UVNode, normalNode prefragment ? TSL

[Samsy]

Description

Hey hello there

I'm re-opening the interest for a UVNode that could overwrite the original UV's

but also trying to get my head about how to get to transform the normal of an object just before the internal normalNode calculation ?

I'm currently building a sphere impostor that replicates the entires shading of a material, but instead usinga billboard plane.

To do so this requires to calculate a new set of normal, and a new set of spherical uv

Problem is, I cannot rewrite the UV's, but also, to extend the normalNode material it requires to reintegrate the default normalNode behavior entirely manually... ( normalmap, bump map etc... )

The idea would be to replace those, just before it goes into the internal material behavior, before the fragment shader happen ? Those calculations needs to happen in the fragment shader.

Is there a way to rewrite those ?

In legacy threejs, this was something quite simple, just replacing a part of a string at the start of the fragment shader for the normals for example, and same for the uvs

normalNode is also a bit misleading, normalNode as the wiki says, is to re-write all the normal calculations ( normalmap / bump etc.. ) but is there a node just to write normals ?

Those things would enhanced the capacity to extend a material, what ever the nature of the material is

This could work on any material / phong / standard / physical / basic the same way for all

Happy to discuss !

[Makio64]

I also miss UVNode in TSL since day one, I think in the material we should have something like :

let vuv = uv().toVar()
if( this.UVNode ) {
vuv.assign( this.UVNode( vuv ) )
}
//... then this vuv is used by all the map etc.. without having to rewrite every single of the map / texture using uv

There might be more elegant solution but please add this UVNode , its a fundamental node to change base behavior of a material and its standard in most 3d nodes system in the game/3d industry

[sunag]

We’ll probably go for a custom context per material to improve this kind of functionality, like:

material.contextNode = context( { getUV: ... } )

[Makio64]

@sunag this feel like an hard synthax material.contextNode = context( { getUV: ... } )

What about the material.UVNode be a shortcut to set getUV in this contextNode ?

I really wish i can write this for example : material.UVNode = uv().sub(.5).mul(2).abs() // uv : 1->0->1
this kind of mirror uvs are often use in case of generative sky / textures / repeated pattern for example.

[sunag]

The context() solution can be used for other things as well, and this practice should not be recommended. I would really like to not have to create a new property on the material every time a new contextual modification or injection is requested.