ClosestPoint() implementation for meshes

Discussed in https://github.com/GSharker/G-Shark/discussions/415

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^{Originally posted by iltabe May 30, 2023} Hi guys!

I know some of you for different reasons! Ciao!

For a client I’m building an algorithm that requires some geometrical operations. I’ve looked into G-Shark and started to use it. It looks promising and does almost everything I need (basic vector, point, plane stuff). Thanks guys for having give birth to this nice project!

The only thing I miss is a mesh.ClosestPoint(Point3 pt) method… Is it in the todo list by any luck? Thanks! Gianluca</div>

It would be nice to implement some functionality for meshes, especially myMesh.ClosestPoint(Point3 test_point). The behaviour I expect is to get back from the function the real closest point:

1. on a mesh vertex, if the mesh vertex is the closest point to the test point
2. on a mesh face boundary (edge) if that is the closest point to the test point
3. a point inside a mesh face if the length of the line perpendicular to the face (and passing per test_point) is shorter to any other line connecting test_point to the mesh.

Long story short: the closest point! 😃

[iltabe]

Hi there!

We found a bit of internal resources to work on this, so we started a first implementation. We will open a PR in the next few days/weeks. Thanks!

[iltabe]

Ciao @d3ssy, The PR regarding mesh closest point is out. Who is the best person to be tagged as reviewer? Thanks!