The goal was to optimize for size and release the result as an intro in the demoscene spirit. That explains why although it is possible to cram a Menger Sponge raymarching in 284 bytes of HTML5 with a very scarce design, the release version fits in the 512b category and retain some of the style and complexity of the original.
Menger sponge ?
The Menger sponge is a three-dimensional extension of the Cantor set and Sierpinski carpet first described by Austrian mathematician Karl Menger in 1926.
It starts as a single cube in which the central pillar is carved out in all three axis to make 20 smaller cubes on which the process is repeated.
<body bgcolor=0 text=snow onload=N=[K=R.getContext('2d')];for(t=B=127,I=K.getImageData(0,0,q=64,q);t--;$=Math.cos)N[t]=t/43&1;setInterval("t++;for(i=y=-1;y<1;y+=A)for(x=-1;x<1;x+=A=1/32,I.data[i+=4]=h+h)for(m=C=$(a=t/86),S=$(a+8),c=$(b=t/B),s=$(b+8),u=x*C+S,v=y*c-u*s,u=u*c+y*s,w=C-x*S,X=q+9*$(a+b),Y=q+9*$(b-a),Z=t,h=B;--h&&m<q;X+=u,Y+=v,Z+=w)for(m=1;N[X*m&B]+N[Y*m&B]+N[Z*m&B]<2&&m<q;m*=3);K.putImageData(I,0,0)",9)>JSpongy by p01<br><canvas id=R width=64 height=64 style=width:3in;height:3in;background:#fff>
<canvas id=R><svg onload=setInterval("for(i=q*q,C=M(t+=R.width=q),S=M(t+8);i--;R.getContext`2d`.fillRect(i/q,i%q,1,h/q))for(x=i%q/66-1,y=i/8712-1,m=w=x*C+S,X=Y=h=q,Z=t/q;m<--h;X+=y*C+w*S,Y+=y*S-w*C,Z+=C-x*S)for(m=1;(X*m%96&32)+(Y*m%96&32)+(Z*m%96&32)<64;)m*=3",M=Math.cos,t=q=132)>
The camera travels in the fractal along a cycloid without ever touching it. The camera target rotates along the Y and Z axis.
The rendering itself is done using Canvas and ImageData by simply changing the Alpha channel of each pixel in order to gain a few bytes necessary to stay under 512b.
The Menger Sponge is raymarched at fixed steps for a maximum of 128 steps. Also the inside of the fractal is computed using the formula:
m represents the generation of the fractal.
The intrisinc resolution of the Canvas is 64 x 64.
Of course Jspongy and Spongy are available on Pouet.net
Other recent projects
There are many experiments and projects like JSPONGY to discover other here.
- MUSIC FOR TINY AIRPORTS AT WEB AUDIO CONFERENCE The Web Audio Conference 2018, held in September 19-21 in Berlin was a great mix of researchers, web developers, artists and performers presenting their projects. I had the chance to provide a deep dive into music for tiny airports, explaining how to generate hours and hours of music in a handful of bytes.
- MUSIC FOR TINY AIRPORTS 2/1 🛫 Celebrating the 40 years anniversary of Brian Eno's "Ambient 1: Music for Airports" with an homage written in 256 bytes with the Web Audio API.
- THEY COME AT DUSK 👺 A survival horror game for JS1k 2018, where you run away from dead miners as you hear your heart beat. Turn around using the arrow keys until all you hear is beeeeeeeep.
- WOLF1K The idea of this entry for the JS1K contest was to do the impossible: a 1K remake of the famous WOLF5K that rocked the final edition of the5K. It does not feature guns, evil grins and violence for in WOLF1K there is no room for guns or any form of violence.
- TILT SHIFT A very fast & simple tilt-shift effect in Canvas.
- TERRA A voxel landscape rendered using a plasma in a valid 480bytes Atari bootsector. TERRA ranked #2 at Outline 2006
- 256B.HTM ROUND 2 The second edition of the 256B.HTM contest allowed 3 entries per author. Mine ranked 1st, 2nd and 4th out of 43. Only a few points shy of a total take over!
- PULPINA Winning 64kb DOS intro at the Volcanic party 1997, made in one week, in Pacal.
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.