Black Hole by 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

remix of d/11455 by u/pavel

function u(t) {

for(r=c.width|=0;--r;)x.stroke(p=new Path2D,p.arc(960,540,r,a=(r+~~(99*t)-t/9)*5**.5/2%(2*Math.PI),a+(x.lineWidth=32)/r))

Dec 19 2018 1:13 AM UTC

}// 121/140

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Black Hole

u/pavel

Deleting %(2*Math.PI) works in Chrome but not in Safari.
u/pavel

Notice that the radius does not change with time. The inward motion is achieved by drawing a smaller radius square next to where the larger radius square was a frame ago.
u/pavel

If the squares were numbered you'd see that the numbers jump around every frame.
u/pavel

I've made an explanation dweet d/11488


      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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