d/2142 by mxfh | 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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mxfh

remix of d/855 by u/mxfh

function u(t) {

r=480;c.width=r*4;λ=t;for(φ=a=Math.PI/2;φ>-a;φ-=a/r/2){λ+=a;x.arc(C(φ)*S(λ-t)*r+2*r,(C(t+=a/r)*S(φ)+S(t)*C(φ)*C(λ-t))*r+r,a,-a,a)}x.fill()

Mar 15 2017 3:12 PM UTC

}// 138/140

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Show more comments…
u/sfz

wtf!
u/donbright

the reflection thing is great!
u/recursive

wow, what?
u/sfz

shaved some bytes by replacing Math.PI/2 with 1.57, have fun remixing!
u/sfz

Also r=480;c.width=r*4 to c.width|=r=480 ... down to 130
u/mxfh

c.width|=r=540 for(λ=φ=a=1.57;φ>-a;)x.arc(C(φ)*S(t-λ)*r+960,(C(t+=a/r)*S(φ)+S(t)*C(φ-=a/r/2)*C(λ-t))*r+r,0,λ+=a,0) x.fill()
u/mxfh

thanks, using the angle offsets in arc gives another two possible spots for variable assignment at a radius of 0, so you get something equivalent at 123
u/sigveseb

Is that the same reflection technique as in https://www.dwitter.net/d/915 ?
u/mxfh

should be, I assume it's that negative winding on polygons messes with the fill rule evaluation
u/mxfh

just to clarify, fill rules looks allright, it's really just non-covered areas due to the zig-zagging of the fill. try a lower decrement like φ-=a/r*8 to see the more graspable source of the effect
u/mxfh

#arc


      u(t) is called 60 times per second.
      t: elapsed time in seconds.
      c: A 1920x1080 canvas.
      x: A 2D context for that canvas.
      S: Math.sin
      C: Math.cos
      T: Math.tan
      R: Generates rgba-strings, ex.: R(255, 255, 255, 0.5)

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