perm filename EUCLID[G,BGB]3 blob sn#049882 filedate 1973-06-26 generic text, type C, neo UTF8
COMMENT ⊗   VALID 00021 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00004 00002	TITLE EUCLID  -  EUCLIDEAN TRANSFORMATIONS  -  JULY 1972.
C00005 00003	SUBR(TRANSLATE)REFRAM+OBJECT,DX,DY,DZ-----------------------------
C00007 00004	SUBR(ROTATE)REFRAM+OBJECT,ABOUTX,ABOUTY,ABOUTZ--------------------
C00010 00005	SUBR(NORM)FRAME---------------------------------------------------
C00012 00006	SUBR(ORTHO2)FRAME-------------------------------------------------
C00014 00007	SUBR(ANGL3V)V1,V2,V3 ---------------------------------------------
C00017 00008	SUBR(ORTHO1)FRAME-------------------------------------------------
C00020 00009	SQRT NOW ON ARITH.FAI
C00022 00010	SUBR(DISTAN)V1,V2-------------------------------------------------
C00023 00011	SIN AND COS ARE NOW IN ARITH.FAI
C00025 00012	ASIN,ACOS,LOG MOVED TO ARITH.FAI
C00028 00013	ATAN MOVED TO ARTIH.FAI
C00031 00014	ATAN2 MOVED TO ARTIH.FAI
C00033 00015	ROTOR:-----------------------------------------------------------
C00035 00016	VTRAN:	TRANSLATE A VERTEX
C00036 00017	SUBR(APTRAN)OBJECT,TRAN-------------------------------------------
C00038 00018	----(APTRAN) BODY ROTATION.
C00039 00019	----(APTRAN) FACE ROTATION.
C00041 00020	SUBR(INTRAN)TRAN -------------------------------------------------
C00044 00021	END
C00045 ENDMK
C⊗;
TITLE EUCLID  -  EUCLIDEAN TRANSFORMATIONS  -  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/
CONTENTS:

	FRAME ← TRANSLATE(REFRAM+OBJECT,DX,DY,DZ);
	FRAME ← ROTATE(REFRAM+OBJECT,ABOUTX,ABOUTY,ABOUTZ);
	FRAME ← SHRINK(REFRAM+OBJECT,KX,KY,KZ);
	NORM(FRAME);
	ORTHO1(FRAME);
	SQRT(X);		! NOW ON ARITH.FAI;
	DISTANCE(V1,V2);
	SIN(X);			! NOW ON ARITH.FAI;
	COS(X);			! NOW ON ARITH.FAI;
	ROTOR; V,Q.
	APTRAN(CBFEV,ETRAN);
	INTRAN(TRAN);
/
SUBR(TRANSLATE)REFRAM+OBJECT,DX,DY,DZ-----------------------------
BEGIN TRANSLATE; OBJECT TRANSLATION WITH RESPECT TO REFRAM.

	CALL(MKFRAME)
	LAC ARG3↔DAC XWC(1)
	LAC ARG2↔DAC YWC(1)
	LAC ARG1↔DAC ZWC(1)

↑QTRAN:	DAC 1,TMP1
	LACM 2,ARG4↔CDR 2,2↔DAC 2,OBJECT
	NIP 1,ARG4↔SKIPGE 1↔GO[
	SETZ 1,↔JUMPE 2,.+1
	CALL(BGET,OBJECT)
	FRAME 1,1↔GO .+1]
	DAC 1,REFRAM

	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

L1:	SKIPN OBJECT↔POP4J		;RETURN TRANSFORMATION.
	CALL(APTRAN,OBJECT,TMP1)
	CALL(KLNODE,TMP1)
	LAC 1,OBJECT↔POP4J		;RETURN OBJECT.

DECLARE{TMP1,TMP2,REFRAM,OBJECT}
BEND TRANSLATE; BGB 18 MARCH 1973 --------------------------------
SUBR(ROTATE)REFRAM+OBJECT,ABOUTX,ABOUTY,ABOUTZ--------------------
BEGIN ROTATE; OBJECT ROTATION WITH RESPECT TO REFRAM.

L1:	DZM TMP1↔SKIPN ARG3↔GO L2↔SETQ(TMP1,{MKFRAME})
	CALL(COS,ARG3)↔LAC 2,TMP1↔DAC 1,JY(2)↔DAC  1,KZ(2)
	CALL(SIN,ARG3)↔LAC 2,TMP1↔DAC 1,JZ(2)↔DACN 1,KY(2)

L2:	DZM TMP2↔SKIPN ARG2↔GO L3↔SETQ(TMP2,{MKFRAME})
	CALL(COS,ARG2)↔LAC 2,TMP2↔DAC 1,IX(2)↔DAC  1,KZ(2)
	CALL(SIN,ARG2)↔LAC 2,TMP2↔DAC 1,KX(2)↔DACN 1,IZ(2)

L3:	DZM TMP3↔SKIPN ARG1↔GO L4↔SETQ(TMP3,{MKFRAME})
	CALL(COS,ARG1)↔LAC 2,TMP3↔DAC 1,IX(2)↔DAC  1,JY(2)
	CALL(SIN,ARG1)↔LAC 2,TMP3↔DAC 1,IY(2)↔DACN 1,JX(2)

L4:	SKIPN 1,TMP2↔GO L5		;TMP1 ← TMP1 * TMP2.
	SKIPN TMP1↔GO[DAC 1,TMP1↔GO L5]
	CALL(APTRAN,TMP1,TMP2)
	CALL(KLNODE,TMP2)

L5:	SKIPN 1,TMP3↔GO L6		;TMP1 ← TMP1 * TMP3.
	SKIPN TMP1↔GO[DAC 1,TMP1↔GO L6]
	CALL(APTRAN,TMP1,TMP3)
	CALL(KLNODE,TMP3)

L6:	SKIPN 1,TMP1↔CALL(MKFRAME)		;IDENTITY.
	GO QTRAN

DECLARE{TMP1,TMP2,TMP3,REFRAM,OBJECT}
BEND ROTATE; BGB 18 MARCH 1973 -----------------------------------


SUBR(SHRINK)REFRAM+OBJECT,KX,KY,KZ--------------------------------
;DILATION-REFLECTION WITH RESPECT TO REFRAM.

	CALL(MKFRAME)
	SKIPN 2,ARG3↔SLACI 2,(1.0)↔DAC 2,IX(1)
	SKIPN 2,ARG2↔SLACI 2,(1.0)↔DAC 2,JY(1)
	SKIPN 2,ARG1↔SLACI 2,(1.0)↔DAC 2,KZ(1)
	GO QTRAN

;SHRINK BGB 18 MARCH 1973 ----------------------------------------
SUBR(NORM)FRAME---------------------------------------------------
BEGIN NORM; NORMALIZE AN ORIENTATION MATRIX.

;ACCUMULATORS:
;	05 06 07	IX  IY  IZ
;	10 11 12	JX  JY  JZ
;	13 14 15	KX  KY  KZ
	SAVAC(15)
	SLAC ARG1↔LAPI 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){
	LACM 1,Q↔CAMG 1,[1.0E-8]↔SETZB 1,Q↔FMPR 1,1
	LACM 1+Q↔CAMG 0,[1.0E-8]↔SETZB 1+Q↔FMPR↔FADR 1,0
	LACM 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,ARG1
	SLACI 5↔LAPI IX(1)↔BLT KZ(1)
	GETAC(15)↔POP1J↔VAR

BEND NORM; BGB 14 JANUARY 1973 -----------------------------------

SUBR(ORTHO2)FRAME-------------------------------------------------
BEGIN ORTHO2; ACCEPT I; K' ← I CROSS J; J' ← K CROSS I;
	LAC 1,ARG1
	DZM KX(1)↔DZM KY(1)↔DZM KZ(1)
	CALL(NORM,1)
	SLAC ARG1↔LAPI 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,ARG1↔SLACI 1
	LAPI IX(15)↔BLT KZ(15)
	POP1J

BEND ORTHO2;BGB 30 MARCH 1973 ------------------------------------


SUBR(DETERM)FRAME-------------------------------------------------
	SLAC ARG1↔LAPI 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
;DETERM - BGB 1 APRIL 1973 ---------------------------------------
SUBR(ANGL3V)V1,V2,V3 ---------------------------------------------
BEGIN ANGL3V; 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,ARG3↔SLACI XWC(V1)↔LAPI 1↔BLT 3
	LAC V2,ARG2↔SLACI XWC(V2)↔LAPI 4↔BLT 6
	LAC V3,ARG1↔SLACI XWC(V3)↔LAPI 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 negative indicates ccw order, 0 to π.
;determ positive indicates cw order, π to 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
BEND ANGL3V; BGB 1 APRIL 1973 ------------------------------------

SUBR(ATEST)FACE
BEGIN ATEST
	ACCUMULATORS{F,E,V1,V2,V3}
	LAC F,ARG1
	PED E,F
	SETQ(V1,{VCW,E,F})
	SETQ(V2,{VCCW,E,F})
	SETQ(E,{ECCW,E,F})
	SETQ(V3,{VCCW,E,F})
	CALL(ANGL3V,V1,V2,V3)
	FMP 1,[180.0]
	FDVR 1,PI
	POP1J
BEND ATEST
SUBR(ORTHO1)FRAME-------------------------------------------------
BEGIN ORTHO1; ORTHOGONIZE AN ORIENTATION MATRIX.
;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,ARG1
	SLACI 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#
	LACI 1,IX(R)↔LACI 2,JX(R)↔LACI 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)
	LACM 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)
	LACM 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)
	LACM 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↔LIT

BEND ORTHO1; BGB 14 JANUARY 1973 ---------------------------------
COMMENT⊗SQRT NOW ON ARITH.FAI
SUBR(SQRT)X ------------------------------------------------------
BEGIN SQRT;MODIFIED OLDE LIB40 SQUARE ROOT.
	A←←0 ↔ B←←1 ↔ C←←2
	LACM B,ARG1↔JUMPE B,POP1J.↔PUSH P,2

;LET X=F*(2↑2B) WHERE 0.25<F<1.00 THEN SQRT(X)=SQRT(F)*(2↑B).
	ASHC B,-=27↔SUBI B,201	;GET EXPONENT IN B, FRACTION IN C.
	ROT B,-1		;CUT EXP IN HALF, SAVE ODD BIT
	DAP B,L↔LSH B,-=35	;USE THAT ODD BIT.
	ASH C,-10↔FSC C,177(B)	;0.25 < FRACTION < 1.00

;LINEAR APPROXIMATION TO SQRT(F).
	DAC C,A
	FMP C,[0.8125↔0.578125](B)
	FAD C,[0.302734↔0.421875](B)

;TWO ITERATIONS OF NEWTON'S METHOD.
	LAC B,A
	FDV B,C↔FAD C,B↔FSC C,-1
	FDV A,C↔FADR A,C
     L: FSC A,0↔LAC 1,A↔POP P,2
	POP1J↔LIT
BEND SQRT; BGB 28 DECEMBER 1972 ----------------------------------
⊗;
SUBR(DISTAN)V1,V2-------------------------------------------------
BEGIN DISTAN; DISTANCE BETWEEN TWO VERTICES.
	LAC 1,ARG1↔LAC 2,ARG2
	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
BEND DISTAN; BGB 10 FEBRUARY 1973 --------------------------------
COMMENT⊗SIN AND COS ARE NOW IN ARITH.FAI
INTERN SIN,COS;---------------------------------------------------
BEGIN SINCOS;MODIFIED OLDE LIB40 SINE & COSINE - BGB.
	A←←1 ↔ B←←2 ↔ C←←3
↑COS:	SKIPA A,ARG1
↑SIN:	SKIPA A,ARG1
	FADR  A,HALFPI			;COS(X) = SIN(X+π/2).
	MOVM B,A↔CAMG B,[17B5]↔POP1J	;FOR SMALL X, SIN(X)=X.

;B ← (ABS(X)MODULO 2π)/HALFPI
;C ← QUADRANT 0, 1, 2 OR 3.
	FDVR B,HALFPI
	LAC C,B↔FIX C,233000
	CAILE C,3↔GO[
	TRZ C,3↔FSC C,233
	FSBR B,C↔GO .-3]		;MODULO 2π.
	GO .+1(C)↔GO .+4↔JFCL↔GO[
	FSBRI B,(2.0)↔MOVNS B↔GO .+2]	;SIN(X+π)=SIN(-X)
	FSBRI B,(4.0)			;SIN(X+2π)=SIN(X)
	SKIPGE A↔MOVNS	B		;SIN(-X) = -SIN(X).

;FOR -1 ≤ B ≤ +1 REPRESENTING -π/2 ≤ X ≤ +π/2,
;COMPUTE SINE(X) APPROXIMATION BY TAYLOR SERIES.
	DAC B,C↔FMPR B,B	
	LAC A,[164475536722]↔FMP A,B
	FAD A,[606315546346]↔FMP A,B
	FAD A,[175506321276]↔FMP A,B
	FAD A,[577265210372]↔FMP A,B
	FAD A,HALFPI↔FMPR A,C↔POP1J
	LIT
BEND;-------------------------------------------------------------
INTERN HALFPI,PI,TWOPI
	HALFPI:	201622077325 ;PI/2
	PI:	202622077325 ;PI
	TWOPI:	203622077325 ;2*PI
⊗;
COMMENT⊗ASIN,ACOS,LOG MOVED TO ARITH.FAI
SUBR(ACOS)--------------------------------------------------------
;ACOS(X)= π/2 - ASIN(X).
;GIVEN -1 ≤ X ≤ +1 RETURN 0 ≤ ACOS(X) ≤ +π.
	PUSH 17,ARG1↔PUSHJ 17,ASIN
	MOVNS 1↔FADR 1,HALFPI↔POP1J
;-----------------------------------------------------------------

SUBR(ASIN)--------------------------------------------------------
BEGIN ASIN
;ASIN(X)=ATAN(X/SQRT(1-X↑2)).
;GIVEN -1 ≤ X ≤ +1 RETURN -π/2 ≤ ASIN(X) ≤ +π/2.
	A←1 ↔ B←2
	LACN A,ARG1↔FMPR A,ARG1↔FADRI A,(1.0)
	JUMPE A,[		;WAS X EITHER -1.0 OR 1.0?
		LAC A,HALFPI
		SKIPGE ARG1
		MOVNS A↔POP1J]
	PUSH 17,A↔PUSHJ 17,SQRT
	LAC B,ARG1↔FDVR B,1↔DAC B,ARG1	;CALCULATE X/SQRT(1-X↑2)
	GO ATAN			;CALCULATE ATAN(SQRT(1-X↑2))
BEND;-------------------------------------------------------------

SUBR(LOG)---------------------------------------------------------
BEGIN LOG
	MOVM ARG1↔SKIPE 1,0↔CAMN 0,[1.0]↔POP1J
	ASHC 0,-33↔ADDI 0,211000↔MOVSM 0,TMP1#
	MOVSI 0,(-128.5)↔FADM 0,TMP1
	ASH 1,-10↔TLC 1,200000↔FAD 1,[-0.70710678]
	LAC 0,1↔FAD 0,[1.4142135]↔FDV 1,0
	DAC 1,TMP2#↔FMP 1,1
	LAC 0,[0.59897864]↔FMP 0,1
	FAD 0,[0.96147063]↔FMP 0,1
	FAD 0,[2.88539120]↔FMP 0,TMP2↔FAD 0,TMP1
	FMP 0,[0.69314718]↔LAC 1,0↔POP1J
	LIT↔VAR
BEND;-------------------------------------------------------------
⊗;
COMMENT⊗ATAN MOVED TO ARTIH.FAI
SUBR(ATAN)--------------------------------------------------------
BEGIN ATAN
;ATAN(X) = X*(B0+A1 / (Z+B1-A2 / (Z+B2-A3 / (Z+B3))) )
;WHERE Z=X↑2, IF 0<X<=1
;IF X>1, THEN ATAN(X) = PI/2 - ATAN(1/X)
;IF X>1, THEN RH(D) =-1, AND LH(D) = -SGN(X)
;IF X<1, THEN RH(D) = 0, AND LH(D) =  SGN(X)
	A←←1 ↔ B←←2 ↔ C←←3 ↔ D←←4 ↔ E←←5
	LAC	A,ARG1		;PICK UP THE ARGUMENT IN A
ATAN1:	LACM	B, A		;GET ABSF OF ARGUMENT
	CAMG	B, A1		;IF X<2↑-33, THEN RETURN WITH...
	POP1J		;ATAN(X) = X
	HLLO	D, A		;SAVE SIGN, SET RH(D) = -1
	CAML	B, A2		;IF A>2↑33, THEN RETURN WITH
	GO[LAC A,HALFPI ↔POP1J];	ATAN(X) = PI/2
	MOVSI	C, 201400	;FORM 1.0 IN C
	CAMG	B, C		;IS ABSF(X)>1.0?
	TRZA	D, -1		;IF B ≤ 1.0, THEN RH(D) = 0
	FDVM	C, B		;B IS REPLACED BY 1.0/B
	TLC	D, (D)		;XOR SIGN WITH > 1.0 INDICATOR

	DAC B,E↔FMP B,B
	LAC C,B↔FAD C,KB3↔LAC A,KA3↔FDVM A,C
	FAD C,B↔FAD C,KB2↔LAC A,KA2↔FDVM A,C
	FAD C,B↔FAD C,KB1↔LAC A,KA1↔FDV  A,C
	FAD A,KB0↔FMP A,E

	TRNE	D, -1		;CHECK > 1.0 INDICATOR
	FSB	A, HALFPI		;ATAN(A) = -(ATAN(1/A)-PI/2)
	SKIPGE	D		;LH(D) = -SGN(B) IF B>1.0
	MOVNS A		;NEGATE ANSWER
	POP1J		;EXIT
A1:	145000000000		;2↑-33
A2:	233000000000		;2↑33

KB0:	176545543401		;0.1746554388
KB1:	203660615617		;6.762139240
KB2:	202650373270		;3.316335425
KB3:	201562663021		;1.448631538

KA1:	202732621643		;3.709256262
KA2:	574071125540		;-7.106760045
KA3:	600360700773		;-0.2647686202
BEND ATAN;--------------------------------------------------------
⊗;
COMMENT⊗ATAN2 MOVED TO ARTIH.FAI
SUBR(ATAN2)-------------------------------------------------------
BEGIN	ATAN2

; OMEGA ← ATAN2(Y,X).
	Y←←1 ↔ X←←2
	LACM Y,ARG2↔LACM X,ARG1
	CAML Y,X↔GO L1

;HORIZONTAL TO π/2; ABS(Y) < ABS(X).
	LAC  Y,ARG2↔FDVR Y,ARG1
	PUSH 17,Y↔PUSHJ 17,ATAN		;ARCTAN(Y/X)
	SKIPL ARG1↔POP2J		;1ST & 2ND QUADRANTS.
	JUMPGE Y,[
	FSBR Y,PI↔POP2J]		;3RD QUADRANT.
	FADR Y,PI↔POP2J			;2ND QUADRANT.

;VERTICAL TO π/2; ABS(X) < ABS(Y).
L1:	LACN X,ARG1↔FDVR X,ARG2
	PUSH 17,X↔PUSHJ 17,ATAN		;ARCTAN(X/Y)
	SKIPG ARG2↔GO[
	FSB Y,HALFPI↔POP2J]
	FADR Y,HALFPI
	POP2J

BEND ATAN2;-------------------------------------------------------
⊗;
ROTOR:;-----------------------------------------------------------
BEGIN ROTOR
;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
BEND ROTOR; BGB 18 MARCH 1973 ------------------------------------
VTRAN:;	TRANSLATE A VERTEX
BEGIN VTRAN
	ACCUMULATORS{B,F,E,V,X,Y,Z,Q}
	CALL ROTOR
	PUSH P,V
LOOP:	PY V,V
	JUMPE V,[POP P,V
		 POP0J]
	YCODE 0,V
	CAIN 0,$TEXTHD
	CALL ROTOR
	GO LOOP
BEND VTRAN
SUBR(APTRAN)OBJECT,TRAN-------------------------------------------
BEGIN APTRAN; APPLY EUCLIDEAN TRANSFORMATION TO THE OBJECT.
	ACCUMULATORS{B,F,E,V,X,Y,Z,TRN,N,OBJ,E0}
	SKIPN TRN,ARG1↔POP2J

;BRANCH ON TYPE OF OBJECT.
	LAC OBJ,ARG2
	LACM 1,(OBJ)↔JUMPE 1,LROTA
	TLNE 1,(1B9)↔GO LROTA			;FRAME.
	ANDI 1,17
	CAIN 1,$BODY↔GO BROTA			;BODY.
	CAIN 1,$CAMERA↔GO CROTA			;CAMERA.
	CAIN 1,$FACE↔GO FROTA			;FACE.
	CAIN 1,$EDGE↔GO EROTA			;EDGE.
	CAIN 1,$VERT↔GO VROTA			;VERT.
	CAIE 1,$YNODE↔POP2J
	YCODE 1,OBJ
	CAIN 1,$TEXTHD↔GO VROTA			;TEXT HEADER
	POP2J

LROTA:	SKIPA V,OBJ			;FRAME CASE.
CROTA:	FRAME V,OBJ			;CAMERA CASE.

	CALL(ROTOR)
	PUSH P,XWC(TRN)↔PUSH P,YWC(TRN)↔PUSH P,ZWC(TRN)
	DZM XWC(TRN)↔DZM YWC(TRN)↔DZM 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)
	POP2J
;----(APTRAN) BODY ROTATION.
BROTA:	LAC B,OBJ
	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(VTRAN)↔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:	PUSH P,N
	CALL(APTRAN,N,TRN)
	POP P,N↔LAC B,ARG2
	BRO N,N↔SON 0,B
	CAME 0,N↔GO L4
	POP2J
;----(APTRAN) FACE ROTATION.
FROTA:	LAC F,OBJ↔NCNT N,F↔MOVMS N
	PED E,F↔DAC E,E0↔JUMPE E0,[	;VERTEX FACE.
	PFACE B,F↔PVT V,B↔CALL(VTRAN)↔POP2J]

	PCW 0,E↔SKIPN N↔CAMN 0,E↔GO[	;WIRE OR SHELL FACE.
	SETQ(V,{VCW,E,F})↔CALL(VTRAN)↔GO .+1]

L5:	SETQ(V,{VCCW,E,F})
	CALL(VTRAN)↔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.

;EDGE ROTATION.
EROTA:	LAC E,OBJ
	PVT V,E↔CALL(VTRAN)
	NVT V,E↔CALL(VTRAN)
	POP2J

;VERTEX ROTATION.
VROTA:	LAC V,OBJ
	CALL(VTRAN)
	POP2J

BEND;1/14/72------------------------------------------------------
SUBR(INTRAN)TRAN -------------------------------------------------
BEGIN INTRAN; INVERT A TRANSFORMATION.
	Q ←← 6

	LAC 2,ARG1
	SLACI XWC(2)↔LAPI 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
	DACN 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
	DACN 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
	DACN 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

BEND INTRAN; BGB 18 MARCH 1973 -----------------------------------
END
EUCLID-EOF.