import multiple animation files

README.md

@@ -47,6 +47,7 @@ Usage:
                                 from the FBX.
       --khr-materials-unlit     Use KHR_materials_unlit extension to specify
                                 Unlit shader.
+      --animation-files         Read multiple fbx animation files.
       --blend-shape-normals     Include blend shape normals, if reported
                                 present by the FBX SDK.
       --blend-shape-tangents    Include blend shape tangents, if reported
@@ -75,6 +76,10 @@ Some of these switches are not obvious:
   Your FBX is likely constructed with the assumption that `(0, 0)` is bottom
   left, whereas glTF has `(0, 0)` as top left. To produce spec-compliant glTF,
   we must flip the texcoords. To request unflipped coordinates:
+- '--animation-files' will try to read in additional animations from multiple
+  fbx files with numbers added to the base name (eg. test1.fbx, test2.fbx, ...).
+  It will apply animations to geometry in the base file by matching the node
+  names, so make sure all nodes have a unique name.
 - `--long-indices` lets you force the use of either 16-bit or 32-bit indices.
   The default option is auto, which make the choice on a per-mesh-size basis.
 - `--compute-normals` controls when automatic vertex normals should be computed

src/FBX2glTF.cpp

@@ -125,6 +125,11 @@ int main(int argc, char* argv[]) {
       [&](size_t count) { gltfOptions.useKHRLightsPunctual = (count == 0); },
       "Don't use KHR_lights_punctual extension to export FBX lights.");
 
+  app.add_flag(
+      "--animation-files",
+	  gltfOptions.readAnimationFiles,
+	  "Read multiple fbx animation files.");
+
   app.add_flag(
       "--user-properties",
       gltfOptions.enableUserProperties,
@@ -302,7 +307,7 @@ int main(int argc, char* argv[]) {
   if (verboseOutput) {
     fmt::printf("Loading FBX File: %s\n", inputPath);
   }
-  if (!LoadFBXFile(raw, inputPath.c_str(), "png;jpg;jpeg")) {
+  if (!LoadFBXFile(raw, inputPath.c_str(), "png;jpg;jpeg", gltfOptions)) {
     fmt::fprintf(stderr, "ERROR:: Failed to parse FBX: %s\n", inputPath);
     return 1;
   }

src/FBX2glTF.h

@@ -95,6 +95,9 @@ struct GltfOptions
     /** Whether to include lights through the KHR_punctual_lights extension. */
     bool useKHRLightsPunctual { true };
 
+	/** Whether to read multiple fbx animation files. */
+    bool readAnimationFiles { false };
+
     /** Whether to include blend shape normals, if present according to the SDK. */
     bool useBlendShapeNormals { false };
     /** Whether to include blend shape tangents, if present according to the SDK. */

src/fbx/Fbx2Raw.cpp

@@ -721,7 +721,7 @@ static void ReadNodeHierarchy(
   }
 }
 
-static void ReadAnimations(RawModel& raw, FbxScene* pScene) {
+static void ReadAnimations(RawModel& raw, FbxScene* pScene, bool nodeNameLookup) {
   FbxTime::EMode eMode = FbxTime::eFrames24;
   const double epsilon = 1e-5f;
 
@@ -772,7 +772,14 @@ static void ReadAnimations(RawModel& raw, FbxScene* pScene) {
       bool hasMorphs = false;
 
       RawChannel channel;
-      channel.nodeIndex = raw.GetNodeById(pNode->GetUniqueID());
+      if (nodeNameLookup) {
+        channel.nodeIndex = raw.GetNodeByName(pNode->GetName());
+      } else {
+        channel.nodeIndex = raw.GetNodeById(pNode->GetUniqueID());
+	  }
+      if (channel.nodeIndex == -1) {
+        continue;
+      }
 
       for (FbxLongLong frameIndex = firstFrameIndex; frameIndex <= lastFrameIndex; frameIndex++) {
         FbxTime pTime;
@@ -996,11 +1003,7 @@ static void FindFbxTextures(
   }
 }
 
-bool LoadFBXFile(RawModel& raw, const char* fbxFileName, const char* textureExtensions) {
-  FbxManager* pManager = FbxManager::Create();
-  FbxIOSettings* pIoSettings = FbxIOSettings::Create(pManager, IOSROOT);
-  pManager->SetIOSettings(pIoSettings);
-
+static FbxScene* LoadScene(FbxManager* pManager, const char* fbxFileName) {
   FbxImporter* pImporter = FbxImporter::Create(pManager, "");
 
   if (!pImporter->Initialize(fbxFileName, -1, pManager->GetIOSettings())) {
@@ -1008,8 +1011,7 @@ bool LoadFBXFile(RawModel& raw, const char* fbxFileName, const char* textureExte
       fmt::printf("%s\n", pImporter->GetStatus().GetErrorString());
     }
     pImporter->Destroy();
-    pManager->Destroy();
-    return false;
+    return nullptr;
   }
 
   FbxScene* pScene = FbxScene::Create(pManager, "fbxScene");
@@ -1017,14 +1019,9 @@ bool LoadFBXFile(RawModel& raw, const char* fbxFileName, const char* textureExte
   pImporter->Destroy();
 
   if (pScene == nullptr) {
-    pImporter->Destroy();
-    pManager->Destroy();
-    return false;
+    return nullptr;
   }
 
-  std::map<const FbxTexture*, FbxString> textureLocations;
-  FindFbxTextures(pScene, fbxFileName, textureExtensions, textureLocations);
-
   // Use Y up for glTF
   FbxAxisSystem::MayaYUp.ConvertScene(pScene);
 
@@ -1037,14 +1034,54 @@ bool LoadFBXFile(RawModel& raw, const char* fbxFileName, const char* textureExte
   if (sceneSystemUnit != FbxSystemUnit::cm) {
     FbxSystemUnit::cm.ConvertScene(pScene);
   }
+
+  return pScene;
+}
+
+bool LoadFBXFile(
+    RawModel& raw,
+    const char* fbxFileName,
+    const char* textureExtensions,
+    const GltfOptions& options) {
+  FbxManager* pManager = FbxManager::Create();
+  FbxIOSettings* pIoSettings = FbxIOSettings::Create(pManager, IOSROOT);
+  pManager->SetIOSettings(pIoSettings);
+
+  FbxScene* pScene = LoadScene(pManager, fbxFileName);
+  if (pScene == nullptr) {
+    pManager->Destroy();
+    return false;
+  }
+
   // this is always 0.01, but let's opt for clarity.
   scaleFactor = FbxSystemUnit::m.GetConversionFactorFrom(FbxSystemUnit::cm);
 
+  std::map<const FbxTexture*, FbxString> textureLocations;
+  FindFbxTextures(pScene, fbxFileName, textureExtensions, textureLocations);
+
   ReadNodeHierarchy(raw, pScene, pScene->GetRootNode(), 0, "");
   ReadNodeAttributes(raw, pScene, pScene->GetRootNode(), textureLocations);
-  ReadAnimations(raw, pScene);
+  ReadAnimations(raw, pScene, false);
 
   pScene->Destroy();
+
+  // read additional animation files
+  bool readAnimationFiles = options.readAnimationFiles;
+  int animationFileNumber = 1;
+  while (readAnimationFiles) {
+    std::string animationFileName = StringUtils::GetFolderString(fbxFileName) +
+        StringUtils::GetFileBaseString(fbxFileName) +
+        std::to_string(animationFileNumber) + ".fbx";
+    FbxScene* pAnimationScene = LoadScene(pManager, animationFileName.c_str());
+    if (pAnimationScene != nullptr) {
+      ReadAnimations(raw, pAnimationScene, true);
+      pAnimationScene->Destroy();
+      animationFileNumber++;
+    } else {
+      readAnimationFiles = false;
+	}
+  }
+
   pManager->Destroy();
 
   return true;

src/fbx/Fbx2Raw.hpp

@@ -11,6 +11,10 @@
 
 #include "raw/RawModel.hpp"
 
-bool LoadFBXFile(RawModel& raw, const char* fbxFileName, const char* textureExtensions);
+bool LoadFBXFile(
+    RawModel& raw,
+    const char* fbxFileName,
+    const char* textureExtensions,
+    const GltfOptions& options);
 
 json TranscribeProperty(FbxProperty& prop);

src/raw/RawModel.cpp

@@ -641,6 +641,15 @@ int RawModel::GetNodeById(const long nodeId) const {
   return -1;
 }
 
+int RawModel::GetNodeByName(const char* name) const {
+  for (size_t i = 0; i < nodes.size(); i++) {
+    if (nodes[i].name == name) {
+      return (int)i;
+    }
+  }
+  return -1;
+}
+
 int RawModel::GetSurfaceById(const long surfaceId) const {
   for (size_t i = 0; i < surfaces.size(); i++) {
     if (surfaces[i].id == surfaceId) {

src/raw/RawModel.hpp

@@ -509,6 +509,7 @@ class RawModel {
     return nodes[index];
   }
   int GetNodeById(const long nodeId) const;
+  int GetNodeByName(const char* name) const;
 
   // Create individual attribute arrays.
   // Returns true if the vertices store the particular attribute.