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From: "Chris M. Thomasson" <no@spam.invalid>
Newsgroups: comp.lang.javascript
Subject: Re: An online circle intersection fractal...
Date: Mon, 4 Nov 2013 14:01:19 -0800
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> "Michael Haufe (TNO)"  wrote in message news:935bd61f-b8bd-456a-8813->
> 3b00b2ebddb4@googlegroups.com...

> On Saturday, November 2, 2013 3:43:00 PM UTC-5, Chris M. Thomasson wrote:
> > The fractal is simple. Find circle intersections, draw circles at those
> > points,
> > then find all of the newly generated intersections, and repeat... You 
> > can
> > create some pretty nice fractals that way. Also, it seems as if circle
> > inter-
> > sections can be used for other applications as well...

> First off, I'm glad to see some more fractal applications
> being displayed.

Thank you.


> Being able to pass in the settings
> through url arguments would be a nice addition I think.

100% agreed!  :^)



> > I was wondering if my code is total crap or not. Please, any advise 
> > would be
> > extremely beneficial. I just hope it does not involve a complete 
> > rewrite.
> > Luckily, this software is in pre-alpha stages:

> The fact that you can produce significant results in a
> timely manner demonstrates that it wouldn't fall under
> "total crap" imo. One must be wary of letting the best
> be the enemy of the good.

> While I've yet to take much time looking at it yet, my
> first thought is to whether using polar coordinates instead
> of Cartesian would make things clearer or not. So thinking
> out loud here: A circle in cartesian "x^2 + y^2 = 1" becomes
> "r = 1" in polar. So while the representations are far
> simpler, the intersection can be a bit more difficult as
> there are infinite equivalent answers.

IMVHO, the algorihtm as-is is fairly nice because it solves for the 
intersection(s) of two circles using only a single sqrt operation. So far, 
this is pretty good when compared to most of the other soultions I have seen 
that rely on more than one sqrt and/or trig functions.

Do you happen have something in mind that can find the true intersection(s) 
of two circles that gets around any sqrt wrt polar coordinates? I am all 
ears if you have something to share!   ;^)



> A requestAnimationFrame wrapper I prefer to use currently:

> window.requestAnimFrame = (function(){
>     return  window.requestAnimationFrame   ||
>         window.webkitRequestAnimationFrame ||
>         window.mozRequestAnimationFrame    ||
>         window.oRequestAnimationFrame      ||
>         window.msRequestAnimationFrame     ||
>         function(run){
>             window.setTimeout(run, 16);
>         };
> })();

> Also, I'm quite certain it will be a bit faster to render
> against the canvas image data instead of using the API.
> You'll have to roll your own circle drawing routine, but
> since this is a labor of love, I suspect you might not
> mind for the performance boost.

> clearRect(...) on the entire display can be slow. Do this instead:

> myCanvas.width = myCanvas.width

> More thoughts to come as time permits


Thank you for all of the suggestions Michael. I really do appreaciate the 
fact that you give a damn about fractals!

;^)