Dwitter - javascript demos in 140 characters

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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rep_movsd

function u(t) {

eval(unescape(escape`𤀽𣰽🡸𛡦𪑬𫁒𩑣𭀨𣰬𮐽𦐭𤰨𨐽𦀯𦠭𛠵𚐪𦀯𝀬𜰬𥀿𜰺𦀽👚𯁼𦀽👗𛐱🰱𝠺𝀪𚁃𚁆𚡏𚡹𚐾𛠸𙠦𦐥𜐶𙠦𨐾𛠷𙠦𨐼𜠮𝰦𙡙🡚𚰶𞐦𙡙🀹𜀰𚐩𒡙🐨𡠽𩡲𨑭𩐩𙐹𞐪𞀫𚁚🐲𞀰𚐬𥀽𦐼👚𯁼𦐾𚁗🐹𝠰𚐊𩡯𬠨𦀽𦠻𡠼𜐰𜀦𙡘🁗𞱘𚰫𚑐𚁘𚐬𤀨𜐹𜠰𛑘𚐻`.replace(/u../g,'')))

Sep 4 2021 9:16 PM UTC

}// 139/140

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The book of dweet

u/neimad

very nice
u/tomxor

Great idea
u/KilledByAPixel

now that's what i call a good book!

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taupelink

remix of d/23806 by u/taupelink

function u(t) {

k=120;for(i=k;i--;)
f=97*i*t,X=f*f%16,Y=X*f%9,
x.fillStyle=R(q=i*2,q*=1+S(X*.6),q*=1-S(Y*.8+1.2),q**-t),
x.fillRect(k*X,k*Y,k/5**t,i)

Sep 8 2021 1:50 AM UTC

}// 133/140

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d/23810 figure 2

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u/taupelink

Changes from figure 1:
u/taupelink

f=97*i*t: I added the "97*" to improve the quasi-random numbers. If you omit it from this dweet, then artifacts appear reflecting small values of f.
u/taupelink

q*=1+S(X*.6): I added the "*.6" to zoom in horizontally. I wanted the picture to have just one vertical red bar.
u/taupelink

q*=1-S(Y*.8+1.2): vertical zoom and translation, positioning the green bars so they look a little like riverbanks. The constants here were found entirely by trial-and-error.
u/taupelink

q**-t: This dweet uses RGBA rather than RGB. Changing the alpha formula can create or destroy an image, or otherwise dramatically affect its appearance. Varying
u/taupelink

q**-t: This dweet uses RGBA rather than RGB. Changing the alpha formula can create or destroy an image, or otherwise dramatically affect its appearance. Varying
u/taupelink

q**-t: This dweet uses RGBA rather than RGB. Changing the alpha formula can create or destroy an image, or otherwise dramatically affect its appearance. Varying
u/taupelink

q**-t: This dweet uses RGBA rather than RGB. Changing the alpha formula can create or destroy an image, or otherwise dramatically affect its appearance. Varying
u/taupelink

q**-t: This dweet uses RGBA rather than RGB. Changing the alpha formula can create or destroy an image, or otherwise dramatically affect its appearance. Varying
u/taupelink

Varying alpha inversely with brightness can create interesting effects. Here, it varies with t as well. This contributes to the texture of the river. Again, I came across this formula by trial-and-error.
u/taupelink

So that's how I ended up with a red bridge across a river. An inky shadowy red river bridge, if you will.
u/taupelink

(sorry about the repeated comment above...if a moderator could delete those, and this request comment, that'd be great. Thank you!)
u/taupelink

More about how the q**-t works: the taller, brighter blues are more transparent. The shorter, darker ones stand out more, appearing as dark horizontal lines.

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tactical_retard

remix of d/23621 by u/tactical_retard

function u(t) {

eval(unescape(escape`󡬽󫜽󟭭󙜲󟬱󟼨󫜥󜜭󛬵󚜪󜬺󚌱󚼭󫜥󜜭󛬵󚜪󜬊󬬽󚍍󟝍󨝴󪌩󛭲󨝮󩍯󫜊󩭯󬬨󪜽󨜽󜭥󜼻󪜭󛜻󣜮󨝢󬼨󦜭󝜰󜌫󡬨󦌯󦜩󚬵󜌰󚜾󝬰󚭴󙬦󚍸󛭦󪝬󫍒󩝣󭌨󦌬󦜬󜬰󛌲󜌩󚜩󦌽󬬨󚜪󨜬󦜽󬬨󮌮󩭩󫍬󤽴󮝬󩜽󨍨󬽬󚌤󮼶󜌪󭍽󛌹󞜥󛌳󝜥󨌩󚭡`.replace(/u../g,'')))

Sep 7 2021 3:41 PM UTC

}// 129/140

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better triangle wave function: F=m=>Math.abs(1-m%2)*2-1

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Joachim

remix of d/23807 by u/Joachim

function u(t) {

eval(unescape(escape`󮬽󨼮󭽩󩍴󪌽󜼰󜌊󘝴󟽰󟝛󧜺󬌮󬍵󬽨󚍻󮜺󜜬󬬺󮬥󤼨󭌩󚬹󯜩󒭦󫽲󚍩󘍯󩬠󬌩󭽩󭍨󚍩󚝹󟬲󜌰󟽰󛭳󪍩󩭴󚌩󞭸󛭦󪝬󫍒󩝣󭌨󜌬󞜹󚽹󛍺󛍺󚜬󮜯󟜮󞜵󛍸󛭦󪝬󫍓󭍹󫍥󟝒󚌰󛌹󞜬󞜹󛍲󛼹󞜩󒭸󛭦󪝬󫍓󭍹󫍥󟜧󘽢󨭢󙼬󮌮󩭩󫍬󚍸󛭡󬭣󚌲󜌬󜬰󛌹󛌰󛌷󚜩`.replace(/u../g,'')))

Sep 8 2021 8:11 AM UTC

}// 135/140

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fly by #sea

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taupelink

function u(t) {

k=120;for(i=k;i--;)
f=i*t,X=f*f%16,Y=X*f%9,
x.fillStyle=R(q=i*2,q*=1+S(X),q*=1-S(Y)),
x.fillRect(k*X,k*Y,k/5**t,i)

Sep 7 2021 2:03 PM UTC

}// 114/140

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d/23806 figure 1

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u/taupelink

this week i will give a line-by-line description here in comments and then maybe in a blog post
u/taupelink

definitely a blog post. the comments will come over time...don't feel obligated to come back and check this dweet for new comments
u/taupelink

k=120: for code golfing purposes, this variable plays multiple roles: loop iteration count per frame, scale factor for X&Y coordinates, width of each rectangle at the start of the animation
u/taupelink

for(i=k;i--;): establishes a loop where i counts down from 120 to 1. "i--" means, If i is 0, then stop here; otherwise, decrement i by 1
u/taupelink

f=i*t,X=f*f%16,Y=X*f%9: this code creates quasi-random decimals X (0.0-15.999) and Y(0.0-8.999). (Hat-tip to whoever suggested this technique... u/pavel ?) If you multiply the upper bounds by 120 each, you get the overall dimensions 1920x1080.
u/taupelink

x.fillStyle=R(red,green,blue): sets the RGB color value for fills. I will take each component one at a time...
u/taupelink

q=i*2: sets the red component to 2x the loop index, i.e. an even number from 2 to 240. This covers most of the possible range 0-255. The red value is tied to i but not to X or Y; rectangles everywhere have a random degree of red.
u/taupelink

q*=1+S(X): sets the green component, and updates the value of q, to q*(1+sin(X)). Where sin(X) is close to -1, around X=1.5*pi and X=3.5*pi, the value of q is close to being zeroed out by this code; that explains the vertical red bands.
u/taupelink

q*=1-S(Y): sets the blue component, and updates the value of q, to q*(1-sin(Y)). This is why you see the green bands (no blue) around Y=0.5*pi and Y=2.5*pi; that's where sin(Y) is close to 1.
u/taupelink

x.fillRect(top,left,width,height): standard Javascript for drawing a rectangle. Again I will take one component at a time...
u/taupelink

k*X,k*Y: the X- and Y-coordinates of the upper left-hand corner of the rectangle, scaled by a factor of k.
u/taupelink

k/5**t: the width of the rectangle, which decreases exponentially over time. This can provide texture at different scales, including fine-grained detail.
u/taupelink

i: the height of the rectangle, equal to the index variable. The height of each rectangle is proportional to the red component, indeed to every component; so, for the 120 rectangles that are drawn in any given frame, some are tall and bright, some short and dark.
u/taupelink

A blog post on this dweet is up: https://medium.com/@taupelink/elements-of-a-…

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Tekmap

remix of d/7814 by u/SpecterPainter

function u(t) {

x.fillStyle="#3061"
x.fillRect(0,0,2e3,2e3)
for(i=-9;i<1900;x.fillStyle=`hsl(${i/9%214},99%,60%)`)
x.fillRect(i+=3,540*(1+T(t*i)/3),3,9)

Sep 6 2021 8:10 PM UTC

}// 136/140

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taupelink

remix of d/23760 by u/taupelink

function u(t) {

for(i=q=k=810;--i;x.fillRect(k*X,k-q*Y,-i/v,q*Y/v))f=i*t,X=f*f%5,Y=X*f%4-2,x.fillStyle=R(s=q+i*Y*.4,q^=-s,q^=255,(k+q)*(Y+3)**2/4e4),v=4**t

Sep 6 2021 6:21 AM UTC

}// 139/140

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d/23766

u/rep_movsd

You need to write a blog about this particular technique
u/taupelink

i'd like to, but it would take time (i'm a super slow writer) and it's honestly not a priority at the moment. I can at least say this: Part of how I get four vertical bands is having Y range from less than -1 to greater than 1 (in this case, -2 to 2). Multiplying or dividing by Y then has four effects: stretch or compress, do or do not reverse sign
u/rep_movsd

A one page breakdown would be nice, or perhaps I'll write one
u/taupelink

ah ok...like a line-by-line explanation? that's doable...i'll write something up next weekend!

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tomxor

remix of d/23746 by u/rep_movsd

function u(t) {

for(Y=t*480%720|0,X=1280;X--;!Z|!Y|Y>640|(Z/480+.75&Y/480+.83&C(Z*Y)>.8&&Y&48)&&x.fillRect(320+X,180+Y-Z/6*S(Z/203),3,4))Z=X>640?1279-X:X

Sep 5 2021 3:30 PM UTC

}// 137/140

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Smolr #book of #music

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taupelink

remix of d/23688 by u/taupelink

function u(t) {

for(i=q=k=720;--i;x.fillRect(k*X,720+q*Y,q/Y/v,-i/v))f=i*t,X=f*f%3,Y=X*f%4-2,x.fillStyle=R(q*=q%2+Y,q*=X/2/t**.5,q-=i*S(q/X+Y),k/q/q),v=2**t

Sep 5 2021 7:00 PM UTC

}// 140/140

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d/23760

u/magna

Wow!

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rodrigo.siqueira

remix of d/23724 by u/taupelink

function u(t) {

for(i=k=630;--i;x.fillRect(X-k,k-i/Y,-Y*i/v,-q*Y/v))f=i*t,X=f*f%3e3,Y=i*f%12-4,x.fillStyle=R(q=i*Y,q*=S(t-k/X)*3,q/t,1e7/X/q/q),v=4*t*(t<9)

Sep 3 2021 8:45 PM UTC

}// 139/140

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Sailing boat at sunset #waitforit (in about 7 seconds the sailboat will appear)

u/tomxor

Wow! #waitforit #impressionist #sailing #boat
u/tomxor

#art
u/Joachim

stunning