Dweets awesomed by u/rodrigo.siqueira

function u(t) {

c.width=1920 // clear the canvas
for(i=0;i<9;i++)
x.fillRect(400+i*100+S(t)*300,400,50,200) // draw 50x200 rects

} // 122/140

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    u(t) is called 60 times per second.
    t: Elapsed time in seconds.
    S: Shorthand for Math.sin.
    C: Shorthand for Math.cos.
    T: Shorthand for Math.tan.
    R: Function that generates rgba-strings, usage ex.: R(255, 255, 255, 0.5)
    c: A 1920x1080 canvas.
    x: A 2D context for that canvas.

Try the new frontend: beta.dwitter.net
Current theme challenge: #Food

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aemkei

remix of d/1231 by u/iverjo

function u(t) {

c.width^=0;for(i=9;i<2e3;i+=2)s=(9/(9-(t/2+i/99)%9))**1.6,x.beginPath(),j=i*7+S(i),x.lineWidth=s/5,x.arc(960,540,s,j,j+.02),x.stroke()

Mar 21 2017 10:57 AM UTC

}// 134/140

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Star Field

u/iverjo

#starfield #stars

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mxfh

function u(t) {

for(x.drawImage(c,b=n=0,-16),i=w=960;a=C(i/w*4),b=!b,i-->-w;n+=C(t*i*i),x.fillStyle=R(e=b*w,e,e))x.fillRect(i+b+w,a>0?w+a*a*n*2+b*4:w,2,w)

Mar 13 2017 10:35 PM UTC

}// 138/140

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dwitter Album Cover Art https://blogs.scientificamerican.com/sa-visu… (deleted the prior version)

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u/donbright

wonderful
u/SpecialAgent

Nice homage to a great band :)
u/p01

Super smart implementation! Wish I saw it before I did https://www.dwitter.net/d/2958
u/zanella

I saw i--> and thought it was a new JS operator. :)
u/lionleaf

#album #album_cover
u/mxfh

#unknownpleasures #joydivision
u/rodrigo.siqueira

Here is the original Ph.D. dissertation page where this were published: https://twitter.com/ChristiansenJen/status/1…

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walsh9

function u(t) {

c.width|=Y=(d,e,a,l)=>l?(x.moveTo(d,e),x.lineTo(d+=l*9*C(a),e+=l*9*S(a)),Y(d,e,a-S(t),--l),Y(d,e,a+S(t),l)):0;Y(960,999,4.71,14),x.stroke()

Mar 4 2017 5:56 PM UTC

}// 140/140

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fullscreen recommended

u/donbright

unbelievable!!!! wow
u/SpecialAgent

wonderful!
u/CocoMeister

#fractal

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sebbert

function u(t) {

c.width=999;for(a=b=z=0,w=140;z<400;z+=.1)a=S(a*2.4-t)*S(t*2)+C(a+b+t)+C(z*2.34+t),b=C(z*1.56),x.fillRect(a*w+500,b*w+w+w,2,2)

Mar 4 2017 12:59 AM UTC

}// 126/140

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u/donbright

woah!
u/SpecialAgent

Energize!
u/FireFly

This one is really cool o.o
u/FireFly

I would love an explanation or pointer about the maths going on here… in particular I don't understand why the 1.56 constant for the b= is so sensitive. It looks like an approximation of π/2, but all of π/2, 1.57 and 1.5 behave vastly differently/more chaotically. So what's the relationship between these numbers/how is 1.56 derived?
u/tapgiles

What the... @.@ Looks so detailed!
u/joeytwiddle

Some other constants with similar behaviour: 1.17, 2.34, 3.12, 3.51, 3.90, 4.68, 6.24
u/joeytwiddle

And a few with different behaviour: 3.08, 6.05 (!), 6.35

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hamptonio

remix of d/1830 by u/hamptonio

function u(t) {

w=c.width=1920;for(i=w;i--;){q=0;a=1;b=1;e=1+9*t%9;for(j=99;j--;){q+=a*C(b*(i-w/2)/100);a/=2;b*=e};x.lineTo(i,200*(2.5-q));x.stroke()}

Mar 3 2017 3:48 PM UTC

}// 135/140

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Animation of Weierstrass's 1872 example of a continuous function that becomes nowhere-differentiable when b>=7.

u/donbright

very interesting!!!! always felt like demoscene is a gateway to math

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hamptonio

function u(t) {

t?i++:i=0;q=0;a=1;b=1;for(j=99;j--;){q+=a*C(b*i/100);a*=.6;b*=8};x.lineTo(i,250*(2+q));x.stroke()

Mar 3 2017 3:31 PM UTC

}// 97/140

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From 1872, Weierstrass's first example of a continuous but nowhere-differentiable function.

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FireFly

remix of d/1689 by u/FireFly

function u(t) {

for(s='0',i=6;i--;c=s[t*60|0])s=s.replace(/\d/g,i=>['+1-0-1+','-0+1+0-'][i]);c<2?x.translate(18,0,x.fillRect(0,0,18,3)):x.rotate(c+60/57.3)

Mar 1 2017 5:45 PM UTC

}// 139/140

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L-system visualizer. Sierpiński arrowhead curve

u/donbright

brilliant.... any description of how it works?
u/donbright

n/m i see you explain it in 1688, thanks!
u/tomkh

haha... using translate/rotate is a cool hack! reminds me of LOGO turtle
u/FireFly

Hehe, it's handy to offload the job of keeping track of the turtle to the canvas.
u/katkip

#fractal

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magna

function u(t) {

c.width=w=3;t?x.putImageData(new ImageData(new Uint8ClampedArray(a),w,1),0,0):a=c.toDataURL().split('').map(k=>k.charCodeAt(0)).slice(0,w*4)

Mar 1 2017 3:35 AM UTC

}// 140/140

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Gradient from nothing

u/sigveseb

Can't explain that!
u/magna

PNG header FTW
u/iverjo

Wait what? This needs an explanation :D
u/magna

@iverjo I export the empty canvas as a PNG image. The PNG file has non-zero bytes (because it needs to have a header and a bare minimum content to encode the empty content) that I directly use as RGBA values for the canvas image data (the pixel array).
u/magna

#glitch

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FireFly

function u(t) {

f = t*60|0
X =  f%120, Y = f/120|0
x.fillStyle = "]!{$${!]".charCodeAt(X%16) + 59 >> Y%12& 1? '#345' : '#DEF'
x.fillRect(X*16, Y*16, 16, 16)

Feb 27 2017 6:20 PM UTC

}// 140/140

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u/sigveseb

cool!
u/sfz

wtf is going on here?!
u/FireFly

The string embeds a tiny bitmap which is simply repeated :)
u/5Mixer

This is an awesome idea! I wonder what else you could do with using strings to encode more complex(?) data. Interesting.
u/PiggyClone205

When I read complex, I immediately thought of maybe importing other javascript and cheating a bit.
u/katkip

#invaders

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SpecialAgent

function u(t) {

a=1103515245,c=12345,m=0x7fffffff,z=t;for(i=111;i--;)z=((a*z+c)%m),g=z&0x3fffffff,z=((a*z+c)%m),h=z&0x3fffffff,x.fillRect(g%1e4,h%1e3,9,9)

Feb 24 2017 8:19 PM UTC

}// 138/140

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A pseudo-random number generator. The parameters you see is used in glibc, it gives a good visual on distribution. If you changed m=0x80000000 (m as used in IBM's C/C++) you will quickly see a bias in the randomness. Oh the irony! Here are some other popular parameters you can try: Borland C/C++: a=22695477,c=1,m=0x100000000 Turbo Pascal: a=134775813,c=1,m=0x100000000 Visual Basic 6: a=1140671485,c=12820163,m=0x1000000 Java: a=25214903917,c=11,m=0x1000000000000 Many more: https://en.wikipedia.org/wiki/Linear_congrue… 🕶

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u/iverjo

This is the probably the best PRNG dweet thus far
u/sigveseb

cool stuff
u/issafly

fullscreen it and stare into it like one of those stereograms for the extra special good.
u/SpecialAgent

thanks folks! also the speed is crippled for dramatic effect, change the loop to "for(i=1e3;i--;)" for turbo mode.
u/iverjo

Speaking of stereograms, it would be cool if anyone could create a stereogram dweet
u/SpecialAgent

Sorry for the malformed link to wikipedia, here is the corrected URL: https://en.wikipedia.org/wiki/Linear_congrue…

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