Voxel-animation history

AnimationDocument is a CommandDocument from @jolly-pixel/history, so it can be registered in a CommandHistory directly. animationHistoryKeys(set) returns the keys that registration needs. Everything below is exported from @jolly-pixel/asset.voxel-animation/client.

import { CommandHistory } from "@jolly-pixel/history";
import {
  AnimationDocument,
  animationHistoryKeys
} from "@jolly-pixel/asset.voxel-animation/client";

const document = new AnimationDocument();
const history = new CommandHistory<"animate">();
history.register({
  id: "set",
  document,
  keys: animationHistoryKeys(document.set),
  resolveScope: () => "animate"
});

const step = history.open("animate", "Add walk");
document.addClip({ name: "Walk" });
step.commit();

history.undo("animate");

Register synced.document when the set is synced: the sync client fills its receipts, so the history can refuse steps a peer overwrote and send undos the server can refuse.

What is recorded

Every local edit of the rig, clips, tracks and keys. A change carries the commands that undo it (inverse) and an image of what it touched, as it was before.

Not recorded: commands applied with apply() (peer commands) or replayPending(), and snapshots loaded with load(), which emits reset.

Steps and refusals

• A step guards the values its undo would write back, per conflict key. Undoing a clip's creation also guards the clip's tracks.
• A peer write to a guarded value refuses the step.
• An undo is sent with the basis of the step, the room version it replays. The server refuses it when a peer wrote a newer value since. See architecture.
• A re-added or moved clip whose former next clip is gone lands last.

API

type AnimationChange = CommandChange<AnimationCommand, AnimationImage>;

function animationHistoryKeys(set: AnimationSetReader): HistoryKeys<AnimationCommand, AnimationImage>;

animationHistoryKeys() writes the conflict keys of each change, plus clip-content:<id> for any key or track change in the clip.