perm filename EUCLID.OLD[GEM,HE] blob sn#100705 filedate 1974-05-03 generic text, type C, neo UTF8
COMMENT ⊗   VALID 00011 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00003 00002	TITLE EUCLID - EUCLIDEAN ROUTINES - BRUCE G. BAUMGART - JULY 1972.
C00005 00003	SUBR(TRANSLATE,FRMOBJ,DX,DY,DZ)	       OBJECT TRANSLATION WRT FRAME.
C00009 00004	SUBR(APTRAN,OBJECT,TRAN) APPLY EUCLIDEAN TRANSFORMATION TO THE OBJECT.
C00013 00005	SUBN(ROTOR)
C00015 00006	SUBR(INTRAN,TRAN)		INVERT A TRANSFORMATION.
C00017 00007	SUBR(MKROT1,PAN,TILT,SWING)
C00022 00008	SUBR(NORM,FRAME)	 NORMALIZE A FRAME MATRIX.
C00033 00009	SUBR(ORTHO2,QFRAME)
C00036 00010	SUBR(ANGL3V,VERT1,VERT2,VERT3)			ANGLE TRI-VERTEX.
C00039 00011	SUBR(DISTAN,V1,V2)		DISTANCE BETWEEN TWO VERTICES.
C00049 ENDMK
C⊗;
TITLE EUCLID - EUCLIDEAN ROUTINES - BRUCE G. BAUMGART - JULY 1972.

	EXTERN ECW,ECCW,OTHER
	EXTERN BGET,FCW,FCCW,VCW,VCCW
	EXTERN MKCOPY,MKFRAME,KLNODE
	EXTERN SIN,COS,SQRT,ATAN,ATAN2,ASIN,ACOS,LOG,HALFPI,PI,TWOPI

COMMENT ⊗----------------------------------------------------------------------

EUCLIDEAN TRANSFORMATIONS

	TRANS	←	TRANSL(XWD(FRAME,BODY),DX,DY,DZ);
	TRANS	←	ROTATE(XWD(FRAME,BODY),DX,DY,DZ);
	TRANS	←	SHRINK(XWD(FRAME,BODY),DX,DY,DZ);
	TRANS	←	APTRAN(ENTITY,TRANS);
			{ROTOR}
	TRANS	←	INTRAN(TRAN);

FRAME MAKERS

	TRANS	←	MKROT1(PAN,TILT,SWING);		MAKE FROM EULER ANGLES.
	TRANS	←	MKFFRM(FACE);			MAKE FACE FRAME.
	TRANS	←	MKQFRM(WX,WY,WZ);		MAKE FROM ROTATION VECTOR.

FRAME ORTHONORMALIZATION.

	NORM(FRAME)	;NORMALIZATION TO UNIT VECTORS.
	ORTHO1(FRAME)	;ORTHOGONALIZE BY WORST CASE.
	ORTHO2(FRAME)	;ORTHOGONALIZE BY K ← (I CROSS J), J ← (K CROSS I).

GEOMETRIC MEASURE ROUTINES.

	DETERM(FRAME)
	ANGL3V(V1,V2,V3)
	DISTANCE(ENTITY,ENTITY);
------------------------------------------------------------------------------⊗
SUBR(TRANSLATE,FRMOBJ,DX,DY,DZ)	       ;OBJECT TRANSLATION WRT FRAME.
COMMENT .-----------------------------------------------------------.
	CALL(MKFRAME)
	HRLZI DX↔HRRI XWC(1)↔BLT ZWC(1)	;DELTA'S OF TRANSLATION.
↑QTRAN:	DAC 1,TMP1			;SECOND ENTRY.
	MOVM 2,FRMOBJ↔CDR 2,2↔DAC 2,OBJECT
	HLRE 1,FRMOBJ↔SKIPGE 1↔GO[
		SETZ 1,↔JUMPE 2,.+1	;JUMP WHEN NO OBJECT.
		CALL(BGET,OBJECT)	;GET BODY OF THE OBJECT.
		FRAME 1,1↔GO .+1]	;GET FRAME OF THE BODY.
	DAC 1,REFRAM			;FRAME OF REFERENCE.
	LAC 1,TMP1↔SKIPN REFRAM↔GO L1
L0:	SETQ(TMP2,{MKCOPY,REFRAM})
	CALL(INTRAN,TMP2)
	CALL(APTRAN,TMP2,TMP1)
	CALL(APTRAN,TMP2,REFRAM)
	CALL(KLNODE,TMP1)
	LAC 1,TMP2↔DAC 1,TMP1		;TMP1 ← TMP2.
L1:	SKIPN OBJECT↔POP4J		;RETURN TRANSFORMATION.
	CALL(APTRAN,OBJECT,TMP1)
	CALL(KLNODE,TMP1)
	LAC 1,OBJECT↔POP4J		;RETURN THE OBJECT.
DECLARE{TMP1,TMP2,REFRAM,OBJECT}
ENDR TRANSLATE;3/18/73(BGB)------------------------------------------

SUBR(ROTATE,FRMOBJ,WX,WY,WZ)  		;OBJECT ROTATION WRT FRAME.
COMMENT .-----------------------------------------------------------.
;COMPONENTS OF ROTATION VECTOR.
	SKIPE 1,WX↔FMPR 1,1↔DAC 1,4
	SKIPE 2,WY↔FMPR 2,2↔DAC 2,5
	SKIPE 3,WZ↔FMPR 3,3
	FADR 1,2↔FADR 1,3↔JUMPE 1,POP1J.
	SETQ(W,{SQRT↑,1})
;ROTATION AXIS FRAME OF REFERENCE.
	SETQ(TMP1,{MKFRAME})↔DAC 1,7
	LAC 1,WX↔FDVR 1,W↔DAC 1,IX(7)
	LAC 2,WY↔FDVR 2,W↔DAC 2,IY(7)
	LAC 3,WZ↔FDVR 3,W↔DAC 3,IZ(7)
	MOVM 2↔CAMG [0.99]↔GO .+3	;W ALMOST COLINEAR WITH J VECTOR.
	SETZM JY(7)↔DAC 2,JX(7)		;CHANGE J VECTOR.
	CALL(ORTHO2,TMP1)↔CALL(NORM,TMP1)
;ROTATION ABOUT I UNIT VECTOR.
	SETQ(TMP2,{MKFRAME})
	CALL(COS,W)↔LAC 2,TMP2↔DAC 1,JY(2)↔DAC   1,KZ(2)
	CALL(SIN,W)↔LAC 2,TMP2↔DAC 1,JZ(2)↔MOVNM 1,KY(2)
	CALL(APTRAN,TMP2,TMP1)
	LAC 1,TMP1			;TRANSPOSITION.
	LAC IY(1)↔EXCH JX(1)↔DAC IY(1)
	LAC IZ(1)↔EXCH KX(1)↔DAC IZ(1)
	LAC JZ(1)↔EXCH KY(1)↔DAC JZ(1)
	CALL(APTRAN,TMP1,TMP2)↔CALL(KLNODE,TMP2)
	LAC 1,TMP1↔GO QTRAN
DECLARE{W,TMP1,TMP2,TMP3,REFRAM,OBJECT}
ENDR ROTATE;3/18/73(BGB)---------------------------------------------

SUBR(SHRINK,FRMOBJ,KKX,KKY,KKZ)	      ;DILATION-REFLECTION WRT FRAME.
COMMENT .-----------------------------------------------------------.
	CALL(MKFRAME)
	SKIPN 2,KKX↔MOVSI 2,(1.0)↔DAC 2,IX(1)
	SKIPN 2,KKY↔MOVSI 2,(1.0)↔DAC 2,JY(1)
	SKIPN 2,KKZ↔MOVSI 2,(1.0)↔DAC 2,KZ(1)↔GO QTRAN
ENDR SHRINK;3/18/73(BGB)---------------------------------------------
SUBR(APTRAN,OBJECT,TRAN); APPLY EUCLIDEAN TRANSFORMATION TO THE OBJECT.
COMMENT .-----------------------------------------------------------.
	ACCUMULATORS{B,F,E,V,X,Y,Z,TRN,N,OBJ,E0}
	SKIPE OBJ,OBJECT↔SKIPN TRN,TRAN↔POP2J	;IGNORE ZERO ARGS.
	MOVM 1,(OBJ)↔JUMPE 1,LROTA	;GET TYPE OF OBJECT.
	TLNE 1,(1B9)↔GO LROTA		;FRAME.
	ANDI 1,17↔GO @.+1(1)		;DISPATCH ON TYPE OF OBJECT.
	POP2J.↔POP2J.↔POP2J.↔CROTA	;FRAME EMPTY UNIVERSE SUN
	CROTA↔POP2J.↔POP2J.↔POP2J.	;CAMERA WORLD WINDOW IMAGE
	POP2J.↔POP2J.↔POP2J.↔POP2J.	;TEXT XNODE YNODE ZNODE
	BROTA↔FROTA↔EROTA↔VROTA		;BODY FACE EDGE VERTEX
;....................................................................
LROTA:	LAC V,OBJ↔SETZM TMP2#↔GO .+3	;FRAME CASE.
CROTA:	FRAME V,OBJ↔DAC V,TMP2#		;CAMERA & SUN CASE.
	CALL(ROTOR)
	PUSH P,XWC(TRN)↔PUSH P,YWC(TRN)↔PUSH P,ZWC(TRN)
	SETZM XWC(TRN)↔SETZM YWC(TRN)↔SETZM ZWC(TRN)
	ADDI V,3↔CALL(ROTOR)
	ADDI V,3↔CALL(ROTOR)
	ADDI V,3↔CALL(ROTOR)
	POP P,ZWC(TRN)↔POP P,YWC(TRN)↔POP P,XWC(TRN)
	SKIPN TMP2↔POP2J
	CALL(NORM,TMP2#)
	CALL(ORTHO1,TMP2#)↔POP2J
;....................................................................
BROTA:	LAC B,OBJ			;BODY ROTATION.
	TESTZ B,BDVBIT↔GO L2		;DON'T MOVE VERTICES.
	LAC V,B		   		;1ST VERTEX.
L1:	PVT V,V
	CAMN V,OBJ↔GO L2		;SKIP WHEN VERTEX.
	CALL(ROTOR)↔GO L1		;ROTATE VERTEX.
L2:	LAC B,OBJ
	TESTZ B,BDLBIT↔GO L3		;DON'T MOVE FRAME.
	FRAME V,B↔SKIPN V↔GO L3
	DAC V,TMP#↔PUSH P,B
	CALL(APTRAN,V,TRN)		;BODY'S FRAME.
	CALL(NORM,TMP#)
	CALL(ORTHO1,TMP#)↔POP P,B
;PARTS OF THIS BODY.
L3:	TESTZ B,BDPBIT↔POP2J		;DON'T MOVE PARTS.
	SON N,B↔JUMPE N,POP2J.
L4:	CALL(APTRAN,N,N,TRN)
	POP P,N↔LAC B,OBJECT
	BRO N,N↔SON 0,B
	CAME 0,N↔GO L4↔POP2J
;....................................................................
FROTA:	LAC F,OBJ↔NCNT N,F↔MOVMS N	;FACE ROTATION.
	PED E,F↔DAC E,E0↔JUMPE E0,[	;VERTEX FACE.
	PFACE B,F↔PVT V,B↔CALL(ROTOR)↔POP2J]
	PCW 0,E↔SKIPN N↔CAMN 0,E↔GO[	;WIRE OR SHELL FACE.
	SETQ(V,{VCW,E,F})↔CALL(ROTOR)↔GO .+1]
L5:	SETQ(V,{VCCW,E,F})
	CALL(ROTOR)↔CALL(ECCW,E,F)
	CAMN 1,E↔POP2J			;END OF WIRE FACE.
	LAC E,1↔CAMN E,E0↔POP2J		;END OF NORMAL FACE.
	SOJN N,L5↔POP2J			;END OF SHELL FACE.
;....................................................................
EROTA:	LAC E,OBJ			;EDGE ROTATION
	PVT V,E↔CALL(ROTOR)
	NVT V,E↔CALL(ROTOR)↔POP2J
VROTA:	LAC V,OBJ↔CALL(ROTOR)↔POP2J	;VERTEX ROTATION.
ENDR APTRAN;1/14/73(BGB)------------------------------------------
SUBN(ROTOR)
COMMENT ⊗------------------------------------------------------------
;  APTRAN's inner most subroutine.
;  Expects arguments in V and Q. Clobbers 1,2,X,Y,Z.
;
;	X ← XWC(V);
;	Y ← YWC(V);
;	Z ← ZWC(V);
;
;	XWC(V) ← X*IX(Q) + Y*JX(Q) + Z*KX(Q) + XWC(Q);
;	YWC(V) ← X*IY(Q) + Y*JY(Q) + Z*KZ(Q) + YWC(Q);
;	ZWC(V) ← X*IZ(Q) + Y*JZ(Q) + Z*KZ(Q) + ZWC(Q);
⊗
	ACCUMULATORS{B,F,E,V,X,Y,Z,Q}
	
	LAC X,XWC(V)↔LAC Y,YWC(V)↔LAC Z,ZWC(V)

	LAC 1,IX(Q)↔CAMN 1,[1.0]↔SKIPA 1,X↔FMPR 1,X
	SKIPE 2,JX(Q)↔GO[FMPR 2,Y↔FADR 1,2↔GO .+1]
	SKIPE 2,KX(Q)↔GO[FMPR 2,Z↔FADR 1,2↔GO .+1]
	SKIPE 2,XWC(Q)↔FADR 1,2↔DAC 1,XWC(V)

	LAC 1,JY(Q)↔CAMN 1,[1.0]↔SKIPA 1,Y↔FMPR 1,Y
	SKIPE 2,IY(Q)↔GO[FMPR 2,X↔FADR 1,2↔GO .+1]
	SKIPE 2,KY(Q)↔GO[FMPR 2,Z↔FADR 1,2↔GO .+1]
	SKIPE 2,YWC(Q)↔FADR 1,2↔DAC 1,YWC(V)

	LAC 1,KZ(Q)↔CAMN 1,[1.0]↔SKIPA 1,Z↔FMPR 1,Z
	SKIPE 2,JZ(Q)↔GO[FMPR 2,Y↔FADR 1,2↔GO .+1]
	SKIPE 2,IZ(Q)↔GO[FMPR 2,X↔FADR 1,2↔GO .+1]
	SKIPE 2,ZWC(Q)↔FADR 1,2↔DAC 1,ZWC(V)

	POP0J
ENDR ROTOR;3/18/73(BGB)-------------------------------------------
SUBR(INTRAN,TRAN)		;INVERT A TRANSFORMATION.
COMMENT .-----------------------------------------------------------.
	Q ←← 6
	LAC 2,TRAN
	MOVSI XWC(2)↔HRRI XWC+Q↔BLT KZ+Q

;XWC' ← -(XWC*IX + YWC*IY + ZWC*IZ);
	LAC 1,XWC+Q↔FMPR 1,IX+Q
	LAC YWC+Q↔FMPR IY+Q↔FADR 1,0
	LAC ZWC+Q↔FMPR IZ+Q↔FADR 1,0
	MOVNM 1,XWC(2)

;YWC' ← -(XWC*JX + YWC*JY + ZWC*JZ);
	LAC 1,XWC+Q↔FMPR 1,JX+Q
	LAC YWC+Q↔FMPR JY+Q↔FADR 1,0
	LAC ZWC+Q↔FMPR JZ+Q↔FADR 1,0
	MOVNM 1,YWC(2)

;ZWC' ← -(XWC*KX + YWC*KY + ZWC*KZ);
	LAC 1,XWC+Q↔FMPR 1,KX+Q
	LAC YWC+Q↔FMPR KY+Q↔FADR 1,0
	LAC ZWC+Q↔FMPR KZ+Q↔FADR 1,0
	MOVNM 1,ZWC(2)

;TRANSPOSE ROTATION MATRIX.
	DAC JX+Q,IY(2)
	DAC KX+Q,IZ(2)
	DAC IY+Q,JX(2)
	DAC KY+Q,JZ(2)
	DAC IZ+Q,KX(2)
	DAC JZ+Q,KY(2)
	LAC 1,2
	POP1J
ENDR INTRAN;3/18/73(BGB)---------------------------------------------
SUBR(MKROT1,PAN,TILT,SWING)
COMMENT .-----------------------------------------------------------.
	SETQ(CP,{COS,PAN})↔	SETQ(SP,{SIN,PAN})
	SETQ(CT,{COS,TILT})↔	SETQ(ST,{SIN,TILT})
	SETQ(CS,{COS,SWING})↔	SETQ(SS,{SIN,SWING})
	CALL(MKFRAME)

	LAC SP↔FMP CT↔FMP SS↔DAC 2↔LAC CP↔FMP CS↔FSB 2↔DAC IX(1)
	LAC CP↔FMP CT↔FMP SS↔DAC 2↔LAC SP↔FMP CS↔FAD 2↔DAC IY(1)
	LAC ST↔FMP SS↔DAC IZ(1)

	LAC SP↔FMP CT↔FMP CS↔DAC 2↔LAC CP↔FMP SS↔FAD 2↔MOVNM JX(1)
	LAC CP↔FMP CT↔FMP CS↔DAC 2↔MOVN SP↔FMP SS↔FAD 2↔DAC JY(1)
	LAC ST↔FMP CS↔DAC JZ(1)

	LAC SP↔FMP ST↔DAC KX(1)
	LAC CP↔FMP ST↔MOVNM KY(1)
	LAC CT↔DAC KZ(1)↔POP3J
	DECLARE{CP,CT,CS,SP,ST,SS}
ENDR MKROT1;10/30/73(BGB)--------------------------------------------

SUBR(MKFFRM,FACE)	;MAKE FACE FRAME.
COMMENT .-----------------------------------------------------------.
	ACCUMULATORS{F,E,E0,V,X,Y,Z,N}

	LAC F,FACE↔PED E,F↔DAC E,E0
	SETZB X,Y↔SETZB Z,N
L1:	SETQ(V,{VCCW,E,F})↔SETQ(E,{ECCW,E,F})
	FADR X,XWC(V)↔FADR Y,YWC(V)↔FADR Z,ZWC(V)
	CAME E,E0↔AOJA N,L1↔AOS N

;CENTER OF FACE BECOMES ORIGIN.
	FLOAT N,↔FDVR X,N↔FDVR Y,N↔FDVR Z,N
	SETQ(F,{MKFRAME})↔DAC F,FRM#
	DAC X,XWC(F)↔DAC Y,YWC(F)↔DAC Z,ZWC(F)

;FIRST TWO VECTORS.
	SETQ(V,{VCW,E0,FACE})
	LAC XWC(V)↔FSBR X↔DAC IX(F)
	LAC YWC(V)↔FSBR Y↔DAC IY(F)
	LAC ZWC(V)↔FSBR Z↔DAC IZ(F)
	SETQ(V,{VCCW,E0,FACE})
	LAC XWC(V)↔FSBR X↔DAC JX(F)
	LAC YWC(V)↔FSBR Y↔DAC JY(F)
	LAC ZWC(V)↔FSBR Z↔DAC JZ(F)
	CALL(ORTHO2,FRM)
	CALL(NORM,FRM)
	CALL(ORTHO1,FRM)
	LAC 1,FRM↔POP1J
ENDR MKFFRM;2/19/74(BGB)---------------------------------------------

SUBR(MKQFRM,DX,DY,DZ)		;MAKE FRAME WITH RESPECT TO VECTOR.
COMMENT .-----------------------------------------------------------.

;NORMALIZE THE COMPONENTS OF THE VECTOR.
	SKIPE 1,DX↔FMPR 1,1↔DAC 1,4
	SKIPE 2,DY↔FMPR 2,2↔DAC 2,5
	SKIPE 3,DZ↔FMPR 3,3
	FADR 1,2↔FADR 1,3
	SETQ(R,{SQRT↑,1})

;ROTATION AXIS FRAME OF REFERENCE.
	SETQ(TMP1,{MKFRAME})↔DAC 1,7↔SKIPN R↔POP3J
	LAC 1,DX↔DAC 1,XWC(7)↔FDVR 1,R↔DAC 1,IX(7)↔DAC 1,JY(7)
	LAC 2,DY↔DAC 2,YWC(7)↔FDVR 2,R↔DAC 2,IY(7)↔DAC 2,JX(7)
	LAC 3,DZ↔DAC 3,ZWC(7)↔FDVR 3,R↔DAC 3,IZ(7)↔SETZM JZ(7)
	MOVM 3↔CAMLE[0.999]↔MOVNM JY(7)
	CALL(ORTHO2,TMP1)↔CALL(NORM,TMP1)
	LAC 1,TMP1
	POP3J
DECLARE{R,TMP1}
ENDR MKQFRM;3/6/74(BGB)----------------------------------------------
SUBR(NORM,FRAME)	; NORMALIZE A FRAME MATRIX.
COMMENT .-----------------------------------------------------------.
;ACCUMULATORS:
;	05 06 07	IX  IY  IZ
;	10 11 12	JX  JY  JZ
;	13 14 15	KX  KY  KZ.
	SAVAC(15)
	MOVS FRAME↔HRRI 5↔BLT 15

; R ← SQRT(A↑2+B↑2+C↑2); A←A/R; B←B/R; C←C/R;
	FOR Q IN (5,10,13){
	MOVM 1,Q↔CAMG 1,[1.0E-8]↔SETZB 1,Q↔FMPR 1,1
	MOVM 1+Q↔CAMG 0,[1.0E-8]↔SETZB 1+Q↔FMPR↔FADR 1,0
	MOVM 2+Q↔CAMG 0,[1.0E-8]↔SETZB 2+Q↔FMPR↔FADR 1,0
	SKIPE 1↔CAMN 1,[1.0]↔GO .+6↔CALL(SQRT,1)
	FDVR Q,1↔FDVR Q+1,1↔FDVR Q+2,1}

;PUT'EM DOWN.
	LAC 1,FRAME
	MOVSI 5↔HRRI IX(1)↔BLT KZ(1)
	GETAC(15)↔POP1J
ENDR NORM;1/14/73----------------------------------------------------

SUBR(ORTHO1,FRAME)		; ORTHOGONIZE AN ORIENTATION MATRIX.
COMMENT .-----------------------------------------------------------.
;IT IS ASSUMED THAT THE ROW VECTORS ARE UNIT VECTORS.
	X←←0 ↔ Y←←1 ↔ Z←←2		;ADDRESS DISPLACEMENTS.
	Q←←9 ↔ R←←13 ↔ A←←14 ↔ B←←15  	;ACCUMULATORS.
	SAVAC(15)↔SETOM FLG# 		;FIRST TIME THRU FLAG.
L0:	LAC R,FRAME
	MOVSI Q,IX(R)↔BLT Q,KZ		;FIRST NINE ACCUMULATORS.

;DOT EACH ROW VECTOR INTO THE NEXT ROW.
	FMPR IX,JX↔FMPR IY,JY↔FMPR IZ,JZ
	FADR IX,IY↔FADR IX,IZ
	FMPR JX,KX↔FMPR JY,KY↔FMPR JZ,KZ
	FADR JX,JY↔FADR JX,JZ
	FMPR KX,IX(R)↔FMPR KY,IY(R)↔FMPR KZ,IZ(R)
	FADR KX,KY↔FADR KX,KZ

;TAKE ABSOLUTE VALUES AND FIND THE WORST TOTAL COSINE.
	MOVMS IX↔MOVMS JX↔MOVMS KX
	LAC Q,KX↔FADR KX,JX↔FADR JX,IX↔FADR Q,IX
	EXCH Q,JX↔SETZM SIGN#
	MOVEI 1,IX(R)↔MOVEI 2,JX(R)↔MOVEI 3,KX(R)	;GET ROW POINTERS.
	CAML Q,IX↔GO .+4
	EXCH 2,1↔EXCH Q,IX↔SETCMM SIGN 	;GET 2 BIGGER THAN 1.
	CAML KX,Q↔GO .+4
	EXCH 3,2↔EXCH KX,Q↔SETCMM SIGN 	;GET 3 BIGGER THAN 2.
	CAMG KX,[0.00001]↔GO L1	  ;GOOD ENUF FOR GOVERNMENT WORK.

;STRAIGHTEN UP THE WORST VECTOR.
	LAC A,Y(1)↔FMPR A,Z(2)
	LAC B,Y(2)↔FMPR B,Z(1)↔FSBR A,B↔DAC A,X(3)
	MOVM A,A↔CAMG A,[1.0E-8]↔SETZM X(3)
	LAC A,X(2)↔FMPR A,Z(1)
	LAC B,X(1)↔FMPR B,Z(2)↔FSBR A,B↔DAC A,Y(3)
	MOVM A,A↔CAMG A,[1.0E-8]↔SETZM Y(3)
	LAC A,X(1)↔FMPR A,Y(2)
	LAC B,X(2)↔FMPR B,Y(1)↔FSBR A,B↔DAC A,Z(3)
	MOVM A,A↔CAMG A,[1.0E-8]↔SETZM Z(3)
	SKIPE SIGN↔GO[MOVNS X(3)↔MOVNS Y(3)↔MOVNS Z(3)↔GO .+1]
	SKIPN FLG↔GO L1↔SETZM FLG↔GO L0
L1:	GETAC(15)↔POP1J
ENDR ORTHO1;1/14/73(BGB)---------------------------------------------
SUBR(ORTHO2,QFRAME)
COMMENT .-----------------------------------------------------------.
; ACCEPT I; K' ← I CROSS J; J' ← K CROSS I;
	LAC 1,QFRAME
	SETZM KX(1)↔SETZM KY(1)↔SETZM KZ(1)
	MOVS QFRAME↔HRRI 1↔BLT 9
	LAC 12,4↔LAC 13,5↔LAC 14,6	;SAVE J VECTOR.
;VECTOR-K ← VECTOR-I CROSS VECTOR-J.
	LAC 2↔FMP 6↔DAC 7
	LAC 5↔FMP 3↔FSB 7,
	LAC 4↔FMP 3↔DAC 8
	LAC 1↔FMP 6↔FSB 8,
	LAC 1↔FMP 5↔DAC 9
	LAC 4↔FMP 2↔FSB 9,
;VECTOR-J ← VECTOR-K CROSS VECTOR-I.
	LAC 8↔FMP 3↔DAC 4
	LAC 2↔FMP 9↔FSB 4,
	LAC 1↔FMP 9↔DAC 5
	LAC 7↔FMP 3↔FSB 5,
	LAC 7↔FMP 2↔DAC 6
	LAC 1↔FMP 8↔FSB 6,
	LAC 15,QFRAME↔MOVSI 1
	HRRI IX(15)↔BLT KZ(15)
	LAC 1,QFRAME↔POP1J
ENDR ORTHO2;3/30/73(BGB)---------------------------------------------

SUBR(DETERM,FRAME)
COMMENT .-----------------------------------------------------------.
	MOVS FRAME↔HRRI 1↔BLT 9
	LAC 5↔FMP 9↔LAC 12,
	LAC 6↔FMP 8↔FSB 12,↔FMP 1,12
	LAC 6↔FMP 7↔LAC 12,
	LAC 4↔FMP 9↔FSB 12,↔FMP 2,12↔FAD 1,2
	LAC 4↔FMP 8↔LAC 12,
	LAC 5↔FMP 7↔FSB 12,↔FMP 3,12↔FAD 1,3↔POP1J
ENDR DETERM;4/1/73(BGB)----------------------------------------------
SUBR(ANGL3V,VERT1,VERT2,VERT3)			;ANGLE TRI-VERTEX.
COMMENT .-----------------------------------------------------------.
;ANGLE V1,V2,V3 CCW; RETURNS VALUE 0 TO 2π.
	V1 ←← 13
	V2 ←← 14
	V3 ←← 15

;DETERMINE WHETHER THE ANGLE IS MORE OR LESS THAN PI.

	LAC V1,VERT1↔MOVSI XWC(V1)↔HRRI 1↔BLT 3
	LAC V2,VERT2↔MOVSI XWC(V2)↔HRRI 4↔BLT 6
	LAC V3,VERT3↔MOVSI XWC(V3)↔HRRI 7↔BLT 9
	FSBR 1,4↔FSBR 2,5↔FSBR 3,6		;V1' ← (V1-V2).
	FSBR 7,4↔FSBR 8,5↔FSBR 9,6		;V3' ← (V3-V2).
	LAC 2↔FMP 9↔LAC 4,↔LAC 3↔FMP 8↔FSB 4,	;V2' ← (V1 X V3).
	LAC 3↔FMP 7↔LAC 5,↔LAC 1↔FMP 9↔FSB 5,
	LAC 1↔FMP 8↔LAC 6,↔LAC 2↔FMP 7↔FSB 6,
	FADR 1,4↔FADR 2,5↔FADR 3,6		;V1" ← (V1'+V2').
	FADR 7,4↔FADR 8,5↔FADR 9,6		;V3" ← (V3'+V2').

;DETERM NGEATIVE INDICATES CCW ORDER, 0 TO π.
;DETERM POSITIVE INDICATES CW  ORDER, π T0 2π.
	CALL({DETERM+3},0)
	SKIPL 1↔SKIPA 1,PI↔SETZ 1,↔PUSH P,1

;COSINE LAW.
	CALL(DISTANCE,V2,V1)↔PUSH P,1
	CALL(DISTANCE,V2,V3)↔PUSH P,1
	CALL(DISTANCE,V1,V3)
	FMPR 1,1↔MOVNS 1
	POP P,2↔LAC 2↔FMPR 2,2
	POP P,3↔FMP 3↔FMPR 3,3
	FSC 1↔FADR 1,2↔FADR 1,3
	FDVR 1,0↔CALL(ACOS,1)
	POP P,0↔FADR 1,0↔POP3J
ENDR ANGL3V;4/1/73(BGB)----------------------------------------------
SUBR(DISTAN,V1,V2)		;DISTANCE BETWEEN TWO VERTICES.
COMMENT .-----------------------------------------------------------.
	LAC 1,V1↔LAC 2,V2
	LAC XWC(1)↔FSBR XWC(2)↔FMPR↔DAC 3
	LAC YWC(1)↔FSBR YWC(2)↔FMPR↔FADRM 3
	LAC ZWC(1)↔FSBR ZWC(2)↔FMPR↔FADR 3
	CALL(SQRT,0)↔POP2J
ENDR DISTAN;2/10/73(BGB)---------------------------------------------

END
EUCLID.FAI  -  EOF.