Host API usability improvements (Babylon)

[Krxtopher]

Issue # SUMERIAN-11037

Description of changes:

Scope

The focus of this pull request is to encapsulate the ~350 lines of boilerplate code required to instantiate a host in BabylonJS (as demonstrated in our old example HTML file) to improve ease of use for users of the Hosts library. That boilerplate code is now encapsulated in a new module called HostUtils which exposes a simple createHost() function and a getCharacterConfig() function.

The old example app has been removed and two new examples have been added. These are the "hello-world-demo" and "gesture-demo" examples found under /packages/amazon-sumerian-hosts-babylon/examples.

Out of Scope

• Improving the implementation of the boilerplate code itself.
• Adding a similar HostUtils module to the Three.js implementation. That implementation will continue to use the verbose example file for now.
• Although I've added some minimal unit tests for HostUtils, most of the functionality must be manually tested by running the provided examples and observing expected host behavior.

Files to review

You can ignore many of the auto-generated files. The files to review explicitly are:

• The following files under /packages/amazon-sumerian-hosts-babylon/src/Babylon.js/
  • HostUtils.js
  • index.js
• The new test spec: /packages/amazon-sumerian-hosts-babylon/test/unit/HostUtils.spec.js
• All files under /packages/amazon-sumerian-hosts-babylon/examples
• Any webpack config files
• Any package.json files
• Review the updated auto-generated API docs in a browser. It is not necessary to review the source code of these autogenerated files. See below for more detail on how to review the updated API docs.

How to test

Prerequisites: You must have a Cognito Identity Pool created in your AWS account. The unauthenticated IAM role for the pool (usually ending in the suffix "Unauth_Role") must have the following managed policies assigned to it:

• AmazonPollyReadOnlyAccess
• (optional) AmazonLexRunBotsOnly (optional for this PR)

Check out the repository.

In a terminal, cd to the repository's root directory.

Run npm install.

Update the following file to reflect your Cognito Identity Pool ID: /packages/amazon-sumerian-hosts-babylon/examples/common/demo-credentials.js

Run npm run babylon-examples-serve from the root of the repo. This will automatically start a web server and open a web browser to a listing of the available demos. Click either of the demos to test. If the hosts work properly, then the code is working!

How to review API doc updates

Open the following file in a browser: /docs/index.html

Use the left-hand nav to navigate to "Namespaces > babylonjs/HostUtils".

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

PR Update 1:

• I've removed generated "docs" files from the repo

[runpiw]

We should probably also update Readme to reflect the new script to run babylon example

[Krxtopher]

We should probably also update Readme to reflect the new script to run babylon example

There are lots of updates needed for the README. There's a whole epic devoted to updating documentation, so this will happen as part of that epic.