Dweets by u/pavel

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: #Opposites

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pavel

function u(t) {

for(c.width|=f=(k,n=9)=>n&&C(n**.9*k)/n+f(k,n-1),x.translate(h=960,i=0);i++<h;x.fillRect(r=h/z,r,-2*r,9/z/z))z=i/42,x.rotate(f(z+3*t)/180)

Apr 24 2020 2:49 AM UTC

}// 138/140

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https://twitter.com/ntsutae/status/121468374…

u/Xen

sexy lines
u/pavel

It seems like Safari plays dweets significantly slower until you tap on them... Giving the iframe focus increases the request animation frame rate.
u/katkip

very sexy

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pavel

function u(t) {

for(let i=2e3,f=(x,n,c=8-(t+6)*n)=>~n&(x*x*n*n+(8+(t-12)*n)**2+c*c-5)**2/16+c*c>1?f(x,n+=.002):c;i--;)x.fillRect(i,t*180,f(i/135-7,.7),3)

Apr 23 2020 7:27 AM UTC

}// 137/140

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Actually #raytracing a #torus using ray marching

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u/Xen

Sweeet!
u/tomxor

Yes! we need more explicit surfaces on dwitter :)
u/Odog8

which expression is the DFT?
u/tomxor

I'm confused... this isn't explicit? it recurses.
u/pavel

This recurses just to advance ray length.
u/pavel

The closed form expression is x*x*n*n+(8+(t-12)*n)**2+c*c-5)**2/16+c*c-1 where c=8-(t+6)*n and n is the free variable.
u/tomxor

Ah, so is this technically ray casting? I have to ask because I still don't intuitively get all of the math.
u/tomxor

Sorry I meant ray marching
u/pavel

Yes. The math constructs a ray from (0,8,8) looking at (0,0,0), varied a bit depending on the pixel being drawn, its length is a function of n. I plug this into the equation for a torus and increment n from .7 to -1 until I find a zero of the equation.
u/pavel

Here is a version without much golfing that makes things clearer for(let i=2e3,f=(o,n,x=o*n,y=t/3*n-n,z=4-n)=>z>-1&(x*x+y*y+z*z+3)**2>16*(x*x+y*y)?f(o,n+.01):z;i--;)x.fillRect(i,t*180,f(i/540-16/9,3),3)
u/pavel

(x*x+y*y+z*z+3)**2>16*(x*x+y*y) is directly from https://en.wikipedia.org/wiki/Torus
u/pavel

with R=2 and r=1
u/pavel

This example shoots rays from (0,0,4). In order to rotate the shape you have to move where the rays come from, the camera!
u/tomxor

Thanks for the explanation 👍

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pavel

function u(t) {

for(let j=3,X,r,f=x=>S(16*x)**420;j--;)for(let Y=t/3+j/540-1,i=2e3;i--;x.fillRect(i,t*180+j,2*r,f(X/r)+f(Y/r)))X=i/540-16/9,r=X*X+Y*Y

Apr 23 2020 5:31 AM UTC

}// 133/140

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Conformal mapping of a grid (1/z), all intersections are at right angles

u/pavel

Set r=1 to see the grid.

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pavel

function u(t) {

for(f=c=>Math.tanh((r>1?3:13)*S(9*c/d)),Y=t/3-1,i=2e3;i--;x.fillRect(i,t*180,(1+f(X)*f(Y))*(d/2+Y/3.6),3))X=i/540-16/9,r=X*X+Y*Y,d=r>1||C(r)

Apr 22 2020 6:18 AM UTC

}// 140/140

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Experimenting with #raytracing. I finally figured out why the cosine trick from d/1112 works.

u/Cloud

WOW!

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pavel

remix of d/18322 by u/pavel

function u(t) {

for(let i=1920,f=(x,y,n=256)=>x*y<n?f(x*x-y*y-.8,2*x*y+.156,n-1):1-n/256;i--;x.fillRect(i,t*180,1,3))x.globalAlpha=f(i/540-16/9,1-t/3)

Apr 18 2020 8:32 AM UTC

}// 134/140

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#julia set for c = −0.8 + 0.156i

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u/pavel

Using x*y<n instead of the normal n&&x*x+y*y<2 is much shorter and creates the black whisps that look pretty cool.
u/pavel

This version makes it easy to play with different values of c. You can find some in https://en.wikipedia.org/wiki/Julia_set#Quad…
u/pavel

https://en.wikipedia.org/wiki/Julia_set#Quad…
u/pavel

Is link pasting broken?
u/Xen

Sexy!
u/katkip

wow
u/katkip

https://en.wikipedia.org/wiki/Julia_set
u/rodrigo.siqueira

Awesome and fast. I am remixing it to add color schemes and colorization methods.
u/Qwitter

SO FAST!

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pavel

function u(t) {

for(let i=1920,f=(x,n=420,a=0,b=0)=>a*a+b*b<n?f(x,n-1,a*a-b*b+x,2*a*b+.1133-t/4615):n/420;i--;)x.fillRect(i,180*t,f(i/8e5-.7467),3)

Apr 18 2020 5:59 AM UTC

}// 131/140

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(X=-0.7453, Y=0.1127, R=6.5e-4) section of the #mandelbrot set

u/pavel

This version draws 1x3 pixels to speed up rendering. for(let i=2e3,f=(x,n=420,a=0,b=0)=>a*a+b*b<n?f(x,n-1,a*a-b*b+x,2*a*b+.1133-t/13845):n/420;i--;)x.fillRect(i,60*t,s=f(i/8e5-.7467),s) looks better in fullscreen but is 3x as slow.
u/pavel

let and the automatic scoping of args in f makes this _really_ quick. I can increase the loop to 4e3 iterations and still have 60fps on my machine. Would be interesting to speed this up by rendering multiple rows per frame.
u/katkip

all dweets made by u/pavel are genius
u/Xen

godlike!
u/Qwitter

agreed !!!!

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pavel

function u(t) {

with(x)for(c.width|=f=i=>C(i/.647)+S(i),i=128;i--;fill(arc(960+f(t*2)*s*3,540+f(t+=.03)*s,s,0,7)))beginPath(fillStyle=R(s=1e4/(79+i),i%3*s))

Apr 18 2020 1:20 AM UTC

}// 140/140

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#snake ?

u/joeytwiddle

Certainly too long for a caterpillar. https://codegolf.dweet.net/a/271
u/pavel

Hah, nice

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pavel

remix of d/12336 by u/pavel

function u(t) {

for(i=t?w=600:a=b=0;i--;x.fillRect(w*b,w-w*a,1,1))[a,b]=[[3.4*a+b/6,a-b,b-a,0][q=Math.random()**t*4|0]/4,[3.4*b-a/6+2,a+b+1,a+b+.5,b][q]/4]

Apr 17 2020 11:24 PM UTC

}// 139/140

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Barnsley #fern #fractal #leaf #uncompressed

u/pavel

This version is also #improved with a #grow effect and a cap on how dark the image gets if you leave it for a while.
u/Xen

nice!

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pavel

function u(t) {

for(c.width=i=640,n=32,q=2*t%1*n|0;i--;x[X>7&X<12&[810,865,1858,9808][q>>3]>>i/8+X+6?'fillRect':'strokeRect'](X*n-q,(i&-n)-q,n,n))X=i%n

Apr 16 2020 7:25 PM UTC

}// 135/140

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Keep Gliding Mr Conway

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u/pavel

#gameoflife #glider
u/pavel

https://www.reddit.com/r/perfectloops/commen…
u/Xen

love it!
u/joeytwiddle

#tribute
u/rodrigo.siqueira

Wow! I've been using this Glider image (also known as HACKER EMBLEM) for years as my computer wallpaper, here is full hd version of my wallpaper: https://in.bot/agi/Hackers-emblem-Carbon-Gli…
u/Qwitter

Life was definitely a gateway drug for me as well.

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pavel

function u(t) {

for(X=7;X--;)for(Y=4;Y--;)for(i=4;i--;x[i+q&1?'clearRect':'fillRect'](135*(1+2*X-r),135*(1+2*Y-r),r*=270,r))q=2*t+X+Y,r=(i+q%1)/4

Apr 16 2020 4:31 AM UTC

}// 129/140

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https://www.reddit.com/r/loadingicon/comment…

u/Xen

that q=t*t+X+Y tho ;-)
u/rep_movsd

#underrated

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