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 experiments
There are many experiments and projects like JSPONGY to discover other here.
- WE DON'T MAKE MISTAKES AT DEVONE 2019 Giving the closing keynote DEV ONE 2019, held on April 11 in Linz, Austria was absolutely fantastic. The conference was very well organized with one track, 11 talks about "scale" and 600 wonderful delegates. I learnt so much that day, got confirmation for some good practices but also learnt about many opportunities to improve our work. Also it was a pleasure to meet new people and see familiar faces among the organizers and attendees from Script'17.
- 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.
- SHEET An Excel-like spreadsheet with arbitrary expressions and persistence using localStorage golfed under 256 bytes with aem1k, subzey, xem, rlauck, odensc, mmastrac, and corruptio
- 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.
- OOMA The winning bootsector of Outline 2005, featuring two images zooming with experimental music in a valid 480bytes Atari bootsector.
- COPTER CRUISE A simple Commanche-like that won the 20lines 'Terrain' contest at the OzoneAsylum in July 2004
- 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.