Demonstrating evolution in 999b

written by Jonas Wagner, on 8/8/10 3:05 PM.

When I saw the JS1K demo contest I knew I had to enter. I first tried to do some GFX demo, but I was lacking an impressive idea. So when I tried to sleep last night at 2 in the morning I had an idea which I needed to implement: Demonstrating evolution by natural selection in 999b/666b gzipped:

x = ('var_a=Math,b=a.random,c=document.g'+
'etElementById("c"),e=c.getContext("2d")'+
',f=[],g=b()*		 16777216<<0,h,i'+
',j,k,l=(g		  &16711680)>>16'+
',m=(g&65		    280)>>8,n=g&'+
'255,o,p		    ;c.width=320'+
';c.height=320;		    e.shadowBlur'+
'=10;for /* */	      (p=   0;p<64;p++)f'+
'.push(b(		    )*16777216<<'+
'0);func		    tion_q(d){fo'+
'r(d=d.t oStr		  ing(16);d.leng'+
'th<6;)			d = " 0"+d;retur'+
'n"#"+		      d } d ocument.body'+
'.sty		     l e .b a c kground='+
'q(g);		    setInterval(function'+
'(){e.		 c l e a r R e c t ( 0 ,'+
'0,320,		3 2 0 ) ; f o r ( p = 0 '+
';p<64;	    p + + ) { h = f [ p ] ; i = '+
'l-((h&	  1 6 7 1 1 6 8 0 ) > > 1 6 ) ;j'+
"=m-((h&65 2 8 0 ) > > 8 ) ; k = n - ( h"+
'&255);o=a.sqrt(i*i+j*j+k*k)/443;if(b()<'+
"o)h=f[p]=(f[b()*64<<0]&16773120|f[b()*6"+
'4<<0]&4095)^1<<(b()*24<<0);e.fillStyle='+
"q(h);e.fillRect(1+p%8<<5,1+p/8<<5,32,32"+
')}},100);e.shadowColor="#000";').replace(
/\s/g,"").replace(/_/g,' ');eval(x);
/*evolution in 999b by 29a.ch**/

+1 if you recognize that guy.

Demo

It's basically a few cells colored cells. The selection criteria is the color difference between the cell and the background. So cells that stand out have a higher chance of getting eaten.

Click me

How it works

You can see the full unminimized sourcecode here evolution.js I'll only explain the meaty stuff.

env = random()*(1<<24)<<0,
...
population.push(random()*(1<<24)<<0)

A random environment and population is initialized. The shift by 0 is a short way to round a number. Both the environment and the genes of the population are random 24 bit integers, that can be viewed as rgb colors.

subject=population[i];
r = r_-((subject&0xff0000)>>16);
g = g_-((subject&0xff00)>>8);
b = b_-(subject&0xff);
distance=M.sqrt(r*r+g*g+b*b)/443;
if(random()<distance){

The fitness for survival is determined by measuring the distance between the color of the individual and the environment. The lower the distance, the higher the chance for survival.

subject = population[i] = (
                // breed
                ((population[random()*popsize<<0]&0xfff000)|
                (population[random()*popsize<<0]&0xfff))
                // Mutate
                ^(1<<(random()*24<<0))
            );

When an individual dies, a new one is bred by sexual reproduction (parthenogenesis and necrophilia are possible as well). The new individual then gets one random mutation. That's pretty much all there is to it.

Comments

Cool demo!
btw - I like the way you formatted the code ;)

Comment by mud — 8/9/10 4:35 AM | # - re
Creative. Environments change though. Could you change the background color after every maybe 1k iterations?

Comment by Ed — 8/11/10 3:48 PM | # - re
wow, i'd really like you to explain this to me in full. lol. I'm in the process of creating an object oriented javascript evolution simulation myself, but still learning the ropes of oojs

Comment by bsmbahamas — 8/23/10 9:32 PM | # - re

29a.ch

Demonstrating evolution in 999b

Demo

How it works

Comments

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