Top 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.

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pavel

function u(t) {

for(x.fillRect(0,0,i=2e3,i),v=540;Y=S(b=--i**3);x.clearRect(960+v*X/d,v-v*Y/d,Z*=6,Z))Y/=Z=1.2+C(++t)*C(b),X=S(t)*C(b)/Z,d=X*X+Y*Y+.1

Dec 19 2019 3:48 AM UTC

}// 133/140

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Black hole

u/Leodude123

wwwwwwwwwwwwooooooowwwww!!!!!!!!

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pavel

function u(t) {

for(w=c.width=1e3,i=99;r=10*i--;i?x.stroke():x.fill())x.beginPath(p=(1+t/2-r/w)%2),x.ellipse(480,270+20*S(p*40)/9**p+!i*w*(p-2),r,r/3,0,0,7)

Mar 6 2019 7:01 AM UTC

}// 140/140

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#water #drop

u/katkip

Looks good
u/aleamb

great!
u/mcdxn

damn!

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pavel

remix of d/13495 by u/pavel

function u(t) {

for(i=t?c.width|=C=_=>u[j=q+n&-n|p/n]=-!u[j]|1:p=q=r=s=571;i--;u[i]||x.fillRect(i?i%n*n:p+=r*=C(p+=r),i?i&-n:q+=s*=C(q+=s),z=i?n:15,-z))n=64

Apr 11 2020 10:31 PM UTC

}// 140/140

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#breakout

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u/pavel

Fixed the tilted look, the missing upper left block, and increased the size of the ball.
u/pavel

Why does changing 571 break the code for most values? :)
u/pavel

472, 582, 593 work well though
u/iznax

The code seems to work with most starting values if you change it to "C=_=>(p|q)<0?-1:u[j=q+n&-n|p/n]=-!u[j]|1" and handle negative coordinates as blockers?
u/KilledByAPixel

👍
u/pavel

Its shorter to init positions and velocities to same number but makes velocities too fast. Another problem is that init needs to happen once and shortest way to do that is t?<spot>:init which creates a spot to do something every non-first frame. I solve both problems by naming my collision detection function C and defining it on every non-first frame. On the first frame C is Math.cos so the velocity update code does r = r*C(p+=r) = 571*Math.cos(571+571) = 17.7 which is a reasonable speed.
u/pavel

The ball needs to be updated once per frame. Since I am iterating with a single index its easiest to check for index 0. This corresponds to the upper left block which is why it was missing in the original. A short fix is to shift everything up one block by using negative height for the blocks and adding a row to ball position encoding. The +n in q+n&-n|p/n.
u/pavel

I encode and decode 2d co-ordinates into one number. The block coordinates are (i%n,i/n|0) and their width is n making their real positions (i%n*n,(i/n|0)*n). Lets simplify the second one. If we choose n=2**k then (i/n|0)*n = (i/2**k|0)*2**k = (i>>k)<<k so we are zeroing out the last k binary digits. But if n=2**k then -n is a bunch of ones followed by k zeroes (https://en.wikipedia.org/wiki/Two%27s_comple…)! Therefore (i/n|0)*n = i&-n.
u/pavel

Need to check if ball pos (p,q) touches a new block. Ball is always in some block, find that blocks pos index. Dividing ball position by n gives the virtual coords and blocks are 1x1 so truncating gives 2d block coordinates (p/n|0,q/n|0). Want to encode this into index j where (x,y)=(j%n,j/n|0). Therefore j=(q/n|0)*n+(p/n|0). If n=2**k then in binary j=[32-k binary digits y-coord][k binary digits of x-coord] so we can use bitwise-or which also auto-truncates so j=(q/n|0)*n|p/n. And as we saw (q/n|0)*n=q&-n so j=q&-n|p/n! Real code uses j=q+n&-n|p/n to add one row to ball pos to account for shift up to hide missing (0,0)` block.
u/pavel

p+=r*=C(p+=r) encodes an unbelievable trick that is perfect for collision detection. For detection we need to independently try advancing vertically and horizontally, check for collision, and reverse course if hit. The temporary state involved in trying can cost a lot of chars. p+=r*=C(p+=r) does it all and C doesn't even read its argument! When C is invoked the global p it sees was already incremented by r. However, the outer p+= will eventually discard that increment. Magic!
u/rep_movsd

Un-effing-believable
u/hvianna

Wow, this is insane!
u/jylikangas

Masterclass in code golfing!
u/13thptr

awesome, looks like the ball escapes without breaking everything after a while though. will read the explanation more thoroughly.
u/pavel

No chars left for bounds checks! It freaks out with negative positions. If I find a way to shorten I will add bounds.
u/ersagun

I need to read and reread that explanation on a loop until I get this. This is incredible.
u/Qwitter

Just wow.

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pavel

function u(t) {

for(c.width|=i=8;--i;)for(w=j=3<<i-1;j--;x.fillRect(-!x.rotate(6.283/w*(j+i/(1+5**(4+i-t%3*5)))),-25*i,2,25))x.setTransform(3,0,0,3,960,540)

Nov 11 2020 8:56 PM UTC

}// 140/140

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#beesandbombs

u/pavel

https://twitter.com/beesandbombs/status/1326…
u/pavel

#symmetry
u/donbright

nnnnnnice

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pavel

remix of d/1112 by u/sigveseb

function u(t) {

for(let w=c.width=127,i=9086,a,b,n,B;a=i&w,b=i--/w;x.fillRect(a,b,1,1/(t+a/n&1^b/n)))n=b-20,B=(w*S(t*9+n/9)+(a-40)**2+n*n)/1e3,n*=B>1||C(B)

Mar 7 2019 8:31 PM UTC

}// 139/140

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#improved performance

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u/pavel

Original runs at 6fps on my machines this runs at 60fps. I lowered the resolution by a quarter (4x perf) and golfed 13 chars to let me declare all vars locally (2x perf).
u/tomxor

wow! this is a massive perf improvement, the original was impressive but I couldn't really see it realtime. Nice one :)
u/katkip

how
u/nender

Wow! This is amazing!
u/sigveseb

Nice!
u/f8f82804

#raytrace #d3 #pbr
u/Cloud

Cool!!!

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pavel

function u(t) {

with(x)for(c.width|=j=-8*t%1;j++<32;clip(fill(arc(960+40*j*S(j/9+t/5),700,5e3/j,9,13))))beginPath(fillStyle=R(a=9*j,a,a))

Jan 23 2019 11:54 PM UTC

}// 121/140

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#tunnel using clip()

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u/joeytwiddle

Sir. *applause*
u/jylikangas

Smooth!
u/katkip

:0
u/magna

#pavel
u/iverjo

Very nice!
u/bekfast2390

sick dude!!!
u/vain

Fucking cool!

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pavel

function u(t) {

c.width|=0;for(let i=4e3,X=Y=Z=w=960;i--;x.fillRect(w+w*X/z,w*Y/z,s=64/z/z,s))a=i**t%5/.64,b=!!a,X=X/2+b*S(a+t),Y=Y/2+b,Z=Z/2+b*C(a+t),z=4+Z

May 2 2019 7:40 PM UTC

}// 140/140

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#sierpinski #pyramid #waitforit #chaosgame

u/pavel

#d3 #perspective
u/Jezza

I really like this!
u/jylikangas

Great! And with performance optimization. :)
u/katkip

UFO :))

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pavel

function u(t) {

for(i=c.width|=h=1.5708;y=i--%3-1||S(i);x.fillRect(960+16*S(a+=i*h+t/3)/p,540-9*C(a)/p+13*r*y,4,4))r=9+9/(1+i**S(i*i+t)),p=S(a=i%3*i%h+.8)/r

Mar 30 2022 10:47 PM UTC

}// 140/140

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Hypercube #beesandbombs

u/vain

very cool. like the morphing / moving dots / lines #cube #3d
u/tomxor

Very neat. The migration of the points gives it quite an etherial look.
u/aleamb

amazing!

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pavel

function u(t) {

eval(unescape(escape`𩡯𬠨𫀽𨰮𭱩𩁴𪁼👴𙐽𝀻𫀭𛐻𮀮𩡩𫁬𤡥𨱴𚀰𛀰𛀵𜀬𫰿𝐰𞠱𩐳𚐩𪐽𫀥𜰬𪠽𫀯𜰦𜐵𛁫👬𛰴𞀦𜐵𛁸𛡦𪑬𫁓𭁹𫁥👒𚁩𚰱🀼𝠩𛁸𛡳𩑴𥁲𨑮𬱦𫱲𫐨𪐭𜑼𜐬𛐮𝐬𫰽𛑩𙐲𛀱𚱯𚠱𛠵𛀵𜀪𚀱𞐫𪰭𪠩𛀲𝐪𚀳𞀫𜠪𭀭𪰭𪠭𞀯𚀱𚰲𚠪𚀴𝐭𪰭𪠭𭀪𜐵𚐩𚐩`.replace(/u../g,'')))

Jul 13 2019 3:37 AM UTC

}// 138/140

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Blocks (https://dribbble.com/shots/1783699-Blocks)

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u/pavel

190 for(l=c.width|=t%=4;l--;x.fillRect(0,0,50,o?50:1e3))i=l%3,j=l/3&15,k=l/48&15,x.fillStyle=R(i+1<<6),x.setTransform(i-1|1,-.5,o=-i%2,1+o*1.5,50*(19+k-j),25*(38+2*t-k-j-8/(1+2**(45-k-j-t*15))))
u/KilledByAPixel

👍
u/aleamb

wow!!
u/username

actual f
u/katkip

awesome #compressed
u/katkip

#d3 #loop

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pavel

function u(t) {

eval(unescape(escape`𩡯𬠨𪐽𭀿𜡥𜰺𨐽𨠽𜀻𪐭𛐻𮀮𩡩𫁬𤡥𨱴𚀱𞐰𚡢𛀶𜀰𛐱𞐰𚡡𛀱𛀱𚐩𬠽𣑡𭁨𛡲𨑮𩁯𫐨𚐪𞐹𛁛𨐬𨡝👲🀱🱛𜀬𛠱𝠪𨡝𞡲🀸𝠿𦰮𞀵𚡡𚱢𛰲𝐬𛑡𛰲𝐫𛠸𝐪𨠫𜐮𝡝𞡲🀹𜰿𦱡𛰵𛐮𜠶𚡢𛀮𜠳𚡡𚰮𜠲𚡢𚰱𛠶𧐺𦰭𛠱𝐪𨐫𛠲𞀪𨠬𛠲𝠪𨐫𛠲𝀪𨠫𛠴𝁝`.replace(/u../g,'')))

Feb 14 2019 1:28 AM UTC

}// 138/140

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Barnsley #fern #fractal #compressed

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u/pavel

190 for(i=t?2e3:a=b=0;i--;x.fillRect(190*b,600-190*a,1,1))r=Math.random()*99,[a,b]=r<1?[0,.16*b]:r<86?[.85*a+b/25,-a/25+.85*b+1.6]:r<93?[a/5-.26*b,.23*a+.22*b+1.6]:[-.15*a+.28*b,.26*a+.24*b+.44]
u/tomxor

Holy ****
u/katkip

nice
u/metamero

this is beautiful!
u/lionleaf

That's amazing! #leaf
u/vain

Very nice barnsley fern
u/Joachim

#nature #organic

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