CLS

PRINT "This is a simple flight simulator written in AmigaBasic."
PRINT "It uses the joystick in port 2 to control the plane."
PRINT "The joystick button increases the throttle, and the 'g'"
PRINT "key on the keyboard raises or lowers the landing gear."
PRINT "Press any key to start"

WHILE INKEY$ = "" 
WEND


ON TIMER(1) GOSUB Inst
TIMER ON
rpt=0
ld=INT(RND*360)
GOTO Loop

Display:
  ev=INT(elev/10)
  GOSUB Roll
  clock=clock+1
  LOCATE 1,1:PRINT x$
  RETURN

Roll: ' With Pitch and ground
  r=INT(wa*10+50)
  p=ev*2
  IF ((98-r)+p)<=0 OR r+p<=0 THEN RETURN
  COLOR 3
  AREA (25,(98-r)+p):AREA (600,r+p):AREA (600,98):AREA (25,98): AREAFILL
  COLOR 0
  AREA (25,(98-r)+p):AREA (600,r+p):AREA (600,2): AREA (25,2): AREAFILL
  RETURN
  
  
Inst:
  COLOR 3
  LOCATE 15,5:PRINT ang,INT(airspd),INT(alt),INT(fuel),ld,elev;
  LOCATE 17,11:PRINT INT((clock)/10);:LOCATE 17,35
  IF uflag=1 THEN PRINT "DOWN" :ELSE PRINT "UP  "
  RETURN

Stickinp:
  IF STRIG(3)=-1 THEN airspd=airspd+3
  horiz=STICK(2)
  vert=STICK(3)
  RETURN    

Loop:
  CLS
  COLOR 1
  LINE (23,100)-(602,0),,b
  LOCATE 14,5: PRINT"Heading","Airspeed","Altitude","Fuel","Dest","Elev","Time"
  LOCATE 17,5: PRINT "Clock:": LOCATE 17,22: PRINT "Landing Gear "
  GOSUB Init
  SAY TRANSLATE$("Get ready for take off")
Main:  
  IF crash=0 THEN
    IF wa>0 THEN wa=wa-0.2
    IF wa<0 THEN wa=wa+0.2
    IF ang<0 THEN ang=ang+360
    IF ang>360 THEN ang=ang-360
  END IF
  GOSUB Display
  IF crash=1 THEN COLOR 1:END
  SOUND 110+airspd/10,2
  SOUND 120+airspd/10,2
  IF land=1 AND uflag=1 THEN CLS:PRINT "Good landing, sir!":END
  IF land=1 AND uflag=0 THEN PRINT"Your wheels were UP":GOSUB Crunch:GOTO Main
  t=airspd : stall=0
In:
  x$=INKEY$
  IF takeoff=1 THEN elev=INT(elev+RND*2-RND*2)
  GOSUB Stickinp
  IF airspd<3 THEN GOTO Airspeed
  IF vert=1 THEN elev=elev+4:eflag=4:IF elev>90 THEN stall=1
  IF vert=-1 THEN elev=elev-4:eflag=-4:IF elev<-90 THEN stall=-1
  IF stall=1 THEN
     SOUND 1000,10                                       
     airspd=airspd/4
  END IF
  IF stall=-1 THEN
     SOUND 500,10
     alt=4*alt/5
  END IF
  IF alt<1 THEN GOTO Airspeed
  GOSUB Stickinp
  IF horiz=-1 THEN wa=wa-1:ang=ang-6:IF wa<-3 THEN wa=-3
  IF horiz=1 THEN wa=wa+1:ang=ang+6:IF wa>3 THEN wa=3
  ang=INT(ang+RND*2-RND*2)
Airspeed:
  IF x$="." THEN airspd=airspd+8
  IF x$="," THEN airspd=airspd-7
  IF x$=" " THEN airspd=0
  airspd=airspd-elev/100
  IF uflag=1 THEN airspd=airspd-0.5:fuel=fuel-0.1
  IF airspd<0 THEN airspd=0
  IF airspd>400 THEN airspd=400
  IF x$="g" AND uflag=0 THEN uflag=1:GOTO Chkfuel:
  IF x$="g" AND uflag=1 THEN uflag=0
Chkfuel:
  fuel=fuel-(ABS(t-airspd)/100)-0.1
  IF fuel<1 THEN GOSUB Crunch
  IF takeoff=1 THEN GOTO Notoff
  IF elev>10 AND airspd>45 AND uflag=1 THEN takeoff=1
  IF takeoff=0 THEN alt=0:GOTO Chkalt
Notoff:
  IF land=0 AND airspd<30 THEN elev=elev-5
  alt=alt+INT(((elev+0.1)*airspd)+eflag*airspd/1000)/40
  IF alt<300 AND takeoff=1 THEN alt=alt+airspd/30+elev
Chkalt:  
  IF alt<0 THEN GOSUB Crunch
  IF (alt>15 AND airspd>20) OR takeoff=0 THEN GOTO Main
  IF ABS(ang-ld)<13 OR ABS(ang+360-ld)<13 THEN land=1:GOTO Main
  GOTO Main
  
Init:
  uflag=1 ' landing gear up or down
  eflag=1
  ang=0
  takeoff=0
  land=0
  airspd=0
  alt=0    ' altitude
  elev=0
  wa=0
  fuel=750
  crash=0
  clock=0
  x$=""
  RETURN
  
Crunch:
  crash=1
  alt=0
  col=3
  GOSUB Inst
  SAY TRANSLATE$("Sorry, you crashed")
  COLOR 1
  RETURN