75byte #physics 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

function u(t) {

c.width=99;x.fillRect(X+=a=S(X/30)<0?-a:a,Y+=b=Y>52?-b:b+.3,4,4)}{X=b=Y=a=1

Oct 26 2019 2:20 PM UTC

}// 75/140

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75byte #physics

u/tomxor

Perfect collision integration, since uniform gravity is constant it should cancel out in such a simple case, in which case integration can be skipped on a collision interval ?-b:b+.3 this is why it doesn't loose or gain significant hight on average
u/tomxor

To make it absolutely perfect this can also be changed to ?-b:b+.25 which will eliminate integration error since .25 is a non periodic binary fraction... it will bounce forever :)
u/tomxor

... but that would cost an extra byte so its no good !


      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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