Animation rows can target behavior variables and shader parameters (#104)

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/core/model/animationPreview.ts

@@ -5,9 +5,9 @@
  */
 import {
   animatableDefs,
-  animatedKind,
+  animatableDefsOf,
   frameCount,
-  isPositionKey,
+  isPositionRow,
   PLACED_ROOT_ID,
   placedRoot,
   playbackOf,
@@ -16,9 +16,7 @@ import {
 import type { AnimationAsset, AnimationTrack, Asset } from './Asset';
 import { instanceChildId, objectRef } from './instance';
 import { findAsset, type ObjectHolder, type Project } from './Project';
-import type { PropertyValue } from './Properties';
 import { resolveSceneObjectProps } from '../properties/resolve';
-import type { SceneObject } from './SceneObject';
 
 /** The one object the preview places the root on – what a row aimed at the root itself writes to. */
 export const PREVIEW_ROOT_ID = PLACED_ROOT_ID;
@@ -91,17 +89,17 @@ function writeObject(
 ): void {
   const ref = objectRef(project, holder, id);
   const asset = ref && findAsset(project, ref.object.assetId);
-  const kind = asset && animatedKind(asset.type, track.property);
-  if (!ref || !asset || !kind) return;
-  const value = trackWriteAt(track, kind, frame, baseOf(project, asset, ref.object, track.property), reverse);
-  if (value === undefined) return;
-  if (isPositionKey(track.property))
-    ref.setPosition({ ...ref.object.position, [track.property]: Number(value) });
-  else ref.setOverride(track.property, value);
-}
-
-/** What the target holds before the animation writes it: the zero of a relative row. */
-function baseOf(project: Project, asset: Asset, object: SceneObject, key: string): PropertyValue | undefined {
-  if (isPositionKey(key)) return object.position[key];
-  return resolveSceneObjectProps(project, asset, object)[key];
+  if (!ref || !asset) return;
+  // Resolved, so a shader worn through an override or an instance edit brings its parameters (#104).
+  const props = resolveSceneObjectProps(project, asset, ref.object);
+  const kind = animatableDefsOf(project, asset, props).find((d) => d.key === track.property)?.kind;
+  if (!kind) return;
+  const key = track.property;
+  if (isPositionRow(asset.type, key)) {
+    const value = trackWriteAt(track, kind, frame, ref.object.position[key], reverse);
+    if (value !== undefined) ref.setPosition({ ...ref.object.position, [key]: Number(value) });
+    return;
+  }
+  const value = trackWriteAt(track, kind, frame, props[key], reverse);
+  if (value !== undefined) ref.setOverride(key, value);
 }