Misc WebGL Example Fixes

[aceslowman]

Changes:

• In the Passing Shader Uniforms example I've fixed an issue where the geometry was being displayed mostly off-screen. It should now be centered.
• The Primitives example was missing an ellipsoid shape.
• Multiple Lights example was missing a spotLight().

Additionally I added describe() in each of these example sketches.

For GSOC 2022
mentor: @kjhollen

[kjhollen]

Looks good to me! I'm going to build this locally, just to make sure everything runs, then I'll merge.

[kjhollen]

Just one question from running code—see below.

[kjhollen]

@aceslowman hmm, this doesn't appear in the center of the sketch for me. it's in the lower left quadrant. using just resolution (or the * 1.0) works. is that expected?

[aceslowman]

That's strange! Just checked on my end, and it's displaying fine for me, in the middle of the screen. Also made sure that it was getting the updated uniforms.frag. Any clue why this might be different between our machines?

[aceslowman]

Also, just caught some issue with line-endings, it wasn't loading for me until I changed the updated example files from CRLF to LF, otherwise I was getting 404s and the files weren't being properly assembled. I thought that the .gitattributes PR resolved this, not sure what is going on.

[Qianqianye]

Thanks @aceslowman and @kjhollen for working on this. Please let us know if you need any help to get this PR merged.

[kjhollen]

@aceslowman I think I figured out what's happening with the center item in the shader uniforms example. I must have been looking at the example on my laptop, which has a 2x retina display. I was able to get the object to center by changing the code to:

theShader.setUniform('resolution', [width * displayDensity(), height * displayDensity()]);

If you make this change, I think we'll be ready to merge from there.

[aceslowman]

@kjhollen Just committed the fix you described and it seems to work well on my end. Quick question, I merged 'main' before making this commit, should I have held off on that?

[kjhollen]

@aceslowman should be fine, I'll build this on my end before I merge it just to be sure!

[davepagurek]

The density fix looks good!