100 REM BASIC Month 4: Lunar Corps
110 REM http://reddit.com/r/RetroBattlestations
120 REM written by FozzTexx
200 REM Clear screen and setup variables
210 MODE 2:x=1:y=25:GOSUB 1010
220 peaks$=" /\_"
230 cols=79:rows=24
240 RANDOMIZE TIME
300 GOSUB 2510
310 ys=SQR(2)*SQR(rows-tl+zl)-1
320 xe=INT((ze-zs)/2)+zs
330 xv=xe/ys:yv=0
340 lx=1:ly=1
400 GOSUB 2010:lm$=sp$
410 GOSUB 2010:ml$=sp$:le$=se$
420 FOR i=1 TO INT(ys)
430 sp$=le$:x=lx:y=ly:GOSUB 1510
440 yv=yv+1
450 lx=lx+xv:ly=ly+yv
460 sp$=lm$:IF i>=ys-2 THEN sp$=ml$
470 x=lx:y=ly:GOSUB 1510
480 FOR j=1 TO 400:NEXT j
490 NEXT i
500 sp$=le$:x=lx:y=ly:GOSUB 1510
510 lx=(ze-zs)/2+zs-1:ly=rows-tl+zl
520 sp$=lm$:x=lx:y=ly:GOSUB 1510
530 sp$="The Eagle has landed":x=(cols-LEN(sp$))/2:y=rows/2:GOSUB 1510
999 END
1000 REM Position cursor at X,Y
1010 LOCATE INT(x),INT(y)
1020 RETURN
1500 REM Draw sprite in SP$ at X,Y
1510 se=1:sb=1
1520 IF x<1 OR x>cols OR y<1 OR y>rows THEN RETURN
1530 se=INSTR(sb,sp$,CHR$(13))
1540 IF se=0 THEN se=LEN(sp$)+1
1550 GOSUB 1010
1560 sl=se-sb:IF sl+x-1>cols THEN sl=cols-x+1
1570 PRINT MID$(sp$,sb,sl);
1580 IF se>=LEN(sp$) THEN RETURN
1590 IF ASC(MID$(sp$,se))=13 THEN se=se+1
1600 sb=se:y=y+1:GOTO 1520
2000 REM Load a sprite from DATA into SP$
2010 sp$="":se$="":sr=0:sc=0
2020 READ t$,s$:IF LEN(sp$)>0 THEN sp$=sp$+CHR$(13)
2030 sp$=sp$+s$:sr=sr+1:IF LEN(s$)>sc THEN sc=LEN(s$)
2040 bl$=SPACE$(LEN(s$))
2050 IF LEN(se$)>0 THEN se$=se$+CHR$(13)
2060 se$=se$+bl$
2070 IF t$<>"SE" THEN 2020
2080 RETURN
2500 REM Draw lunar surface
2510 didup=0:l1$="":FOR i=1 TO cols+4:l1$=l1$+" ":NEXT i
2520 zs=0:ze=0:tl=0
2530 l2$="  ":up=didup: IF NOT up AND MID$(l1$,3,1)<>" " THEN up=1
2540 IF NOT didup AND up THEN didup=up
2550 z1=0:z2=0
2560 FOR i=3 TO cols+2:PRINT".";CHR$(8);
2570 c1$=MID$(l2$,i-2,1):c2$=MID$(l2$,i-1,1)
2580 c3$=MID$(l1$,i-1,1):c4$=MID$(l1$,i,1)
2590 c5$=MID$(l1$,i+1,1):c6$=MID$(l1$,i+2,1)
2600 IF peak=0 AND MID$(l1$,i-1,4)="    " THEN peak=INT(RND(1)*3):peak=peak+(peak=2)*-1:peak=peak*INT(RND(1)*2)
2610 IF c2$="/" AND c4$=" " THEN peak=2
2620 IF (c1$="_" OR c1$="\") AND c2$=" " THEN peak=0
2630 IF c4$<>" " THEN peak=0
2640 IF (c3$="\" OR c3$="_") AND c4$=" " THEN peak=2
2650 IF c2$="_" AND c6$="/" THEN peak=3
2660 IF (c2$="\" OR c2$=" " OR c2$="_") AND c4$=" " AND (c5$="_" OR c5$="/") THEN peak=1
2670 IF c2$="\" AND c6$<>" " THEN peak=3
2680 IF (c5$="/" OR c5$="_") THEN peak=1
2690 IF c4$<>" " THEN peak=0
2700 IF up AND peak<>2 THEN peak=0
2710 IF peak=1 THEN up=1
2720 IF peak=2 THEN up=0
2730 p$=MID$(peaks$,peak+1,1):PRINT p$;:l2$=l2$+p$
2740 IF peak=3 AND z1=0 THEN z1=i
2750 IF peak<>3 AND c2$="_" THEN z2=i
2760 IF z1 AND z2 THEN z3=z1:z4=z2:z1=0:z2=0:IF z4-z3 >= 3 AND z3>zs THEN zs=z3:ze=z4:zl=tl
2770 IF peak<>3 OR (c1$="_" AND c2$="_") THEN peak=0
2780 NEXT
2790 l1$=l2$
2800 c2=0
2810 FOR i=3 TO cols+2
2820 IF MID$(l1$,i,1)=" " THEN c2=c2+1
2830 NEXT
2840 tl=tl+1
2850 IF c2<cols THEN PRINT:GOTO 2530
2860 zs=zs-2:ze=ze-2:RETURN
9000 DATA SP,"(I)"
9010 DATA SE,"/T\"
9020 DATA SP,"(I)"
9030 DATA SP,"/T\"
9040 DATA SE," V "