Snake
Snake is a game where the player maneuvers a line which grows in length every time the snake reaches a food source.
You are encouraged to solve this task according to the task description, using any language you may know.
| This page uses content from Wikipedia. The original article was at Snake_(video_game). The list of authors can be seen in the page history. As with Rosetta Code, the text of Wikipedia is available under the GNU FDL. (See links for details on variance) |
- Task
Implement a variant of the Snake game, in any interactive environment, in which a sole player attempts to eat items by running into them with the head of the snake.
Each item eaten makes the snake longer and a new item is randomly generated somewhere else on the plane.
The game ends when the snake attempts to eat himself.
Amazing Hopper
<lang Amazing Hopper> /* Snake */ /* Implementing this task in Hopper-FLOW-MATIC++ */ /* The snake must catch a bite before time runs out, which decreases by
10 points every 800 milliseconds. The remaining time will be added to your total score. */
- include <flow.h>
- include <flow-term.h>
- include <keys.h>
- enum 1,N,E,S,W
- enum 1,SPACE,FOOD,BORDER
DEF-MAIN(argv, argc)
BREAK-ON STACK 16 CLR-SCR MSET(C, quit, nHead, dir, Size, SCORE, counter, T,TPlay,ConsPrey ) SET( symbol, " $@" )
SET( w, 50 ) //50 SET( h, 28 ) // 24 SET( TIME, 100 ) LET( Size := MUL(w,h) ) SET( TLimit := 100 ) VOID( big number, numL1, numL2, numL3 ) GOSUB( set score )
DIM( Size ) AS-ONES( board ) HIDE-CURSOR
GOSUB( put titles )
GOSUB( start )
GOSUB( show )
GOSUB( ready ), SLEEP(3)
TIC( T ), TIC( TPlay )
WHILE( NOT (quit) )
DEVIATE-IF( TLimit ~= TPlay ){
GOSUB( show )
WHEN( KEY-PRESSED? ){
SCAN-CODE( C )
SWITCH( C )
CASE( K_UP ) { dir = N, EXIT }
CASE( K_RIGHT ){ dir = E, EXIT }
CASE( K_DOWN ) { dir = S, EXIT }
CASE( K_LEFT ) { dir = W, EXIT }
CASE( K_ESC ) { quit = 1, EXIT }
CASE( 32 ) { PAUSE, EXIT }
SWEND
}
GOSUB( step )
}
DEVIATE-IF( 800 ~= T ) {
TIME-=10, CLAMP(0,100,TIME)
{TIME, 12, 52} GOSUB( put time )
}
WEND
GOSUB(you lost), SLEEP(1)
GOSUB(game over ), SLEEP(2)
LOCATE(ADD(h,1),1) PRNL
SHOW-CURSOR
PRNL
END
RUTINES
// initialize the board, plant a very first food item DEF-FUN( start )
SET( i,1 )
[1:w] {BORDER} CPUT(board) // top
[ SUB(MUL(h,w),MINUS-ONE(w)) : end] {BORDER} CPUT(board) // bottom
[1:w:end] {BORDER} CPUT(board) // left
SET(i, 1)
FOR( LE?(i, h), ++i )
[ MUL(i, w )] {BORDER} PUT(board) // right
NEXT
LET( nHead := MUL( w, SUB( SUB( h, 1 ), MOD(h,2) )) DIV-INTO(2) )
[ nHead ] {-5} CPUT( board )
LET( dir := N )
SRAND( ~SECONDS)
GOSUB( plant )
RET
DEF-FUN( you lost )
SET(i,1), SET(k,0), SET(n,1)
LOCATE(1,1)
FOR( LE?(i, h), ++i)
SET(j,1)
FOR( LE?(j, w), ++j)
LET( k := [ n ] GET(board) )
COND( IS-NEG?( k ))
LOCATE(i,j)
PRNL("\033[38;15;3m\033[48;5;9m~\OFF")
CEND
++n
NEXT
NEXT
RET
DEF-FUN( show )
SET(i,1) MSET(j, k)
SET(n,1)
LOCATE(1,1)
FOR( LE?(i, h), ++i)
SET(j,1),
FOR( LE?(j, w), ++j)
LET( k := [ n ] GET(board) )
COND( IS-NEG?( k ))
PRN("\033[38;5;3m\033[48;5;15m~\OFF")
ELS-COND( {k} IS-EQ?(BORDER))
{"\033[38;5;4m\033[48;5;2m"}
PRN( [k] GET(symbol),"\OFF")
ELS-COND( {k}IS-EQ?(FOOD) )
{"\033[38;5;15m\033[48;5;9m"}
PRN( [k] GET(symbol),"\OFF")
ELS
{"\033[48;5;28m"}
PRN( [k] GET(symbol),"\OFF")
CEND
++n
NEXT
PRNL
NEXT
RET
// negative values denote the snake (a negated time-to-live in given cell)
// reduce a time-to-live, effectively erasing the tail DEF-FUN( age )
MSET( r, jAge, jR ) CART( IS-NEG?( board ) ) »» (r), SET-RANGE(r)
GET( board ) PLUS(1) »» (jAge)
// this is necessary, because Hopper arrays begining in 1
CART( IS-ZERO?(jAge) ) »» (jR)
COND( IS-ARRAY?(jR) )
SET-RANGE(jR), SET(jAge, 1), SET-RANGE(r)
CEND
// ******
{jAge} PUT(board), CLR-RANGE
RET
DEF-FUN( step )
SET(len,0)
LET( len := [nHead] GET(board) )
SWITCH(dir)
CASE (N){ nHead -= w, EXIT }
CASE (S){ nHead += w, EXIT }
CASE (W){ --nHead, EXIT }
CASE (E){ ++nHead, EXIT }
SWEND
SWITCH( [nHead]CGET(board))
CASE (SPACE){
--len, LET( len := IF( IS-ZERO?(len), 1, len) )
[nHead] { len }, CPUT(board) // keep in mind len is negative
GOSUB( age )
EXIT
}
CASE (FOOD){
--len, LET( len := IF( IS-ZERO?(len), 1, len) )
[nHead] { len }, CPUT(board)
GOSUB( plant )
ADD(SCORE,TIME), MOVE-TO(SCORE)
{SCORE, 4, 52} GOSUB( put score )
LET( TIME := 100 )
++counter, COND( GT?( counter, 5 ) )
LET( TLimit := SUB( TLimit,5 ))
CLAMP(30,100,TLimit)
LET( counter := 0 )
CEND
++ConsPrey
COLOR-FG(10)
LOCATE(20,52) PRNL("SPEED: ")
LOC-ROW(21), SET-ROUND(2)
PRNL( MUL(INV(TLimit),100), " M/S" )
SET-ROUND(-1)
LOC-ROW(23) PRNL("CONSUMED PREY:")
LOC-ROW(24) PRNL(ConsPrey,"\OFF")
TIC( T ),{TIME, 12, 52} GOSUB( put time )
EXIT
}
LET( quit := 1 )
SWEND
RET
// put a piece of food at random empty position DEF-FUN( plant )
SET(r, 0)
LOOP( search position )
LET( r := MOD( CEIL(RAND(MINUS-ONE(Size))), Size ) )
BACK-IF-NOT-EQ( [r] GET(board), SPACE, search position)
[r] {FOOD} CPUT( board )
RET
DEF-FUN( put titles )
LOCATE(2,52) PRNL("\033[38;5;15mSCORE\OFF")
{SCORE, 4, 52} GOSUB( put score )
LOCATE(10,52) PRNL("\033[38;5;11mTIME\OFF")
{TIME, 12, 52} GOSUB( put time )
COLOR-FG(15)
LOCATE(26,52) SET-ITALIC, PRNL(" S P E E D")
LOC-ROW(27) PRNL("S N A K E!\OFF")
RET
DEF-FUN( put time, B, posx, posy )
MSET( i,j,x ) MSET( sb, lsb,nB, p4 ) SET( k,1 )
LOCATE (posx, posy) FILL-BOX(" ",5,20)
LET( sb := STR(B) )
LET( lsb := LEN(sb) )
SET( rx, posy )
LET( p4 := ADD( posx, 4 ))
{"\033[38;5;11m\ENF"}
PERF-UP(k, lsb, 1)
LET( nB := VAL( MID( 1, k, sb )) )
SET(x, 1), SET( i, posx )
FOR( LE?(i, p4), ++i )
SET( j, rx )
FOR( LE?(j, ADD( rx, 2 ) ), ++j )
LOCATE(i, j) PRNL( STR-TO-UTF8(CHAR( [ PLUS-ONE(nB), x] CGET(big number) MUL-BY(219) )))
++x
NEXT
NEXT
rx += 4
NEXT
PRNL("\OFF")
RET
DEF-FUN( put score, SCORE, posx, posy )
MSET( ln,s, sp )
LET( sp := STR( SCORE )) LET( ln := LEN(sp))
LOCATE ( posx, posy ) FILL-BOX(" ",4,20)
SET(i, 1)
{"\033[38;5;15m"}
PERF-UP( i, ln, 1)
LET( s := VAL( MID( 1, i, sp )) )
[ PLUS-ONE(s) ] // set interval to read element of arrays
LOCATE( posx, posy )
PRNL ( STR-TO-UTF8( GET(numL1) ))
LOCATE( PLUS-ONE(posx),posy )
PRNL ( STR-TO-UTF8( GET(numL2) ))
LOCATE( PLUS-TWO(posx),posy )
PRNL ( STR-TO-UTF8( GET(numL3) ))
posy += 2
NEXT
PRNL("\OFF")
RET
DEF-FUN( set score )
{"┌┐"," ┐","┌┐","┌┐","┐┐","┌┐","┌┐","┌┐","┌┐","┌┐"} APND-LST(numL1)
{"││"," │","┌┘"," ┤","└┤","└┐","├┐"," │","├┤","└┤"} APND-LST(numL2)
{"└┘"," ┴","└┘","└┘"," ┘","└┘","└┘"," ┴","└┘","└┘"} APND-LST(numL3)
{1,1,1,1,0,1,1,0,1,1,0,1,1,1,1} APND-ROW( big number )
{1,1,0,0,1,0,0,1,0,0,1,0,1,1,1} APND-ROW( big number )
{1,1,1,0,0,1,1,1,1,1,0,0,1,1,1} APND-ROW( big number )
{1,1,1,0,0,1,0,1,1,0,0,1,1,1,1} APND-ROW( big number )
{1,0,1,1,0,1,1,1,1,0,0,1,0,0,1} APND-ROW( big number )
{1,1,1,1,0,0,1,1,1,0,0,1,1,1,1} APND-ROW( big number )
{1,0,0,1,0,0,1,1,1,1,0,1,1,1,1} APND-ROW( big number )
{1,1,1,0,0,1,0,0,1,0,0,1,0,0,1} APND-ROW( big number )
{1,1,1,1,0,1,1,1,1,1,0,1,1,1,1} APND-ROW( big number )
{1,1,1,1,0,1,1,1,1,0,0,1,0,0,1} APND-ROW( big number )
RET
DEF-FUN( ready )
{"\033[38;5;4m\033[48;5;11m"}
LOC-COL(16)
LOC-ROW(13); PRNL( STR-TO-UTF8(" ▄ ▄▄ ▄ ▄▄ ▄ ▄ "))
LOC-ROW(14); PRNL( STR-TO-UTF8(" █▄▀ █▀ █▄█ █ █ ▀▄▀ "))
LOC-ROW(15); PRNL( STR-TO-UTF8(" ▀ ▀ ▀▀ ▀ ▀ ▀▄▀ ▀ "))
PRNL("\OFF")
RET
DEF-FUN( game over )
{"\033[38;5;15m\033[48;5;9m"}
LOC-COL(17)
LOC-ROW(12); PRNL( STR-TO-UTF8(" ▄▄ ▄ ▄ ▄ ▄▄ "))
LOC-ROW(13); PRNL( STR-TO-UTF8(" █ ▄ █▄█ █ █ █ █▀ "))
LOC-ROW(14); PRNL( STR-TO-UTF8(" ▀▀ ▀ ▀ ▀ ▀ ▀ ▀▀ "))
LOC-ROW(15); PRNL( STR-TO-UTF8(" ▄ ▄ ▄ ▄▄ ▄ "))
LOC-ROW(16); PRNL( STR-TO-UTF8(" █ █ █ █ █▀ █▄▀ "))
LOC-ROW(17); PRNL( STR-TO-UTF8(" ▀ ▀ ▀▀ ▀ ▀ "))
PRNL("\OFF")
RET </lang>
- Output:
Init game:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ @ SCORE @ @ @ @ ┌┐ @ @ ││ @ @ └┘ @ @ @ @ @ @ @ @ TIME @ @ @ @ ██ ███ ███ @ ▄ ▄▄ ▄ ▄▄ ▄ ▄ @ █ █ █ █ █ @ █▄▀ █▀ █▄█ █ █ ▀▄▀ @ █ █ █ █ █ @ ▀ ▀ ▀▀ ▀ ▀ ▀▄▀ ▀ @ █ █ █ █ █ @ @ ███ ███ ███ @ @ @ $ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ S P E E D @ @ S N A K E! @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Play game:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ @ SCORE @ @ @ @ ┌┐┌┐┌┐ @ @ ├┐┌┘││ @ @ └┘└┘└┘ @ @ @ @ @ @ @ @ TIME @ @ @ @ ███ ███ @ @ █ █ █ @ @ █ █ █ @ @ █ █ █ @ @ █ ███ @ @ @ @ @ @ @ ~~~~~~ @ SPEED: @ ~ @ 1.00 M/S @ ~ @ @ ~~~~~~ $ @ CONSUMED PREY: @ @ 11 @ @ @ @ S P E E D @ @ S N A K E! @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
Game over:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ @ @ SCORE @ @ @ @ ┐┌┐┌┐┌┐ @ @ │└┐└┐││ @ @ ┴└┘└┘└┘ @ @ @ @ @ @ @ @ TIME @ @ @ ▄▄ ▄ ▄ ▄ ▄▄ @ █ █ ███ @ █ ▄ █▄█ █ █ █ █▀ @ █ █ █ █ @ ▀▀ ▀ ▀ ▀ ▀ ▀ ▀▀ @ ███ █ █ @ ▄ ▄ ▄ ▄▄ ▄ @ █ █ █ @ █ █ █ █ █▀ █▄▀ @ █ ███ @ ~ ▀ ▀ ▀▀ ▀ ▀ @ @ ~ @ @ ~ @ @ ~ @ SPEED: @ ~ @ 1.10 M/S @ ~~~~~~~~~~~~~ @ @ ~ @ CONSUMED PREY: @ ~ @ 17 @ ~ @ @ ~ @ S P E E D @ ~ $ @ S N A K E! @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
AutoHotkey
<lang AutoHotkey>gosub Init Gui, +AlwaysOnTop Gui, font, s12, consolas Gui, add, Edit, vEditGrid x10 y10 ReadOnly, % grid2Text(oGrid) Gui, add, Text, vScore x10 y+10 w200 ReadOnly, % "Your Score = " Score Gui, show,, Snake GuiControl, Focus, Score return
- -----------------------------------------
Init: Width := 100, Height := 30 ; set grid size tail := 20, step := 10 Timer := 75 item := 0, direction := "" oTrail := [], Score := 0 xx := generateGrid(width, Height) oGrid := xx.1 row := xx.2, col := xx.3 return
- -----------------------------------------
Move: if !item { loop { Random, itemC, 3, % width-2 Random, itemR, 3, % Height-2 } until, !oGrid[itemR, itemC] oGrid[itemR, itemC] := "@" item := true } gosub, crawl return
- -----------------------------------------
- IfWinActive, Snake
left:: Right:: up:: Down:: if ((A_ThisHotkey = "right") && (Direction = "left")) || ((A_ThisHotkey = "left") && (Direction = "right")) || ((A_ThisHotkey = "up") && (Direction = "Down")) || ((A_ThisHotkey = "Down") && (Direction = "up")) || ((A_ThisHotkey = "right") && (Direction = "right")) || ((A_ThisHotkey = "left") && (Direction = "left")) || ((A_ThisHotkey = "up") && (Direction = "up")) || ((A_ThisHotkey = "Down") && (Direction = "Down")) return
Direction := A_ThisHotkey gosub, crawl return
- IfWinActive
- -----------------------------------------
crawl: switch, Direction { case "left" : oGrid[row , col--] := 1 case "Right" : oGrid[row , col++] := 1 case "up" : oGrid[row--, col ] := 1 case "Down" : oGrid[row++, col ] := 1 }
- out of bounds or snake eats itself
if oGrid[row, col] = 1 || col < 1 || col > width || row < 1 || row > height gosub, YouLose
- snake eats item
if (oGrid[row, col] = "@") { item := false tail += step GuiControl,, Score, % "Your Score = " ++Score }
- snake advances
oGrid[row, col] := 2 oTrail.Push(row "," col) if (oTrail.count() >= tail) x := StrSplit(oTrail.RemoveAt(1), ","), oGrid[x.1, x.2] := false
GuiControl,, EditGrid, % grid2Text(oGrid) SetTimer, Move, % 0-Timer return
- -----------------------------------------
YouLose: SetTimer, Move, Off MsgBox, 262180, ,% "Your Score is " Score "`nPlay Again?" IfMsgBox, No ExitApp
gosub Init GuiControl,, EditGrid, % grid2Text(oGrid) return
- -----------------------------------------
grid2Text(oGrid){ for row, obj in oGrid { for col, val in obj ; @=item, 2=Head, 1=tail text .= val = "@" ? "@" : val =2 ? "█" : val = 1 ? "▓" : " " text .= "`n" } return trim(text, "`n") }
- -----------------------------------------
generateGrid(width, Height){ global oTrail oGrid := [] loop, % width { col := A_Index loop, % Height row := A_Index, oGrid[row, col] := false } Random, col, 3, % width-2 Random, row, 3, % Height-2 oGrid[row, col] := 2 oTrail.Push(row "," col) return [oGrid, row, col] }
- -----------------------------------------</lang>
BASIC
FreeBASIC
<lang freebasic> REM Snake
- define EXTCHAR Chr(255)
Dim Shared As Integer puntos, contar, longitud, posX, posY, oldhi = 0 Dim Shared As Integer x(500), y(500) For contar = 1 To 500
x(contar) = 0 : y(contar) = 0
Next contar Dim Shared As Byte fruitX, fruitY, convida Dim Shared As Single delay Dim Shared As String direccion, usuario
Sub Intro
Cls
Color 15, 0
Print " _ _ _ _ "
Print " / \ / \ / \ / \ "
Print " ___________/ _\/ _\/ _\/ _\____________ "
Print " __________/ /_/ /_/ /_/ /______________ "
Print " | /\ /\ /\ / \ \___ "
Print " |/ \_/ \_/ \_/ \ "+Chr(248)+"\ "
Print " \___/--< "
Color 14, 0
Locate 10, 28: Print "---SNAKE---"
Locate 12, 4: Print "Para jugar, usa las teclas de flecha para moverte."
Locate 13, 4: Print "Pulsa <1-3> para velocidad, o <Esc> para salir."
If puntos > oldhi Then oldhi = puntos
Locate 14, 4: Print "M xima puntuaci¢n: "; oldhi
usuario = ""
While usuario = ""
usuario = Inkey
Wend
If usuario = Chr(27) Then End 'ESC
delay = .14
If usuario = "1" Then delay = .26
If usuario = "3" Then delay = .08
Cls
longitud = 9
puntos = 0
posX = 40 : posY = 10
direccion = "derecha"
convida = true
fruitX = Int(Rnd * 79) + 1
fruitY = Int(Rnd * 20) + 1
Locate 22, 1
For contar = 1 To 80
Print Chr(196); "-";
Next contar
End Sub
Sub MenuPrincipal
Dim As Integer num, oldX, oldY
Dim As Single tm, tm2
Color 10
Locate 23, 2: Print "SNAKE - <Esc> salir - Puntos: "; puntos
If posX = fruitX And posY = fruitY Then
longitud += 1
puntos += 1
fruitX = Int(Rnd * 79) + 1
fruitY = Int(Rnd * 21) + 1
End If
Locate fruitY, fruitX : Color 12: Print Chr(01) : Color 10'"@"
x(0) = posX : y(0) = posY
For contar = 1 To 499
num = 500 - contar
x(num) = x(num - 1)
y(num) = y(num - 1)
Next contar
oldX = x(longitud) : oldY = y(longitud)
If oldX > 0 And oldY > 0 Then Locate oldY, oldX : Print " "
Locate posY, posX: Print Chr(219) '"Û"
tm = Timer
tm2 = tm + delay
While tm < tm2
tm = Timer
usuario = Inkey
If usuario = EXTCHAR & "H" Then direccion = "arriba"
If usuario = EXTCHAR & "P" Then direccion = "abajo"
If usuario = EXTCHAR & "K" Then direccion = "izquierda"
If usuario = EXTCHAR & "M" Then direccion = "derecha"
If usuario = Chr(27) Then Intro
Wend
If direccion = "derecha" Then posX += 1
If posX > 80 Then convida = false
If direccion = "izquierda" Then posX -= 1
If posX < 1 Then convida = false
If direccion = "arriba" Then posY -= 1
If posY < 1 Then convida = false
If direccion = "abajo" Then posY += 1
If posY > 21 Then convida = false
For contar = 0 To longitud
If posX = x(contar) And posY = y(contar) Then convida = false
Next contar
If convida = false Then
Cls : Locate 11, 19: Print "Pulsa <space>..."
Locate 10, 18: Print "Has muerto! Con"; puntos; " puntos." : Sleep
While Inkey = "": Wend
Intro
End If
MenuPrincipal
End Sub
'--- Programa Principal --- Randomize Timer Intro MenuPrincipal End '-------------------------- </lang>
Locomotive Basic
Use the cursor keys to control movement direction. Lower the skill parameter in line 20 or increase ml (maximum length) if you find gameplay too easy.
If you are playing this in CPCBasic, first click on the CPC screen so it gets keyboard input and then enter "run" (clicking the Run button would deselect the screen again). <lang locobasic>10 mode 1:randomize time 20 sx=20:sy=5:dx=1:dy=0:ml=20:dim ox(ml),oy(ml):oi=1:ll=4:skill=6 30 f$=chr$(228):w$=chr$(127):b$=chr$(231) 40 print string$(40,w$); 50 for i=2 to 20:print w$;space$(38);w$;:next 60 print string$(40,w$); 70 locate 10, 12:print string$(20,w$); 80 gosub 260 90 frame 100 if inkey(1)>-1 then dx=1:dy=0 110 if inkey(8)>-1 then dx=-1:dy=0 120 if inkey(0)>-1 then dx=0:dy=-1 130 if inkey(2)>-1 then dx=0:dy=1 140 locate sx,sy:print chr$(224);:ox(oi)=sx:oy(oi)=sy 150 oi=oi+1:if oi>ml then oi=1 160 nx=sx+dx:ny=sy+dy 170 locate nx,ny:a$=copychr$(#0) 180 if a$=w$ or a$=b$ then sound 2,62500/20,100:locate 13,6:print "You have died!":end 190 if a$=f$ then sound 2,62500/500,10: sound 1,62500/1000,10: sound 4,62500/2000,10:p=p+100:print " ";:gosub 260:if ll<ml then ll=ll+1 200 locate 1,24:print "SCORE:"p 210 for i=1 to skill:frame:next 220 locate sx,sy:print b$; 230 nn=1+((oi+ml-ll) mod ml) 240 if ox(nn)>0 then locate ox(nn),oy(nn):print " "; 250 sx=nx:sy=ny:goto 90 260 fx=rnd*39+1:fy=rnd*19+1 270 locate fx,fy:a$=copychr$(#0) 280 if a$<>" " then 260 290 print f$; 300 return</lang>
ZX Spectrum Basic
By ancient tradition, the controls are Q for up, A for down, O for left, and P for right.
A screenshot is here.
Note that lines 10 to 210 and 580 to 890—more than half the program—define graphics characters for the snake's head (facing in different directions) and for its food. If you're happy to make do with characters from the standard character set, you can easily adapt lines 220 to 570 to work on their own. The things the snake eats are supposed to be apples, although they don't look too much like them.
<lang zxbasic> 10 FOR i=0 TO 7
20 READ bits 30 POKE USR "L"+i,bits 40 NEXT i 50 FOR i=0 TO 7 60 READ bits 70 POKE USR "R"+i,bits 80 NEXT i 90 FOR i=0 TO 7
100 READ bits 110 POKE USR "P"+i,bits 120 NEXT i 130 RESTORE 740 140 FOR i=7 TO 0 STEP -1 150 READ bits 160 POKE USR "D"+i,bits 170 NEXT i 180 FOR i=0 TO 7 190 READ bits 200 POKE USR "F"+i, bits 210 NEXT i 220 PAPER 0 230 CLS 240 LET snakex=19 250 LET snakey=15 260 LET dx=-1 270 LET dy=0 280 LET s$=CHR$ 15+CHR$ 20+CHR$ 15+CHR$ 21 290 LET foodx=INT (RND*32) 300 LET foody=INT (RND*22) 310 IF SCREEN$ (foody,foodx)<>" " THEN GO TO 290 320 INK 2 330 PRINT AT foody,foodx;CHR$ 149 340 INK 4 350 INVERSE 1 360 PRINT AT CODE s$,CODE s$(1);"#" 370 INVERSE 0 380 IF INKEY$="q" AND dy=0 THEN LET dx=0: LET dy=-1 390 IF INKEY$="a" AND dy=0 THEN LET dx=0: LET dy=1 400 IF INKEY$="o" AND dx=0 THEN LET dx=-1: LET dy=0 410 IF INKEY$="p" AND dx=0 THEN LET dx=1: LET dy=0 420 IF dx=-1 THEN PRINT AT snakey,snakex;CHR$ 155 430 IF dx=1 THEN PRINT AT snakey,snakex;CHR$ 161 440 IF dy=1 THEN PRINT AT snakey,snakex;CHR$ 159 450 IF dy=-1 THEN PRINT AT snakey,snakex;CHR$ 147 460 LET s$=CHR$ snakey+CHR$ snakex+s$ 470 IF snakex=foodx AND snakey=foody THEN GO TO 290 480 PRINT AT CODE s$(LEN s$-1),CODE s$(LEN s$);" " 490 LET s$=s$( TO LEN s$-2) 500 LET snakex=snakex+dx 510 LET snakey=snakey+dy 520 IF snakex=-1 THEN LET snakex=31 530 IF snakex=32 THEN LET snakex=0 540 IF snakey=-1 THEN LET snakey=21 550 IF snakey=22 THEN LET snakey=0 560 IF SCREEN$ (snakey,snakex)="#" THEN STOP 570 GO TO 340 580 DATA BIN 00001111 590 DATA BIN 00111111 600 DATA BIN 01110011 610 DATA BIN 11110011 620 DATA BIN 11111111 630 DATA BIN 01111111 640 DATA BIN 00000111 650 DATA BIN 00011111 660 DATA BIN 11110000 670 DATA BIN 11111100 680 DATA BIN 11001110 690 DATA BIN 11001111 700 DATA BIN 11111111 710 DATA BIN 11111110 720 DATA BIN 11100000 730 DATA BIN 11111000 740 DATA BIN 00011000 750 DATA BIN 00111100 760 DATA BIN 01111100 770 DATA BIN 01111101 780 DATA BIN 11001101 790 DATA BIN 11001111 800 DATA BIN 11111111 810 DATA BIN 11111111 820 DATA BIN 00000100 830 DATA BIN 00001000 840 DATA BIN 01101011 850 DATA BIN 11111100 860 DATA BIN 11111100 870 DATA BIN 11111100 880 DATA BIN 01111111 890 DATA BIN 00110110</lang>
C
As some implementation below (C++) works on Windows console, let it work on Linux. Other implementations could be added as well, reusing the api. <lang c>// Snake
// The problem with implementing this task in C is, the language standard // does not cover some details essential for interactive games: // a nonblocking keyboard input, a positional console output, // a and millisecond-precision timer: these things are all system-dependent.
// Therefore the program is split in two pieces, a system-independent // game logic, and a system-dependent UI, separated by a tiny API: char nonblocking_getch(); void positional_putch(int x, int y, char ch); void millisecond_sleep(int n); void init_screen(); void update_screen(); void close_screen();
// The implementation of a system-dependent part. // Requires POSIX IEEE 1003.1-2008 compliant system and ncurses library.
- ifdef __linux__
- define _POSIX_C_SOURCE 200809L
- include <time.h> // nanosleep
- include <ncurses.h> // getch, mvaddch, and others
char nonblocking_getch() { return getch(); } void positional_putch(int x, int y, char ch) { mvaddch(x, y, ch); } void millisecond_sleep(int n) { struct timespec t = { 0, n * 1000000 }; nanosleep(&t, 0); // for older POSIX standards, consider usleep() } void update_screen() { refresh(); } void init_screen() { initscr(); noecho(); cbreak(); nodelay(stdscr, TRUE); } void close_screen() { endwin(); }
- endif
// An implementation for some other system...
- ifdef _WIN32
- error "not implemented"
- endif
// The game logic, system-independent
- include <time.h> // time
- include <stdlib.h> // rand, srand
- define w 80
- define h 40
int board[w * h]; int head; enum Dir { N, E, S, W } dir; int quit;
enum State { SPACE=0, FOOD=1, BORDER=2 }; // negative values denote the snake (a negated time-to-live in given cell)
// reduce a time-to-live, effectively erasing the tail void age() {
int i;
for(i = 0; i < w * h; ++i) if(board[i] < 0) ++board[i]; }
// put a piece of food at random empty position void plant() { int r; do r = rand() % (w * h); while(board[r] != SPACE); board[r] = FOOD; }
// initialize the board, plant a very first food item void start(void) {
int i;
for(i = 0; i < w; ++i) board[i] = board[i + (h - 1) * w] = BORDER; for(i = 0; i < h; ++i) board[i * w] = board[i * w + w - 1] = BORDER; head = w * (h - 1 - h % 2) / 2; // screen center for any h board[head] = -5; dir = N; quit = 0; srand(time(0)); plant(); }
void step() { int len = board[head]; switch(dir) { case N: head -= w; break; case S: head += w; break; case W: --head; break; case E: ++head; break; } switch(board[head]) { case SPACE: board[head] = len - 1; // keep in mind len is negative age(); break; case FOOD: board[head] = len - 1; plant(); break; default: quit = 1; } }
void show() { const char * symbol = " @.";
int i;
for(i = 0; i < w * h; ++i) positional_putch(i / w, i % w, board[i] < 0 ? '#' : symbol[board[i]]); update_screen(); }
int main (int argc, char * argv[]) { init_screen(); start(); do { show(); switch(nonblocking_getch()) { case 'i': dir = N; break; case 'j': dir = W; break; case 'k': dir = S; break; case 'l': dir = E; break; case 'q': quit = 1; break; } step(); millisecond_sleep(100); // beware, this approach // is not suitable for anything but toy projects like this } while(!quit); millisecond_sleep(999); close_screen(); return 0; }</lang>
C++
Simple Windows console implementation.
<lang cpp>
- include <windows.h>
- include <ctime>
- include <iostream>
- include <string>
const int WID = 60, HEI = 30, MAX_LEN = 600; enum DIR { NORTH, EAST, SOUTH, WEST };
class snake { public:
snake() {
console = GetStdHandle( STD_OUTPUT_HANDLE ); SetConsoleTitle( "Snake" );
COORD coord = { WID + 1, HEI + 2 }; SetConsoleScreenBufferSize( console, coord );
SMALL_RECT rc = { 0, 0, WID, HEI + 1 }; SetConsoleWindowInfo( console, TRUE, &rc );
CONSOLE_CURSOR_INFO ci = { 1, false }; SetConsoleCursorInfo( console, &ci );
}
void play() {
std::string a;
while( 1 ) {
createField(); alive = true;
while( alive ) { drawField(); readKey(); moveSnake(); Sleep( 50 ); }
COORD c = { 0, HEI + 1 }; SetConsoleCursorPosition( console, c );
SetConsoleTextAttribute( console, 0x000b );
std::cout << "Play again [Y/N]? "; std::cin >> a;
if( a.at( 0 ) != 'Y' && a.at( 0 ) != 'y' ) return;
}
}
private:
void createField() {
COORD coord = { 0, 0 }; DWORD c;
FillConsoleOutputCharacter( console, ' ', ( HEI + 2 ) * 80, coord, &c );
FillConsoleOutputAttribute( console, 0x0000, ( HEI + 2 ) * 80, coord, &c );
SetConsoleCursorPosition( console, coord );
int x = 0, y = 1; for( ; x < WID * HEI; x++ ) brd[x] = 0;
for( x = 0; x < WID; x++ ) {
brd[x] = brd[x + WID * ( HEI - 1 )] = '+';
}
for( ; y < HEI; y++ ) {
brd[0 + WID * y] = brd[WID - 1 + WID * y] = '+';
}
do {
x = rand() % WID; y = rand() % ( HEI >> 1 ) + ( HEI >> 1 );
} while( brd[x + WID * y] );
brd[x + WID * y] = '@';
tailIdx = 0; headIdx = 4; x = 3; y = 2;
for( int c = tailIdx; c < headIdx; c++ ) {
brd[x + WID * y] = '#';
snk[c].X = 3 + c; snk[c].Y = 2;
}
head = snk[3]; dir = EAST; points = 0;
}
void readKey() {
if( GetAsyncKeyState( 39 ) & 0x8000 ) dir = EAST;
if( GetAsyncKeyState( 37 ) & 0x8000 ) dir = WEST;
if( GetAsyncKeyState( 38 ) & 0x8000 ) dir = NORTH;
if( GetAsyncKeyState( 40 ) & 0x8000 ) dir = SOUTH;
}
void drawField() {
COORD coord; char t;
for( int y = 0; y < HEI; y++ ) {
coord.Y = y;
for( int x = 0; x < WID; x++ ) {
t = brd[x + WID * y]; if( !t ) continue;
coord.X = x; SetConsoleCursorPosition( console, coord );
if( coord.X == head.X && coord.Y == head.Y ) {
SetConsoleTextAttribute( console, 0x002e );
std::cout << 'O'; SetConsoleTextAttribute( console, 0x0000 );
continue;
}
switch( t ) {
case '#': SetConsoleTextAttribute( console, 0x002a ); break;
case '+': SetConsoleTextAttribute( console, 0x0019 ); break;
case '@': SetConsoleTextAttribute( console, 0x004c ); break;
}
std::cout << t; SetConsoleTextAttribute( console, 0x0000 );
}
}
std::cout << t; SetConsoleTextAttribute( console, 0x0007 );
COORD c = { 0, HEI }; SetConsoleCursorPosition( console, c );
std::cout << "Points: " << points;
}
void moveSnake() {
switch( dir ) {
case NORTH: head.Y--; break;
case EAST: head.X++; break;
case SOUTH: head.Y++; break;
case WEST: head.X--; break;
}
char t = brd[head.X + WID * head.Y];
if( t && t != '@' ) { alive = false; return; }
brd[head.X + WID * head.Y] = '#';
snk[headIdx].X = head.X; snk[headIdx].Y = head.Y;
if( ++headIdx >= MAX_LEN ) headIdx = 0;
if( t == '@' ) {
points++; int x, y;
do {
x = rand() % WID; y = rand() % ( HEI >> 1 ) + ( HEI >> 1 );
} while( brd[x + WID * y] );
brd[x + WID * y] = '@'; return;
}
SetConsoleCursorPosition( console, snk[tailIdx] ); std::cout << ' ';
brd[snk[tailIdx].X + WID * snk[tailIdx].Y] = 0;
if( ++tailIdx >= MAX_LEN ) tailIdx = 0;
}
bool alive; char brd[WID * HEI];
HANDLE console; DIR dir; COORD snk[MAX_LEN];
COORD head; int tailIdx, headIdx, points;
}; int main( int argc, char* argv[] ) {
srand( static_cast<unsigned>( time( NULL ) ) ); snake s; s.play(); return 0;
} </lang>
Delphi
<lang Delphi> unit SnakeGame;
interface
uses
Winapi.Windows, System.SysUtils, System.Classes, Vcl.Graphics, Vcl.Forms, Vcl.Dialogs, System.Generics.Collections, Vcl.ExtCtrls;
type
TSnakeApp = class(TForm)
procedure FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
procedure FormPaint(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure DoFrameStep(Sender: TObject);
procedure Reset;
private
{ Private declarations }
FrameTimer: TTimer;
public
{ Public declarations }
end;
TSnake = class len: Integer; alive: Boolean; pos: TPoint; posArray: TList<TPoint>; dir: Byte; private function Eat(Fruit: TPoint): Boolean; function Overlap: Boolean; procedure update; public procedure Paint(Canvas: TCanvas); procedure Reset; constructor Create; destructor Destroy; override; end;
TFruit = class FruitTime: Boolean; pos: TPoint; constructor Create; procedure Reset; procedure Paint(Canvas: TCanvas); private procedure SetFruit; end;
const
L = 1; R = 2; D = 4; U = 8;
var
SnakeApp: TSnakeApp; block: Integer = 24; wid: Integer = 30; hei: Integer = 20; fruit: TFruit; snake: TSnake;
implementation
{$R *.dfm}
function Rect(x, y, w, h: Integer): TRect; begin
Result := TRect.Create(x, y, x + w, y + h);
end;
{ TSnake }
constructor TSnake.Create; begin
posArray := TList<TPoint>.Create; Reset;
end;
procedure TSnake.Paint(Canvas: TCanvas); var
pos: TPoint; i, l: Integer; r: TRect;
begin
with Canvas do begin Brush.Color := rgb(130, 190, 0);
i := posArray.count - 1;
l := posArray.count;
while True do
begin
pos := posArray[i];
dec(i);
r := rect(pos.x * block, pos.y * block, block, block);
FillRect(r);
dec(l);
if l = 0 then
Break;
end;
end;
end;
procedure TSnake.Reset; begin
alive := true; pos := Tpoint.Create(1, 1); posArray.Clear; posArray.Add(Tpoint.Create(pos)); len := posArray.Count; dir := r;
end;
destructor TSnake.Destroy; begin
posArray.Free; inherited;
end;
function TSnake.Eat(Fruit: TPoint): Boolean; begin
result := (pos.X = Fruit.X) and (pos.y = Fruit.y);
if result then
begin
inc(len);
if len > 5000 then
len := 500;
end;
end;
function TSnake.Overlap: Boolean; var
aLen: Integer; tp: TPoint; i: Integer;
begin
aLen := posArray.count - 1;
for i := 0 to aLen - 1 do
begin
tp := posArray[i];
if (tp.x = pos.x) and (tp.y = pos.y) then
Exit(True);
end;
Result := false;
end;
procedure TSnake.update; begin
if not alive then
exit;
case dir of
l:
begin
dec(pos.X);
if pos.X < 1 then
pos.x := wid - 2
end;
r:
begin
inc(pos.x);
if (pos.x > (wid - 2)) then
pos.x := 1;
end;
U:
begin
dec(pos.y);
if (pos.y < 1) then
pos.y := hei - 2
end;
D:
begin
inc(pos.y);
if (pos.y > hei - 2) then
pos.y := 1;
end;
end;
if Overlap then
alive := False
else
begin
posArray.Add(TPoint(pos));
if len < posArray.Count then
posArray.Delete(0);
end;
end;
{ TFruit }
constructor TFruit.Create; begin
Reset;
end;
procedure TFruit.Paint(Canvas: TCanvas); var
r: TRect;
begin
with Canvas do begin Brush.Color := rgb(200, 50, 20);
r := Rect(pos.x * block, pos.y * block, block, block);
FillRect(r); end;
end;
procedure TFruit.Reset; begin
fruitTime := true; pos := Tpoint.Create(0, 0);
end;
procedure TFruit.SetFruit; begin
pos.x := Trunc(Random(wid - 2) + 1); pos.y := Trunc(Random(hei - 2) + 1); fruitTime := false;
end;
procedure TSnakeApp.DoFrameStep(Sender: TObject); begin
Invalidate;
end;
procedure TSnakeApp.FormClose(Sender: TObject; var Action: TCloseAction); begin
FrameTimer.Free; snake.Free; Fruit.Free;
end;
procedure TSnakeApp.FormCreate(Sender: TObject); begin
Canvas.pen.Style := psClear; ClientHeight := block * hei; ClientWidth := block * wid; DoubleBuffered := True; KeyPreview := True;
OnClose := FormClose; OnKeyDown := FormKeyDown; OnPaint := FormPaint;
snake := TSnake.Create; Fruit := TFruit.Create(); FrameTimer := TTimer.Create(nil); FrameTimer.Interval := 250; FrameTimer.OnTimer := DoFrameStep; FrameTimer.Enabled := True;
end;
procedure TSnakeApp.FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
function ValidDir(value: Byte): Byte;
var
combination: Byte;
begin
combination := (value or snake.dir);
if (combination = 3) or (combination = 12) then
Result := snake.dir
else
Result := value;
end;
begin
case Key of
VK_LEFT:
snake.dir := ValidDir(l);
VK_RIGHT:
snake.dir := ValidDir(r);
VK_UP:
snake.dir := ValidDir(U);
VK_DOWN:
snake.dir := ValidDir(D);
VK_ESCAPE:
Reset;
end;
end;
procedure TSnakeApp.FormPaint(Sender: TObject); var
i: Integer; r: TRect; frameR: Double;
begin
with Canvas do begin Brush.Color := rgb(0, $22, 0); FillRect(ClipRect); Brush.Color := rgb(20, 50, 120);
for i := 0 to wid - 1 do
begin
r := rect(i * block, 0, block, block);
FillRect(r);
r := rect(i * block, ClientHeight - block, block, block);
FillRect(r);
end;
for i := 1 to hei - 2 do
begin
r := Rect(1, i * block, block, block);
FillRect(r);
r := Rect(ClientWidth - block, i * block, block, block);
FillRect(r);
end;
if (Fruit.fruitTime) then
begin
Fruit.setFruit();
frameR := FrameTimer.Interval * 0.95;
if frameR < 30 then
frameR := 30;
FrameTimer.Interval := trunc(frameR);
end;
Fruit.Paint(Canvas); snake.update();
if not snake.alive then
begin
FrameTimer.Enabled := False;
Application.ProcessMessages;
ShowMessage('Game over');
Reset;
exit;
end;
if (snake.eat(Fruit.pos)) then
Fruit.fruitTime := true;
snake.Paint(Canvas);
Brush.Style := bsClear; Font.Color := rgb(200, 200, 200); Font.Size := 18; TextOut(50, 0, (snake.len - 1).ToString); end;
end;
procedure TSnakeApp.Reset; begin
snake.Reset; Fruit.Reset; FrameTimer.Interval := 250; FrameTimer.Enabled := True;
end; end.</lang> Form resources: <lang Delphi> object SnakeApp: TSnakeApp
OnCreate = FormCreate
end </lang>
Go
This uses the termbox package for terminal input and output. This makes the code fairly cross-platform, it successfully built for FreeBSD, OpenBSD, NetBSD, DragonFly BSD, Linux, MS Windows, and MacOS (tested on FreeBSD and MS Windows). <lang Go>package main
import ( "errors" "fmt" "log" "math/rand" "time"
termbox "github.com/nsf/termbox-go" )
func main() { rand.Seed(time.Now().UnixNano()) score, err := playSnake() if err != nil { log.Fatal(err) } fmt.Println("Final score:", score) }
type snake struct { body []position // tail to head positions of the snake heading direction width, height int cells []termbox.Cell }
type position struct { X int Y int }
type direction int
const ( North direction = iota East South West )
func (p position) next(d direction) position { switch d { case North: p.Y-- case East: p.X++ case South: p.Y++ case West: p.X-- } return p }
func playSnake() (int, error) { err := termbox.Init() if err != nil { return 0, err } defer termbox.Close()
termbox.Clear(fg, bg) termbox.HideCursor() s := &snake{ // It would be more efficient to use a circular // buffer instead of a plain slice for s.body. body: make([]position, 0, 32), cells: termbox.CellBuffer(), } s.width, s.height = termbox.Size() s.drawBorder() s.startSnake() s.placeFood() s.flush()
moveCh, errCh := s.startEventLoop() const delay = 125 * time.Millisecond for t := time.NewTimer(delay); ; t.Reset(delay) { var move direction select { case err = <-errCh: return len(s.body), err case move = <-moveCh: if !t.Stop() { <-t.C // handles race between moveCh and t.C } case <-t.C: move = s.heading } if s.doMove(move) { time.Sleep(1 * time.Second) break } }
return len(s.body), err }
func (s *snake) startEventLoop() (<-chan direction, <-chan error) { moveCh := make(chan direction) errCh := make(chan error, 1) go func() { defer close(errCh) for { switch ev := termbox.PollEvent(); ev.Type { case termbox.EventKey: switch ev.Ch { // WSAD and HJKL movement case 'w', 'W', 'k', 'K': moveCh <- North case 'a', 'A', 'h', 'H': moveCh <- West case 's', 'S', 'j', 'J': moveCh <- South case 'd', 'D', 'l', 'L': moveCh <- East case 0: switch ev.Key { // Cursor key movement case termbox.KeyArrowUp: moveCh <- North case termbox.KeyArrowDown: moveCh <- South case termbox.KeyArrowLeft: moveCh <- West case termbox.KeyArrowRight: moveCh <- East case termbox.KeyEsc: // Quit return } } case termbox.EventResize: // TODO errCh <- errors.New("terminal resizing unsupported") return case termbox.EventError: errCh <- ev.Err return case termbox.EventInterrupt: return } } }() return moveCh, errCh }
func (s *snake) flush() { termbox.Flush() s.cells = termbox.CellBuffer() }
func (s *snake) getCellRune(p position) rune { i := p.Y*s.width + p.X return s.cells[i].Ch } func (s *snake) setCell(p position, c termbox.Cell) { i := p.Y*s.width + p.X s.cells[i] = c }
func (s *snake) drawBorder() { for x := 0; x < s.width; x++ { s.setCell(position{x, 0}, border) s.setCell(position{x, s.height - 1}, border) } for y := 0; y < s.height-1; y++ { s.setCell(position{0, y}, border) s.setCell(position{s.width - 1, y}, border) } }
func (s *snake) placeFood() { for { // a random empty cell x := rand.Intn(s.width-2) + 1 y := rand.Intn(s.height-2) + 1 foodp := position{x, y} r := s.getCellRune(foodp) if r != ' ' { continue } s.setCell(foodp, food) return } }
func (s *snake) startSnake() { // a random cell somewhat near the center x := rand.Intn(s.width/2) + s.width/4 y := rand.Intn(s.height/2) + s.height/4 head := position{x, y} s.setCell(head, snakeHead) s.body = append(s.body[:0], head) s.heading = direction(rand.Intn(4)) }
func (s *snake) doMove(move direction) bool { head := s.body[len(s.body)-1] s.setCell(head, snakeBody) head = head.next(move) s.heading = move s.body = append(s.body, head) r := s.getCellRune(head) s.setCell(head, snakeHead) gameOver := false switch r { case food.Ch: s.placeFood() case border.Ch, snakeBody.Ch: gameOver = true fallthrough case empty.Ch: s.setCell(s.body[0], empty) s.body = s.body[1:] default: panic(r) } s.flush() return gameOver }
const ( fg = termbox.ColorWhite bg = termbox.ColorBlack )
// Symbols to use. // Could use Unicode instead of simple ASCII. var ( empty = termbox.Cell{Ch: ' ', Bg: bg, Fg: fg} border = termbox.Cell{Ch: '+', Bg: bg, Fg: termbox.ColorBlue} snakeBody = termbox.Cell{Ch: '#', Bg: bg, Fg: termbox.ColorGreen} snakeHead = termbox.Cell{Ch: 'O', Bg: bg, Fg: termbox.ColorYellow | termbox.AttrBold} food = termbox.Cell{Ch: '@', Bg: bg, Fg: termbox.ColorRed} )</lang>
Haskell
<lang haskell>{-# LANGUAGE TemplateHaskell #-} import Control.Monad.Random (getRandomRs) import Graphics.Gloss.Interface.Pure.Game import Lens.Micro ((%~), (^.), (&), set) import Lens.Micro.TH (makeLenses)
-- all data types
data Snake = Snake { _body :: [Point], _direction :: Point } makeLenses Snake
data World = World { _snake :: Snake , _food :: [Point]
, _score :: Int , _maxScore :: Int }
makeLenses World
-- everything snake can do
moves (Snake b d) = Snake (step b d : init b) d eats (Snake b d) = Snake (step b d : b) d bites (Snake b _) = any (== head b) step ((x,y):_) (a,b) = (x+a, y+b)
turn (x',y') (Snake b (x,y)) | (x+x',y+y') == (0,0) = Snake b (x,y)
| otherwise = Snake b (x',y')
-- all randomness
createWorld = do xs <- map fromIntegral <$> getRandomRs (2, 38 :: Int)
ys <- map fromIntegral <$> getRandomRs (2, 38 :: Int)
return (Ok, World snake (zip xs ys) 0 0)
where
snake = Snake [(20, 20)] (1,0)
-- A tyny DSL for declarative description of business logic
data Status = Ok | Fail | Stop
continue = \x -> (Ok, x) stop = \x -> (Stop, x) f >>> g = \x -> case f x of { (Ok, y) -> g y; b -> b } -- chain composition f <|> g = \x -> case f x of { (Fail, _) -> g x; b -> b } -- alternative p ==> f = \x -> if p x then f x else (Fail, x) -- condition l .& f = continue . (l %~ f) -- modification l .= y = continue . set l y -- setting
-- all business logic
updateWorld _ = id >>> (snakeEats <|> snakeMoves)
where
snakeEats = (snakeFindsFood ==> (snake .& eats)) >>>
(score .& (+1)) >>> (food .& tail)
snakeMoves = (snakeBitesTail ==> stop) <|>
(snakeHitsWall ==> stop) <|>
(snake .& moves)
snakeFindsFood w = (w^.snake & moves) `bites` (w^.food & take 1) snakeBitesTail w = (w^.snake) `bites` (w^.snake.body & tail) snakeHitsWall w = (w^.snake.body) & head & isOutside isOutside (x,y) = or [x <= 0, 40 <= x, y <= 0, 40 <= y]
-- all event handing
handleEvents e (s,w) = f w
where f = case s of
Ok -> case e of
EventKey (SpecialKey k) _ _ _ -> case k of
KeyRight -> snake .& turn (1,0)
KeyLeft -> snake .& turn (-1,0)
KeyUp -> snake .& turn (0,1)
KeyDown -> snake .& turn (0,-1)
_-> continue
_-> continue
_-> \w -> w & ((snake.body) .= [(20,20)]) >>>
(maxScore .& max (w^.score)) >>> (score .= 0)
-- all graphics
renderWorld (s, w) = pictures [frame, color c drawSnake, drawFood, showScore]
where c = case s of { Ok -> orange; _-> red }
drawSnake = foldMap (rectangleSolid 10 10 `at`) (w^.snake.body)
drawFood = color blue $ circleSolid 5 `at` (w^.food & head)
frame = color black $ rectangleWire 400 400
showScore = color orange $ scale 0.2 0.2 $ txt `at` (-80,130)
txt = Text $ mconcat ["Score: ", w^.score & show
," Maximal score: ", w^.maxScore & show]
at p (x,y) = Translate (10*x-200) (10*y-200) p
main = do world <- createWorld
play inW white 7 world renderWorld handleEvents updateWorld where inW = InWindow "The Snake" (400, 400) (10, 10)</lang>
Extra credit
It is easy to make snake to seek food automatically. Just change the first line of the updateWorld definition:
<lang haskell>updateWorld _ = id >>> snakeSeeksFood >>> (snakeEats <|> snakeMoves) </lang>
and add local definition:
<lang haskell> snakeSeeksFood w = w & snake .& turns optimalDirection
where
optimalDirection = minimumBy (comparing distanceToFood) safeTurns
safeTurns = filter safe [(x,y),(-y,x),(y,-x)] `ifEmpty` [(x,y)]
where (x,y) = w^.snake.direction
safe d = let w = w & snake %~ moves . turns d
in not (snakeBitesTail w || snakeHitsWall w)
lst `ifEmpty` x = if null lst then x else lst
distanceToFood d = let (a,b) = w^.snake & turns d & moves & (^.body) & head
(x,y) = w^.food & head
in (a-x)^2 + (b-y)^2</lang>
Java
See Snake/Java.
JavaScript
You need the P5 Library to run this code! <lang javascript> const L = 1, R = 2, D = 4, U = 8; var block = 24, wid = 30, hei = 20, frameR = 7, fruit, snake; function Snake() {
this.length = 1;
this.alive = true;
this.pos = createVector( 1, 1 );
this.posArray = [];
this.posArray.push( createVector( 1, 1 ) );
this.dir = R;
this.draw = function() {
fill( 130, 190, 0 );
var pos, i = this.posArray.length - 1, l = this.length;
while( true ){
pos = this.posArray[i--];
rect( pos.x * block, pos.y * block, block, block );
if( --l == 0 ) break;
}
}
this.eat = function( frut ) {
var b = this.pos.x == frut.x && this.pos.y == frut.y;
if( b ) this.length++;
return b;
}
this.overlap = function() {
var len = this.posArray.length - 1;
for( var i = len; i > len - this.length; i-- ) {
tp = this.posArray[i];
if( tp.x === this.pos.x && tp.y === this.pos.y ) return true;
}
return false;
}
this.update = function() {
if( !this.alive ) return;
switch( this.dir ) {
case L:
this.pos.x--; if( this.pos.x < 1 ) this.pos.x = wid - 2;
break;
case R:
this.pos.x++; if( this.pos.x > wid - 2 ) this.pos.x = 1;
break;
case U:
this.pos.y--; if( this.pos.y < 1 ) this.pos.y = hei - 2;
break;
case D:
this.pos.y++; if( this.pos.y > hei - 2 ) this.pos.y = 1;
break;
}
if( this.overlap() ) { this.alive = false; } else {
this.posArray.push( createVector( this.pos.x, this.pos.y ) );
if( this.posArray.length > 5000 ) { this.posArray.splice( 0, 1 ); }
}
}
} function Fruit() {
this.fruitTime = true;
this.pos = createVector();
this.draw = function() {
fill( 200, 50, 20 );
rect( this.pos.x * block, this.pos.y * block, block, block );
}
this.setFruit = function() {
this.pos.x = floor( random( 1, wid - 1 ) );
this.pos.y = floor( random( 1, hei - 1 ) );
this.fruitTime = false;
}
} function setup() {
createCanvas( block * wid, block * hei ); noStroke(); frameRate( frameR ); snake = new Snake();fruit = new Fruit();
} function keyPressed() {
switch( keyCode ) {
case LEFT_ARROW: snake.dir = L; break;
case RIGHT_ARROW: snake.dir = R; break;
case UP_ARROW: snake.dir = U; break;
case DOWN_ARROW: snake.dir = D;
}
} function draw() {
background( color( 0, 0x22, 0 ) );
fill( 20, 50, 120 );
for( var i = 0; i < wid; i++ ) {
rect( i * block, 0, block, block );
rect( i * block, height - block, block, block );
}
for( var i = 1; i < hei - 1; i++ ) {
rect( 1, i * block, block, block );
rect( width - block, i * block, block, block );
}
if( fruit.fruitTime ) {
fruit.setFruit();
frameR += .2;
frameRate( frameR );
}
fruit.draw();
snake.update();
if( snake.eat( fruit.pos ) ) {
fruit.fruitTime = true;
}
snake.draw();
fill( 200 );
textStyle( BOLD ); textAlign( RIGHT ); textSize( 120 );
text( ""+( snake.length - 1 ), 690, 440 );
if( !snake.alive ) text( "THE END", 630, 250 );
} </lang>
Julia
Makie version in 99 lines. <lang julia>using Makie
mutable struct SnakeGame
height width snake food
end
function SnakeGame(;height=6, width=8)
snake = [rand(CartesianIndices((height, width)))]
food = rand(CartesianIndices((height, width)))
while food == snake[1]
food = rand(CartesianIndices((height, width)))
end
SnakeGame(height, width, snake, food)
end
function step!(game, direction)
next_head = game.snake[1] + direction
next_head = CartesianIndex(mod.(next_head.I, Base.OneTo.((game.height, game.width)))) # allow crossing boundry
if is_valid(game, next_head)
pushfirst!(game.snake, next_head)
if next_head == game.food
length(game.snake) < game.height * game.width && init_food!(game)
else
pop!(game.snake)
end
true
else
false
end
end
is_valid(game, position) = position ∉ game.snake
function init_food!(game)
p = rand(CartesianIndices((game.height, game.width)))
while !is_valid(game, p)
p = rand(CartesianIndices((game.height, game.width)))
end
game.food = p
end
function play(;n=10,t=0.5)
game = Node(SnakeGame(;width=n,height=n)) scene = Scene(resolution = (1000, 1000), raw = true, camera = campixel!) display(scene)
area = scene.px_area poly!(scene, area)
grid_size = @lift((widths($area)[1] / $game.height, widths($area)[2] / $game.width))
snake_boxes = @lift([FRect2D((p.I .- (1,1)) .* $grid_size , $grid_size) for p in $game.snake]) poly!(scene, snake_boxes, color=:blue, strokewidth = 5, strokecolor = :black)
snake_head_box = @lift(FRect2D(($game.snake[1].I .- (1,1)) .* $grid_size , $grid_size)) poly!(scene, snake_head_box, color=:black) snake_head = @lift((($game.snake[1].I .- 0.5) .* $grid_size)) scatter!(scene, snake_head, marker='◉', color=:blue, markersize=@lift(minimum($grid_size)))
food_position = @lift(($game.food.I .- (0.5,0.5)) .* $grid_size) scatter!(scene, food_position, color=:red, marker='♥', markersize=@lift(minimum($grid_size)))
score_text = @lift("Score: $(length($game.snake)-1)")
text!(scene, score_text, color=:gray, position = @lift((widths($area)[1]/2, widths($area)[2])), textsize = 50, align = (:center, :top))
direction = Ref{Any}(nothing)
on(scene.events.keyboardbuttons) do but
if ispressed(but, Keyboard.left)
direction[] = CartesianIndex(-1,0)
elseif ispressed(but, Keyboard.up)
direction[] = CartesianIndex(0,1)
elseif ispressed(but, Keyboard.down)
direction[] = CartesianIndex(0,-1)
elseif ispressed(but, Keyboard.right)
direction[] = CartesianIndex(1,0)
end
end
last_dir = nothing
while true
# avoid turn back
if !isnothing(direction[]) && (isnothing(last_dir) || direction[] != -last_dir)
last_dir = direction[]
end
if !isnothing(last_dir)
if step!(game[], last_dir)
game[] = game[]
else
break
end
end
sleep(t)
end
end
play() </lang>
Kotlin
<lang scala>// Kotlin Native v0.5
import kotlinx.cinterop.* import platform.posix.* import platform.windows.*
const val WID = 60 const val HEI = 30 const val MAX_LEN = 600 const val NUL = '\u0000'
enum class Dir { NORTH, EAST, SOUTH, WEST }
class Snake {
val console: HANDLE var alive = false val brd = CharArray(WID * HEI) var dir = Dir.NORTH val snk = nativeHeap.allocArray<COORD>(MAX_LEN) lateinit var head: COORD var tailIdx = 0 var headIdx = 0 var points = 0
init {
console = GetStdHandle(STD_OUTPUT_HANDLE)!!
SetConsoleTitleW("Snake")
memScoped {
val coord = alloc<COORD>().apply { X = (WID + 1).toShort(); Y = (HEI + 2).toShort() }
SetConsoleScreenBufferSize(console, coord.readValue())
val rc = alloc<SMALL_RECT>().apply {
Left = 0; Top = 0; Right = WID.toShort(); Bottom = (HEI + 1).toShort()
}
SetConsoleWindowInfo(console, TRUE, rc.ptr)
val ci = alloc<CONSOLE_CURSOR_INFO>().apply { dwSize = 1; bVisible = FALSE }
SetConsoleCursorInfo(console, ci.ptr)
}
}
fun play() {
while (true) {
createfield()
alive = true
while (alive) {
drawfield()
readKey()
moveSnake()
Sleep(50)
}
memScoped {
val c = alloc<COORD>().apply { X = 0; Y = (HEI + 1).toShort() }
SetConsoleCursorPosition(console, c.readValue())
}
SetConsoleTextAttribute(console, 0x000b)
print("Play again [Y/N]? ")
val a = readLine()!!.toLowerCase()
if (a.length > 0 && a[0] != 'y') {
nativeHeap.free(snk)
return
}
}
}
private fun createfield() {
memScoped {
val coord = alloc<COORD>().apply { X = 0; Y = 0 }
val c = alloc<DWORDVar>()
FillConsoleOutputCharacterW(console, 32, (HEI + 2) * 80, coord.readValue(), c.ptr)
FillConsoleOutputAttribute(console, 0x0000, (HEI + 2) * 80, coord.readValue(), c.ptr)
SetConsoleCursorPosition(console, coord.readValue())
}
for (x in 0 until WID * HEI) brd[x] = NUL
for (x in 0 until WID) {
brd[x + WID * (HEI - 1)] = '+'
brd[x] = '+'
}
for (y in 1 until HEI) {
brd[WID - 1 + WID * y] = '+'
brd[WID * y] = '+'
}
var xx: Int
var yy: Int
do {
xx = rand() % WID
yy = rand() % (HEI shr 1) + (HEI shr 1)
}
while (brd[xx + WID * yy] != NUL)
brd[xx + WID * yy] = '@'
tailIdx = 0
headIdx = 4
xx = 3
yy = 2
for (cc in tailIdx until headIdx) {
brd[xx + WID * yy] = '#'
snk[cc].X = (3 + cc).toShort()
snk[cc].Y = 2
}
head = snk[3]
dir = Dir.EAST
points = 0
}
private fun readKey() {
if ((GetAsyncKeyState(39).toInt() and 0x8000) != 0) dir = Dir.EAST
if ((GetAsyncKeyState(37).toInt() and 0x8000) != 0) dir = Dir.WEST
if ((GetAsyncKeyState(38).toInt() and 0x8000) != 0) dir = Dir.NORTH
if ((GetAsyncKeyState(40).toInt() and 0x8000) != 0) dir = Dir.SOUTH
}
private fun drawfield() {
memScoped {
val coord = alloc<COORD>()
var t = NUL
for (y in 0 until HEI) {
coord.Y = y.toShort()
for (x in 0 until WID) {
t = brd[x + WID * y]
if (t == NUL) continue
coord.X = x.toShort()
SetConsoleCursorPosition(console, coord.readValue())
if (coord.X == head.X && coord.Y == head.Y) {
SetConsoleTextAttribute(console, 0x002e)
print('O')
SetConsoleTextAttribute(console, 0x0000)
continue
}
when (t) {
'#' -> SetConsoleTextAttribute(console, 0x002a)
'+' -> SetConsoleTextAttribute(console, 0x0019)
'@' -> SetConsoleTextAttribute(console, 0x004c)
}
print(t)
SetConsoleTextAttribute(console, 0x0000)
}
}
print(t)
SetConsoleTextAttribute(console, 0x0007)
val c = alloc<COORD>().apply { X = 0; Y = HEI.toShort() }
SetConsoleCursorPosition(console, c.readValue())
print("Points: $points")
}
}
private fun moveSnake() {
when (dir) {
Dir.NORTH -> head.Y--
Dir.EAST -> head.X++
Dir.SOUTH -> head.Y++
Dir.WEST -> head.X--
}
val t = brd[head.X + WID * head.Y]
if (t != NUL && t != '@') {
alive = false
return
}
brd[head.X + WID * head.Y] = '#'
snk[headIdx].X = head.X
snk[headIdx].Y = head.Y
if (++headIdx >= MAX_LEN) headIdx = 0
if (t == '@') {
points++
var x: Int
var y: Int
do {
x = rand() % WID
y = rand() % (HEI shr 1) + (HEI shr 1)
}
while (brd[x + WID * y] != NUL)
brd[x + WID * y] = '@'
return
}
SetConsoleCursorPosition(console, snk[tailIdx].readValue())
print(' ')
brd[snk[tailIdx].X + WID * snk[tailIdx].Y] = NUL
if (++tailIdx >= MAX_LEN) tailIdx = 0
}
}
fun main(args: Array<String>) {
srand(time(null).toInt()) Snake().play()
}</lang>
- Output:
Similar to C++ entry
Nim
As in the C version, the code is provided for Linux. We use the tiny API defined in the C version, only adjusted to work with Nim and the library “nim-ncurses”. <lang Nim>import macros, os, random import ncurses
when defined(Linux):
proc positional_putch(x, y: int; ch: char) = mvaddch(x.cint, y.cint, ch.chtype) proc updateScreen = refresh() proc nonBlockingGetch(): char = let c = getch() result = if c in 0..255: char(c) else: '\0' proc closeScreen = endwin()
else:
error "Not implemented"
const
W = 80 H = 40 Space = 0 Food = 1 Border = 2 Symbol = [' ', '@', '.']
type
Dir {.pure.} = enum North, East, South, West
Game = object
board: array[W * H, int]
head: int
dir: Dir
quit: bool
proc age(game: var Game) =
## Reduce a time-to-live, effectively erasing the tail. for i in 0..<W*H: if game.board[i] < 0: inc game.board[i]
proc plant(game: var Game) =
## Put a piece of food at random empty position. var r: int while true: r = rand(W * H - 1) if game.board[r] == Space: break game.board[r] = Food
proc start(game: var Game) =
## Initialize the board, plant a very first food item. for i in 0..<W: game.board[i] = Border game.board[i + (H - 1) * W] = Border for i in 0..<H: game.board[i * W] = Border game.board[i * W + W - 1] = Border game.head = W * (H - 1 - (H and 1)) shr 1 # Screen center for any H. game.board[game.head] = -5 game.dir = North game.quit = false game.plant()
proc step(game: var Game) =
let len = game.board[game.head] case game.dir of North: dec game.head, W of South: inc game.head, W of West: dec game.head of East: inc game.head
case game.board[game.head] of Space: game.board[game.head] = len - 1 # Keep in mind "len" is negative. game.age() of Food: game.board[game.head] = len - 1 game.plant() else: game.quit = true
proc show(game: Game) =
for i in 0..<W*H: positionalPutch(i div W, i mod W, if game.board[i] < 0: '#' else: Symbol[game.board[i]]) updateScreen()
var game: Game
randomize()
let win = initscr()
cbreak() # Make sure thre is no buffering.
noecho() # Suppress echoing of characters.
nodelay(win, true) # Non-blocking mode.
game.start()
while not game.quit:
game.show() case nonBlockingGetch() of 'i': game.dir = North of 'j': game.dir = West of 'k': game.dir = South of 'l': game.dir = East of 'q': game.quit = true else: discard game.step() os.sleep(300) # Adjust here: 100 is very fast.
sleep(1000) closeScreen()</lang>
OCaml
<lang ocaml>(* A simple Snake Game *) open Sdl
let width, height = (640, 480)
type pos = int * int
type game_state = {
pos_snake: pos; seg_snake: pos list; dir_snake: [`left | `right | `up | `down]; pos_fruit: pos; sleep_time: int; game_over: bool;
}
let red = (255, 0, 0) let blue = (0, 0, 255) let green = (0, 255, 0) let black = (0, 0, 0) let alpha = 255
let fill_rect renderer (x, y) =
let rect = Rect.make4 x y 20 20 in Render.fill_rect renderer rect;
let display_game renderer state =
let bg_color, snake_color, fruit_color = if state.game_over then (red, black, green) else (black, blue, red) in Render.set_draw_color renderer bg_color alpha; Render.clear renderer; Render.set_draw_color renderer fruit_color alpha; fill_rect renderer state.pos_fruit; Render.set_draw_color renderer snake_color alpha; List.iter (fill_rect renderer) state.seg_snake; Render.render_present renderer;
let proc_events dir_snake = function
| Event.KeyDown { Event.keycode = Keycode.Left } -> `left
| Event.KeyDown { Event.keycode = Keycode.Right } -> `right
| Event.KeyDown { Event.keycode = Keycode.Up } -> `up
| Event.KeyDown { Event.keycode = Keycode.Down } -> `down
| Event.KeyDown { Event.keycode = Keycode.Q }
| Event.KeyDown { Event.keycode = Keycode.Escape }
| Event.Quit _ -> Sdl.quit (); exit 0
| _ -> (dir_snake)
let rec event_loop dir_snake =
match Event.poll_event () with
| None -> (dir_snake)
| Some ev ->
let dir = proc_events dir_snake ev in
event_loop dir
let rec pop = function
| [_] -> [] | hd :: tl -> hd :: (pop tl) | [] -> invalid_arg "pop"
let rec new_pos_fruit seg_snake =
let new_pos =
(20 * Random.int 32,
20 * Random.int 24)
in
if List.mem new_pos seg_snake
then new_pos_fruit seg_snake
else (new_pos)
let update_state req_dir ({
pos_snake;
seg_snake;
pos_fruit;
dir_snake;
sleep_time;
game_over;
} as state) =
if game_over then state else
let dir_snake =
match dir_snake, req_dir with
| `left, `right -> dir_snake
| `right, `left -> dir_snake
| `up, `down -> dir_snake
| `down, `up -> dir_snake
| _ -> req_dir
in
let pos_snake =
let x, y = pos_snake in
match dir_snake with
| `left -> (x - 20, y)
| `right -> (x + 20, y)
| `up -> (x, y - 20)
| `down -> (x, y + 20)
in
let game_over =
let x, y = pos_snake in
List.mem pos_snake seg_snake
|| x < 0 || y < 0
|| x >= width
|| y >= height
in
let seg_snake = pos_snake :: seg_snake in
let seg_snake, pos_fruit, sleep_time =
if pos_snake = pos_fruit
then (seg_snake, new_pos_fruit seg_snake, sleep_time - 1)
else (pop seg_snake, pos_fruit, sleep_time)
in
{ pos_snake;
seg_snake;
pos_fruit;
dir_snake;
sleep_time;
game_over;
}
let () =
Random.self_init ();
Sdl.init [`VIDEO];
let window, renderer =
Render.create_window_and_renderer ~width ~height ~flags:[]
in
Window.set_title ~window ~title:"Snake OCaml-SDL2";
let initial_state = {
pos_snake = (100, 100);
seg_snake = [
(100, 100);
( 80, 100);
( 60, 100);
];
pos_fruit = (200, 200);
dir_snake = `right;
sleep_time = 120;
game_over = false;
} in
let rec main_loop state = let req_dir = event_loop state.dir_snake in let state = update_state req_dir state in display_game renderer state; Timer.delay state.sleep_time; main_loop state in main_loop initial_state</lang>
Perl
<lang perl>use utf8; use Time::HiRes qw(sleep); use Term::ANSIColor qw(colored); use Term::ReadKey qw(ReadMode ReadLine);
binmode(STDOUT, ':utf8');
use constant {
VOID => 0,
HEAD => 1,
BODY => 2,
TAIL => 3,
FOOD => 4,
};
use constant {
LEFT => [+0, -1],
RIGHT => [+0, +1],
UP => [-1, +0],
DOWN => [+1, +0],
};
use constant {
BG_COLOR => "on_black",
SLEEP_SEC => 0.05,
};
use constant {
SNAKE_COLOR => ('bold green' . ' ' . BG_COLOR),
FOOD_COLOR => ('red' . ' ' . BG_COLOR),
};
use constant {
U_HEAD => colored('▲', SNAKE_COLOR),
D_HEAD => colored('▼', SNAKE_COLOR),
L_HEAD => colored('◀', SNAKE_COLOR),
R_HEAD => colored('▶', SNAKE_COLOR),
U_BODY => colored('╹', SNAKE_COLOR),
D_BODY => colored('╻', SNAKE_COLOR),
L_BODY => colored('╴', SNAKE_COLOR),
R_BODY => colored('╶', SNAKE_COLOR),
U_TAIL => colored('╽', SNAKE_COLOR),
D_TAIL => colored('╿', SNAKE_COLOR),
L_TAIL => colored('╼', SNAKE_COLOR),
R_TAIL => colored('╾', SNAKE_COLOR),
A_VOID => colored(' ', BG_COLOR),
A_FOOD => colored('❇', FOOD_COLOR),
};
local $| = 1;
my $w = eval { `tput cols` } || 80; my $h = eval { `tput lines` } || 24; my $r = "\033[H";
my @grid = map {
[map { [VOID] } 1 .. $w]
} 1 .. $h;
my $dir = LEFT; my @head_pos = ($h / 2, $w / 2); my @tail_pos = ($head_pos[0], $head_pos[1] + 1);
$grid[$head_pos[0]][$head_pos[1]] = [HEAD, $dir]; # head $grid[$tail_pos[0]][$tail_pos[1]] = [TAIL, $dir]; # tail
sub create_food {
my ($food_x, $food_y);
do {
$food_x = rand($w);
$food_y = rand($h);
} while ($grid[$food_y][$food_x][0] != VOID);
$grid[$food_y][$food_x][0] = FOOD;
}
create_food();
sub display {
my $i = 0;
print $r, join("\n",
map {
join("",
map {
my $t = $_->[0];
if ($t != FOOD and $t != VOID) {
my $p = $_->[1];
$i =
$p eq UP ? 0
: $p eq DOWN ? 1
: $p eq LEFT ? 2
: 3;
}
$t == HEAD ? (U_HEAD, D_HEAD, L_HEAD, R_HEAD)[$i]
: $t == BODY ? (U_BODY, D_BODY, L_BODY, R_BODY)[$i]
: $t == TAIL ? (U_TAIL, D_TAIL, L_TAIL, R_TAIL)[$i]
: $t == FOOD ? (A_FOOD)
: (A_VOID);
} @{$_}
)
} @grid
);
}
sub move {
my $grew = 0;
# Move the head
{
my ($y, $x) = @head_pos;
my $new_y = ($y + $dir->[0]) % $h;
my $new_x = ($x + $dir->[1]) % $w;
my $cell = $grid[$new_y][$new_x];
my $t = $cell->[0];
if ($t == BODY or $t == TAIL) {
die "Game over!\n";
}
elsif ($t == FOOD) {
create_food();
$grew = 1;
}
# Create a new head
$grid[$new_y][$new_x] = [HEAD, $dir];
# Replace the current head with body
$grid[$y][$x] = [BODY, $dir];
# Save the position of the head
@head_pos = ($new_y, $new_x);
}
# Move the tail
if (not $grew) {
my ($y, $x) = @tail_pos;
my $pos = $grid[$y][$x][1];
my $new_y = ($y + $pos->[0]) % $h;
my $new_x = ($x + $pos->[1]) % $w;
$grid[$y][$x][0] = VOID; # erase the current tail
$grid[$new_y][$new_x][0] = TAIL; # create a new tail
# Save the position of the tail
@tail_pos = ($new_y, $new_x);
}
}
ReadMode(3); while (1) {
my $key;
until (defined($key = ReadLine(-1))) {
move();
display();
sleep(SLEEP_SEC);
}
if ($key eq "\e[A" and $dir ne DOWN ) { $dir = UP }
elsif ($key eq "\e[B" and $dir ne UP ) { $dir = DOWN }
elsif ($key eq "\e[C" and $dir ne LEFT ) { $dir = RIGHT }
elsif ($key eq "\e[D" and $dir ne RIGHT) { $dir = LEFT }
}</lang>
Phix
<lang Phix>constant W = 60, H = 30, MAX_LEN = 600 enum NORTH, EAST, SOUTH, WEST
sequence board, snake bool alive integer tailIdx, headIdx, hdX, hdY, d, points
procedure createField()
clear_screen()
board = repeat("+"&repeat(' ',W-2)&'+',H)
for x=1 to W do
board[1,x] = '+'
end for
board[H] = board[1]
board[1+rand(H-2),1+rand(W-2)] = '@';
snake = repeat(0,MAX_LEN)
board[3,4] = '#'; tailIdx = 1; headIdx = 5;
for c=tailIdx to headIdx do
snake[c] = {3,3+c}
end for
{hdY,hdX} = snake[headIdx-1]; d = EAST; points = 0;
end procedure
procedure drawField()
for y=1 to H do
for x=1 to W do
integer t = board[y,x]
if t!=' ' then
position(y,x)
if x=hdX and y=hdY then
text_color(14); puts(1,'O');
else
text_color({10,9,12}[find(t,"#+@")]); puts(1,t);
end if
end if
end for
end for
position(H+1,1); text_color(7); printf(1,"Points: %d",points)
end procedure
procedure readKey()
integer k = find(get_key(),{333,331,328,336})
if k then d = {EAST,WEST,NORTH,SOUTH}[k] end if
end procedure
procedure moveSnake() integer x,y
switch d do
case NORTH: hdY -= 1
case EAST: hdX += 1
case SOUTH: hdY += 1
case WEST: hdX -= 1
end switch
integer t = board[hdY,hdX];
if t!=' ' and t!='@' then alive = false; return; end if
board[hdY,hdX] = '#'; snake[headIdx] = {hdY,hdX};
headIdx += 1; if headIdx>MAX_LEN then headIdx = 1 end if
if t=='@' then
points += 1
while 1 do
x = 1+rand(W-2); y = 1+rand(H-2);
if board[y,x]=' ' then
board[y,x] = '@'
return
end if
end while
end if
{y,x} = snake[tailIdx]; position(y,x); puts(1,' '); board[y,x] = ' ';
tailIdx += 1; if tailIdx>MAX_LEN then tailIdx = 1 end if
end procedure
procedure play()
while true do
createField(); alive = true; cursor(NO_CURSOR)
while alive do drawField(); readKey(); moveSnake(); sleep(0.05) end while
cursor(BLOCK_CURSOR); position(H+2,1); bk_color(0); text_color(11);
puts(1,"Play again [Y/N]? ")
if upper(wait_key())!='Y' then return end if
end while
end procedure play()</lang>
Python
Using Pygame. Works with Python >= 3.7. <lang python>from __future__ import annotations
import itertools import random
from enum import Enum
from typing import Any from typing import Tuple
import pygame as pg
from pygame import Color from pygame import Rect
from pygame.surface import Surface
from pygame.sprite import AbstractGroup from pygame.sprite import Group from pygame.sprite import RenderUpdates from pygame.sprite import Sprite
class Direction(Enum):
UP = (0, -1) DOWN = (0, 1) LEFT = (-1, 0) RIGHT = (1, 0)
def opposite(self, other: Direction):
return (self[0] + other[0], self[1] + other[1]) == (0, 0)
def __getitem__(self, i: int):
return self.value[i]
class SnakeHead(Sprite):
def __init__(
self,
size: int,
position: Tuple[int, int],
facing: Direction,
bounds: Rect,
) -> None:
super().__init__()
self.image = Surface((size, size))
self.image.fill(Color("aquamarine4"))
self.rect = self.image.get_rect()
self.rect.center = position
self.facing = facing
self.size = size
self.speed = size
self.bounds = bounds
def update(self, *args: Any, **kwargs: Any) -> None:
# Move the snake in the direction it is facing.
self.rect.move_ip(
(
self.facing[0] * self.speed,
self.facing[1] * self.speed,
)
)
# Move to the opposite side of the screen if the snake goes out of bounds.
if self.rect.right > self.bounds.right:
self.rect.left = 0
elif self.rect.left < 0:
self.rect.right = self.bounds.right
if self.rect.bottom > self.bounds.bottom:
self.rect.top = 0
elif self.rect.top < 0:
self.rect.bottom = self.bounds.bottom
def change_direction(self, direction: Direction):
if not self.facing == direction and not direction.opposite(self.facing):
self.facing = direction
class SnakeBody(Sprite):
def __init__(
self,
size: int,
position: Tuple[int, int],
colour: str = "white",
) -> None:
super().__init__()
self.image = Surface((size, size))
self.image.fill(Color(colour))
self.rect = self.image.get_rect()
self.rect.center = position
class Snake(RenderUpdates):
def __init__(self, game: Game) -> None:
self.segment_size = game.segment_size
self.colours = itertools.cycle(["aquamarine1", "aquamarine3"])
self.head = SnakeHead(
size=self.segment_size,
position=game.rect.center,
facing=Direction.RIGHT,
bounds=game.rect,
)
neck = [
SnakeBody(
size=self.segment_size,
position=game.rect.center,
colour=next(self.colours),
)
for _ in range(2)
]
super().__init__(*[self.head, *neck])
self.body = Group()
self.tail = neck[-1]
def update(self, *args: Any, **kwargs: Any) -> None:
self.head.update()
# Snake body sprites don't update themselves. We update them here.
segments = self.sprites()
for i in range(len(segments) - 1, 0, -1):
# Current sprite takes the position of the previous sprite.
segments[i].rect.center = segments[i - 1].rect.center
def change_direction(self, direction: Direction):
self.head.change_direction(direction)
def grow(self):
tail = SnakeBody(
size=self.segment_size,
position=self.tail.rect.center,
colour=next(self.colours),
)
self.tail = tail
self.add(self.tail)
self.body.add(self.tail)
class SnakeFood(Sprite):
def __init__(self, game: Game, size: int, *groups: AbstractGroup) -> None:
super().__init__(*groups)
self.image = Surface((size, size))
self.image.fill(Color("red"))
self.rect = self.image.get_rect()
self.rect.topleft = (
random.randint(0, game.rect.width),
random.randint(0, game.rect.height),
)
self.rect.clamp_ip(game.rect)
# XXX: This approach to random food placement might end badly if the
# snake is very large.
while pg.sprite.spritecollideany(self, game.snake):
self.rect.topleft = (
random.randint(0, game.rect.width),
random.randint(0, game.rect.height),
)
self.rect.clamp_ip(game.rect)
class Game:
def __init__(self) -> None:
self.rect = Rect(0, 0, 640, 480)
self.background = Surface(self.rect.size)
self.background.fill(Color("black"))
self.score = 0
self.framerate = 16
self.segment_size = 10
self.snake = Snake(self)
self.food_group = RenderUpdates(SnakeFood(game=self, size=self.segment_size))
pg.init()
def _init_display(self) -> Surface:
bestdepth = pg.display.mode_ok(self.rect.size, 0, 32)
screen = pg.display.set_mode(self.rect.size, 0, bestdepth)
pg.display.set_caption("Snake")
pg.mouse.set_visible(False)
screen.blit(self.background, (0, 0))
pg.display.flip()
return screen
def draw(self, screen: Surface):
dirty = self.snake.draw(screen)
pg.display.update(dirty)
dirty = self.food_group.draw(screen)
pg.display.update(dirty)
def update(self, screen):
self.food_group.clear(screen, self.background)
self.food_group.update()
self.snake.clear(screen, self.background)
self.snake.update()
def main(self) -> int:
screen = self._init_display()
clock = pg.time.Clock()
while self.snake.head.alive():
for event in pg.event.get():
if event.type == pg.QUIT or (
event.type == pg.KEYDOWN and event.key in (pg.K_ESCAPE, pg.K_q)
):
return self.score
# Change direction using the arrow keys.
keystate = pg.key.get_pressed()
if keystate[pg.K_RIGHT]:
self.snake.change_direction(Direction.RIGHT)
elif keystate[pg.K_LEFT]:
self.snake.change_direction(Direction.LEFT)
elif keystate[pg.K_UP]:
self.snake.change_direction(Direction.UP)
elif keystate[pg.K_DOWN]:
self.snake.change_direction(Direction.DOWN)
# Detect collisions after update.
self.update(screen)
# Snake eats food.
for food in pg.sprite.spritecollide(
self.snake.head, self.food_group, dokill=False
):
food.kill()
self.snake.grow()
self.score += 1
# Increase framerate to speed up gameplay.
if self.score % 5 == 0:
self.framerate += 1
self.food_group.add(SnakeFood(self, self.segment_size))
# Snake hit its own tail.
if pg.sprite.spritecollideany(self.snake.head, self.snake.body):
self.snake.head.kill()
self.draw(screen)
clock.tick(self.framerate)
return self.score
if __name__ == "__main__":
game = Game() score = game.main() print(score)
</lang>
Raku
(formerly Perl 6)
This is a variation of a demo script included in the examples folder for the Raku SDL2::Raw library bindings.
<lang perl6>use SDL2::Raw; use Cairo;
constant W = 1280; constant H = 960;
constant FIELDW = W div 32; constant FIELDH = H div 32;
SDL_Init(VIDEO);
my $window = SDL_CreateWindow(
'Snake', SDL_WINDOWPOS_CENTERED_MASK, SDL_WINDOWPOS_CENTERED_MASK, W, H, OPENGL
);
my $render = SDL_CreateRenderer($window, -1, ACCELERATED +| PRESENTVSYNC);
my $snake_image = Cairo::Image.record(
-> $_ {
.save;
.rectangle: 0, 0, 64, 64;
.clip;
.rgb: 0, 1, 0;
.rectangle: 0, 0, 64, 64;
.fill :preserve;
.rgb: 0, 0, 0;
.stroke;
.restore;
.save;
.translate: 64, 0;
.rectangle: 0, 0, 64, 64;
.clip;
.rgb: 1, 0, 0;
.arc: 32, 32, 30, 0, 2 * pi;
.fill :preserve;
.rgb: 0, 0, 0;
.stroke;
.restore;
}, 128, 128, Cairo::FORMAT_ARGB32);
my $snake_texture = SDL_CreateTexture(
$render, %PIXELFORMAT<ARGB8888>, STATIC, 128, 128
);
SDL_UpdateTexture(
$snake_texture,
SDL_Rect.new(
:x(0),
:y(0),
:w(128),
:h(128)
),
$snake_image.data,
$snake_image.stride // 128 * 4
);
SDL_SetTextureBlendMode($snake_texture, 1);
SDL_SetRenderDrawBlendMode($render, 1);
my $snakepiece_srcrect = SDL_Rect.new(:w(64), :h(64)); my $nompiece_srcrect = SDL_Rect.new(:w(64), :h(64), :x(64));
my $event = SDL_Event.new;
enum GAME_KEYS (
K_UP => 82, K_DOWN => 81, K_LEFT => 80, K_RIGHT => 79,
);
my Complex @snakepieces = 10+10i; my Complex @noms; my Complex $snakedir = 1+0i; my $nomspawn = 0; my $snakespeed = 0.1; my $snakestep = 0; my $nom = 4;
my $last_frame_start = now; main: loop {
my $start = now;
my $dt = $start - $last_frame_start // 0.00001;
while SDL_PollEvent($event) {
my $casted_event = SDL_CastEvent($event);
given $casted_event {
when *.type == QUIT { last main }
when *.type == KEYDOWN {
if GAME_KEYS(.scancode) -> $comm {
given $comm {
when 'K_LEFT' { $snakedir = -1+0i unless $snakedir == 1+0i }
when 'K_RIGHT' { $snakedir = 1+0i unless $snakedir == -1+0i }
when 'K_UP' { $snakedir = 0-1i unless $snakedir == 0+1i }
when 'K_DOWN' { $snakedir = 0+1i unless $snakedir == 0-1i }
}
}
}
}
}
if ($nomspawn -= $dt) < 0 {
$nomspawn += 1;
@noms.push: (^FIELDW).pick + (^FIELDH).pick * i unless @noms > 3;
@noms.pop if @noms[*-1] == any(@snakepieces);
}
if ($snakestep -= $dt) < 0 {
$snakestep += $snakespeed;
@snakepieces.unshift: do given @snakepieces[0] {
($_.re + $snakedir.re) % FIELDW
+ (($_.im + $snakedir.im) % FIELDH) * i
}
if @snakepieces[2..*].first( * == @snakepieces[0], :k ) -> $idx {
@snakepieces = @snakepieces[0..($idx + 1)];
}
@noms .= grep(
{ $^piece == @snakepieces[0] ?? ($nom += 1) && False !! True }
);
if $nom == 0 {
@snakepieces.pop;
} else {
$nom = $nom - 1;
}
}
for @snakepieces {
SDL_SetTextureColorMod(
$snake_texture,
255,
(cos((++$) / 2) * 100 + 155).round,
255
);
SDL_RenderCopy(
$render,
$snake_texture,
$snakepiece_srcrect,
SDL_Rect.new(.re * 32, .im * 32, 32, 32)
);
}
SDL_SetTextureColorMod($snake_texture, 255, 255, 255);
for @noms {
SDL_RenderCopy(
$render,
$snake_texture,
$nompiece_srcrect,
SDL_Rect.new(.re * 32, .im * 32, 32, 32)
)
}
SDL_RenderPresent($render); SDL_SetRenderDrawColor($render, 0, 0, 0, 0); SDL_RenderClear($render);
$last_frame_start = $start; sleep(1 / 50);
}
SDL_Quit();</lang>
Rust
Implemented smooth (per-pixel) animation on Win32 API (tested on Windows 7)
Used winsafe - a safe rust bindings library for Win32 GUI: young but very handy, with links to docs.microsoft.com from doc and src for all Win32 entities involved.
Along the way, the possibility of restarting while maintaining the length of the snake has been implemented. Now a long snake is available to everyone!
snake game screenshot <lang fsharp>/* add to file Cargo.toml: [dependencies] winsafe = "0.0.8" rand = "0.8.4"
- /
- ![windows_subsystem = "windows"]
use rand::Rng; use std::{cell::RefCell, rc::Rc}; use winsafe::{co, gui, prelude::*, COLORREF, HBRUSH, HPEN, SIZE};
const STEP: i32 = 3; // px, motion per frame. STEP and FPS determine the smoothness and speed of the animation. const FPS: u32 = 90; const CELL: i32 = 21; // px, game grid (logical step). Will be aligned by STEP const FIELD_W: i32 = 20; // width of the square field in CELLs const SNAKE_W: i32 = 20; // px const ROUNDING: SIZE = SIZE::new(SNAKE_W / 2, SNAKE_W / 2);
const RATIO: i32 = CELL / STEP; const START_CELL: i32 = FIELD_W / 2 * RATIO; /// total field width (with overlap for collisions) in STEPs const TW: i32 = (FIELD_W + 2) * RATIO;
- [derive(Clone, Copy)]
- [repr(i32)]
enum Direction {
Start = 0, A = -1, D = 1, W = -TW, S = TW,
} use Direction::*;
struct Context {
wnd: gui::WindowMain, snake: Vec<i32>, // [ids_rect] where id_rect = y * TW + x (where x, y: nSTEPs) id_r: [i32; 6], // ID 6 rectangles to color in next frame (bg, tail, turn, body, food, head) gap: i32, // gap in STEPs between animation and logic cell (negative - remove tail) dir: Direction, ordered_dir: Direction,
} impl Context {
fn new(wnd: gui::WindowMain, len: usize) -> Self {
Self {
wnd,
snake: vec![START_CELL; len.saturating_sub(RATIO as usize)],
id_r: [START_CELL; 6],
gap: 0,
dir: Start,
ordered_dir: S,
}
}
}
pub fn main() {
let [bg, tail, turn, body, food, head] = [0usize, 1, 2, 3, 4, 5]; let mut colors = [(0x00, 0xF0, 0xA0); 6]; // color tail, turn, body colors[bg] = (0x00, 0x50, 0x90); colors[food] = (0xFF, 0x50, 0x00); colors[head] = (0xFF, 0xFF, 0x00); let brushes = COLORREF::new_array(&colors).map(|c| HBRUSH::CreateSolidBrush(c).unwrap());
let wnd = gui::WindowMain::new(gui::WindowMainOpts {
title: "Snake - Start: Space, then press W-A-S-D".to_string(),
size: winsafe::SIZE::new(FIELD_W * RATIO * STEP, FIELD_W * RATIO * STEP),
ex_style: co::WS_EX::CLIENTEDGE,
class_bg_brush: brushes[bg],
..Default::default()
});
let context = Rc::new(RefCell::new(Context::new(wnd.clone(), 0)));
wnd.on().wm_key_down({
let context = Rc::clone(&context);
move |k| {
let mut ctx = context.borrow_mut();
match (ctx.dir, k.char_code as u8) {
(Start, bt @ (b' ' | 113)) => {
let len = ctx.snake.len(); // 113 == F2 key
*ctx = Context::new(ctx.wnd.clone(), if bt == b' ' { len } else { 0 });
ctx.wnd.hwnd().InvalidateRect(None, true)?; // call .wm_paint() with erase
ctx.wnd.hwnd().SetTimer(1, 1000 / FPS, None)?;
}
(W | S, bt @ (b'A' | b'D')) => ctx.ordered_dir = if bt == b'A' { A } else { D },
(A | D, bt @ (b'S' | b'W')) => ctx.ordered_dir = if bt == b'S' { S } else { W },
_ => (),
}
Ok(())
}
});
wnd.on().wm_timer(1, {
let context = Rc::clone(&context);
let cells: Vec<i32> = (1..=FIELD_W)
.flat_map(|y| (1..=FIELD_W).map(move |x| (y * TW + x) * RATIO))
.collect();
move || {
let mut ctx = context.borrow_mut();
let new_h = ctx.id_r[head] + ctx.dir as i32;
ctx.id_r[body] = ctx.id_r[head];
ctx.id_r[head] = new_h;
if ctx.gap < 0 {
ctx.id_r[bg] = ctx.snake.remove(0);
ctx.id_r[tail] = ctx.snake[0];
ctx.id_r[turn] = ctx.snake[RATIO as usize / 2];
}
ctx.gap -= ctx.gap.signum();
if ctx.gap == 0 {
ctx.dir = ctx.ordered_dir;
let hw = ctx.wnd.hwnd();
let eat = new_h == ctx.id_r[food];
if !eat && (cells.binary_search(&new_h).is_err() || ctx.snake.contains(&&new_h)) {
hw.KillTimer(1)?;
hw.SetWindowText(&(hw.GetWindowText()? + " Restart: F2 (with save - Space)"))?;
ctx.dir = Start;
return Ok(());
} else if eat || ctx.id_r[food] == 0 && ctx.id_r[tail] != START_CELL {
let mut snk_cells: Vec<_> = ctx.snake.iter().step_by(RATIO as usize).collect();
if eat && snk_cells.len() == cells.len() - 2 {
hw.SetWindowText(&format!("Snake - EATEN ALL: {} !!!", snk_cells.len()))?
} else if eat {
hw.SetWindowText(&format!("Snake - Eaten: {}.", snk_cells.len()))?
}
if ctx.id_r[tail] == START_CELL || eat && snk_cells.len() == cells.len() - 2 {
ctx.id_r[food] = 0; // hide food if not all of the saved snake has come out or everything is eaten
} else if snk_cells.len() + 1 < cells.len() {
snk_cells.sort();
ctx.id_r[food] = *(cells.iter())
.filter(|i| **i != new_h && snk_cells.binary_search(i).is_err())
.nth(rand::thread_rng().gen_range(0..cells.len() - snk_cells.len() - 1))
.unwrap();
}
}
ctx.gap = if eat { RATIO } else { -RATIO }
}
ctx.snake.push(new_h);
ctx.wnd.hwnd().InvalidateRect(None, false)?; // call .wm_paint() without erase
Ok(())
}
});
wnd.on().wm_paint(move || {
let ctx = context.borrow();
let mut ps = winsafe::PAINTSTRUCT::default();
let hdc = ctx.wnd.hwnd().BeginPaint(&mut ps)?;
hdc.SelectObjectPen(HPEN::CreatePen(co::PS::NULL, 0, COLORREF::new(0, 0, 0))?)?;
for (&id_rect, &brush) in ctx.id_r.iter().zip(&brushes) {
hdc.SelectObjectBrush(brush)?;
let left = id_rect % TW * STEP - (STEP * RATIO + SNAKE_W) / 2;
let top = id_rect / TW * STEP - (STEP * RATIO + SNAKE_W) / 2;
hdc.RoundRect(
winsafe::RECT {
left,
top,
right: left + SNAKE_W,
bottom: top + SNAKE_W,
},
ROUNDING,
)?;
}
ctx.wnd.hwnd().EndPaint(&ps);
Ok(())
});
if let Err(e) = wnd.run_main(None) {
winsafe::HWND::NULL
.MessageBox(&e.to_string(), "Uncaught error", co::MB::ICONERROR)
.unwrap();
}
}</lang>
Sidef
<lang ruby>class SnakeGame(w, h) {
const readkey = frequire('Term::ReadKey')
const ansi = frequire('Term::ANSIColor')
enum (VOID, HEAD, BODY, TAIL, FOOD)
define (
LEFT = [+0, -1],
RIGHT = [+0, +1],
UP = [-1, +0],
DOWN = [+1, +0],
)
define BG_COLOR = "on_black"
define FOOD_COLOR = ("red" + " " + BG_COLOR)
define SNAKE_COLOR = ("bold green" + " " + BG_COLOR)
define SLEEP_SEC = 0.02
const (
A_VOID = ansi.colored(' ', BG_COLOR),
A_FOOD = ansi.colored('❇', FOOD_COLOR),
A_BLOCK = ansi.colored('■', SNAKE_COLOR),
)
has dir = LEFT has grid = [[]] has head_pos = [0, 0] has tail_pos = [0, 0]
method init {
grid = h.of { w.of { [VOID] } }
head_pos = [h//2, w//2]
tail_pos = [head_pos[0], head_pos[1]+1]
grid[head_pos[0]][head_pos[1]] = [HEAD, dir] # head
grid[tail_pos[0]][tail_pos[1]] = [TAIL, dir] # tail
self.make_food() }
method make_food {
var (food_x, food_y)
do {
food_x = w.rand.int
food_y = h.rand.int
} while (grid[food_y][food_x][0] != VOID)
grid[food_y][food_x][0] = FOOD }
method display {
print("\033[H", grid.map { |row|
row.map { |cell|
given (cell[0]) {
when (VOID) { A_VOID }
when (FOOD) { A_FOOD }
default { A_BLOCK }
}
}.join()
}.join("\n")
)
}
method move {
var grew = false
# Move the head
var (y, x) = head_pos...
var new_y = (y+dir[0] % h)
var new_x = (x+dir[1] % w)
var cell = grid[new_y][new_x]
given (cell[0]) {
when (BODY) { die "\nYou just bit your own body!\n" }
when (TAIL) { die "\nYou just bit your own tail!\n" }
when (FOOD) { grew = true; self.make_food() }
}
# Create a new head
grid[new_y][new_x] = [HEAD, dir]
# Replace the current head with body
grid[y][x] = [BODY, dir]
# Update the head position
head_pos = [new_y, new_x]
# Move the tail
if (!grew) {
var (y, x) = tail_pos...
var pos = grid[y][x][1]
var new_y = (y+pos[0] % h)
var new_x = (x+pos[1] % w)
grid[y][x][0] = VOID # erase the current tail
grid[new_y][new_x][0] = TAIL # create a new tail
tail_pos = [new_y, new_x]
}
}
method play {
STDOUT.autoflush(true)
readkey.ReadMode(3)
try {
loop {
var key
while (!defined(key = readkey.ReadLine(-1))) {
self.move()
self.display()
Sys.sleep(SLEEP_SEC)
}
given (key) {
when ("\e[A") { if (dir != DOWN ) { dir = UP } }
when ("\e[B") { if (dir != UP ) { dir = DOWN } }
when ("\e[C") { if (dir != LEFT ) { dir = RIGHT } }
when ("\e[D") { if (dir != RIGHT) { dir = LEFT } }
}
}
}
catch {
readkey.ReadMode(0)
}
}
}
var w = `tput cols`.to_i var h = `tput lines`.to_i
SnakeGame(w || 80, h || 24).play</lang>
Wren
An embedded program so we can ask the C host to call ncurses and another library function for us. <lang ecmascript>/* snake.wren */
import "random" for Random import "./dynamic" for Enum, Lower
foreign class Window {
construct initscr() {}
foreign nodelay(bf)
}
class Ncurses {
foreign static cbreak()
foreign static noecho()
foreign static refresh()
foreign static getch()
foreign static mvaddch(y, x, ch)
foreign static endwin()
}
class C {
foreign static usleep(usec)
}
var Dir = Enum.create("Dir", ["N", "E", "S", "W"]) var State = Enum.create("State", ["space", "food", "border"])
var w = 80 var h = 40 var board = List.filled(w * h, 0) var rand = Random.new() var head var dir var quit
// ASCII values var hash = 35 var at = 64 var dot = 46 var spc = 32
/* negative values denote the snake (a negated time-to-live in given cell) */
// reduce a time-to-live, effectively erasing the tail var age = Fn.new {
for (i in 0...w * h) {
if (board[i] < 0) board[i] = board[i] + 1
}
}
// put a piece of food at random empty position var plant = Fn.new {
var r
while (true) {
r = rand.int(w * h)
if (board[r] = State.space) break
}
board[r] = State.food
}
// initialize the board, plant a very first food item var start = Fn.new {
for (i in 0...w) board[i] = board[i + (h - 1) * w] = State.border for (i in 0...h) board[i * w] = board[i * w + w - 1] = State.border head = (w * (h - 1 - h % 2) / 2).floor // screen center for any h board[head] = -5 dir = Dir.N quit = false plant.call()
}
var step = Fn.new {
var len = board[head]
if (dir == Dir.N) {
head = head - w
} else if (dir == Dir.S) {
head = head + w
} else if (dir == Dir.W) {
head = head - 1
} else if (dir == Dir.E) {
head = head + 1
}
if (board[head] == State.space) {
board[head] = len - 1 // keep in mind len is negative
age.call()
} else if (board[head] == State.food) {
board[head] = len - 1
plant.call()
} else {
quit = true
}
}
var show = Fn.new {
var symbol = [spc, at, dot]
for (i in 0...w*h) {
Ncurses.mvaddch((i/w).floor, i % w, board[i] < 0 ? hash : symbol[board[i]])
}
Ncurses.refresh()
}
var initScreen = Fn.new {
var win = Window.initscr() Ncurses.cbreak() Ncurses.noecho() win.nodelay(true)
}
initScreen.call() start.call() while (true) {
show.call()
var ch = Ncurses.getch()
if (ch == Lower.i) {
dir = Dir.N
} else if (ch == Lower.j) {
dir = Dir.W
} else if (ch == Lower.k) {
dir = Dir.S
} else if (ch == Lower.l) {
dir = Dir.E
} else if (ch == Lower.q) {
quit = true
}
step.call()
C.usleep(300 * 1000) // 300 ms is a reasonable delay
if (quit) break
}
C.usleep(999 * 1000)
Ncurses.endwin()</lang>
Now embed this script in the following C program, compile and run it.
<lang c>/* gcc snake.c -o snake -lncurses -lwren -lm */
- include <stdio.h>
- include <stdlib.h>
- include <string.h>
- include <ncurses.h>
- include <unistd.h>
- include "wren.h"
/* C <=> Wren interface functions */
void C_windowAllocate(WrenVM* vm) {
WINDOW** pwin = (WINDOW**)wrenSetSlotNewForeign(vm, 0, 0, sizeof(WINDOW*)); *pwin = initscr();
}
void C_nodelay(WrenVM* vm) {
WINDOW* win = *(WINDOW**)wrenGetSlotForeign(vm, 0); bool bf = wrenGetSlotBool(vm, 1); nodelay(win, bf);
}
void C_cbreak(WrenVM* vm) {
cbreak();
}
void C_noecho(WrenVM* vm) {
noecho();
}
void C_refresh(WrenVM* vm) {
refresh();
}
void C_getch(WrenVM* vm) {
int ch = getch(); wrenSetSlotDouble(vm, 0, (double)ch);
}
void C_mvaddch(WrenVM* vm) {
int y = (int)wrenGetSlotDouble(vm, 1); int x = (int)wrenGetSlotDouble(vm, 2); const chtype ch = (const chtype)wrenGetSlotDouble(vm, 3); mvaddch(y, x, ch);
}
void C_endwin(WrenVM* vm) {
endwin();
}
void C_usleep(WrenVM* vm) {
useconds_t usec = (useconds_t)wrenGetSlotDouble(vm, 1); usleep(usec);
}
WrenForeignClassMethods bindForeignClass(WrenVM* vm, const char* module, const char* className) {
WrenForeignClassMethods methods;
methods.allocate = NULL;
methods.finalize = NULL;
if (strcmp(module, "main") == 0) {
if (strcmp(className, "Window") == 0) {
methods.allocate = C_windowAllocate;
}
}
return methods;
}
WrenForeignMethodFn bindForeignMethod(
WrenVM* vm,
const char* module,
const char* className,
bool isStatic,
const char* signature) {
if (strcmp(module, "main") == 0) {
if (strcmp(className, "Window") == 0) {
if (!isStatic && strcmp(signature, "nodelay(_)") == 0) return C_nodelay;
} else if (strcmp(className, "Ncurses") == 0) {
if (isStatic && strcmp(signature, "cbreak()") == 0) return C_cbreak;
if (isStatic && strcmp(signature, "noecho()") == 0) return C_noecho;
if (isStatic && strcmp(signature, "refresh()") == 0) return C_refresh;
if (isStatic && strcmp(signature, "getch()") == 0) return C_getch;
if (isStatic && strcmp(signature, "mvaddch(_,_,_)") == 0) return C_mvaddch;
if (isStatic && strcmp(signature, "endwin()") == 0) return C_endwin;
} else if (strcmp(className, "C") == 0) {
if (isStatic && strcmp(signature, "usleep(_)") == 0) return C_usleep;
}
}
return NULL;
}
static void writeFn(WrenVM* vm, const char* text) {
printf("%s", text);
}
void errorFn(WrenVM* vm, WrenErrorType errorType, const char* module, const int line, const char* msg) {
switch (errorType) {
case WREN_ERROR_COMPILE:
printf("[%s line %d] [Error] %s\n", module, line, msg);
break;
case WREN_ERROR_STACK_TRACE:
printf("[%s line %d] in %s\n", module, line, msg);
break;
case WREN_ERROR_RUNTIME:
printf("[Runtime Error] %s\n", msg);
break;
}
}
char *readFile(const char *fileName) {
FILE *f = fopen(fileName, "r"); fseek(f, 0, SEEK_END); long fsize = ftell(f); rewind(f); char *script = malloc(fsize + 1); fread(script, 1, fsize, f); fclose(f); script[fsize] = 0; return script;
}
static void loadModuleComplete(WrenVM* vm, const char* module, WrenLoadModuleResult result) {
if( result.source) free((void*)result.source);
}
WrenLoadModuleResult loadModule(WrenVM* vm, const char* name) {
WrenLoadModuleResult result = {0};
if (strcmp(name, "random") != 0 && strcmp(name, "meta") != 0) {
result.onComplete = loadModuleComplete;
char fullName[strlen(name) + 6];
strcpy(fullName, name);
strcat(fullName, ".wren");
result.source = readFile(fullName);
}
return result;
}
int main(int argc, char **argv) {
WrenConfiguration config;
wrenInitConfiguration(&config);
config.writeFn = &writeFn;
config.errorFn = &errorFn;
config.bindForeignClassFn = &bindForeignClass;
config.bindForeignMethodFn = &bindForeignMethod;
config.loadModuleFn = &loadModule;
WrenVM* vm = wrenNewVM(&config);
const char* module = "main";
const char* fileName = "snake.wren";
char *script = readFile(fileName);
WrenInterpretResult result = wrenInterpret(vm, module, script);
switch (result) {
case WREN_RESULT_COMPILE_ERROR:
printf("Compile Error!\n");
break;
case WREN_RESULT_RUNTIME_ERROR:
printf("Runtime Error!\n");
break;
case WREN_RESULT_SUCCESS:
break;
}
wrenFreeVM(vm);
free(script);
return 0;
}</lang>
XPL0
XPL0, like implementations of BASIC on early personal computers, was designed to support video games like this. The 40x25 character color screen is a display mode built into the IBM-PC and simulated by XPL0 in the Raspberry Pi and Windows (EXPL) versions.
The initial length of the snake and the number of food items constantly available can be changed in the defined constants at the beginning. The speed is regulated by the duration of the Sound routine (intrinsic), which has a granularity of one DOS system tick, or about 1/18 second. The speed is currently set at nine steps per second.
<lang XPL0>def Width=40, Height=25-1, \playing area including border
StartLength = 10, \starting length of snake including head
Morsels = 10; \number of food items constantly offered
int Heading; \direction snake is heading def Up, Down, Left, Right; int Length, \current length of snake including head
Score; \number of food items eaten
char SnakeX(10000), \location of each segment including head
SnakeY(10000), \ample room to grow
FoodX(Morsels), FoodY(Morsels); \location of each food item
def Black, Blue, Green, Cyan, Red, Magenta, Brown, White, \attribute colors
Gray, LBlue, LGreen, LCyan, LRed, LMagenta, Yellow, BWhite; \EGA palette
proc PlaceFood(N); \Place Nth food item in playing area int N; [FoodX(N):= Ran(Width-3) + 1; \pick random location inside borders
FoodY(N):= Ran(Height-3) + 1;
Cursor(FoodX(N), FoodY(N)); \show food Attrib(Red<<4+LRed); ChOut(6, ^@); ]; \PlaceFood
int X, Y, I, C;
[SetVid($01); \set 40x25 text mode
ShowCursor(false); \turn off flashing cursor
Attrib(Blue<<4+LBlue); \show borders Cursor(0, 0); for X:= 0 to Width-1 do ChOut(6, ^+); Cursor(0, Height-1); for X:= 0 to Width-1 do ChOut(6, ^+); for Y:= 0 to Height-1 do
[Cursor(0, Y); ChOut(6, ^+);
Cursor(Width-1, Y); ChOut(6, ^+);
];
Attrib(Black<<4+White); \show initial score Cursor(0, 24); Text(6, "Score: 0"); Score:= 0;
SnakeX(0):= Width/2; \start snake head at center SnakeY(0):= Height/2; Heading:= Left; Length:= StartLength; for I:= 1 to Length-1 do \segments follow head to the right
[SnakeX(I):= SnakeX(I-1) + 1;
SnakeY(I):= SnakeY(I-1);
];
for I:= 0 to Morsels-1 do PlaceFood(I); \sow some tasty food
\Continuously move snake loop \-------------------------------------------------------------------------- [Attrib(Black<<4+White); \remove tail-end segment Cursor(SnakeX(Length-1), SnakeY(Length-1)); ChOut(6, ^ ); Attrib(Green<<4+Yellow); \add segment at head location Cursor(SnakeX(0), SnakeY(0)); ChOut(6, ^#);
\Shift coordinates toward tail (+1 in case a segment gets added) for I:= Length downto 1 do \segment behind head gets head's coords
[SnakeX(I):= SnakeX(I-1);
SnakeY(I):= SnakeY(I-1);
];
if ChkKey then \key hit--get new movement direction
[repeat C:= ChIn(1) until C # 0; \remove arrow keys' prefix byte
case C of
$1B: exit; \Escape, and scan codes for arrow keys
$48: if Heading # Down then Heading:= Up;
$50: if Heading # Up then Heading:= Down;
$4B: if Heading # Right then Heading:= Left;
$4D: if Heading # Left then Heading:= Right
other []; \ignore any other keystrokes
];
case Heading of \move head to its new location
Up: SnakeY(0):= SnakeY(0)-1; Down: SnakeY(0):= SnakeY(0)+1; Left: SnakeX(0):= SnakeX(0)-1; Right:SnakeX(0):= SnakeX(0)+1
other []; Cursor(SnakeX(0), SnakeY(0)); \show head at its new location ChOut(6, ^8);
for I:= 0 to Morsels-1 do
if SnakeX(0)=FoodX(I) & SnakeY(0)=FoodY(I) then
[Score:= Score+1; \ate a morsel
Attrib(Black<<4+White);
Cursor(7, 24);
IntOut(6, Score*10);
PlaceFood(I); \replenish morsel
Length:= Length+1; \grow snake one segment
I:= Morsels; \over eating can be bad--quit for loop
Sound(1, 1, 1500); \BURP!
Sound(1, 1, 1000);
];
if I = Morsels then Sound(0, 2, 1); \no sound adds delay of 2/18th second
if SnakeX(0)=0 or SnakeX(0)=Width-1 or
SnakeY(0)=0 or SnakeY(0)=Height-1 then
quit; \snake hit border--game over
for I:= 1 to Length-1 do
if SnakeX(0)=SnakeX(I) & SnakeY(0)=SnakeY(I) then
quit; \snake bit itself--game over
]; \loop ----------------------------------------------------------------------- for I:= 1 to 8 do Sound(1, 1, 4000*I); \death dirge Sound(0, 36, 1); \pause 2 seconds to see result OpenI(1); \flush any pending keystrokes ]</lang>