[rmodels] Fix normal transform in `UpdateModelAnimationBones` (#4634)

* remove duplicate calculation of `invRotation` in `UpdateModelAnimationBones`

* fix normal transform in `UpdateModelAnimation`

src/rmodels.c

@@ -2296,13 +2296,12 @@ void UpdateModelAnimationBones(Model model, ModelAnimation anim, int frame)
             Quaternion outRotation = anim.framePoses[frame][boneId].rotation;
             Vector3 outScale = anim.framePoses[frame][boneId].scale;
 
-            Vector3 invTranslation = Vector3RotateByQuaternion(Vector3Negate(inTranslation), QuaternionInvert(inRotation));
             Quaternion invRotation = QuaternionInvert(inRotation);
+            Vector3 invTranslation = Vector3RotateByQuaternion(Vector3Negate(inTranslation), invRotation);
             Vector3 invScale = Vector3Divide((Vector3){ 1.0f, 1.0f, 1.0f }, inScale);
 
-            Vector3 boneTranslation = Vector3Add(
-                Vector3RotateByQuaternion(Vector3Multiply(outScale, invTranslation),
-                outRotation), outTranslation);
+            Vector3 boneTranslation = Vector3Add(Vector3RotateByQuaternion(
+                Vector3Multiply(outScale, invTranslation), outRotation), outTranslation);
             Quaternion boneRotation = QuaternionMultiply(outRotation, invRotation);
             Vector3 boneScale = Vector3Multiply(outScale, invScale);
 
@@ -2384,7 +2383,7 @@ void UpdateModelAnimation(Model model, ModelAnimation anim, int frame)
                 if ((mesh.normals != NULL) && (mesh.animNormals != NULL ))
                 {
                     animNormal = (Vector3){ mesh.normals[vCounter], mesh.normals[vCounter + 1], mesh.normals[vCounter + 2] };
-                    animNormal = Vector3Transform(animNormal,model.meshes[m].boneMatrices[boneId]);
+                    animNormal = Vector3Transform(animNormal, MatrixTranspose(MatrixInvert(model.meshes[m].boneMatrices[boneId])));
                     mesh.animNormals[vCounter] += animNormal.x*boneWeight;
                     mesh.animNormals[vCounter + 1] += animNormal.y*boneWeight;
                     mesh.animNormals[vCounter + 2] += animNormal.z*boneWeight;