CONTRIBUTING.md

Contributing

Quickstart

# Install dependencies.
yarn

# Build source, watch for changes.
yarn watch

# Build source, watch for changes, and run examples.
yarn dev

# Run tests.
yarn test

Concepts

The project is designed around a few common object types, loosely based on reactive programming patterns.

• Subject: Each glTF definition (e.g. Material) is bound to a single Subject (e.g. MaterialSubject). The Subject is responsible for receiving change events published by the definition, generating a derived three.js object (e.g. THREE.Material), and publishing the new value to all Observers. More precisely, this is a BehaviorSubject, which holds a single current value at any given time.
• Observer: An Observer is subscribed to the values published by a particular Subject, and passes those events along to a parent — usually another Subject. For example, a MaterialSubject subscribes to updates from a TextureSubject using an Observer. Observers are parameterized: for example, a single Texture may be used by many Materials, with different offset/scale/encoding parameters in each. The TextureSubject treats each of these Observers as a different "output", and uses the parameters associated with the Observer to publish the appropriate value. This library implements three observer types: RefObserver, RefListObserver, and RefMapObserver; the latter two are collections of RefObservers used to collate events from multiple Subjects (e.g. lists of Nodes).
• Pool: As Subjects publish many variations of the same values to Observers, it's important to allocate those variations efficiently, reuse instances where possible, and clean up unused instances. That bookkeeping is assigned to Pools (not a Reactive concept).

The diagram below shows a subset of the data flow sequence connecting Texture, Material, Primitive, and Node data types.