grav_wars_forces2.bas

1 PLANETS=3
5 DEG 
6 EXEC INIT_MISSILE
7 EXEC INIT_PLANETS
25 DEG 
50 GRAPHICS 8
60 COLOR 1
65 EXEC DRAW_PLANETS
70 ------------------------------
80 IF X>0 AND X<319 AND Y>0 AND Y<160 THEN PLOT X,Y
90 X=X+VX:Y=Y+VY
91 FOR I=0 TO 2
92   XD=PLANETX(I)-X
93   YD=PLANETY(I)-Y
94   L=SQR(XD*XD+YD*YD)
95   L=L^3
96   FPX=XD/L
97   FPY=YD/L
98   VX=VX+FPX*PLANETM(I)
99   VY=VY+FPY*PLANETM(I)
100 NEXT I
200 GOTO 80
999 STOP 
11000 PROC INIT_PLANETS
11001   REM DIM ARRAYS
11002   DIM PLANETX(PLANETS)
11003   DIM PLANETY(PLANETS)
11004   DIM PLANETM(PLANETS)
11005   DIM PLANETR(PLANETS)
11010   REM PLANET #1
11020   PLANETX(0)=200
11030   PLANETY(0)=80
11040   PLANETM(0)=50
11050   PLANETR(0)=25
11060   REM PLANET #2
11070   PLANETX(1)=100
11080   PLANETY(1)=40
11090   PLANETM(1)=50
11100   PLANETR(1)=25
11110   REM PLANET #3
11120   PLANETX(2)=120
11130   PLANETY(2)=130
11140   PLANETM(2)=50
11150   PLANETR(2)=25
11180 ENDPROC 
12000 PROC DRAW_PLANETS
12010   FOR I=0 TO PLANETS-1
12020     CIRCLE PLANETX(I),PLANETY(I),PLANETR(I)
12030   NEXT I
12040 ENDPROC 
13000 PROC INIT_MISSILE
13010   ALPHA=90
13020   SPEED=2
13030   X=120
13040   Y=90
13050   VX=SPEED*SIN(ALPHA)
13060   VY=-1*SPEED*COS(ALPHA)
13099 ENDPROC