Fixed wrong marginal function.

[thogerig]

The marginal function to mask a MoMo gave wrong results. The reason was that the masked mesh can result in a different amount of PointIds. Since the mask MoMo function depends on the mesh in contrast to the marginal function for the GP, I would propose to rename it to mask().

[BernhardEgger]

See https://github.com/unibas-gravis/scalismo-faces/pull/95 for previous discussions

[thogerig]

I like the second idea also the most. How about passing the MeshCompactifier instead of a PointId list?

  def mask(originalMomo: MoMo, reducedMesh: MeshCompactifier): MoMo = {

      val maskedMesh = reducedMesh.transformedMesh
      val remainingPtIds = maskedMesh.pointSet.pointIds.map(id => reducedMesh.pointBackMap(id)).toIndexedSeq
      val maskedModelShape = originalMomo.neutralModel.shape.marginal(remainingPtIds)
      val maskedModelColor = originalMomo.neutralModel.color.marginal(remainingPtIds)
      MoMo(maskedMesh, maskedModelShape, maskedModelColor)
...

This is, however also not completely clean because the mesh given to the MeshCompactifier must be the models reference mesh.

[thogerig]

After some discussions, here a revised implementation:

• Since it does not behave as the original marginal function, I removed them from the MoMo class and moved them over to ModelHelpers.
• In addition to the Seq[PointId] also the masked mesh itself is supported.

What do you think of this change?

[Andreas-Forster]

Thank you for your update. I think it might be a good idea to make the things that can go wrong more transparent and provide the user with feedback what went wrong. So I encapsulated the return type in a Try and provided feedback in erroneous situations. What do you think about this?

[Andreas-Forster]

I added some tests and fixed a bug I discovered while developing the tests.

[thogerig]

Thanks for the additions and the bug fix. From my side the changes are fine.