Complete Flash Sokoban game in less than 2KB

May 19, 2010 • Actionscript 3, Flash, Game design, PROgramming by Emanuele Feronato • 25 Comments

Some days ago I blogged about 6 games you must be able to make in less than a day.

Among these games I included Sokoban, and since I don’t remember if I’ve ever tried to make a complete Sokoban game, I did it today.

In less than a day and, above all, in less than 2KB!!

And don’t expect an incomplete prototype… my Sokoban game features:

* 10 levels
* Tiles of different color and shape
* Shared objects to save the games
* Eye-candy effects (being only 2KB!!) to show completed levels and current level
* Copyable level moves to publish your own level solution
* In game instructions
* No external files or other tricks to reduce file size.

As said, in less than 2KB. My latest build is 2,002 bytes that’s less than 2,048.

This is the source code, that wasn’t written with readability or performance in mind, just aiming to stay under 2KB… just an exercise:

package {
	import flash.display.Sprite;
	import flash.events.KeyboardEvent;
	import flash.text.TextField;
	import flash.net.SharedObject;
	public class s extends Sprite {
		var m:Array=[[[1,1,1,1],[1,0,0,1,1,1,1,1],[1,0,2,0,0,3,0,1],[1,0,3,0,0,2,4,1],[1,1,1,0,0,1,1,1],[0,0,1,1,1,1]],[[0,0,1,1,1,1],[0,0,1,0,0,1],[1,1,1,0,0,1,1,1],[1,0,3,5,2,4,0,1],[1,0,0,0,0,0,0,1],[1,1,1,1,1,1,1,1]],[[0,0,1,1,1,1],[1,1,1,0,0,1],[1,0,0,5,4,1],[1,0,0,3,2,1,1],[1,1,1,0,0,0,1],[0,0,1,0,0,0,1],[0,0,1,1,1,1,1]],[[0,1,1,1,1,1,1,1],[1,1,0,4,0,0,0,1],[1,0,3,2,0,0,0,1],[1,0,2,3,1,1,1,1],[1,1,0,0,1],[0,1,0,0,1],[0,1,1,1,1,0]],[[1,1,1,1,1,1,1],[1,0,0,0,2,4,1,1,1],[1,0,0,5,5,5,0,0,1],[1,0,0,0,3,0,0,0,1],[1,1,1,1,1,1,0,0,1],[0,0,0,0,0,1,1,1,1]],[[0,0,1,1,1,1],[0,0,1,0,0,1],[0,0,1,0,0,1],[1,1,1,0,4,1,1],[1,0,5,3,2,0,1],[1,0,0,0,0,0,1],[1,1,0,0,1,1,1],[0,1,1,1,1,0,0]],[[0,0,1,1,1,1],[0,0,1,0,0,1,1,1],[1,1,1,2,3,2,0,1],[1,0,0,3,2,3,0,1],[1,0,0,0,4,1,1,1],[1,0,0,0,0,1],[1,1,1,1,1,1]],[[1,1,1,1],[1,0,0,1],[1,0,4,1],[1,2,3,1,1,1],[1,0,0,0,0,1],[1,2,3,1,0,1],[1,1,0,0,0,1],[0,1,1,1,1,1]],[[1,1,1,1,1,1,1],[1,0,0,1,0,0,1],[1,2,3,1,0,0,1],[1,6,3,0,0,0,1],[1,2,3,0,0,0,1],[1,1,1,1,1,1,1]],[[1,1,1,1,1,1,1,1],[1,0,0,1,0,0,0,1],[1,0,0,0,0,0,0,1],[1,3,3,3,1,1,1,1],[1,6,2,0,2,1],[1,1,1,1,1,1]]];
		public var l,h:int=0;
		public var p,r:Array;
		public var f:Sprite=new Sprite();
		public var g,o:Sprite;
		public var u:TextField = new TextField();
		public var c:SharedObject=SharedObject.getLocal("s");
		public function s():void {
			if (c.data.l==undefined) {
				c.data.l="0000000000";
			}
			for (var i:int=0; i<10; i++) {
				g=new Sprite();
				g.graphics.beginFill(0x00ff00);
				g.alpha=0.2+0.8*c.data.l.charAt(i);
				g.graphics.drawRect(0,0,9,9);
				g.x=130+i*11;
				g.y=35;
				g.name="g"+i;
				addChild(g);
			}
			o = new Sprite();
			o.graphics.beginFill(0xff0000);
			o.graphics.drawRect(0,0,3,3);
			addChild(o);
			o.y=38;
			u.text="ARROWS KEYS: MOVE\n0-9: SELECT LEVEL\nCOMPLETED LEVELS:\nLEVEL MOVES: ";
			u.width=490;
			addChild(u);
			addChild(f);
			d(l);
			stage.addEventListener(KeyboardEvent.KEY_UP, k);
		}
		public function d(l:int):void {
			o.x=133+l*11;
			var n:int;
			r=new Array();
			for (var i:int=0; i<m[l].length; i++) {
				r[i]=new Array();
				for (var j:int=0; j<m[l][i].length; j++) {
					n=m[l][i][j];
					r[i][j]=n;
					if (n) {
						if (n<5) {
							q(n,i,j);
						} else {
							q(2,i,j);
							q(n-2,i,j);
						}
					}
				}
			}
		}
		public function q(n:int,i:int,j:int):void {
			u.text=u.text.substr(0,67);
			f.y=64;
			var t:Sprite;
			var c:Array=[0x000000,0xff0000,0x00ff00,0x0000ff];
			t = new Sprite();
			t.graphics.beginFill(c[n-1]);
			t.graphics.drawRoundRect(0,0,32,32,(n-1)*20);
			t.x=j*32;
			t.y=i*32;
			f.addChild(t);
			if (n==2) {
				f.setChildIndex(t,0);
			}
			if (n==3) {
				t.name="d"+i+"_"+j;
			}
			if (n==4) {
				p=[i,j];
				r[i][j]-=4;
				t.name="b";
			}
		}
		public function k(e:KeyboardEvent):void {
			h=e.keyCode;
			switch (h) {
				case 37 :
					w(-1,0);
					break;
				case 38 :
					w(0,-1);
					break;
				case 39 :
					w(1,0);
					break;
				case 40 :
					w(0,1);
					break;
				default :
					if (h>47&&h<58) {
						l=h-48;
						removeChild(f);
						f = new Sprite();
						addChild(f);
						d(l);
					}
			}
		}
		public function w(a:int,b:int):void {
			var v:Boolean=false;
			var _z:String="RULD";
			var d:String="";
			if (r[p[0]+b][p[1]+a]==0||r[p[0]+b][p[1]+a]==2) {
				v=true;
			} else {
				if ((r[p[0]+b][p[1]+a]==3||r[p[0]+b][p[1]+a]==5)&&(r[p[0]+2*b][p[1]+2*a]==0||r[p[0]+2*b][p[1]+2*a]==2)) {
					d=f.getChildByName("d"+(p[0]+b)+"_"+(p[1]+a)).name;
					v=true;
				}
			}
			if (v) {
				u.appendText(_z.charAt(h-37));
				f.getChildByName("b").x+=32*a;
				f.getChildByName("b").y+=32*b;
				p[0]+=b;
				p[1]+=a;
				if (d!="") {
					f.getChildByName(d).x+=32*a;
					f.getChildByName(d).y+=32*b;
					f.getChildByName(d).name="d"+(p[0]+1*b)+"_"+(p[1]+1*a);
					r[p[0]][p[1]]-=3;
					r[p[0]+b][p[1]+a]+=3;
					d="";
					if (r.toString().indexOf(2)==-1) {
						c.data.l=c.data.l.substr(0,l)+"1"+c.data.l.substr(l+1);
						getChildByName("g"+l).alpha=1;
					}
				}
			}
		}
	}
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

package {

import flash.display.Sprite;

import flash.events.KeyboardEvent;

import flash.text.TextField;

import flash.net.SharedObject;

public class s extends Sprite {

var m:Array=[[[1,1,1,1],[1,0,0,1,1,1,1,1],[1,0,2,0,0,3,0,1],[1,0,3,0,0,2,4,1],[1,1,1,0,0,1,1,1],[0,0,1,1,1,1]],[[0,0,1,1,1,1],[0,0,1,0,0,1],[1,1,1,0,0,1,1,1],[1,0,3,5,2,4,0,1],[1,0,0,0,0,0,0,1],[1,1,1,1,1,1,1,1]],[[0,0,1,1,1,1],[1,1,1,0,0,1],[1,0,0,5,4,1],[1,0,0,3,2,1,1],[1,1,1,0,0,0,1],[0,0,1,0,0,0,1],[0,0,1,1,1,1,1]],[[0,1,1,1,1,1,1,1],[1,1,0,4,0,0,0,1],[1,0,3,2,0,0,0,1],[1,0,2,3,1,1,1,1],[1,1,0,0,1],[0,1,0,0,1],[0,1,1,1,1,0]],[[1,1,1,1,1,1,1],[1,0,0,0,2,4,1,1,1],[1,0,0,5,5,5,0,0,1],[1,0,0,0,3,0,0,0,1],[1,1,1,1,1,1,0,0,1],[0,0,0,0,0,1,1,1,1]],[[0,0,1,1,1,1],[0,0,1,0,0,1],[0,0,1,0,0,1],[1,1,1,0,4,1,1],[1,0,5,3,2,0,1],[1,0,0,0,0,0,1],[1,1,0,0,1,1,1],[0,1,1,1,1,0,0]],[[0,0,1,1,1,1],[0,0,1,0,0,1,1,1],[1,1,1,2,3,2,0,1],[1,0,0,3,2,3,0,1],[1,0,0,0,4,1,1,1],[1,0,0,0,0,1],[1,1,1,1,1,1]],[[1,1,1,1],[1,0,0,1],[1,0,4,1],[1,2,3,1,1,1],[1,0,0,0,0,1],[1,2,3,1,0,1],[1,1,0,0,0,1],[0,1,1,1,1,1]],[[1,1,1,1,1,1,1],[1,0,0,1,0,0,1],[1,2,3,1,0,0,1],[1,6,3,0,0,0,1],[1,2,3,0,0,0,1],[1,1,1,1,1,1,1]],[[1,1,1,1,1,1,1,1],[1,0,0,1,0,0,0,1],[1,0,0,0,0,0,0,1],[1,3,3,3,1,1,1,1],[1,6,2,0,2,1],[1,1,1,1,1,1]]];

public var l,h:int=0;

public var p,r:Array;

public var f:Sprite=new Sprite();

public var g,o:Sprite;

public var u:TextField = new TextField();

public var c:SharedObject=SharedObject.getLocal("s");

public function s():void {

if (c.data.l==undefined) {

c.data.l="0000000000";

}

for (var i:int=0; i<10; i++) {

g=new Sprite();

g.graphics.beginFill(0x00ff00);

g.alpha=0.2+0.8*c.data.l.charAt(i);

g.graphics.drawRect(0,0,9,9);

g.x=130+i*11;

g.y=35;

g.name="g"+i;

addChild(g);

}

o = new Sprite();

o.graphics.beginFill(0xff0000);

o.graphics.drawRect(0,0,3,3);

addChild(o);

o.y=38;

u.text="ARROWS KEYS: MOVE\n0-9: SELECT LEVEL\nCOMPLETED LEVELS:\nLEVEL MOVES: ";

u.width=490;

addChild(u);

addChild(f);

d(l);

stage.addEventListener(KeyboardEvent.KEY_UP, k);

}

public function d(l:int):void {

o.x=133+l*11;

var n:int;

r=new Array();

for (var i:int=0; i<m[l].length; i++) {

r[i]=new Array();

for (var j:int=0; j<m[l][i].length; j++) {

n=m[l][i][j];

r[i][j]=n;

if (n) {

if (n<5) {

q(n,i,j);

} else {

q(2,i,j);

q(n-2,i,j);

}

public function q(n:int,i:int,j:int):void {

u.text=u.text.substr(0,67);

f.y=64;

var t:Sprite;

var c:Array=[0x000000,0xff0000,0x00ff00,0x0000ff];

t = new Sprite();

t.graphics.beginFill(c[n-1]);

t.graphics.drawRoundRect(0,0,32,32,(n-1)*20);

t.x=j*32;

t.y=i*32;

f.addChild(t);

if (n==2) {

f.setChildIndex(t,0);

}

if (n==3) {

t.name="d"+i+"_"+j;

}

if (n==4) {

p=[i,j];

r[i][j]-=4;

t.name="b";

}

public function k(e:KeyboardEvent):void {

h=e.keyCode;

switch (h) {

case 37 :

w(-1,0);

break;

case 38 :

w(0,-1);

break;

case 39 :

w(1,0);

break;

case 40 :

w(0,1);

break;

default :

if (h>47&&h<58) {

l=h-48;

removeChild(f);

f = new Sprite();

addChild(f);

d(l);

}

public function w(a:int,b:int):void {

var v:Boolean=false;

var _z:String="RULD";

var d:String="";

if (r[p[0]+b][p[1]+a]==0||r[p[0]+b][p[1]+a]==2) {

v=true;

} else {

if ((r[p[0]+b][p[1]+a]==3||r[p[0]+b][p[1]+a]==5)&&(r[p[0]+2*b][p[1]+2*a]==0||r[p[0]+2*b][p[1]+2*a]==2)) {

d=f.getChildByName("d"+(p[0]+b)+"_"+(p[1]+a)).name;

v=true;

}

if (v) {

u.appendText(_z.charAt(h-37));

f.getChildByName("b").x+=32*a;

f.getChildByName("b").y+=32*b;

p[0]+=b;

p[1]+=a;

if (d!="") {

f.getChildByName(d).x+=32*a;

f.getChildByName(d).y+=32*b;

f.getChildByName(d).name="d"+(p[0]+1*b)+"_"+(p[1]+1*a);

r[p[0]][p[1]]-=3;

r[p[0]+b][p[1]+a]+=3;

d="";

if (r.toString().indexOf(2)==-1) {

c.data.l=c.data.l.substr(0,l)+"1"+c.data.l.substr(l+1);

getChildByName("g"+l).alpha=1;

}

This class was compiled with “Compress movie” checked and “Include XMP metadata” unchecked

And this is the result:

Move with arrow keys, select levels with 0-9, leave a comment with your solutions… and try to give me an idea about another game to make it fit under 2KB.

If you want to check file size, save this file and see…

Rate this post: 1 Star

(21 votes, average: 4.95 out of 5)

Loading ...

Flash Templates provided by Template Monster are pre-made web design products developed using Flash technology.
They can be easily customized to meet the unique requirements of your project.

Be my fan on Facebook and follow me on Twitter! Exclusive content for my Facebook fans and Twitter followers

This post has 25 comments

AnotherGuest

on May 19, 2010 at 5:30 pm

Pac-man can probably be done in a few KBs…not sure it can be as small as 2KB but still, an interesting challenge, isn’t it ?

Easier : checkers.
Andreas Renberg

on May 19, 2010 at 7:55 pm

How about Snake? I’m pretty sure it could fit under 2kb.
Shawn

on May 19, 2010 at 10:13 pm

On Sokoban: I notice that when you move right, the “level moves” indicates left and verse visa… Other than that, amazing! Also, it seems a bit awkward that Stages 1, 2 and 7 are harder than stages 8 and 9. (I’ve cleared all but 7 so far, that one makes me scratch my head.)

On other possibilities: Can’t space invaders be crammed into a few K?
grapefrukt

on May 19, 2010 at 11:22 pm

Yes! I love this bytehunting stuff, so I amused myself by seeing if I could slim your code down even more. I managed to shave 131 bytes off, that’s 6.5% smaller.

I put both our versions on wonderfl, mostly to get the nice diff.

your original version: http://wonderfl.net/c/4oMt
my, slightly smaller, version: http://wonderfl.net/c/5PAV

I think there’s a few more bytes to save if one could get rid of all those getChildByName calls, but that’ll require a bit more of a rewrite.

Keep up the nice work!
Emanuele Feronato

on May 20, 2010 at 11:33 am

Yeah, removing the “switch” was a great idea
Colin Diam

on May 20, 2010 at 11:40 am

1st Level…
RRRULRRRDLULLDDRULURDLLLURRDRRRUULDRDUDLLLUR
Josh

on May 20, 2010 at 12:54 pm

I think Frogger would be a good one to try and do in under 2k
Yago

on May 21, 2010 at 1:43 pm

There’s a bug, when I finished the first level debugger says:

TypeError: Error #1009: No se puede acceder a una propiedad o a un método de una referencia a un objeto nulo (it’s in spanish, I think it could be traduced as “Can’t get access to a null object”).
at s/w()
at s/k()

Any way, great game and incredible that 2Kbs optimization!! I still remember that little man with frozen arms moving blocks in the oldest version… Ciao!!
Alon

on May 21, 2010 at 8:42 pm

There is no restart mechanism =D I will add one and post it if someone wants.
Emanuele Feronato

on May 21, 2010 at 11:22 pm

You can restart a level simply pressing the relative 0-9 key…
Bruno

on May 23, 2010 at 3:18 am

You could shrink it a little more by removing the first if in w() method by making

var v:Boolean=(r[p[0]+b][p[1]+a]==0||r[p[0]+b][p[1]+a]==2);

along with grapefrukt’s removal of the switch statement.

Anyway, great code! I follow your blog since a while ago, and your codes are always inspiring.
Yarden Refaeli

on May 24, 2010 at 10:42 am

You shouldn’t use one-letter names… Even when you want a lightweight game…

Nice game!
Nigel

on May 27, 2010 at 1:42 am

I can’t get past the first level :(
Ezell Burke

on May 27, 2010 at 7:34 am

This is really great it inspires me to challenge myself. I am thinking of writing a graphical zork-like game.
Wolfos

on June 1, 2010 at 12:35 am

normally it’s fun,but this game is impossible to beat.
Lev Blake

on June 9, 2010 at 6:27 pm

Hi Emanuele

Great coding tuitions, shall try them.

I finished all the levels on this, with 5 being the trickiest for me.

The coding IS clever, but even more than that the content, ie the puzzles you set, is fiendish!!! How did you work out the layout and problems for each level? Think you need to be a mathematical genius :-)
Cum se inventeaza un joc? (2) « Gramo

on June 14, 2010 at 11:29 am

[...] acum ajung la problema mea. Cum am inventat jocul asta? E clar ca seamana cu Sokoban (vezi si aici), nu? La un nivel mai abstract, seamana cu toate jocurile care nu se desfasoara intr-un spatiu [...]
Pepe

on July 25, 2010 at 1:53 am

Could someone explain the variables? 4 the noobs pls! That would be great.!
Vingador

on August 27, 2010 at 5:08 pm

It doesnt working for me, sorry.
Im using Adobe Flash Professional with AS3. Are this game for AS3 or AS2?

Thanks and i will wait for an answer.
Cyclone

on October 27, 2010 at 11:47 pm

I have a shorter solution: RRURRRDLULLDDRULURDLLLURRDRRRUULDRDLLLUR
Anonymous

on February 20, 2011 at 5:13 pm

LVL0:RRRURRDLULLDLLURRRLDDRURRUULDRDLLLUR
LVL1:RDRUDRRULLLUURDLDDLLUR
Mike

on February 21, 2011 at 12:42 am

I am with Nigel on this one, I can not get past the first level either. To do this in less than a day and have 10 levels is good going.
Simon Gleizes

on May 1, 2011 at 2:17 pm

:

[0]:RRRURRDLULLDLLURRRLDDRURRUULDRDLLLUR

[1]:DRRUDRRULLLUURDLDDLLUR

[2]:RDRRULLDLDDRULURUULDDURRRDLLDDLLURDRUU

[3]:DDRDDLURURULLLRRDDLURUULLDRURDULLLLDRR

[4]:RRRDDLLLRRRUULLLDURRRDDLLURLLLLDDRULURRURRDDRRUULLRRDLDLLLULLDDRULUR

[5]:DDRUDRRULLULUURDDDRDDLULURUULD

[6]:URUULDDRDRRULDLULULLDRRRDDLURULUURDDLDDRRRUULDDLLURLURLULLDRURRDDLURULDDDRR RULLDLUDRRRUULDLU

[7]:RDDLUDLLDDRRUDLLUURRURUULDDDLLDDRRURUUDDLDLLUURRURDLUUURD

[8]:LLDLURRRDLLRRUUULDRDDLLURDRUDLLULLDRRRLLLUUURDLDRRR

[9]:UDLLUDRRULUURDLLDRDLUURRDULLLULLDRRRDRRUULDD

I know, I know…6 is a bit long, haha. Great game and nicely done making it ~2KB!!
Simon Gleizes

on May 2, 2011 at 10:13 pm

Much shorter solutions to 3, 6, 7, 8, and 9:

[3]: DDRRULLLRRDDDLUURUULLDRLULLDRRURRD

[6]:URUULDDRDRRULDLULULLDRRRDDLURULUURDDLDRUULLLDRURRDDLURULDDDRRRUULRDLLDLURU
(!!!)

[7]: RDDLLLDDRRUDLLUURRURUULDDDLLDDRRURUUDDLDLLUURRURDULUURD

[8]: LLDLURRRDLLRRUUULDRDDLLURDRULLLLUURDLDRRRLLLDRRR

[9]: UDLLUDRRULULLRRURDDLULDULULLDRRRDRRUULDD
mahongquan

on March 10, 2012 at 4:29 pm

I made a classic sokoban game ,It is on base of source code from your flash game making book.
and I add solved methods in game,thus it is good news for sokoban newbie.

italian geek and PROgrammer

This post has 25 comments

AnotherGuest

Shawn

Emanuele Feronato

Colin Diam

Josh

Yago

Alon

Emanuele Feronato

Bruno

Nigel

Ezell Burke

Wolfos

Lev Blake

Pepe

Anonymous

Simon Gleizes

Simon Gleizes