Add rotation from one vector3 to another

[BabylonJSGuide]

First commit wherever a result was returned this is now reflected in comments. Only comments changed, if current vector was returned then this was kept and and comment not changed. Ref https://forum.babylonjs.com/t/comments-refer-to-wrong-vectors-returned-by-method-using-toref/34093/3?u=johnk

An alternative way of managing an animation along a curve by calculating the rotation needed from a set rotation to a tangent. Example PGs to follow.

[azure-pipelines]

Please make sure to label your PR with "bug", "new feature" or "breaking change" label(s).
To prevent this PR from going to the changelog marked it with the "skip changelog" label.

[azure-pipelines]

Snapshot stored with reference name:
refs/pull/13004/merge

Test environment:
https://babylonsnapshots.z22.web.core.windows.net/refs/pull/13004/merge/index.html

To test a playground add it to the URL, for example:

https://babylonsnapshots.z22.web.core.windows.net/refs/pull/13004/merge/index.html#WGZLGJ#4600

Links to test babylon tools with this snapshot:

https://playground.babylonjs.com/?snapshot=refs/pull/13004/merge
https://sandbox.babylonjs.com/?snapshot=refs/pull/13004/merge
https://gui.babylonjs.com/?snapshot=refs/pull/13004/merge
https://nme.babylonjs.com/?snapshot=refs/pull/13004/merge

To test the snapshot in the playground with a playground ID add it after the snapshot query string:

https://playground.babylonjs.com/?snapshot=refs/pull/13004/merge#BCU1XR#0

[RaananW]

Just two comments! thanks :-)

[RaananW]

changes look good to me. i'll let @sebavan give the final ok

[james-pre]

@BabylonJSGuide I tried to make a PG with this but it does not work: https://playground.babylonjs.com/#QYA3JC#24

[BabylonJSGuide]

@dr-vortex Will produce a working PG tomorrow. Will also study your PR to see if it has any advantages.

[james-pre]

Thanks!

Might I also recommend we move the rotation between vectors related stuff to #13012?

[sebavan]

Flagging as Request changes to prevent accidental merge waiting on #13012 comments resolution.

[BabylonJSGuide]

Thanks!

Might I also recommend we move the rotation between vectors related stuff to #13012?

No for the following reasons.

1. Each need to stand seperately on their own merits.
2. At the moment I do not understand the way your function is used and would need to see if they were sufficient differences
3. As I stated earlier I will study your method and get to understand it and see if it has any advantages/differences

[BabylonJSGuide]

Finally undertsand @dr-vortex 's method. As a mathematician when I talk about vectors I automatically think direction, whilst for his finction he his thinking position. My function finds the rotation between to direction vectors, whilst his find the rotation needed for the mesh to travel along a straight line joining two position vectors or points. Hence the confusion.

dr-vortex examples that I now follow https://playground.babylonjs.com/#QYA3JC#28, https://playground.babylonjs.com/#QYA3JC#29

@RaananW and @sebavan I will leave it up to you whether you decide whether either, both or neither are sufficiently different to what is already possible to accept the PRs.

I have made some suggests on #13012

[BabylonJSGuide]

First PG test for my method https://playground.babylonjs.com/?snapshot=refs/pull/13004/merge#S7HDGQ
2nd test for my method https://playground.babylonjs.com/?snapshot=refs/pull/13004/merge#S7HDGQ#1

[sebavan]

Only one tiny comment and good to go !!! thanks

[BabylonJSGuide]

1st test rotationQuaternion method https://playground.babylonjs.com/?snapshot=refs/pull/13004/merge#S7HDGQ#6
2nd test rotationQuaternion method https://playground.babylonjs.com/?snapshot=refs/pull/13004/merge#S7HDGQ#7