SimplifyModifier: Add check if face are not undefined.

[Suprhimp]

add check if face are not undefined

check with u.faces[i]

Description

add condition for undefined for loop

Now I’m making code for web 3d world viewer. I want to make lod system for my world and for that, I have to use simplify modifier for this.

Anyway, when I use simplify modifier to simplify gltf model it shows error with this

SimplifyModifier.js:293 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'hasVertex')
    at collapse (SimplifyModifier.js:293:1)
    at SimplifyModifier.modify (SimplifyModifier.js:99:1)

I spend lot of time to search about it, but I can’t find the hint

So I console log it to find out what happen to simplify modifier and I think this might be reason.

I console log this loop

  for (let i = u.faces.length - 1; i >= 0; i--) {
    console.log(u, i);
    if (u.faces[i].hasVertex(v)) {
      removeFace(u.faces[i], faces);
    }
  }

I found that when removeFace function run, it sometimes remove two faces at one loop. As you can see in picture above, first length of u.faces.length = 8, and value i = 7, at second loop u.faces.length = 6, and value i = 6 this cause error.

Is it okay with just add if (!u.faces[i]) continue; in for loop?
it seems running but I think it work not propery.

This contribution is funded by forum

[mrdoob]

Thanks!