solved Align ArcRotate camera alpha

[Xav]

Hi!

I'm having a problem with my camera alignment on the alpha axis.
I would like that when I click on a box my camera is aligned in the axis.
It works on small variation of rotation but if I pass on rotations higher than about 180 ° on my dome my camera makes a complete turn on itself and aligns itself.
Would anyone have a solution to fix the problem.
I probably do not use the good method I put you a playground with my code used:

http://www.babylonjs-playground.com/#XCGI1K

Thank you!

[Wingnut]

Hiya Xav!  OMG, 6 days with no replies?  Sorry.

I looked at your code... it is very cool.  You are very inventive.

I think what we need, here... is... orientCamPerMesh(cam, mesh) 

That would make our life easier, huh?  I will keep thinking.  Perhaps others will help.

For future info, do you want camera to z-rotate to match mesh, too?  If so, perhaps good start is to parent (Universal?) camera... to an invisible/blank "camGizmo" mesh. 

Then, don't use camera alpha, beta, at all (not available on universal cam, if used).  Just use camGizmo to do all camera orientations/positioning.

When camGizmo orientation == mesh orientation... success!  (or something explodes and scares the dog)   

I will work on this.  Sorry again for slow replies....I'm on it.

As-for animating cam/gizmo position/orientation to a DIFFERENT mesh-axis...  phew... that seems harrrrrd.    Gods are nearby, though. 

I think we need "Quorbits".  Quarter-orbits... around the mesh (after doing an initial orientCamPerMesh(), of course (after someone codes it). 

Continuous/locked camGizmo.lookAt(mesh.position) might be handy, here, too.  Stay tuned.

Update:  I did some goofing-around with this playground... having some fun trying "meshAddingMode"    [ link ]  Control-drag for ArcCam target-moving.  Many camera adjustments made, added click-on-dome -> re-init cam, added click-on-mesh -> camera.target == picked mesh.   Lots of experimental stuff.   I haven't begun anything difficult, yet.  I think I'm stalling. 

[Xav]

Hello Wingnut thank you for your help.

I simplified the playground:

http://www.babylonjs-playground.com/#XCGI1K#7

There are now only two cubes. A blue and a yellow.
When we click on everything works (until everything is fine;).

The problem is that after several clicks in transition the camera makes a complete turn on itself?
The problem would not it that the camera returns an angle of 6.2831853072 rad for 360 ° at a time whereas finally one does only half turn of 3.1415926536 rad for 180 °?

Is there not a tool to normalize the angle of rotation so that it takes the shortest path rather than making a complete turn?

I hope to be clear enough in my explanation because you have to click several times to see the bug and the camera that runs a lot too.
 

Thank you.

[RaananW]

Oh, this playground made my eyes a bit soar

But all good!

You found the problem, now here is the simple solution - http://www.babylonjs-playground.com/#XCGI1K#8 . % (math.PI*2) times the alpha (and beta), will keep the path liner, as it will never be above Math.PI*2

Hope this helped!

[Wingnut]

Hi @RaananW, thx4help!

   I still see a "long animation", under certain circumstances.

Run #8, then pan camera right... past the yellow box, past the blue box again, and then click on yellow.

I see camera alpha animation "unwind".  Anyone else see that?  Probably easier to see with slower animation.  *scratch scratch*

[RaananW]

Ohhh, negative values

Here - http://www.babylonjs-playground.com/#XCGI1K#9 . JavaScript % operator is sometimes weird...

[Wingnut]

Thx @RaananW!   Did you test the other way?  Pan left, past yellow, past blue, then click yellow.  Same problem, the other way, it seems.

What a pain-in-the-butt I am, eh?  Sorry.

[RaananW]

It is all about getting both values to be maximum Math.PI*2 apart from each other.  I allow you guys to find a nice solution to achieve that  

[Wingnut]

Ok Xav, Raanan says it's time for helper-bail, so I guess you have all the tools to get the job done.  I have plenty of other stalled user-issues to work-on, so, good luck.  Thx for info/help, Raanan... I think you are correct... Xav has some new knowledge, now.  Me, too.

Give it a good try, Xav.  Holler-back later if you get stuck.

[Xav]

Thank you for your time.
I will take the time to look at this to find the solution.

Good luck and thank you again 

[Xav]

Hi !

I think I have fixed the problem:

Ligne 52 with this condition  if (EndAlpha - StartAlpha > Math.PI){ EndAlpha = EndAlpha - (Math.PI*2); }

http://www.babylonjs-playground.com/#XCGI1K#11

Thank you for putting me on the right path