PUSH P,X↔PUSH P,B
LAC B,ARG3↔NED X,B↔PED. Q,X
NED. Q,B↔PED. B,Q↔NED. X,Q ;RINGIN.
CCW. B,Q
POP P,B↔POP P,X↔POP1J
BEND MKE; 1/13/73 ------------------------------------------------
SUBR(MKV)BODY ----------------------------------------------------
BEGIN MKV; MAKE VERTEX NODE.
Q←1 ↔ X←2 ↔ B←3
AOS VTOTAL↔CALL(MKNODE,{[VBIT+$VERT]}) ;VERTEX NODE.
PUSH P,X↔PUSH P,B
LAC B,ARG3↔NVT X,B↔PVT. Q,X
NVT. Q,B↔PVT. B,Q↔NVT. X,Q ;RINGIN.
POP P,B↔POP P,X↔POP1J
BEND MKV; 1/13/73 ------------------------------------------------
SUBR(KLF)B,FNEW --------------------------------------------------
BEGIN KLF; KILL FACE NODE.
X←2 ↔ Y←B←3
LAC 1,ARG1↔PUSH P,2↔PUSH P,3
NFACE X,1↔PFACE Y,1 ;DELETE FROM FACE RING.
NFACE. X,Y↔PFACE. Y,X
CALL(KLNODE,1)
SOS FTOTAL ;DECREMENT THE COUNTERS.
POP P,3↔POP P,2↔POP2J
BEND;1/13/73------------------------------------------------------
SUBR(KLE)B,ENEW --------------------------------------------------
BEGIN KLE; KILL EDGE NODE.
X←2 ↔ Y←B←3
LAC 1,ARG1↔PUSH P,2↔PUSH P,3
NED X,1↔PED Y,1 ;DELETE FROM EDGE RING.
NED. X,Y↔PED. Y,X
CALL(KLNODE,1)
SOS ETOTAL ;DECREMENT THE COUNTERS.
POP P,3↔POP P,2↔POP2J
POP2J
BEND;1/13/73------------------------------------------------------
SUBR(KLV)B,VNEW --------------------------------------------------
BEGIN KLV; KILL VERTEX NODE.
X←2 ↔ Y←B←3
LAC 1,ARG1↔PUSH P,2↔PUSH P,3
NVT X,1↔PVT Y,1 ;DELETE FROM VERTEX RING.
NVT. X,Y↔PVT. Y,X
CALL(KLNODE,1)
SOS VTOTAL ;DECREMENT THE COUNTERS.
POP P,3↔POP P,2↔POP2J
BEND;1/13/73------------------------------------------------------
SUBR(WING)E1,E2---------------------------------------------------
BEGIN WING;PLACE WING POINTERS BETWEEN TWO EDGES.
;THE AC-0 CONTROL BITS:
;[0-NV2-NV1] [0-PV2-PV1] [0-NF2-NF1] [0-PF2-PF1].
E1←3 ↔ E2←4
SAVAC(4)↔SETZ↔CDR E1,ARG2↔CDR E2,ARG1
;FIND THE COMMON VERTEX.
;AC-1 ← (NV1,,PV1) ⊗ (NV2,,PV2) NN,,PP IN COMMON.
;AC-2 ← (PV1,,NV1) ⊗ (NV2,,PV2) PN,,NP IN COMMON.
LAC 1,3(E1)↔MOVS 2,1↔XOR 1,3(E2)↔XOR 2,3(E2)
TLNN 1,-1↔TRO 3000↔TRNN 1,-1↔TRO 0300
TLNN 2,-1↔TRO 2100↔TRNN 2,-1↔TRO 1200
;FIND THE COMMON FACE.
LAC 1,1(E1)↔MOVS 2,1↔XOR 1,1(E2)↔XOR 2,1(E2)
TLNN 1,-1↔TRO 0030↔TRNN 1,-1↔TRO 0003
TLNN 2,-1↔TRO 0021↔TRNN 2,-1↔TRO 0012
;STORE THE WINGS AS INDICATED.
SETCA
TRNN 2020↔NCW. E1,E2↔TRNN 1010↔NCW. E2,E1
TRNN 2002↔PCCW. E1,E2↔TRNN 1001↔PCCW. E2,E1
TRNN 0220↔NCCW. E1,E2↔TRNN 0110↔NCCW. E2,E1
TRNN 0202↔PCW. E1,E2↔TRNN 0101↔PCW. E2,E1
GETAC(4)↔POP2J
BEND;1/13/73------------------------------------------------------
SUBR(LINKED)Q1,Q2 ------------------------------------------------
BEGIN LINKED; DETERMINE WHETHER TWO FEV ENTITIES ARE LINKED.
ACCUMULATORS{Q1,Q2,E}
CDR Q1,ARG2↔CDR Q2,ARG1
;BRANCH ON THE COMBINATION OF ARGUMENT TYPES.
LDB 0,[POINT 3,(Q1),16]↔LDB 1,[POINT 3,(Q2),16]
CAMLE 0,1↔EXCH Q1,Q2
IOR 1,0↔GO@[FALSE↔FF↔EE↔FE↔VV↔FV↔EV↔FALSE](1)
;FACES WITH COMMON EDGE.
FF: PED E,Q1↔DAC E,E0#
CALL OTHER,E,Q1↔CAMN 1,Q2↔GO TRUE
SETQ(E,{ECCW,E,Q1})↔CAME E,E0↔GO FF+2↔GO FALSE
;EDGE IN FACE PERIMETER.
FE: PFACE 1,Q2↔CAMN 1,Q1↔GO TRUE
NFACE 1,Q2↔CAMN 1,Q1↔GO TRUE↔GO FALSE
;VERTEX IN FACE PERIMETER.
FV: PED E,Q2↔DAC E,E0
JUMPE E,[PFACE 1,Q1↔PVT 0,Q2↔CAME 0,1↔GO FALSE↔GO TRUE]
PFACE 1,E↔CAMN 1,Q1↔GO TRUE↔NFACE 1,E↔CAMN 1,Q1↔GO TRUE
SETQ(E,{ECCW,E,Q2})↔CAME E,E0↔GO FV+2↔GO FALSE
;EDGES WITH A COMMON VERTEX.
EE: PVT 0,Q1↔PVT 1,Q2↔CAMN 0,1↔GO TRUE
NVT 1,Q2↔CAMN 0,1↔GO TRUE
NVT 0,Q1↔PVT 1,Q2↔CAMN 0,1↔GO TRUE
NVT 1,Q2↔CAMN 0,1↔GO TRUE↔GO FALSE
;VERTEX IN EDGE.
EV: PVT 1,Q1↔CAMN 1,Q2↔GO TRUE
NVT 1,Q1↔CAMN 1,Q2↔GO TRUE↔GO FALSE
;VERTICES WITH A COMMON EDGE.
VV: PED E,Q1↔DAC E,E0
CALL OTHER,E,Q1↔CAMN 1,Q2↔GO TRUE
SETQ(E,{ECCW,E,Q1})↔CAME E,E0↔GO VV+2↔GO FALSE
FALSE: SETZ 1,↔POP2J
TRUE: SETO 1,↔POP2J
LIT↔VAR
BEND;1/13/73------------------------------------------------------
INTERN ERIGHT,ELEFT-----------------------------------------------
ERIGHT: TDZA 1,1 ;E ← ERIGHT(FROM-V,ABOUT-F).
ELEFT: SETO 1, ;E ← ELEFT(FROM-V,ABOUT-F).
BEGIN EFETCH
ACCUMULATORS{V,F,E1,E2}
Q←←1
SAVAC(5)
DAC Q,QFLAG#↔LAC V,ARG2↔LAC F,ARG1
TEST V,VBIT↔GO[SETCMM QFLAG↔EXCH F,V↔GO .+1]
PED E2,V↔DAC E2,E0#
L1: LAC E1,E2
;E2←ECW(E1,V) AND Q←FCW(E1,V).
PVT Q,E1↔CAME Q,V↔GO .+4
NCCW E2,E1↔NFACE Q,E1↔GO .+6
NVT Q,E1↔CAME Q,V↔GO[FATAL(EFETCH1)]
PCCW E2,E1↔PFACE Q,E1
CAMN Q,F↔GO L2
CAME E2,E0↔GO L1
FATAL(EFETCH2)
L2: LAC 1,E1↔SKIPE QFLAG↔LAC 1,E2
GETAC(5)↔POP2J
COMMENT . V EDGE FETCH MANDALA
/ \
/ \
/ \
ELEFT F ERIGHT
/ \
/ \ .
BEND;1/13/73------------------------------------------------------
SUBR(ECW)FEV,FV --------------------------------------------------
BEGIN ECW; FETCH EDGE CLOCKWISE FROM FEV ABOUT FV.
Q←1 ↔ X←2 ↔ E←3
CDR 1,ARG2↔TEST 1,EBIT↔GO ERIGHT
DAC 2,AC2↔ DAC 3,AC3
CDR X,ARG1↔LAC E,1
TEST X,VBIT↔GO[
PFACE Q,E↔CAME Q,X↔GO L1↔ PCW Q,E↔GO L
L1: NFACE Q,E↔CAME Q,X↔GO DIE↔ NCW Q,E↔GO L]
PVT Q,E↔CAME Q,X↔GO L2↔ NCCW Q,E↔GO L
L2: NVT Q,E↔CAME Q,X↔GO DIE↔ PCCW Q,E↔GO L
DIE: FATAL(ECW)
L: LAC 2,AC2↔ LAC 3,AC3↔ POP2J
LIT
BEND;1/13/73------------------------------------------------------
SUBR(ECCW)FEV,FV -------------------------------------------------
BEGIN ECCW; FETCH EDGE COUNTER CLOCKWISE FROM FEV ABOUT FV.
Q←1 ↔ X←2 ↔ E←3
CDR 1,ARG2↔TEST 1,EBIT↔GO ELEFT
DAC 2,AC2↔ DAC 3,AC3
CDR X,ARG1↔LAC E,1
TEST X,VBIT↔GO[
PFACE Q,E↔CAME Q,X↔GO L1↔ PCCW Q,E↔GO L
L1: NFACE Q,E↔CAME Q,X↔GO DIE↔ NCCW Q,E↔GO L]
PVT Q,E↔CAME Q,X↔GO L2↔ PCW Q,E↔GO L
L2: NVT Q,E↔CAME Q,X↔GO DIE↔ NCW Q,E↔GO L
DIE: FATAL(ECCW)
L: LAC 2,AC2↔ LAC 3,AC3↔ POP2J
LIT
BEND;1/13/73------------------------------------------------------
SUBR(OTHER)E,Q----------------------------------------------------
BEGIN OTHER
Q←←1↔X←←2↔E←←3
DAC 2,AC2↔DAC 3,AC3
CDR X,ARG1↔CDR E,ARG2
TEST X,FBIT↔GO L1
;OTHER FACE OF THE EDGE.
PFACE Q,E↔CAME Q,X↔GO .+3↔NFACE Q,E↔GO .+5
NFACE Q,E↔CAME Q,X↔GO[FATAL({OTHER FACE})]
PFACE Q,E↔LAC 2,AC2↔LAC 3,AC3↔POP2J
;OTHER VERTEX OF THE EDGE.
L1: PVT Q,E↔CAME Q,X↔GO .+3↔NVT Q,E↔GO .+5
NVT Q,E↔CAME Q,X↔GO[FATAL({OTHER VERTEX})]
PVT Q,E↔LAC 2,AC2↔LAC 3,AC3↔POP2J
LIT
BEND;1/13/73------------------------------------------------------
SUBR(OTHER.)Q,E,X-------------------------------------------------
BEGIN OTHER.
Q←←1↔X←←2↔E←←3
DAC 2,AC2↔DAC 3,AC3
CDR X,ARG1↔CDR E,ARG2↔CDR Q,ARG3
TEST X,VBIT↔GO[
PFACE 0,E↔CAME 0,X↔GO L1↔NFACE. Q,E↔GO L
L1: NFACE 0,E↔CAME 0,X↔GO DIE↔PFACE. Q,E↔GO L]
NVT 0,E↔CAME 0,X↔GO L2↔PVT. Q,E↔GO L
L2: PVT 0,E↔CAME 0,X↔GO DIE↔NVT. Q,E↔GO L
DIE: FATAL(OTHER.)
L: LAC 2,AC2↔LAC 3,AC3
POP3J↔LIT
BEND;1/13/73------------------------------------------------------
SUBR(BGET)BFEVY --------------------------------------------------
BEGIN BODY; FETCH THE BODY OF A BODY, FACE, EDGE, VERTEX OR YNODE.
Q←1
COMMENT ⊗ OLDE CODE
CDR Q,ARG1
TESTZ Q,BBIT
POP1J ;Q'S ALREADY A BODY.
TESTZ Q,EBIT
L1: GO [CCW Q,Q↔POP1J] ;Q WAS AN EDGE.
TESTZ Q,FBIT
GO [PFACE 0,Q↔PED Q,Q↔JUMPN Q,L1↔GO L2] ;FACE
TESTZ Q,VBIT
GO [PVT 0,Q↔PED Q,Q↔JUMPN Q,L1↔GO L2] ;VERTEX
POP1J; Q AIN'T GOT NO BODY.
L2: LAC 1,0↔POP1J ;VERTEX BODY CASE.
⊗;
CDR Q,ARG1
L1: LAC 0,(Q)
TLNE 0,1B9
POP1J ;FRAMES LOSE QUICKLY
ANDI 0,17
ADD 0,[@TABLE]
GO @0
TABLE: POP1J.↔POP1J.↔POP1J.↔POP1J. ;FRAME,EMTPY,UNIVERSE,LAMP
POP1J.↔POP1J.↔POP1J.↔POP1J. ;CAMERA,WORLD,WINDOW,IMAGE
[TCW Q,Q↔GO L1]↔POP1J. ;TEXT,XNODE
[NY Q,Q↔GO L1]↔POP1J. ;YNODE,ZNODE
POP1J.↔[PFACE 0,Q↔GO L2] ;BODY,FACE
[CCW Q,Q↔POP1J]↔[PVT 0,Q↔GO L2] ;EDGE,VERTEX
L2: PED Q,Q↔JUMPN Q,[CCW Q,Q↔POP1J]↔LAC 1,0↔POP1J
LIT
BEND;1/13/73------------------------------------------------------
SUBR(BDET)B ------------------------------------------------------
BEGIN BDET; BODY DETACH - BGB - 17 FEBRUARY 1973.
LAC 1,ARG1↔TESTZ 1,FBIT+EBIT+VBIT↔POP1J
BRO 2,1↔SIS 3,1
BRO. 2,3↔SIS. 3,2 ;RINGO.
CAMN 2,1↔SETZ 2,
DAD 3,1↔SON 0,3
CAMN 0,1↔SON. 2,3 ;DAD OUT.
SETZ↔DAD. 0,1
BRO. 0,1↔SIS. 0,1 ;CLEAR SELF.
POP1J
BEND;2/17/73------------------------------------------------------
SUBR(BATT)B1,B2 --------------------------------------------------
BEGIN BATT; BODY ATTACH B1 TO B2 - BGB - 17 FEBRUARY 1973.
LAC 1,ARG2↔LAC 2,ARG1↔CAMN 1,2↔POP2J
$TYPE 0,2↔CAIN 0,$WINDOW↔GO[ ;SPECIAL WINDOW CASES.
$TYPE 0,1↔CAIN 0,$CAMERA↔GO[ALT. 1,2↔POP2J]
CAIE 0,$IMAGE↔CAIN 0,$WORLD↔GO[ALT2. 1,2↔POP2J]↔GO .+1]
TESTZ 1,FBIT+EBIT+VBIT↔POP2J
DAD 0,1
JUMPN[CALL(BDET,1)↔GO .+1] ;MAKE B1 AN ORPHAN.
LAC 2,ARG1
TESTZ 2,FBIT+EBIT+VBIT↔POP2J
DAD. 2,1 ;B2 IS B1'S NEW DADDY.
SON 3,2↔JUMPE 3,[SON. 1,2
BRO. 1,1↔SIS. 1,1↔POP2J] ;FIRST CHILD CASE.
BRO 2,3
BRO. 2,1↔SIS. 1,2 ;MANY CHILD CASE.
SIS. 3,1↔BRO. 1,3
POP2J
BEND;2/17/73------------------------------------------------------
SUBR(VCW)EDGE,FACE -----------------------------------------------
BEGIN VCW; FETCH VERTEX CLOCKWISE FROM EDGE ABOUT FACE.
Q←1↔E←2
DAC 2,AC2↔CDR E,ARG2
PFACE Q,E↔CAME Q,ARG1↔GO .+3↔PVT Q,E↔GO L
NFACE Q,E↔CAME Q,ARG1↔GO[FATAL(VCW)]↔NVT Q,E
L: LAC 2,AC2↔POP2J↔LIT
BEND VCW; BGB 1/13/73 --------------------------------------------
SUBR(VCCW)EDGE,FACE ----------------------------------------------
BEGIN VCCW; FETCH VERTEX COUNTER-CLOCKWISE FROM EDGE ABOUT FACE.
Q←1↔E←2
DAC 2,AC2↔CDR E,ARG2
PFACE Q,E↔CAME Q,ARG1↔GO .+3↔NVT Q,E↔GO L
NFACE Q,E↔CAME Q,ARG1↔GO[FATAL(VCCW)]↔PVT Q,E
L: LAC 2,AC2↔POP2J↔LIT
BEND VCCW; BGB 1/13/73 -------------------------------------------
SUBR(FCW)EDGE,VERTEX ---------------------------------------------
BEGIN FCW; FETCH FACE CLOCKWISE FROM EDGE ABOUT VERTEX.
Q←1↔E←2
DAC 2,AC2↔CDR E,ARG2
PVT Q,E↔CAME Q,ARG1↔GO .+3↔NFACE Q,E↔GO L
NVT Q,E↔CAME Q,ARG1↔GO[FATAL(FCW)]↔PFACE Q,E
L: LAC 2,AC2↔POP2J↔LIT
BEND FCW; BGB 1/13/73 --------------------------------------------
SUBR(FCCW)EDGE,VERTEX --------------------------------------------
BEGIN FCCW; FETCH FACE COUNTER-CLOCKWISE FROM EDGE ABOUT VERTEX.
Q←1↔E←2
DAC 2,AC2↔CDR E,ARG2
PVT Q,E↔CAME Q,ARG1↔GO .+3↔PFACE Q,E↔GO L
NVT Q,E↔CAME Q,ARG1↔GO[FATAL(FCCW)]↔NFACE Q,E
L: LAC 2,AC2↔POP2J↔LIT
BEND FCCW; BGB 1/13/73 -------------------------------------------
END
WING.FAI - EOF.