; Spacewar, in Alan Kay's hand, as printed in Stewart Brand,
; "SPACEWAR: Fanatic Life and Symbolic Death Among the Computer Bums",
; Rolling Stone, 7 December 1972, in the sidebar "Your Own Spacewar".
;
; A LOGO / turtle-graphics-style sketch (penup / pendown / forward / right),
; close in spirit to the language ideas Kay was then developing toward Smalltalk
; and the Dynabook. Transcribed from the magazine scan; spacing and a few
; characters are approximate to the 1972 original.

to ship :size
  penup, left 180, forward 2 * :size, right 90
  forward 1 * :size, right 90
  pendown, forward 4 * :size, right 30, forward 2 * :size
  right 120, forward 2 * :size
  right 30, forward 4 * :size
  right 30, forward 2 * :size
  right 120, forward 2 * :size
  left 150, forward :size * 2 * sqrt 3
  left 330, forward :size * 2
  right 60, forward :size * 2
  left 330, forward :size * 2 * sqrt 3
  penup, left 90, forward :size, right 90
  forward 2 * :size
end to

to flame :size
  penup, left 180, forward 2 + sqrt 3, pendown
  triangle :size, forward .5 * :size
  triangle 1.5 * :size, forward .5 * :size
  triangle 2 * :size, forward .5 * :size
  triangle 1 * :size, forward :size
  etc.
end to

to flash
  etc.
end to

to retro
  etc.
end to

to torp
  etc.
end to

to spaceship :pilot :thrust :steer :trigger
  use :numtorps :location (:x :y) :speed :direction
  repeat
    moveship
    if :trigger and :numtorps < 3
      then create torpedo :speed :direction :location
    ?crash :self
    display ship
    pause until clock = :time + :movelag
end to

to moveship
  make :speed be :speed + (:spscale * :thrust)
  make :direction be :direction + (:dirscale * :steer) rem 360
  make :location:x be :location:x + (:lscale * :speed * cos :direction) rem 1024
  make :location:y be :location:y + (:lscale * :speed * sin :direction) rem 1024
end to

to display :obj
  penup, moveto :location, turn :direction
  create :obj :size
  if :thrust > 0 then create flame :size
  if :thrust < 0 then create retro flame :size
  pause until clock = :time + :framelag
end to

to ?crash :object
  find all (create spaceship :s)
    if :object = :s
      and /:object:location:x - :s:location:x/ < close
      and /:object:location:y - :s:location:y/ < close
      then explode :s, explode :obj
end to

to explode :object
  penup, moveto :object:location
  flash
  finish :object
end to

to torpedo :speed :direction :location
  use :thrust 0
  bump :numtorps
  moveship
  if not (0 < :location:x < 1024 and 0 < :location:y < 1024)
    then debump :numtorps, finish :self
  ?crash :self
  display :torp
end to

to start
  repeat ask "how many will be playing?" times
    create spaceship ask "pilot's name?"
    stick.(make :sn be ask "stick number?").y
    stick :sn:x
    stick :sn:but
  end repeat
  repeat
    if (make :char be ask) = "s" then done
    find all (create spaceship :x)
    start :x
end to


; A sample run, as printed (user input marked with *):

*start
  how many will be playing?
*2
  pilot's name?
*Jimmy
  stick number?
*2
  pilot's name?
*Bill
  stick number?
*3