Triplanar Shader & Deform Plugin about deform

[andybak]

Not to preempt Keenan but it strikes me that Triplanar is the wrong tool for the job here. The behaviour you're complaining about is the defining character of a triplanar shader. That's what they do.

Instead you probably want to add a post-processing step after deform to assign UV coords in an approximation of how triplanar works (matching it exactly would be very tricky - you'd probably have to settle for seams at the triangle level)

[andybak]

Using UV is not possible for us unfortunatly :/ we are thinking of a way to make it work (even partially) without UV.

In blender it is possible to solve this problem by using the Generated output of the Texture Coordinate node

https://docs.blender.org/manual/en/latest/render/shader_nodes/input/texture_coordinate.html

so is it possible to reproduce this node in Unity?

I guess the equivalent in Unity would be to store the worldspace coordinates BEFORE deform has been run and use those in the triplanar shader.

But you can't do it all in an actual Unity shader because by that point it's too late. You need to do some calculations in C# (or maybe a compute shader) prior to hitting the Unity material shader.

[usernameHed]

Using UV is not possible for us unfortunatly :/ we are thinking of a way to make it work (even partially) without UV.

In blender it is possible to solve this problem by using the Generated output of the Texture Coordinate node

https://docs.blender.org/manual/en/latest/render/shader_nodes/input/texture_coordinate.html

so is it possible to reproduce this node in Unity?

[keenanwoodall]

Thanks for hoppin in, @andybak - I agree. I would recommend storing the original/undeformed vertex position in the vertex color or a uv channel for use by your shader. You could write a tool to do this in your modeling program, or write some editor code in Unity to automate the process on import.

To test, here's a simple asset post processor I wrote that saves the object-space vertex position to the vertex color when a model is imported into Unity. (I would be hesitant to use this unmodified in a large project, just posting it in case it helps!)

public class VertexColorModelPostProcessor : AssetPostprocessor
{
    private void OnPostprocessModel(GameObject g)
    {
        var meshFilters = g.GetComponentsInChildren<MeshFilter>();
        foreach (var meshFilter in meshFilters)
        {
            CopyPositionToColorFor(meshFilter);
        }
    }

    private void CopyPositionToColorFor(MeshFilter mf)
    {
        Mesh mesh = mf.sharedMesh;
        Vector3[] vertices = mesh.vertices;
        Color[] colors = new Color[vertices.Length];

        for (int i = 0; i < vertices.Length; i++)
        {
            var v = vertices[i];
            colors[i] = new Color(v.x, v.y, v.z, 0f);
        }

        mesh.colors = colors;
    }
}