Code golfing a tiny demo using maths and a pinch of insanity

(blog.pkh.me)

105 points | by ux 4 days ago ago

21 comments

  • recursive 4 days ago ago

    I don't know much about 3d stuff or shaders or this language, but I know golf, and I think I found a byte to save.

        w = g-g*exp(-mix(h*3e2,d*2.5,a=h<.001?0.:1.))
        w = g-g/exp(mix(h*3e2,d*2.5,a=h<.001?0.:1.))
    • lifthrasiir 4 days ago ago

      You can also premultiply w with a, as every occurrence of `w` looks like `w*a`. This should shave three more bytes:

        w=g-g*exp(...),g-=w*a,c+=w*a*d*9.+...,c.r+=w*a*a*2,...
        w=g-g*exp(...),g-=w*=a,c+=w*d*9.+...,c.r+=w*a*2,...
      
      (I've tested this with the Shadertoy version. YMMV.)
      • ux 4 days ago ago

        This is not equivalent; the `a` in `c.r+=w*a` is different, you need the original untouched w. The mountain looses its crack with your version.

        But! You can save 1 char by replacing w with a:

            g -= a*=w,
            c += a*d*9.+...
            a = min(...),
            c.r += w*a*a*.2,
        
        So thank you for the idea!
    • ux 4 days ago ago

      Hey, thank you, that's a nice one. I added the change to the Shadertoy version with your credit. I will add a note/update on the blog and demo page later. Thanks again :)

      • zahlman 4 days ago ago

        Is it actually necessary to specify `a` as a floating-point literal? Will it not be implicitly converted?

        • ux 4 days ago ago

          Yeah. If you want implicit conversion, you need to specify a constructor like float(cond), but that would be longer than the ternary form. I thought about using a vec3() but vec3(...).x is still too long and using the vec3 directly doesn't look viable. Declaring a bool adds more characters as well. There is also step() giving the same number of chars: a=step(.001,h), but it's not more optimal: https://iquilezles.org/articles/gpuconditionals/

          If you see a way to make it shorter, feel free to share :)

  • vintermann 4 days ago ago

    Using maths, insanity, and a ton of calculation horsepower... That made my graphic card fan turn on instantly!

  • ForHackernews 4 days ago ago

    If anyone is interested in learning more about this kind of coding https://thebookofshaders.com/ is a fantastic intro.

    • ux 3 days ago ago

      Is this tutorial kind of abandoned? There are many teased chapters that never seem to have materialized somehow.

  • mkbosmans 17 hours ago ago

    Another two bytes found (I think)

      (d==0.?K*.01*h:c-c)
    
    could become

      (d>0.?.0:.01)*K*h
    • ux 13 hours ago ago

      Ah nice for noticing d!=0 is d>0. Not sure how I missed the multiplication to get rid of the vector form; I guess I was too obsessed with the x-x trick...

      I added your changes to the Shadertoy version with your HN nickname. I'll integrate it to the original later.

      Thanks!

  • bangaladore 4 days ago ago

    The top demo doesn't function on Edge or Chrome on Windows due to too many webgl contexts.

    > WARNING: Too many active WebGL contexts. Oldest context will be lost.

    • ux 4 days ago ago

      Ah, someone reported this to me today, but I must admit I have no idea how to address the issue. Currently the canvas animations are stopped when out of context, but yeah they have to be loaded.

      The code on the blog is pretty simple and naive (I'm not a webdev): https://github.com/ubitux/scripts/blob/main/share/blog/shade...

      Any suggestion on how to address the issue is welcome.

      Note: I don't have any Windows machine to test with

      • greggman65 4 days ago ago

        If you just want it to work, stick this script on your page

        https://github.com/greggman/virtual-webgl

        If you want to make your own solution there's one listed here about 1/2 way down the page

        https://webglfundamentals.org/webgl/lessons/webgl-multiple-v...

        As an aside, WebGPU doesn't have this issue or at least has it less. For one, WebGPU can use a single device to render to multiple canvases, something WebGL can't. Another is that WebGPU is mostly stateless making it easier for both the user and the browser.

        • ux 4 days ago ago

          Incredible, thank you very much. I've included the script for a quick fix, I'll see how to make to cook something myself at some point!

      • timojaask 4 days ago ago

        Similar issue on iOS Safari: all examples work except for the very first one.

        • sgarland 3 days ago ago

          It loaded fine for me. iOS 26.0, iPhone 16 Pro.

    • user1093298 4 days ago ago

      Works fine with Firefox on Windows.

      What am I saying? Fine? It's freaking awesome.

  • samwhiteUK 4 days ago ago

    Unbelievably cool, well done!

  • sgarland 3 days ago ago

    This is utterly bonkers to me, well done.

  • mielioort 3 days ago ago

    Needs dragons flying sunwards