100 REM THE PROJECTOR - PERSPECTIVE PLOTTER
110 REM BY  IAN ADAM  VANCOUVER, BC
120 REM REQUIRES HIRES PLOTTING ROUTINES
130 REM FROM THE TRANSACTOR VOL 5 ISS 06
140 : 
150 REM SETUP
160 HI=49152: CO=49173: DR=49155
170 MO=49161: PR=49182: DM=49167: TE=49179
180 CD$=CHR$(17)
190 :
200 IF PEEK(HI+1)=194 THEN 240
210 LOAD"HIRES",8,1
220 : 
230 REM PARAMETERS
240 M=20: REM X-DIMENSION
250 N=16: REM Y-DIMENSION
260 DIM Z(M,N),R(M,N)
270 DIM XH(M),YH(N),YV(N)
280 : 
290 REM DATA TO PLOT
300 PRINT "CREATING DATA"
310 FOR X=0 TO M
320 FOR Y=0 TO N
330 Z(X,Y)=12*X+10*Y-1.25*X*Y
340 NEXT Y: PRINT X: NEXT X
350 : 
360 A$="HYPERBOLIC PARABOLOID": REM TITLE
370 : 
380 REM INSERT OTHER EXPRESSIONS IN 330, AND CHANGE TITLE IN 360
390 REM Z(X,Y)=X*X-X*X*X/22+75*Y-12*Y*Y+Y*Y*Y/2
400 REM A$="CONTOURS"
410 REM Z(X,Y)=560-EXP(SQR(ABS((X-10)*(Y-8)/2)))
420 REM A$="SHELL ROOF"
430 REM TM=SQR(X*X+1.5*Y*Y): Z(X,Y)=10+SIN(TM)+Y/4
440 REM A$="GRAVITY WAVES"
450 REM TM=SQR((X-10)^2+(Y-8)^2): Z(X,Y)=150-TM*55+TM*TM*8-TM*TM*TM/3
460 REM A$="SPLASH"
470 REM A=20-ABS(X-10): B=18-ABS(Y-8): Z(X,Y)=A: IFB>ATHENZ(X,Y)=B
480 REM A$="HOUSE"
490 REM Z(X,Y)=Y+(8-Y)*((X>4)AND(X<16))*((Y>3)AND(Y<13))
500 REM A$="PLATEAU"
510 REM OR READ EMPIRICAL RESULTS FROM DATA
520 : 
530 REM PROJECTION
540 THETA=60: REM DEFAULT ANGLE
550 PRINT CD$"ENTER VIEWING ANGLE, OR PRESS RETURN
560 [153] "FOR 60 DEGREES: 
570 INPUT TH
580 TH=TH*3.14159265/180
590 TMP=120*COS(TH)
600 XGRID=INT((309-TM)/M)
610 YGRID=INT(96*SIN(TH)/N)
620 YSTP=INT(TM/N)
630 : 
640 REM CALCULATE OFFSETS
650 FOR X=0 TO M
660 XHRIZ(X)=10+X*XG
670 NEXT
680 FOR Y=0 TO N
690 YHRIZ(Y)=Y*YS
700 YVERT(Y)=10+Y*YG
710 NEXT
720 : 
730 REM VERTICAL SCALING
740 PRINT "SCALING DATA
750 VSCALAR[178]9E9
760 [129] Y[178]0 [164] N
770 A[178]0: [129] X[178]0 [164] M
780 [139] Z(X,Y)[177]A [167] A[178]Z(X,Y)
790 [130]: [143] FIND HIGHEST POINT ON LINE
800 [139] A [167] TMP[178](199[171]YV(Y))[173]A
810 [139]  VS[177]TM  [167]  VS[178]TM
820 [130]: [143] SELECT BEST FEASIBLE SCALE
830 :
840 [143] CALCULATE RISE
850 [153] "...STILL SCALING!
860 FOR Y=0 TO N
870 TM=YV(Y)
880 FOR X=0 TO M
890 R(X,Y)=Z(X,Y)*VS+TM
900 NEXT X,Y
910 : 
920 REM SET UP SCREEN
930 SYS HI,0,0,8
940 SYS DM,1
950 : 
960 REM PLOT HORIZONTAL LINES
970 FOR Y=0 TO N
980 TM=YH(Y)
990 SYS MO,TM+10,R(0,Y)
1000 FOR X=1 TO M
1010 SYS DR,TM+XH(X),R(X,Y)
1020 NEXT X,Y
1030 : 
1040 REM PLOT VERTICAL LINES
1050 FOR X=0 TO M
1060 TM=XH(X)
1070 SYS MO,TM,R(X,0)
1080 FOR Y=1 TO N
1090 SYS DR,TM+YH(Y),R(X,Y)
1100 NEXT Y,X
1110 : 
1120 REM DRAW BOX
1130 SYS MO,10,R(0,0)
1140 SYS DR,10,10
1150 SYS DR,XH(M),10
1160 SYS DR,XH(M),R(M,0)
1170 SYS MO,XH(M),10
1180 SYS DR,XH(M)+YH(N),YV(N)
1190 SYS DR,XH(M)+YH(N),R(M,N)
1200 :
1210 REM TITLE
1220 SYS CO,13: SYS PR,1,24,A$
1230 :
1240 REM WAIT FOR HUMAN
1250 WAIT 198,1: GET B$
1260 SYS TE
1270 :
1280 PRINT CD$"PRESS R TO REVIEW FROM ANOTHER ANGLE
1290 [153] "PRESS ANY OTHER KEY TO END
1300 WAIT 198,1: GET B$
1310 IF B$="R" THEN 540
1320 END