XaoS.js - a real-time fractal zoomer | Hacker News Reader

XaoS.js - a real-time fractal zoomer

jblangston.com

40 pointsm_for_monkey16 comments

I've seen tons of different Mandelbrot implementations in Javascript and Processing.js (it's a pretty popular example of the ImageData object) and I can say that this particular one is indeed fast considering that is using 128 iterations on a relatively big canvas.

Would using WebGL could give smoother animation or use less CPU?

Probably not. The XaoS algorithm depends on nearest-neighbour scaling and recalculating just the interpolated rows/columns. You could do that in a texture then scale the texture to the screen with WebGL, but it probably wouldn't be any more efficient than just doing it in a non-accellerated frame-buffer.

If there was a way to offload the Mandelbrot calculations to the GPU, that might make things faster, depending on how tedious it would be to composite them back onto the framebuffer afterward.

Here's a Mandelbrot zoomer implemented entirely with WebGL:

http://learningwebgl.com/lessons/example01/

It doesn't use the XaoS algorithm, it recalculates the entire frame from scratch on the GPU. On my machine at least, it's noticeably choppier than the XaoS version, and at a smaller frame-size, too.

Listen to this while zooming: http://www.youtube.com/watch?v=MWqdO74iApc

awesome. Does get blurry after a while though :(

Yeah, I managed to hit the limit where it stopped being fractal. Damn these limited-precision floating point numbers!

No, it's because the maximum number of iterations is too low for that zoom level.

That won't cause it to be "blurry" -- that just causes it to be black. "Blurriness" is indeed due to floating-point errors in the coordinates system.

For me, in the browser, the edges just smooth out to a straight line, and seem blurry only because of the color scheme. In the desktop version, however, I see this when zoomed in maximally: http://i.imgur.com/ryhai.png.

Ah, fair enough. It's probably the iterations then.

This is what I maxed out at. It did start to look blurry right before it started lagging, and these staggered lines were revealed, but they look much different from yours. http://i.imgur.com/R5PbQ.jpg

After a while? Seems like it does it fairly quickly in both directions. Neat concept, though.

...i'm not sure these guys understand the difference between "fractal" and "not a fractal"

Er... did you mean to leave this comment on some other article? I've seen the term "fractal" misused recently, but this is very much a fractal.

OK I concede it meets a definition of fractal. I'm recalling having seen Mandelbrot speak at my high school and identify a property of his eponymous set in particular: that no matter how closely you zoom, no part of it ever appears to be a straight line, unlike, for instance, a circle.

I just feel cheated.

But sure, it's a fractal capped at a disappointingly low number of iterations.

Kinda like how an equilateral triangle is a sierpinski's gasket at zero iterations.

Try the desktop version, this is a very limited alpha. But no, not even the desktop version offers unlimited precision.

http://wmi.math.u-szeged.hu/xaos/doku.php

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