Cannot override `vertexNode` of instanced mesh with morphTargets (TSL)

[Bug-Reaper]

Description

I've had mixed luck in the past doing a custom vertexNode for instanced mesh like so:

// insty is a shared instanced buffer attribute
const vOverride= Fn(()=>{
return mul(
      cameraProjectionMatrix, // Takes the shape of the camera into account?
      modelViewMatrix, // Takes the position of the camera into account
      insty.element(instanceIndex),
      vec4(mul(positionGeometry.xyz,noiseMix), 1)
    );
}

However when I go to try this with my instanced-mesh with morph-targets I get no errors but also nothing draws on screen.

Reproduction steps

Spent a day trying to figure this out and AFAIK it's impossible to do a VertexNode that properly replicates the original behavior of an instancedMesh material's vertexNode so it can be modified?

Ideally I'd also be able to use the InstanceMatrix and other built-in attributes instead of rolling my own?

Code

Best attempt so far:

// insty is a shared instanced buffer attribute
const vOverride= Fn(()=>{
return mul(
      cameraProjectionMatrix, // Takes the shape of the camera into account?
      modelViewMatrix, // Takes the position of the camera into account
      insty.element(instanceIndex),
      vec4(mul(positionGeometry.xyz,noiseMix), 1)
    );
}

Live example

Will try and setup fiddle if I have time.
EDIT: https://jsfiddle.net/q28ast3k/9/

Screenshots

No response

Version

r176

Device

Desktop, Mobile

Browser

Firefox, Safari, Chrome

OS

MacOS, Windows, Linux

[Mugen87]

Try it with positionLocal instead of positionGeometry.

positionGeometry represents the plain position attribute data. positionLocal instead honors vertex transformations that have been added via skinning or morphing as well as additional transformations via instancing and batching.

[Bug-Reaper]

Hey @Mugen87 very much appreciate the explanation, unfortunately no-dice w/ positionLocal for me.

🎉 : Got a Fiddle up:
https://jsfiddle.net/q28ast3k/9/

It has a simple vertexNode replacement logic at the bottom.

you can observe the instanced-mesh normally by commenting out the vertexNode override. pictured below:

Feels like when you replace the vertexNode it breaks things and/or doesn't expose GPU vars you'd want via TSL.

CC fellow TSL instanced mesh pioneers [ @Makio64 @cmhhelgeson ]