3
points
ux
Joined 1,919 karma
- > Thanks for putting this together.
I'm glad it reaches an audience :)
> Only critique is.. if you're sharing to teach, your compact/one line [460] char GLSL code is a poor delivery mechanism.
Understandable. Though, the demos are here to illustrate "what you can do with the trick I'm sharing". It's like, I'm teaching you how to do watercolor, and illustrate it with some paintings you won't be able to perform just with that knowledge. They're meant to inspire you to create. You're not looking at a tutorial, you're looking at art.
- > What's a good way to get started learning to build/customize shaders with GLSL?
I gave some directions and resources in a comment here, it might help you: https://www.reddit.com/r/GraphicsProgramming/comments/1pgqis...
> And GLSL syntax looks a bit tedious to be honest, but I'd love to dive in.
With the vectorization everywhere, it's surprisingly convenient given how simple the syntax is. I personally just miss some sinpi/cospi/etc, and/or a PI and TAU constant.
- 19 points
- Thank you! Do we have a guarantee that these subcurves are solvable with Newton's method? The approach with derivatives has this because we know there is one crossing, and also clipping them to the zero-derivatives makes sure there won't be multiple curve "pits".
- What you described in your first message seemed similar to the approach used in the degree N root solving algorithm by Cem Yuksel; splitting the curve in simpler segments, then bisect into them. I'd be happy to explore what you suggested, but I'm not mathematically literate, so I'll be honest with you; what you're saying here is complete gibberish to me, and it's very hard to follow your point. It will take me weeks to figure out your suggestion and make a call as to whether it's actually simpler or more performant than what is proposed in the article.
- Thanks, I'll look into this. BTW, your 2nd shadertoy link is off (maybe it's private? Edit: seems you fixed it, thanks)
- I'm interested in the approach you're describing but it's hard to follow a comment in the margin. Is there a paper or an implementation example somewhere?
- Finding the sign of the distance has been extremely challenging to me in many ways, so I'm very curious about the approach you're presenting. The snippet you shared has a "a³-bcd ≤ 0" formula which is all I get without more context. Can you elaborate on it or provide resources?
The winding number logic is usually super involved, especially when multiple sub-shapes start overlap and subtracting each other. Is this covered or orthogonal to what you are talking about?
- 157 points
- 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!
- Is this tutorial kind of abandoned? There are many teased chapters that never seem to have materialized somehow.
- 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:
So thank you for the idea!g -= a*=w, c += a*d*9.+... a = min(...), c.r += w*a*a*.2, - 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!
- 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 :)
- 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
- 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 :)
- 107 points
- 5 points
I started 2-3 months ago or so doing this stuff, so don't be too intimidated to start. Especially with the two articles (Red Alp and this one), it should make it more accessible, hopefully :)