Red rays from the Mandelbrot Set #mande… by rodrigo.siqueira

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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rodrigo.siqueira

remix of d/14525 by u/rodrigo.siqueira

function u(t) {

for(var I=960;I--;)for(var U=P=X=I/190-3,Q=Y=t/3-1.85,k=14;k--;)U=X,X=X*X-Y*Y+P,Y=2*U*Y+Q,X*X>2?x.fillRect(I*2,t*99,2,2):x.fillStyle=R(k**2)

Jun 14 2019 2:56 PM UTC

}// 140/140

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Red rays from the Mandelbrot Set #mandelbrot #fractal

Show more comments…
u/KilledByAPixel

Amazing.
u/artfarnaa

Is there a way to make these fractal examples render faster? Perhaps offload the calculations to web assembly?
u/username

"Red rays" also known as low iteration count
u/13thptr

u/artfarnaa wasm isn't much faster than js on most platforms and it takes a lot of space to set up
u/13thptr

see u/rbong's work on it
u/katkip

i don't understand this so awesome
u/rodrigo.siqueira

Artfarnaa, it is possible to make super fast, see this pure JS fast implementation: https://csl.name/mandelbrot/ There are many tricks specifically created to calculate Mandelbrot Set (e.g. avoid calculations in a rectangle inside the main set because all pixels are white and calculations in this white area is slower than other parts), but no speed optimization were used here because of space constraints. Some tricks to make it faster: do not use time variable to do calculations (because it is max 60 fps), do not plot each pixel, but store them in an array and plot at once using c.putImageData(img)...
u/KilledByAPixel

There is one way to make it very very fast. I just made a quick shader of it for you! https://www.shadertoy.com/view/wtjGz3
u/artfarnaa

Thanks guys, great inspiration.


      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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