

Warcraft: Skies of Azeroth – 360 video - Betelgeuse90
https://www.youtube.com/watch?v=K_J8k43gUhY

======
Betelgeuse90
Does anyone know what makes this "video" tick?

I have a couple of ideas but I prefer informed answers over my guesswork.

~~~
RGamma
If you want more than just an idea, download the video with e.g. youtube-dl
and see what it looks like in its unprojected form.

Example screenshot:
[https://i.imgur.com/z2fwIzJ.png](https://i.imgur.com/z2fwIzJ.png)

~~~
Betelgeuse90
Thanks! Interesting..

So if I'm understanding correctly it's doing a spherical projection onto a
plane, we get to navigate that plane, and every snippet of that plane-
projection we see is being projected back into 3D somehow?

It can't actually reconstruct the 3D environment from the projection, so
what's actually happening there at the end?

~~~
RGamma
I'm no expert on this topic, but browsing
[http://paulbourke.net/geometry/transformationprojection/](http://paulbourke.net/geometry/transformationprojection/)
this seems a lot like an "equirectangular projection" (purely visually), which
according to
[http://mathworld.wolfram.com/CylindricalEquidistantProjectio...](http://mathworld.wolfram.com/CylindricalEquidistantProjection.html)
can be inverted.

So if we navigate the plane with the projection of the sphere on it and apply
the reverse transform to the snippet we're viewing (genuine question: what
form and size would the snippet need to have?) it seems we would get the
effect of being inside the sphere.

~~~
Betelgeuse90
I don't know the form and size of the snippet, I'm assuming it's rectangular
because I don't see a reason for it not to be..

I think We're still having an issue at the poles: If you take a rectangular
snippet out of the image you've uploaded which its topmost edge coincides with
the topmost part of the image, what can we expect the transformation to yield?

They might be dealing with edge cases behind the scenes in some way.
Mathematically speaking there can't be a way to fully invert a transformation
from 3D to 2D, so I guess they settled for something that they can still work
around.

In any case even though I'd like to know the exact details, at this point my
curiosity seems to be satiated.

Thanks for the friendly conversation. :)

