PrimeFORTH/snake.fth
diemheych 8b08f501b2
simple FORTH graphical game example, snake
Snake game in FORTH using HP Prime graphics
2023-10-02 11:22:06 +11:00

156 lines
2.7 KiB
Forth

variable snake-x-head
500 cells allot
variable snake-y-head
500 cells allot
variable apple-x
variable apple-y
0 constant left
1 constant up
2 constant right
3 constant down
80 constant width
60 constant height
variable direction
variable length
: snake-x
cells snake-x-head + ;
: snake-y
cells snake-y-head + ;
: convert-x-y 24 cells * + ;
: draw pixon4 ;
: draw-black 0 col draw ;
: draw-white 16777215 col draw ;
: draw-red 16711680 col draw ;
: draw-walls
width 0 do
i 0 draw-black
i height 1 - draw-black
loop
height 0 do
0 i draw-black
width 1 - i draw-black
loop ;
: initialize-snake
4 length !
length @ 1 + 0 do
12 i - i snake-x !
12 i snake-y !
loop
down direction ! ;
: set-apple-position apple-x ! apple-y ! ;
: initialize-apple 50 50 set-apple-position ;
: initialize
width 0 do
height 0 do
j i draw-white
loop
loop
draw-walls
initialize-snake
initialize-apple ;
: move-up -1 snake-y-head +! ;
: move-left -1 snake-x-head +! ;
: move-down 1 snake-y-head +! ;
: move-right 1 snake-x-head +! ;
: move-snake-head direction @
left over = if move-left else
up over = if move-up else
right over = if move-right else
down over = if move-down
then then then then drop ;
: move-snake-tail 0 length @ do
i snake-x @ i 1 + snake-x !
i snake-y @ i 1 + snake-y !
-1 +loop ;
: is-horizontal direction @ dup
left = swap
right = or ;
: is-vertical direction @ dup
up = swap
down = or ;
: turn-up is-horizontal if up direction ! then ;
: turn-left is-vertical if left direction ! then ;
: turn-down is-horizontal if down direction ! then ;
: turn-right is-vertical if right direction ! then ;
: change-direction
7 over = if turn-left else
2 over = if turn-up else
8 over = if turn-right else
12 over = if turn-down
then then then then drop ;
: check-input
lastkey change-direction
;
: random-position
height 4 - random 2 +
width 4 - random 2 + ;
: move-apple
apple-x @ apple-y @ draw-white
random-position
set-apple-position ;
: grow-snake 1 length +! ;
: check-apple
snake-x-head @ apple-x @ =
snake-y-head @ apple-y @ =
and if
move-apple
grow-snake
then ;
: check-collision
snake-x-head @ snake-y-head @
getpix4
0 = ;
: draw-snake
length @ 0 do
i snake-x @ i snake-y @ draw-black
loop
length @ snake-x @
length @ snake-y @
draw-white ;
: draw-apple
apple-x @ apple-y @ draw-red ;
: game-loop
begin
draw-snake
draw-apple
50 length @ - dup 0< if drop 5 then sleep
check-input
move-snake-tail
move-snake-head
check-apple
check-collision
until ;
: snake cls initialize game-loop length @ . ;