Prevent to generate redundant morph targets for glTF2

code/AssetLib/glTF2/glTF2Importer.cpp

@@ -453,11 +453,16 @@ void glTF2Importer::ImportMeshes(glTF2::Asset &r) {
                 aim->mNumAnimMeshes = (unsigned int)targets.size();
                 aim->mAnimMeshes = new aiAnimMesh *[aim->mNumAnimMeshes];
                 for (size_t i = 0; i < targets.size(); i++) {
-                    aim->mAnimMeshes[i] = aiCreateAnimMesh(aim);
+                    bool needPositions = targets[i].position.size() > 0;
+                    bool needNormals = targets[i].normal.size() > 0;
+                    bool needTangents = targets[i].tangent.size() > 0;
+                    // GLTF morph does not support colors and texCoords
+                    aim->mAnimMeshes[i] = aiCreateAnimMesh(aim,
+                            needPositions, needNormals, needTangents, false, false);
                     aiAnimMesh &aiAnimMesh = *(aim->mAnimMeshes[i]);
                     Mesh::Primitive::Target &target = targets[i];
 
-                    if (target.position.size() > 0) {
+                    if (needPositions) {
                         aiVector3D *positionDiff = nullptr;
                         target.position[0]->ExtractData(positionDiff);
                         for (unsigned int vertexId = 0; vertexId < aim->mNumVertices; vertexId++) {
@@ -465,7 +470,7 @@ void glTF2Importer::ImportMeshes(glTF2::Asset &r) {
                         }
                         delete[] positionDiff;
                     }
-                    if (target.normal.size() > 0) {
+                    if (needNormals) {
                         aiVector3D *normalDiff = nullptr;
                         target.normal[0]->ExtractData(normalDiff);
                         for (unsigned int vertexId = 0; vertexId < aim->mNumVertices; vertexId++) {
@@ -473,7 +478,7 @@ void glTF2Importer::ImportMeshes(glTF2::Asset &r) {
                         }
                         delete[] normalDiff;
                     }
-                    if (target.tangent.size() > 0) {
+                    if (needTangents) {
                         Tangent *tangent = nullptr;
                         attr.tangent[0]->ExtractData(tangent);
 

code/Common/CreateAnimMesh.cpp

@@ -44,42 +44,46 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 namespace Assimp    {
 
-aiAnimMesh *aiCreateAnimMesh(const aiMesh *mesh)
+aiAnimMesh *aiCreateAnimMesh(const aiMesh *mesh, bool needPositions, bool needNormals, bool needTangents, bool needColors, bool needTexCoords)
 {
     aiAnimMesh *animesh = new aiAnimMesh;
     animesh->mNumVertices = mesh->mNumVertices;
-    if (mesh->mVertices) {
+    if (needPositions && mesh->mVertices) {
         animesh->mVertices = new aiVector3D[animesh->mNumVertices];
         std::memcpy(animesh->mVertices, mesh->mVertices, mesh->mNumVertices * sizeof(aiVector3D));
     }
-    if (mesh->mNormals) {
+    if (needNormals && mesh->mNormals) {
         animesh->mNormals = new aiVector3D[animesh->mNumVertices];
         std::memcpy(animesh->mNormals, mesh->mNormals, mesh->mNumVertices * sizeof(aiVector3D));
     }
-    if (mesh->mTangents) {
+    if (needTangents && mesh->mTangents) {
         animesh->mTangents = new aiVector3D[animesh->mNumVertices];
         std::memcpy(animesh->mTangents, mesh->mTangents, mesh->mNumVertices * sizeof(aiVector3D));
     }
-    if (mesh->mBitangents) {
+    if (needTangents && mesh->mBitangents) {
         animesh->mBitangents = new aiVector3D[animesh->mNumVertices];
         std::memcpy(animesh->mBitangents, mesh->mBitangents, mesh->mNumVertices * sizeof(aiVector3D));
     }
 
-    for (int i = 0; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i) {
-        if (mesh->mColors[i]) {
-            animesh->mColors[i] = new aiColor4D[animesh->mNumVertices];
-            std::memcpy(animesh->mColors[i], mesh->mColors[i], mesh->mNumVertices * sizeof(aiColor4D));
-        } else {
-            animesh->mColors[i] = nullptr;
+    if (needColors) {
+        for (int i = 0; i < AI_MAX_NUMBER_OF_COLOR_SETS; ++i) {
+            if (mesh->mColors[i]) {
+                animesh->mColors[i] = new aiColor4D[animesh->mNumVertices];
+                std::memcpy(animesh->mColors[i], mesh->mColors[i], mesh->mNumVertices * sizeof(aiColor4D));
+            } else {
+                animesh->mColors[i] = nullptr;
+            }
         }
     }
 
-    for (int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
-        if (mesh->mTextureCoords[i]) {
-            animesh->mTextureCoords[i] = new aiVector3D[animesh->mNumVertices];
-            std::memcpy(animesh->mTextureCoords[i], mesh->mTextureCoords[i], mesh->mNumVertices * sizeof(aiVector3D));
-        } else {
-            animesh->mTextureCoords[i] = nullptr;
+    if (needTexCoords) {
+        for (int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
+            if (mesh->mTextureCoords[i]) {
+                animesh->mTextureCoords[i] = new aiVector3D[animesh->mNumVertices];
+                std::memcpy(animesh->mTextureCoords[i], mesh->mTextureCoords[i], mesh->mNumVertices * sizeof(aiVector3D));
+            } else {
+                animesh->mTextureCoords[i] = nullptr;
+            }
         }
     }
     return animesh;

include/assimp/CreateAnimMesh.h

@@ -57,10 +57,20 @@ namespace Assimp {
 
 /**
  *  Create aiAnimMesh from aiMesh.
- *  @param  mesh    The input mesh to create an animated mesh from.
+ *  @param  mesh            The input mesh to create an animated mesh from.
+ *  @param  needPositions   If true, positions will be copied from.
+ *  @param  needNormals     If true, normals will be copied from.
+ *  @param  needTangents    If true, tangents and bitangents will be copied from.
+ *  @param  needColors      If true, colors will be copied from.
+ *  @param  needTexCoords   If true, texCoords will be copied from.
  *  @return The new created animated mesh.
  */
-ASSIMP_API aiAnimMesh *aiCreateAnimMesh(const aiMesh *mesh);
+ASSIMP_API aiAnimMesh *aiCreateAnimMesh(const aiMesh *mesh,
+                                        bool needPositions = true,
+                                        bool needNormals = true,
+                                        bool needTangents = true,
+                                        bool needColors = true,
+                                        bool needTexCoords = true);
 
 } // end of namespace Assimp