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.
Click here to open the tool!
Jonas Wagner
