ai-chatbot/lib/video-canvas/director-object-tracks.ts

import type { DirectorScene, DirectorObject, DirectorVector } from "./director-scene";
export type DirectorObjectFrame = {
  id: string;
  time: number;
  position: DirectorVector;
  rotation: DirectorVector;
  scale: DirectorVector;
  visible: boolean;
};
export type DirectorObjectTrack = {
  muted: boolean;
  easing: "linear" | "smooth";
  keyframes: DirectorObjectFrame[];
};
export function readObjectTracks(
  value: unknown,
  objects: DirectorObject[],
  duration: number,
): Record<string, DirectorObjectTrack> {
  if (!value || typeof value !== "object" || Array.isArray(value)) return {};
  const vector = (v: any, positive = false) =>
    Array.isArray(v) &&
    v.length === 3 &&
    v.every(
      (n: any) =>
        typeof n === "number" && Number.isFinite(n) && Math.abs(n) <= 10000 && (!positive || n > 0),
    );
  return Object.fromEntries(
    Object.entries(value)
      .filter(([id]) => objects.some((o) => o.id === id))
      .map(([id, raw]) => {
        const t = raw as any,
          seen = new Set<number>(),
          ids = new Set<string>();
        const keyframes = (Array.isArray(t?.keyframes) ? t.keyframes : [])
          .filter((k: any) => {
            if (
              !k ||
              typeof k.id !== "string" ||
              ids.has(k.id) ||
              typeof k.time !== "number" ||
              !Number.isFinite(k.time) ||
              k.time < 0 ||
              k.time > duration ||
              seen.has(k.time) ||
              !vector(k.position) ||
              !vector(k.rotation) ||
              !vector(k.scale, true)
            )
              return false;
            seen.add(k.time);
            ids.add(k.id);
            return true;
          })
          .slice(0, 100)
          .map((k: any) => ({
            id: k.id,
            time: k.time,
            position: [...k.position],
            rotation: [...k.rotation],
            scale: [...k.scale],
            visible: k.visible !== false,
          }))
          .sort((a: any, b: any) => a.time - b.time);
        return [
          id,
          {
            muted: t?.muted === true,
            easing: t?.easing === "smooth" ? "smooth" : "linear",
            keyframes,
          },
        ];
      }),
  );
}
export function sampleDirectorObjects(scene: DirectorScene, time: number | null): DirectorObject[] {
  if (time === null) return scene.objects;
  return scene.objects.map((object) => {
    const track = scene.objectTracks?.[object.id];
    if (!track || track.muted || !track.keyframes.length) return object;
    const keys = track.keyframes,
      t = Math.max(0, Math.min(scene.motion.duration, time)),
      right = keys.findIndex((k) => k.time > t);
    const a = right < 0 ? keys[keys.length - 1] : keys[Math.max(0, right - 1)],
      b = right < 0 ? a : keys[right];
    let u = a === b ? 0 : Math.max(0, Math.min(1, (t - a.time) / (b.time - a.time)));
    if (track.easing === "smooth") u = u * u * (3 - 2 * u);
    const vector = (x: DirectorVector, y: DirectorVector, rotation = false): DirectorVector =>
      x.map((n, i) => {
        let delta = y[i] - n;
        if (rotation) delta = Math.atan2(Math.sin(delta), Math.cos(delta));
        return n + delta * u;
      }) as DirectorVector;
    return {
      ...object,
      position: vector(a.position, b.position),
      rotation: vector(a.rotation, b.rotation, true),
      scale: vector(a.scale, b.scale),
      visible: a.visible,
    };
  });
}
export function recordObjectFrames(
  scene: DirectorScene,
  ids: string[],
  time: number,
  id: () => string,
): DirectorScene {
  if (!Number.isFinite(time) || time < 0 || time > scene.motion.duration)
    throw Error("关键帧时间超出时间轴");
  const tracks = { ...scene.objectTracks };
  for (const object of scene.objects.filter((o) => ids.includes(o.id))) {
    const track = tracks[object.id] || { muted: false, easing: "linear" as const, keyframes: [] };
    const existing = track.keyframes.find((k) => Math.abs(k.time - time) < 0.01);
    if (!existing && track.keyframes.length >= 100) throw Error("每个对象最多 100 个关键帧");
    const frame = {
      id: existing?.id || id(),
      time: existing?.time ?? Math.round(time * 100) / 100,
      position: [...object.position] as DirectorVector,
      rotation: [...object.rotation] as DirectorVector,
      scale: [...object.scale] as DirectorVector,
      visible: object.visible !== false,
    };
    tracks[object.id] = {
      ...track,
      keyframes: [...track.keyframes.filter((k) => k.id !== frame.id), frame].sort(
        (a, b) => a.time - b.time,
      ),
    };
  }
  return { ...scene, objectTracks: tracks };
}
export function resizeObjectTracks(
  tracks: Record<string, DirectorObjectTrack> | undefined,
  oldDuration: number,
  newDuration: number,
) {
  return Object.fromEntries(
    Object.entries(tracks || {}).map(([id, t]) => [
      id,
      {
        ...t,
        keyframes: t.keyframes.map((k) => ({ ...k, time: (k.time * newDuration) / oldDuration })),
      },
    ]),
  );
}