Random dweets | Dwitter

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.

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Current theme challenge: #Food

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rodrigo.siqueira

remix of d/14639 by u/rodrigo.siqueira

function u(t) {

if(t<2){A=Z=a=b=-.1+t/15;s=90
for(i=1e4;--i;)x.fillStyle=R(a*50,b*30,S(b)*s),x.fillRect(800+a*s,310+b*s,.7,.6),
a=1-b+Math.abs(a),
b=A,A=a}

Jun 17 2019 1:59 PM UTC

}// 139/140

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The Gingerbread Man #attractor from dynamical systems theory. "The Gingerbreadman Map is chaotic in the filled region and stable in the six hexagonal regions."

u/katkip

#chaos
u/rodrigo.siqueira

"Even the simplest mathe-matical expressions, when interpreted as dynamical systems, yield fractals." (Robert L. Devaney) #gingerbreadman

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GreenBeans

function u(t) {

c.width=1920
for(i=0;i<23;i++){x.beginPath();;x.arc(950+700*C(3*(t+i)),550+460*S(3*(t+i)),500,0,2*Math.PI);x.fillStyle=R(0,i*9,0);x.fill()}

May 16 2020 1:51 PM UTC

}// 139/140

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n o b e a n s

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Xen

remix of d/16261 by u/katkip

function u(t) {

for(c.style.background=R(),i=299;i--;x.fillRect(0,i*5+C(t*i),2e3,1))x.fillStyle=`hsl(${i*t} 40%50%`

Oct 23 2019 3:32 PM UTC

}// 99/140

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Dont do drugs 99

u/katkip

all your dweets are drugs lol
u/KilledByAPixel

Dwitter is a drug
u/joeytwiddle

Kids, if someone offers you a dweet, just say null
u/katkip

wise
u/Xen

#rainbow #trippy

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bokoskokos

function u(t) {

c.width|=0;for(i=0,w=100;i++<18;)for(j=0;j++<10;){x.beginPath(),x.fillStyle=R(200-i*20*C(t));x.arc(i*w,j*w,50,C(t)*j,3.14+C(t)*j);x.fill()}

Jan 11 2018 3:44 PM UTC

}// 139/140

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FireFly

function u(t) {

for(c.width|=M=Math,i=2e4;i--;x.fillRect(A*8,B*8,W=9+M.atan2(M.sqrt(1-X*X-Y*Y),X)*3-t*4&7^4-M.asin(Y)*3,W))X=(A=i%135)/67-1,Y=(B=i/135)/67-1

Mar 4 2017 6:26 PM UTC

}// 140/140

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Raycasted rotating sphere with UV-mapping!

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u/sfz

... ??? !!!
u/iverjo

Impressive! I like the c.width|=M=Math hack. Apparently Math is evaluated to NaN in the process.
u/iverjo

http://stackoverflow.com/a/11037887/2319697
u/alien

god... i can't understand this yet but is awesome...
u/sigveseb

So good!
u/donbright

standing ovation
u/tomkh

great job! some tricks here really opens new possibilities
u/mxfh

you can do M.sqrt() with ES6 power operator as **.5 should yield a net gain of 2 chars
u/FireFly

Oh right! I haven't gotten used to it yet since I'm on Fx51, which doesn't seem to support ** yet. Thanks!
u/FireFly

Oh, and also thanks for all the positive responses, everyone :)
u/iverjo

#sphere
u/lionleaf

#disco
u/f8f82804

#halftone #dithering #shading

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pythech

remix of d/8539 by u/pythech

function u(t) {

x.beginPath()
x.fillStyle=R()
c.width|=0
for(i=500;--i;) {
x.arc(S(k=i*1043+t)*C(i)*400+900,C(k)*400+500,19,0,9)
}
x.fill()

Jun 11 2018 6:30 AM UTC

}// 123/140

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tomxor

remix of d/10534 by u/tomxor

function u(t) {

eval(unescape(escape`𨰮𬱴𮑬𩐽𙱦𪑬𭁥𬠺𪑮𭡥𬡴𚀱𙰻𩡯𬠨𨐽𨠽𤀽𜰮𜐴𛁩🐱𩐴𞱰👩𙠴𛁳🐲𝀰𚱰𚡡𚠳𝐬𪐭𛐻𨐫🐨𚁴𚡩𛱢𙠱𚐭𨐫𨠪𤰨𨐪𤀩𚐯𜠬𨠫🐨𛑡𚡢𚱃𚁡𚡐𚐩𛰲𚑸𛡦𪑬𫁒𩑣𭀨𞀸𜀫𬰪𤰨𦐽𨠪𤀫𬀪𨠪𞐩𚡃𚀡𬀪𨐪𤀩𛀴𞐵𚱳𚡃𚁙𛑰𛰲𚐬𛠰𜰭𤰨𦐫𬀪𛠴𚐪𛠰𜰬𜐩`.replace(/u../g,'')))

Jan 18 2020 7:52 PM UTC

}// 140/140

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#space #planet not #saturn 2

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u/KilledByAPixel

👍
u/KilledByAPixel

can you link us to more info on these equations?
u/tomxor

i'm not sure i can, much of it is just from messing around here on dwitter, and all of the chaotic stuff i've been doing has evolved from some distant bifructation thing here ages ago. Which part are you interested in specifically? I can try to explain as far as I understand it.
u/tomxor

Assuming you are refering to the pattern rather than the mapping, it's essentially just a+=(R-a+b*S(a*P))/2,b+=(-a*b+C(a*P))/2 where i've generated R{0,1} deterministically with a basic LCG type PRNG that feeds off the variables themselves: t*i/b&1, everything else is mapping. For the pattern i've just been messing with the coefficients and number of itterations between fresh generation of R for my various other dweets, but ultimately it all started here d/15329 which I adapted from u/taupelink so maybe he can tell us what it's formal name is because I can't figure it out.
u/KilledByAPixel

thanks, i will look into it!
u/denzen

wow, amazing!
u/magna

wow!
u/denzen

a bit buggy in safari
u/tomxor

I can't see safari, but if it's anything like blink's renderer then the compositor seems to change it's bias torards ceiling into 256 for high alpha, at least when derived from antialiasing subpixel shapes as in this case. Firefox seems to be less biased and faster to boot, so the ring will dissappear around the back as it's supposed to as the pixel area approaches epsilon. These differences are inevitable when exploiting something as sensitive as antialiasing or downsampling.
u/rodrigo.siqueira

I'm trying to understand how the "R" part works in the equation. Do you know? I see it's a number that varies between a few values. Is it a sort of "radius"? Is it randomness important or can it be non-random? Why a constant doesn't work?
u/metamero

one of my favorites ever
u/tomxor

@rodrigo The R part (t*i/b&1) is just a smaller replacement for Math.random(), formally it's an LCG PRNG, informally it's a bunch of stuff I multiplied together modulo 2 that I found to be sufficiently unifom (it would be a terrible PRNG more generally if analysed in detail it's probably full of regularities).
u/tomxor

A replacement for 0|Math.random()*2 (floored) I meant to say.
u/rodrigo.siqueira

I was trying to understand what is the intuitive meaning of this value "0|Math.random()*2" in the equation. I am still not sure (and I am probably wrong) but It seems that adding this "R" value to variable "a" (X position), it will displace the image to the right or left and create a similar image. It seems that it also works as a radius (zoom factor).
u/tomxor

Well my intuition from my limited understand here is that it's kind of like a fork at each point in the path that [a,b] is taking, as long as R is uniform enough the bias in the function sort of emerges and makes [a,b] follow certain paths more than others... I imagine it like a stochastic marble rolling into certain grooves in a landscape, just goto roll enough marbles to start to see the grooves.
u/tomxor

Sounds a bit like 2d gradient descent O_o

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Odog8

function u(t) {

t?x.fillRect(a%32,a/32|c,1,'翿耀瑍魷⑕ꤢ╕鬢⛕ꤢ瑍ꬢ耀翿쀀쀀찀3ﰀ찀3쀀쀀쀀쀀쀀쀀쀀쀀쀀쀀쀀쀀쀀쀀쀀耀쀀'.charCodeAt(a/16)>>(a++%16)&1):(a=0,c.width=100)

Feb 26 2021 5:48 PM UTC

}// 139/140

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THIS WAY

u/magna

Lovely!
u/384.cz

#pixelart

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pavel

remix of d/15194 by u/robbyg

function u(t) {

with(x)for(i=99;i--;clip(fill(arc(960-r,540-r,500*(1-j**3),0,7))))j=1-i/98,r=200*j,beginPath(fillStyle=`hsl(60,90%,${9+j*40}%)`)

Jul 30 2019 3:52 AM UTC

}// 128/140

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Poor man's ray tracing

u/pavel

Using clip so the light can 'spill over.'
u/katkip

#d3 #ball #sphere
u/rep_movsd

#underrated

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f8f82804

remix of d/9777 by u/f8f82804

function u(t) {

with(x){for(shadowColor=R(fillRect(0,0,i=c.width=294,i),i,i);i-=3;lineTo(i,y+32))moveTo(i-6,y=99*S(i^7*t));for(j=9;shadowBlur=j--;)stroke()}

Sep 12 2018 5:42 PM UTC

}// 140/140

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#electric #neon #rain, as requested by u/donbright

u/f8f82804

This is the best solution I found to having them not be too fast; we only change the pattern 7 times a second. Using S() means there are occasional patterns in the drops. Change to y=99*Math.random() to see the difference.
u/f8f82804

also see d/9803
u/donbright

hee hee, thanks