Dweets awesomed by u/hvianna

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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rodrigo.siqueira

remix of d/18458 by u/rodrigo.siqueira

function u(t) {

for(X=f=c=>S(S(9*c/d)*t),Y=t/8-1.1,i=2e3;i--;x.fillRect(i,t*60,(1+f(X=i/480-2)*f(Y))*(d/2+Y),3))x.fillStyle=R(C(r=X*X+Y*Y)*125),d=r>1||T(r)

Apr 23 2020 5:58 PM UTC

}// 139/140

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Red Sphere Reflection #raytracing (high resoluton)

Show more comments…
u/Xen

Tf Dude! top dweet right here 😍
u/lionleaf

That's amazing!
u/lionleaf

#glass #sphere
u/stiaje

#witchcraft
u/Ath0r

Impressive, great job!
u/katkip

genius script
u/PoweredByWill

wow. dwitter povray.
u/mole

I am shooketh. This is absolutely incredible.
u/katkip

#slowrender
u/cli

This is great.
u/Nascretis

Actually insane. #witchcraft

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KilledByAPixel

function u(t) {

eval(unescape(escape`𩡯𬠨𮀮𩡩𫁬𤡥𨱴𚀰𛀰𛀲𩐳𛀲𩐳𚐬𪐽𜰻𪐭𛐻𪑼𦐼𜁼𘑱𙠦𮀮𩡩𫁬𥁥𮁴𚁱🰧𧁵𜠶𜀰𧁵𡡅𜁆𙰺𭑮𩑳𨱡𬁥𚁠𙑵𡀸𜱃𙑵𡁆𜐤𮰨𭀪𝀯𣑡𭁨𛡐𢐫𛠵𚐥𞀫𜑼𜁽𨀩𛁱🰵𜠰𞠸𝠰𛑓𚁴𚐪𝠹𞐬𬐿𝰶𝐺𝠰𜀫𦐩𚑱👩𛐱𛁸𛡦𫱮𭀽𨀤𮱱🰴𜀺𞑽𩑭𘡠𛁙👃𚁴𚐪𞐹`.replace(/u../g,'')))

Apr 22 2020 8:11 PM UTC

}// 139/140

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☀️+🌗

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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/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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KilledByAPixel

function u(t) {

eval(unescape(escape`𭱩𭁨𚁸𚑴🠱𛠰𜠿𩡩𫁬𥁥𮁴𚁓𭁲𪑮𩰮𩡲𫱭𠱯𩁥𤁯𪑮𭀨𝐵𜰵𝠬𝐶𝀸𜐫𠑛𭀽𭀪𝠰𛐶𜡼𜁝𚐬𭀥𜐳𚠱𝀸𛀲𞀹𚰨𭀯𜐳𯀰𚐪𜠱𞐩𞡴🰫𚱩𙐱𝠭𜐱𙠦𪐥𜐶🀱𝀿𠐮𬱰𫁩𨱥𚀨𠐮𫁥𫡧𭁨𚰱𚐪𣑡𭁨𛡲𨑮𩁯𫐨𚐬𜀬𪐩𞡦𫱮𭀽𙰱𝁥𫐢𙰺𠐽𦱩🐰𧐻`.replace(/u../g,'')))

Apr 8 2020 3:04 PM UTC

}// 134/140

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Shuffled Deck of Playing #Cards 🃏

u/katkip

#text

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KilledByAPixel

remix of d/18160 by u/rodrigo.siqueira

function u(t) {

for(c.width&=j=3e3;j--;x.lineTo(448+S(a=i*.209+t*9)*r,600+C(a)*r/2-i))i=(j/4+(j%4!=2)*60|0)-t%1*40,r=i**3/2e5
x.stroke()

Apr 6 2020 10:04 PM UTC

}// 120/140

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#Vortex

u/ivylab

I have been waiting for the view to zoom out more for a minute. But it's seriously continuous! Amazing
u/KilledByAPixel

Thank you, it was tricky to get this one right.
u/KilledByAPixel

#illusion

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pavel

function u(t) {

for(c.width=i=620;i--;x.lineTo(310*(z+p*S(b))/z,300*(3+q*C(a))/z))q=i/8&1||-1,p=4-q*S(a=S(a=S(b=i/98+2*t)+b)/2+a/2),z=8+p*C(b-=t);x.stroke()

Apr 4 2020 7:12 PM UTC

}// 140/140

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#mobius strip

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u/pavel

Using sin(sin(x)+x)+sin(x)+x as a smooth staircase function to implement the flip as a pulse.
u/KilledByAPixel

👍
u/Xen

love it
u/aleamb

love it!
u/danny@hille.dk

Nice - möbius tape
u/Qwitter

Im sorry, but I find only one side of this to be Awesome.
u/vain

beautiful and smooth transformation / animation

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KilledByAPixel

function u(t) {

eval(unescape(escape`𩡯𬠨𮀮𩡩𫁬𤡥𨱴𚀰𛀰𛁺🐱𩐴𛁺𚐬𪐽𜠰𞱩𛐭𞰩𩡯𬠨𪠽𬠽𚁩𚠱𞐭𪐪𪐫𞐩𚠪𛠵𚠴𯀰𞱪𛐭𞱸𛡦𪑬𫁒𩑣𭀨𞐶𜀫𚁪🡲𛰲🱔🐹𞐺𜐲𚐪𬠪𠰨𨐪🐶𛱲𚐬𪐪𝐰𛁔𚡓𚁡𚐬𝐰𚐩𮀮𩡩𫁬𤱴𮑬𩐽𤠨𭠽𪐿𜐴𜀭𠰨𤰨𪐩𚡔𚠨𚁡👪𚱴𙐱𚐯𮠫𥀩𚠪𜠩𚡔𞠰𛁶𚡩𛰹𛁶𚐻`.replace(/u../g,'')))

Apr 1 2020 3:25 PM UTC

}// 140/140

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#Disco #Dancing

u/tomxor

nooice
u/sigveseb

Oh damn this looks great

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jylikangas

function u(t) {

x[f="fillRect"](0,0,2e3,2e3)
for(i=600;i--;x.fillStyle=R(i*T))x[f](T=800,199+i,i?M=24+C(t)*20:320,6),x[f](T-i*2,T+i,M+i,C(i/150))

Mar 25 2020 5:19 PM UTC

}// 129/140

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Quarantine Door

u/sigveseb

Nice concept
u/joeytwiddle

#spooky #door #halloween

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KilledByAPixel

function u(t) {

eval(unescape(escape`𭱩𭁨𚁸𚑦𫱲𚁫🐰𞱫🀱𩐳𞱦𪑬𫀨𩑬𫁩𬁳𩐨𪐪𝀫𤰨𭀪𞐫𪐩𚠳𛀨𤰨𪐪𪐩𚡔𚱔𚱴𚠨𪐥𝐫𜠩𚠵𞐩𙐲𩐳𛑪𚠹𛐹𛁷👫𚰫🰹𛑪𚠳𛑓𚁩𚱴𚐪𜰺𥀽𜑥𝐬𭰪𠰨𪐫𭀩𛰲𚱷𛀰𛀰𛀷𚐩𚑩👫🠾𜐬𪠽𪰥𜠬𨡥𩱩𫡐𨑴𪀨𩡩𫁬𤱴𮑬𩐽𤠨𭠽𞐹𚰱𝐵𚡪𚰡𪰪𜠹𛁶𛁶𛀮𜰩𚐻`.replace(/u../g,'')))

Mar 22 2020 7:01 PM UTC

}// 140/140

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Rain on #Glass 🌧

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