Start to backfill some protocol documentation

[jwnimmer-tri]

See here for a rendered preview.

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This change is 

[jwnimmer-tri]

+@SeanCurtis-TRI could I ask for any early feature-review feedback here? I still have some TODOs to fill out, but I should probably check if I'm moving in the right direction.

[SeanCurtis-TRI]

I think this is good. I do somewhat bemoan the informality. There's a part of me wondering if some kind of grammar definition wouldn't be helpful. Especially for the complex set_object(). But this is a definite improvement.

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[jwnimmer-tri]

Thanks. I'll ping you again once I have the additional JSON examples filled in. My hope is that will help mitigate the lack of a more structured specification.

[jwnimmer-tri]

This is ready for a full review no.

No particular rush, I just want to have this baseline ready for when I start changing the protocol (by allowing url instead of data for assets).

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[jwnimmer-tri]

This is ready for a full review now*.

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[jwnimmer-tri]

Reviewed 1 of 1 files at r3, all commit messages.
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[SeanCurtis-TRI]

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test/texture_text.html line 50 at r3 (raw file):

                        transparent: true,
                        map: "0c8c99a8-bba8-11ee-b7a2-4b79088b524d",
                    }

BTW If you change the default sided-ness to "2", you can read the text on both sides. The test, as is, is sufficient to show that the text textures work. Extending it slightly to make the text visible from both sides may serve further pedagogical value.

Suggestion:

                    {
                        uuid: "6fe7011b-bba7-11ee-b7a2-4b79088b524d",
                        type: "MeshPhongMaterial",
                        transparent: true,
                        map: "0c8c99a8-bba8-11ee-b7a2-4b79088b524d",
                        // Make the text visible front and back (double sided).
                        side: 2,
                    }

[jwnimmer-tri]

Reviewed 1 of 1 files at r4, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @jwnimmer-tri)