reorder morph animations according to actual mesh morph targets

lib/animations/animation_builder.dart

@@ -49,7 +49,6 @@ class AnimationBuilder {
         meshName,
         morphData,
         _morphTargets.map((i) => availableMorphs[i]).toList(),
-        _morphTargets,
         _frameLengthInMs);
   }
 

lib/animations/animation_data.dart

@@ -1,32 +1,30 @@
-//
-// A wrapper for morph target animation data.
-// [data] is laid out as numFrames x numMorphTargets (where each morph target is ordered according to [animatedMorphNames]).
-// [data] frame data for the morph weights used to animate the morph targets [animatedMorphNames] in mesh [meshName].
-// the morph targets specified in [morphNames] attached to mesh [meshName].
-// [animatedMorphNames] must be provided but is not used directly; this is only used to check that the eventual asset being animated contains the same morph targets in the same order.
-//
 import 'dart:typed_data';
 
+///
+/// Specifies frame data (i.e. weights) to animate the morph targets contained in [morphTargets] under a mesh named [mesh].
+/// [data] is laid out as numFrames x numMorphTargets.
+/// Each frame is [numMorphTargets] in length, where the index of each weight corresponds to the respective index in [morphTargets].
+/// [morphTargets] must be some subset of the actual morph targets under [mesh] (though the order of these does not need to match).
+///
 class MorphAnimationData {
   final String meshName;
-  final List<String> animatedMorphNames;
-  final List<int> animatedMorphIndices;
+  final List<String> morphTargets;
 
   final List<double> data;
 
-  MorphAnimationData(this.meshName, this.data, this.animatedMorphNames,
-      this.animatedMorphIndices, this.frameLengthInMs) {
-    assert(data.length == animatedMorphNames.length * numFrames);
+  MorphAnimationData(
+      this.meshName, this.data, this.morphTargets, this.frameLengthInMs) {
+    assert(data.length == morphTargets.length * numFrames);
   }
 
-  int get numMorphTargets => animatedMorphNames.length;
+  int get numMorphTargets => morphTargets.length;
 
   int get numFrames => data.length ~/ numMorphTargets;
 
   final double frameLengthInMs;
 
   Iterable<double> getData(String morphName) sync* {
-    int index = animatedMorphNames.indexOf(morphName);
+    int index = morphTargets.indexOf(morphName);
     for (int i = 0; i < numFrames; i++) {
       yield data[(i * numMorphTargets) + index];
     }

lib/filament_controller.dart

@@ -229,10 +229,10 @@ abstract class FilamentController {
       FilamentEntity entity, int animationIndex);
 
   ///
-  /// Create/start a dynamic morph target animation for [asset].
-  /// Animates morph target weights/bone transforms (where each frame requires a duration of [frameLengthInMs].
-  /// [morphWeights] is a list of doubles in frame-major format.
-  /// Each frame is [numWeights] in length, and each entry is the weight to be applied to the morph target located at that index in the mesh primitive at that frame.
+  /// Animate the morph targets in [entity]. See [MorphTargetAnimation] for an explanation as to how to construct the animation frame data.
+  /// This method will check the morph target names specified in [animation] against the morph target names that actually exist exist under [meshName] in [entity],
+  /// throwing an exception if any cannot be found.
+  /// It is permissible for [animation] to omit any targets that do exist under [meshName]; these simply won't be animated.
   ///
   Future setMorphAnimationData(
       FilamentEntity entity, MorphAnimationData animation);

lib/filament_controller_ffi.dart

@@ -570,7 +570,7 @@ class FilamentControllerFFI extends FilamentController {
 
   @override
   Future setMorphAnimationData(
-      FilamentEntity asset, MorphAnimationData animation) async {
+      FilamentEntity entity, MorphAnimationData animation) async {
     if (_viewer == null) {
       throw Exception("No viewer available, ignoring");
     }
@@ -580,14 +580,27 @@ class FilamentControllerFFI extends FilamentController {
       dataPtr.elementAt(i).value = animation.data[i];
     }
 
-    Pointer<Int> idxPtr = calloc<Int>(animation.animatedMorphIndices.length);
+    // the morph targets in [animation] might be a subset of those that actually exist in the mesh (and might not have the same order)
+    // we don't want to reorder the data (?? or do we? this is probably more efficient for the backend?)
+    // so let's get the actual list of morph targets from the mesh and pass the relevant indices to the native side.
+    var meshMorphTargets =
+        await getMorphTargetNames(entity, animation.meshName);
+
+    Pointer<Int> idxPtr = calloc<Int>(animation.morphTargets.length);
     for (int i = 0; i < animation.numMorphTargets; i++) {
-      idxPtr.elementAt(i).value = animation.animatedMorphIndices[i];
+      var index = meshMorphTargets.indexOf(animation.morphTargets[i]);
+      if (index == -1) {
+        calloc.free(dataPtr);
+        calloc.free(idxPtr);
+        throw Exception(
+            "Morph target ${animation.morphTargets[i]} is specified in the animation but could not be found in the mesh ${animation.meshName} under entity ${entity}");
+      }
+      idxPtr.elementAt(i).value = index;
     }
 
     _lib.set_morph_animation(
         _assetManager!,
-        asset,
+        entity,
         animation.meshName.toNativeUtf8().cast<Char>(),
         dataPtr,
         idxPtr,

lib/filament_controller_method_channel.dart

@@ -360,19 +360,7 @@ class FilamentControllerMethodChannel extends FilamentController {
   ///
   Future setMorphAnimationData(
       FilamentEntity asset, MorphAnimationData animation) async {
-    if (_viewer == null || _resizing) {
-      throw Exception("No viewer available, ignoring");
-    }
-    await _channel.invokeMethod("setMorphAnimation", [
-      _assetManager,
-      asset,
-      animation.meshName,
-      animation.data,
-      animation.animatedMorphIndices,
-      animation.numMorphTargets,
-      animation.numFrames,
-      animation.frameLengthInMs
-    ]);
+    throw Exception("No viewer available, ignoring");
   }
 
   ///