optimize performance when normal and tangent are not necessary

[pasu]

No description provided.

[hpinkos]

Thanks @pasu, good catch!

[hpinkos]

@pasu Do we have a CLA (Contributor's License Agreement) from you? If not, can you please send one over so we can merge this? You can find instructions here: https://github.com/AnalyticalGraphicsInc/cesium/blob/master/CONTRIBUTING.md#contributor-license-agreement-cla

Thanks!

[pasu]

I add name to CONTRIBUTORS.md
But it seems there is a conflict and I have no access to modify it
It is my pleasure to make this little contribution and I hope I can make more contributions in the next year
I really think Cesium is a great virtual globe project.

[pasu]

Shall I close this request?
It is a small improvement,and I feel a little shy to interrupt you:)
@hpinkos

[hpinkos]

@pasu this is a good fix and we'd love to take it! I'm not sure if we've received your signed CLA though. Did you email that over to us? That's the only thing holding this up, the code looks good to me =)

[hpinkos]

Hi @pasu! Our contracts department is being really slow to review your CLA, so I opened my own pull request with this fix so we can get it merged in for the next release #4948

Thanks for bringing this up! It's a good improvement.

[pasu]

OK so glad to see it @hpinkos

last week, it was the Chinese Spring Festive, that is why I did not visit here in time,
Happy Chinese new year~