### Problem description
There are some obvious constrains in the various array data sizes that
we can use to determine if their sizes and in some cases their values
are correct.
### Implementation description
To test their validity, the most important of the various arrays are the
indices, so their definition and use has been simplified a great deal.
In order to treat all variables in a similar manner the changes to the
uv variable posted in an earlier PR were also added here.
With this one, all the recently opened PR's combined should contain
exactly the same changes and fixes as the older 3-d visualizer PR #1850
which I will close shortly after this one is opened.
---------
Co-authored-by: Nik <werwolv98@gmail.com>
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### Problem description
Because of `s_drawTexture` never being set to true, textures rarely or
never drew in the 3D visualizer.
### Implementation description
Set `s_drawTexture` to true when correct (valid texture file/object).
