Week 11 - Multiple transformations support and adding tests
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.. post:: August 31 2022
   :author: Shivam Anand
   :tags: google
   :category: gsoc

What did you do this week?
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As decided last week, I added support for multiple animations at the same timestamp. But this didn't solve the animation problems of ``RiggedSimple`` model.

- I figured out that I was not applying the global transform of joints in the skinning matrix causing the joints to move to a new position. I referred to this `answer by irradicator <https://www.gamedev.net/forums/topic/703803-gltf-skinning-matrix-calculation/>`_.

- We had to invert the multiplication order  (ie, ``np.dot(skin_mat, vertex)`` instead of ``np.dot(vertex, skin_mat)``) for this model. We still need to figure out from where we get the multiplication order of the two.

    .. raw:: html

        <iframe id="player" type="text/html"   width="600" height="390" src="https://user-images.githubusercontent.com/74976752/187798821-7306cb13-dfc8-477c-8f86-1f5a6181f08a.mp4" frameborder="0"></iframe>

- I also tried to create a custom Interpolator that does all calculations required for vertex skinning. However, we couldn't get this working. I got a few suggestions from Mohamed in our meeting, I'll try to implement those.

- Added tests for animations.


What is coming up next week?
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- Adding more tests.
- Fixing the Interpolator.
- Order of multiplication in the skinning matrix.

Did you get stuck anywhere?
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No, I didn't get stuck this week.
