ZX81 Listing for sphere.p

**SPHERE**SLR/1984***** (sphere.p)

A simple graphic program that plots a sphere. Runs in FAST mode, press any key to pause and show progress.

SYSTEM VARIABLES

PROG  : 16509
D-FILE: 16994
VARS  : 17787
E-LINE: 17788
STKBOT: 17788
STKEND: 17788

LEGEND

9999 means line number
PRINT means treat as KEYWORD P

PROGRAM LISTING

   1 REM **SPHERE**SLR/1984*****
  10 LET P2=PI*2
  20 LET S=2.5*PI/180
  25 LET RA=20
  28 LET R=20*PI/180
  30 FOR B=0 TO P2 STEP R
  40 FOR A=0 TO P2 STEP S
  50 LET Y=20+SIN A*RA*COS B
  60 LET X=30+COS A*RA
  70 LET X=INT X
  80 LET Y=INT Y
  90 PLOT X,Y
  95 IF INKEY$<>"" THEN PAUSE 10
 100 NEXT A
 105 PAUSE 100
 110 NEXT B
 120 FOR B=0 TO P2 STEP R
 130 FOR A=0 TO P2 STEP S
 140 LET Y=20+COS A*RA
 150 LET X=30+SIN A*RA*COS B
 160 LET X=INT X
 170 LET Y=INT Y
 180 PLOT X,Y
 185 IF INKEY$<>"" THEN PAUSE 10
 190 NEXT A
 195 PAUSE 100
 200 NEXT B
 210 SLOW
 220 STOP
 300 SAVE "SPHERE"
 310 FAST
 320 RUN