[Tutorial] how to calculate vertex normals in shader graph

Update: Now in video form on YouTube!

I recently crated this tutorial and would welcome any feedback:

https://gamedevbill.com/shader-graph-normal-calculation/

 

By request, I've added a github to make following along here easier...

https://github.com/gamedevbill/Tutorials/tree/master/NormalCalculation


As always, let me know if you have any feedback on the tutorial!

-gdb

 

This is a really great tutorial! However I have a hard time to get it running in my experiment.
Maybe you can give me some tips.

I basically create a crater like shape with this sub graph:


Using your Neighbors and NewNormal Subgraphs here.


The resulting mesh looks like this:


Calculating the normals doesn't work.

I'm pretty sure it's because I'm using the World Position in my displacement part, and only add the Y part later, but I don't know how to incorporate your neighbor sub graph correctly.

 

I just saw this question... Yeah, the world position is a good guess, but i would have thought it'd still work. I'll try to build a test project from your screenshot in a week or so. I'll update here once i have something.

Thanks
gdb

 

Ok, I've looked into it. The issue is that your "DispalceSub" graph is not actually outputting a position. It outputs xyz=[0,offset,0]. You correctly calculate that offset for the neighbors, but are feeding in a value to the normal calculator that has x & z components both set to 0.

What you need to do is change DisplaceSub to include both positions as an input. Take the PositionWorld at the front end (as you currently do), then at the end, take PositionObject as an additional input and add it in before returning.



This wraps your entire vertex displacement into one subgraph. Then to do the normal calculations, you'll have to have two "Neighbors" nodes. One that calculates neighbors in world space, and one in object space.

Then it works. Hope this helps.

 

Thanks! I'm sure this will help!

 

I've made this tutorial into a video! Be sure to check it out in the start of the thread above!

 

Hello how this possible to recalculate normals for blend shape?