#sphere by f8f82804

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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f8f82804

remix of d/9674 by u/f8f82804

function u(t) {

with(x)for(i=c.width^=0;i--;beginPath(fill()))C(a=2*t-i)>0&&arc(960+((s=750+330*S(t))*i-i*i)**.5*S(a),s-i,18*C(a)*(1-(i*2/s-1)**2)**.5,0,7)

Sep 5 2018 10:40 PM UTC

}// 139/140

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#sphere

u/donbright

thats cool... how does it work?
u/joeytwiddle

Very nice! #halftone
u/f8f82804

u/donbright: I used the parameterization from d/5600. I like it a lot because it keeps fairly even density of dots on the surface. It's based on cylindrical coordinates where each point is at a different vertical level and the points spiral around. The key is that not all values of i result in drawing a dot. We drop the back half of the sphere with C(a) >0, but we also implicitly drop points where s*i-i*i is negative
u/donbright

thanks... fascinating...


      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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