From bcdb173e0936b191c2a150819ddc1b0942582cda Mon Sep 17 00:00:00 2001
From: Frooxius <tomas.mariancik@gmail.com>
Date: Sat, 13 Jul 2019 22:20:47 +0200
Subject: [PATCH] - Fixed anim meshes generated from blendshapes not being
 copied to output for multi-material meshes - Fixed first vertex of each
 blendshape on a multi-material mesh having all unmapped vertice offsets being
 added to it - Fixed blendshapes not importing for multi-material FBX meshes
 with no bones

---
 code/FBX/FBXConverter.cpp | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/code/FBX/FBXConverter.cpp b/code/FBX/FBXConverter.cpp
index a4c1015bf..9f940d322 100644
--- a/code/FBX/FBXConverter.cpp
+++ b/code/FBX/FBXConverter.cpp
@@ -1247,10 +1247,10 @@ namespace Assimp {
             ai_assert(count_faces);
             ai_assert(count_vertices);
 
-            // mapping from output indices to DOM indexing, needed to resolve weights
+            // mapping from output indices to DOM indexing, needed to resolve weights or blendshapes
             std::vector<unsigned int> reverseMapping;
             std::map<unsigned int, unsigned int> translateIndexMap;
-            if (process_weights) {
+            if (process_weights || mesh.GetBlendShapes().size() > 0) {
                 reverseMapping.resize(count_vertices);
             }
 
@@ -1407,7 +1407,10 @@ namespace Assimp {
                             unsigned int count = 0;
                             const unsigned int* outIndices = mesh.ToOutputVertexIndex(index, count);
                             for (unsigned int k = 0; k < count; k++) {
-                                unsigned int index = translateIndexMap[outIndices[k]];
+                                unsigned int outIndex = outIndices[k];
+                                if (translateIndexMap.find(outIndex) == translateIndexMap.end())
+                                    continue;
+                                unsigned int index = translateIndexMap[outIndex];
                                 animMesh->mVertices[index] += vertex;
                                 if (animMesh->mNormals != nullptr) {
                                     animMesh->mNormals[index] += normal;
@@ -1421,6 +1424,15 @@ namespace Assimp {
                 }
             }
 
+            const size_t numAnimMeshes = animMeshes.size();
+            if (numAnimMeshes > 0) {
+                out_mesh->mNumAnimMeshes = static_cast<unsigned int>(numAnimMeshes);
+                out_mesh->mAnimMeshes = new aiAnimMesh*[numAnimMeshes];
+                for (size_t i = 0; i < numAnimMeshes; i++) {
+                    out_mesh->mAnimMeshes[i] = animMeshes.at(i);
+                }
+            }
+
             return static_cast<unsigned int>(meshes.size() - 1);
         }