[Completed] Add Fractal Voronoi Noise

Contributing to Blender
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Hi everyone,

I have been using Blender for quite a few years now and during those years I have seen Blender evolve at speeds that I wouldn’t have thought possible. Because Blender was evolving so quickly whenever I encountered something that bothered me I would just hope that the devs would fix/add it soon.
But recently I thought why not just contribute the things, that the devs might not have time for or overlooked, myself?

So here I am making my first contribution to the Blender sorce code, which is Fractal Voronoi Noise.

The idea is simple, take a layer of Voronoi Noise and add layers (or octaves) on top of it, with each subsequent layer having a larger scale and smaller amplitude than the previous.

Since I have read the Advice for New Developers I have only implemented the concept for 3D F1 Voronoi Noise in Cycles for starters but I think the results are already convincing enough:

Using Fractal Voronoi Noise one can easily create a fully procdural Ocean with shader nodes (Displacement and Bump):

And what personally find even cooler is that it also looks great when used as a bump map (Bump only):

As for controlling the Fractal Voronoi Noise I would want to add three new parameters:

  1. Detail, which controls the amount of layers just like in the Noise Texture
  2. Roughness, which controls how big the amplitude of a layer is compared to the layer before, just like in the Noise Texture
  3. Lacunarity which controls how big the scale of a layer is compared to the layer before, just like in the Musgrave Texture
  4. Normalize, a boolean value, which if set to true will divide the entire Fractal Voronoi Noise texture by the maximal possible value, just like what the Noise Texture does.

The complexity of my Fractal Voronoi Noise implemtation has a time complexity of O(number of layers), meaning that it the amount of time needed to evaluate it is proportional to the number of layers to evaluate.

One important aspect of my implementation is that for the case where Detail==0, which gives the current non-fractal Voronoi Noise texture, there was no measurable performance loss on my machine.

I would love to hear feedback.

Thank you for reading through my post and have a nice day!

Update:

The Pull Request for Fractal Voronoi noise has been merged into the main branch.
Fractal Voronoi is scheduled to be released in Blender 4.0.
Any 4.0 builds released after 14.06.2023 should already include it.

Thanks to everyone for helping!

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From a user perspective, it looks like this will work great and will simplify a lot of node setups.

This is one important piece of procedural texturing that the old Blender Internal engine was able to do but was lost in the Cycles era. The initial idea was that people who needed more complete functionality would just use the OSL kernel (as the first generation of CUDA compilers had issues with larger kernels), but it did not exactly pan out as planned.

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Oh, man, that looks great! I wish I had the knowledge to do the same as you did! I’ve had an idea of hexagonal voronoi (for randomness = 0) but I don’t code anything yet.

I hope the Blender devs can help you to submit it into Blender master. Did you reach out to the devs at blender.chat ?

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Judgin from the number of tutorials surrounding OSL it can be arguably said, that it is a rather niche thing in Blender, which considering that the vast majority of Blender users are artist, not programmers, isn’t all that surprising, but I think that the fact that it can’t be used for GPU rendering is what made it so niche after all.

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Oh, man, that looks great! I wish I had the knowledge to do the same as you did! I’ve had an idea of hexagonal voronoi (for randomness = 0) but I don’t code anything yet.

Hexagonal Voronoi? Oh boy I have good news. I actually made a Hexagonal Voronoi node prior to this. Unfortunately the implementation was rather convoluted and a result of multiple tests I ran.

But if there is demand for it I will consider developing an efficient implementation at some point.

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Looks nice. Did you already create a diff so others can test it?

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As the Blender source code is both in Github and on Home (blender.org) I am not sure where and how exactly I am supposed to contribute my code.

Furthermore my current implementation is rather incomplete as I have only implemented it for 3D F1 Voronoi Noise in Cycles. Apart from that it is implemented directly in the voronoi_f1_3d function in \blender\intern\cycles\kernel\svm\voronoi.h, but I plan to do the final implementation in whichever function does the call to voronoi_f1_3d.

Thus I figured that I should probably just open a Devtalk post and wait for feedback first, but I would of course be willing to create a diff.

So where and how do you create a diff?

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You can find our guide on how to contribute code on our wiki over at :

https://wiki.blender.org/wiki/Process/Contributing_Code

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That’s awesome! Just to be sure we are talking about the same idea. Did yours look something like this?

Q6CNuZy
Q6CNuZy684×685 148 KB

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It never hurts to create a diff. That way others can try it out as well and you can get better feedback. The diff doesn’t need to be the final version, you can update it anytime.

Look at lazydodo’s guide for creating a diff.

One thing to note: arc is being phased out. So even though the wiki said to use arcanist I wouldn’t spend too much time on it. If it works first time trying it’s a nice easy way to upload diffs, if it doesn’t just create a diff from within git and upload it.

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I got this:

Hexagonal Voronoi
Hexagonal Voronoi1080×1080 88.6 KB

The distance value should be 0 wherever the feature points are.
But I think this is getting a little off topic now…

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So I created a diff here:

:gear: D16262 Add Fractal Voronoi Noise (blender.org)

As this initial version is far from complete, please read through the summary to make sure everything works.

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Awesome, exactly what I meant. Yeah, should be part of another conversation. If you ever have time to make it, that’d be fantastic. Have a nice day!

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I think the problem is not necessarily the difficulty of implementation, but rather that it would probably be a rather niche feature and therefore unlikely to be accepted in the first place.

You could open another topic here on Devtalk or on Right-Click-Select and see how the rest of community reacts.

Of course if you do so, it would be handy if you somehow posted a link so that I will actually see the topic.

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You could open another topic here on Devtalk or on Right-Click-Select and see how the rest of community reacts.

The primary place for feature requests is on rightclickselect, any “wouldn’t it be nice if…” threads without clearly having a dev attached to it on devtalk are bound to be closed rather rapidly.

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Great work!
I wonder, whether performance is N times slower for N octaves compared to single Voronoi? This is the case for the nodes implementation. Although for Musgrave and Noise textures number of octaves seem to effect performance slower than linearly, I guess there are some optimizations for fbm. I hope that would be the case for this node as well.

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this noise pattern is a great addition!

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Good news!

I have finished developing the Fractal Voronoi Noise implementation.
The final Diff along with example pictures, videos and .blend files can be found here: ⚙ D16262 Add Fractal Voronoi Noise

I will ask a Blender Developer to kick off a patch build for the final implementation for everyone to try.

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The patch build containing the full implementation of Fractal Voronoi Noise can be found here:

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The functionality seems useful!
With that being said, it doesn’t seem to add something that wasn’t possible before, it just makes it more convenient. This is a good thing of course – but I never had any problems layering noises on top of each other – which is usually really straightforward and flexible in node-based systems.

What’s really tough to do is generate a procedural Voronoi with varying cell sizes:

I’d love to see a solution to that.

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