add method for setting material color

example/lib/main.dart

@@ -218,6 +218,9 @@ class _ExampleWidgetState extends State<ExampleWidget> {
             .build();
         _filamentController.setMorphAnimationData(_cube!, animation);
       }, "animate morph weights #3 and #4"),
+      _item(() {
+        _filamentController.setMaterialColor(_cube!, "Cone", 0, Colors.purple);
+      }, "set cone material color to purple")
     ];
     if (_animations != null) {
       children.addAll(_animations!.map((a) => _item(() {

ios/Classes/SwiftPolyvoxFilamentPlugin.swift

@@ -615,7 +615,18 @@ public class SwiftPolyvoxFilamentPlugin: NSObject, FlutterPlugin, FlutterTexture
         case "setCameraFocusDistance":
             set_camera_focus_distance(viewer, call.arguments as! Float)
             result(true)
-            
+        case "setMaterialColor":
+            guard let args = call.arguments as? [Any], args.count == 5,
+                  let assetManager = args[0] as? Int64,
+                  let asset = args[1] as? EntityId,
+                  let meshName = args[2] as? String, 
+                  let materialIndex = args[3] as? Int32, 
+                  let color = args[4] as? [Double] else {
+                result(FlutterError(code: "INVALID_ARGUMENTS", message: "Expected correct arguments for setMaterialColor", details: nil))
+                return
+            }
+            set_material_color(unsafeBitCast(assetManager, to:UnsafeMutableRawPointer.self), asset, meshName, materialIndex, Float(color[0]), Float(color[1]), Float(color[2]), Float(color[3]))
+            result(true)
             
         case "hideMesh":
             guard let args = call.arguments as? [Any], args.count == 3,

ios/include/AssetManager.hpp

@@ -40,6 +40,7 @@ namespace polyvox {
             const utils::Entity* getLightEntities(EntityId e) const noexcept;
             size_t getLightEntityCount(EntityId e) const noexcept;
             void updateAnimations();
+            bool setMaterialColor(EntityId e, const char* meshName, int materialInstance, const float r, const float g, const float b, const float a);
 
             bool setMorphAnimationBuffer(
                 EntityId entityId,

ios/include/PolyvoxFilamentApi.h

@@ -82,6 +82,7 @@ void remove_asset(const void* const viewer, EntityId asset);
 void clear_assets(const void* const viewer);
 void load_texture(void* assetManager, EntityId asset, const char *assetPath, int renderableIndex);
 void set_texture(void* assetManager, EntityId asset);
+bool set_material_color(void* assetManager, EntityId asset, const char* meshName, int materialIndex, const float r, const float g, const float b, const float a);
 void transform_to_unit_cube(void* assetManager, EntityId asset);
 void set_position(void* assetManager, EntityId asset, float x, float y, float z);
 void set_rotation(void* assetManager, EntityId asset, float rads, float x, float y, float z);

ios/src/AssetManager.cpp

@@ -273,11 +273,12 @@ void AssetManager::updateAnimations() {
                             frameNumber = lengthInFrames - frameNumber;
                         }
                         auto baseOffset = frameNumber * asset.mMorphAnimationBuffer.mMorphIndices.size();
-                for(auto morphIndex : asset.mMorphAnimationBuffer.mMorphIndices) {
+                        for(int i = 0; i < asset.mMorphAnimationBuffer.mMorphIndices.size(); i++) {
+                            auto morphIndex = asset.mMorphAnimationBuffer.mMorphIndices[i];
                             // set the weights appropriately
                             rm.setMorphWeights(
                                                rm.getInstance(asset.mMorphAnimationBuffer.mMeshTarget),
-                                    asset.mMorphAnimationBuffer.mFrameData.data() + baseOffset + morphIndex,
+                                               asset.mMorphAnimationBuffer.mFrameData.data() + baseOffset + i,
                                                1,
                                                morphIndex
                                                );
@@ -459,6 +460,35 @@ bool AssetManager::setMorphAnimationBuffer(
     return true;
 }
 
+bool AssetManager::setMaterialColor(EntityId entityId, const char* meshName, int materialIndex, const float r, const float g, const float b, const float a) {
+    
+    const auto& pos = _entityIdLookup.find(entityId);
+    if(pos == _entityIdLookup.end()) {
+        Log("ERROR: asset not found for entity.");
+        return false;
+    }
+    auto& asset = _assets[pos->second];
+    auto entity = findEntityByName(asset, meshName);
+    
+    RenderableManager& rm = _engine->getRenderableManager();
+    
+    auto renderable = rm.getInstance(entity);
+    
+    if(!renderable.isValid()) {
+        return false;
+    }
+    
+    MaterialInstance* mi = rm.getMaterialInstanceAt(renderable, materialIndex);
+    
+    if(!mi) {
+        Log("ERROR: material index must be less than number of material instances");
+        return false;
+    }
+    mi->setParameter("baseColorFactor", RgbaType::sRGB, math::float4(r, g, b, a));
+    return true;
+}
+
+
 bool AssetManager::setBoneAnimationBuffer(
                                           EntityId entityId,
                                           const float* const frameData,
@@ -557,6 +587,10 @@ bool AssetManager::setBoneAnimationBuffer(
 
 
 void AssetManager::playAnimation(EntityId e, int index, bool loop, bool reverse, bool replaceActive, float crossfade) {
+    if(index < 0) {
+        Log("ERROR: glTF animation index must be greater than zero.");
+        return;
+    }
     const auto& pos = _entityIdLookup.find(e);
     if(pos == _entityIdLookup.end()) {
         Log("ERROR: asset not found for entity.");

ios/src/PolyvoxFilamentApi.cpp

@@ -337,6 +337,10 @@ extern "C" {
     // ((AssetManager*)assetManager)->setTexture();
   }
 
+  bool set_material_color(void* assetManager, EntityId asset, const char* meshName, int materialIndex, const float r, const float g, const float b, const float a) {
+    return ((AssetManager*)assetManager)->setMaterialColor(asset, meshName, materialIndex, r, g, b, a);
+  }
+
   FLUTTER_PLUGIN_EXPORT void transform_to_unit_cube(void* assetManager, EntityId asset) {
       ((AssetManager*)assetManager)->transformToUnitCube(asset);
   }

lib/filament_controller.dart

@@ -260,13 +260,12 @@ class FilamentController {
   ///
   void setMorphAnimationData(
       FilamentEntity asset, MorphAnimationData animation) async {
-    print("SETTING animation with ${animation.data}");
     await _channel.invokeMethod("setMorphAnimation", [
       _assetManager,
       asset,
       animation.meshName,
       animation.data,
-      animation.morphIndices,
+      animation.animatedMorphIndices,
       animation.numMorphTargets,
       animation.numFrames,
       animation.frameLengthInMs
@@ -402,6 +401,22 @@ class FilamentController {
     await _channel.invokeMethod("setTexture", [_assetManager, asset]);
   }
 
+  void setMaterialColor(FilamentEntity asset, String meshName,
+      int materialIndex, Color color) async {
+    await _channel.invokeMethod("setMaterialColor", [
+      _assetManager,
+      asset,
+      meshName,
+      materialIndex,
+      [
+        color.red.toDouble() / 255.0,
+        color.green.toDouble() / 255.0,
+        color.blue.toDouble() / 255.0,
+        color.alpha.toDouble() / 255.0
+      ]
+    ]);
+  }
+
   void transformToUnitCube(FilamentEntity asset) async {
     await _channel.invokeMethod("transformToUnitCube", [_assetManager, asset]);
   }