Projection Faster and Uncompressed by KilledByAPixel

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

Please log in (or register) to post a dweet (copy-paste the code somewhere safe to save it meanwhile)


    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.

show FPS hide FPS share 2 remixes fullscreen

KilledByAPixel

remix of d/27866 by u/@noel

function u(t) {

for(c.width=i=w=255;i--;)for(j=142;j--;)x.fillRect(i,j,1,((w*(C(a=Math.atan2(X=2*i/w-1,Y=2*j/w-.6))/(d=(X*X+Y*Y)**.5)+t)^w*(S(a)/d+t))&w)/w)

Jun 6 2023 5:16 AM UTC

}// 140/140

Please log in (or register) to post as a new dweet (copy-paste code somewhere safe to save it meanwhile).

Projection Faster and Uncompressed

u/@noel

I love this one and I follow the logic, until the z & w performing. I know it's a bitwise AND operation on z and w, but I don't actually grasp it.
u/@noel

I mean on this one: x.fillRect(i, j, 1, (z & w) / w)
u/joeytwiddle

Here (z & w) / w is the height of the rectangle. If that height is less than 1, then the canvas anti-aliasing renders a grey pixel, instead of a black one.
u/@noel

Thanks u/joeytwiddle Now I think I get it. (z & w) ensures that the value of z remains within the range of the canvas width 'w', and the dividing by w normalizes the height value. Great trick!


      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)

dwitter.net