An itsy bitsy Dragon curve renderer in 121 bytes.
<body onload=with(c.getContext('2d'))for(m=8e4;m;rotate(--m&-m&m/2?11:-11))fillRect(0,0,1,1),translate(1,0)><canvas id=c>
The dragon curve is a nice little space filling curve made of π/2 turns.
Drawing a tiny dragon
The easiest iterative way to draw the curve is to determine in which direction to turn at each step of the curve.
The direction of the turn is given by the expression:
(((n & −n) << 1) & n) != 0
m & -m & m / 2
At each step, the curve takes a π/2 turn. Dealing with exact fractions of
11 which is very close to π*3.5, in other words -π/2 module 2π.
The Canvas API works a bit like Logo and provides simple and compact methods to move, rotate, and draw which are perfectly suited to render the dragon curve.
- draw a pixel
- move forward
Which becomes the following Canvas API calls:
fillRect(0,0,1,1); translate(1,0); rotate(angle);
Looping backwards is a bit more compact as you only need to check if the iterator is truthy.
All in all, the code is rather self explanatory but that's part of its charm.
Karma and all
This 121 bytes dragon punch was a nudge to JS1k 2014: Here be dragons for which I am part of the jury and waits for your submissions until the end of March 2014. As usual, this production is available on Pouet.net for comments.
Hope you liked this one.
Other recent projects
There are many experiments and projects like DRAGON PUNCH to discover other here.
- FRONTFEST MOSCOW It was an honour to be invited to Fronfest Moscow 2017 with the little family to give my first workshop; implementing a Twin-stick shooter using ES6 and Canvas, and to continue my CODE🎙ART series of talks + live coding aiming to inspire new web developer artists.
- BREATHING EARTH Another take on Nadieh Bremer mesmerizing Breathing Earth visualisation, running at 60fps on a 2D Canvas without libraries or frameworks.
- THREAD The "10 print" maze generator in 15 bytes of x86 assembler.
- COTTON CANDY First stab at webGL, in 1k between two nappy changes. It's glitchy and tiny but I quite like this puppy. It ranked #3 at DemoJS.
Don't be shy; get in touch by mail, twitter, github, linkedin or pouet if you have any questions, feedback, speaking, workshop or performance opportunity.