Smoother #Amiga #Ball by tomxor

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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tomxor

remix of d/23544 by u/pavel

function u(t) {

for(a=Math.abs,c.width&=i=4352;X=1-(T+i/32)%2,Y=--i/2e3;x.fillRect(X*r+64*T,Y*r+96-64*a(S(t)),T=a(2-t%4)+1,(i^i/64)/8&1))r=64/(--Y*Y+X*X+1)

Aug 13 2021 12:57 AM UTC

}// 139/140

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Smoother #Amiga #Ball

Show more comments…
u/tomxor

..But less authentic. Remaps the pixel positions rather than texture, which gives "free" antialiasing, with spare space to correct the spin.
u/pavel

Oh yeah, nice. This is definitely a better way of doing it. The other mapping has an incorrect center that I have to waste characters to correct.
u/pavel

-2 char using S(t%3.14) to bounce and inlining the single Math.abs call
u/danny@hille.dk

What a clever trick, using modulus pi of t, to only get the positive part of the sinus curve
u/danny@hille.dk

3.2 works fine, while 3 and 3.1 looks wrong
u/danny@hille.dk

test code: c.width|=0,x.fillRect(o=860,o-S(t*4%3.2)*o,200,200)


      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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