glTF v2 importer morph targets support

code/glTF2Asset.h

@@ -766,10 +766,17 @@ namespace glTF2
             Ref<Accessor> indices;
 
             Ref<Material> material;
+
+            struct Target {
+                AccessorList position, normal, tangent;
+            };
+            std::vector<Target> targets;
         };
 
         std::vector<Primitive> primitives;
 
+        std::vector<float> weights;
+
         Mesh() {}
 
 		/// \fn void Read(Value& pJSON_Object, Asset& pAsset_Root)

code/glTF2Asset.inl

@@ -931,6 +931,21 @@ namespace {
         else return false;
         return true;
     }
+
+    inline bool GetAttribTargetVector(Mesh::Primitive& p, const int targetIndex, const char* attr, Mesh::AccessorList*& v, int& pos)
+    {
+        if ((pos = Compare(attr, "POSITION"))) {
+            v = &(p.targets[targetIndex].position);
+        }
+        else if ((pos = Compare(attr, "NORMAL"))) {
+            v = &(p.targets[targetIndex].normal);
+        }
+        else if ((pos = Compare(attr, "TANGENT"))) {
+            v = &(p.targets[targetIndex].tangent);
+        }
+        else return false;
+        return true;
+    }
 }
 
 inline void Mesh::Read(Value& pJSON_Object, Asset& pAsset_Root)
@@ -965,6 +980,26 @@ inline void Mesh::Read(Value& pJSON_Object, Asset& pAsset_Root)
                 }
             }
 
+            if (Value* targetsArray = FindArray(primitive, "targets")) {
+                prim.targets.resize(targetsArray->Size());
+                for (unsigned int i = 0; i < targetsArray->Size(); ++i) {
+                    Value& target = (*targetsArray)[i];
+                    if (!target.IsObject()) continue;
+                    for (Value::MemberIterator it = target.MemberBegin(); it != target.MemberEnd(); ++it) {
+                        if (!it->value.IsUint()) continue;
+                        const char* attr = it->name.GetString();
+                        // Valid attribute semantics include POSITION, NORMAL, TANGENT
+                        int undPos = 0;
+                        Mesh::AccessorList* vec = 0;
+                        if (GetAttribTargetVector(prim, i, attr, vec, undPos)) {
+                            size_t idx = (attr[undPos] == '_') ? atoi(attr + undPos + 1) : 0;
+                            if ((*vec).size() <= idx) (*vec).resize(idx + 1);
+                            (*vec)[idx] = pAsset_Root.accessors.Retrieve(it->value.GetUint());
+                        }
+                    }
+                }
+            }
+
             if (Value* indices = FindUInt(primitive, "indices")) {
 				prim.indices = pAsset_Root.accessors.Retrieve(indices->GetUint());
             }
@@ -974,6 +1009,16 @@ inline void Mesh::Read(Value& pJSON_Object, Asset& pAsset_Root)
             }
         }
     }
+
+    if (Value* weights = FindArray(pJSON_Object, "weights")) {
+        this->weights.resize(weights->Size());
+        for (unsigned int i = 0; i < weights->Size(); ++i) {
+          Value& weightValue = (*weights)[i];
+          if (weightValue.IsNumber()) {
+            this->weights[i] = weightValue.GetFloat();
+          }
+        }
+    }
 }
 
 inline void Camera::Read(Value& obj, Asset& /*r*/)

code/glTF2Importer.cpp

@@ -51,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include <assimp/ai_assert.h>
 #include <assimp/DefaultLogger.hpp>
 #include <assimp/importerdesc.h>
+#include <assimp/CreateAnimMesh.h>
 
 #include <memory>
 
@@ -65,6 +66,13 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 using namespace Assimp;
 using namespace glTF2;
 
+namespace {
+    // generate bitangents from normals and tangents according to spec
+    struct Tangent {
+        aiVector3D xyz;
+        ai_real w;
+    };
+} // namespace
 
 //
 // glTF2Importer
@@ -416,10 +424,7 @@ void glTF2Importer::ImportMeshes(glTF2::Asset& r)
                 // only extract tangents if normals are present
                 if (attr.tangent.size() > 0 && attr.tangent[0]) {
                     // generate bitangents from normals and tangents according to spec
-                    struct Tangent {
+                    Tangent *tangents = nullptr;
-                        aiVector3D xyz;
-                        ai_real w;
-                    } *tangents = nullptr;
 
                     attr.tangent[0]->ExtractData(tangents);
 
@@ -445,6 +450,52 @@ void glTF2Importer::ImportMeshes(glTF2::Asset& r)
                 }
             }
 
+            std::vector<Mesh::Primitive::Target>& targets = prim.targets;
+            if (targets.size() > 0) {
+                aim->mNumAnimMeshes = targets.size();
+                aim->mAnimMeshes = new aiAnimMesh*[aim->mNumAnimMeshes];
+                for (size_t i = 0; i < targets.size(); i++) {
+                    aim->mAnimMeshes[i] = aiCreateAnimMesh(aim);
+                    aiAnimMesh& aiAnimMesh = *(aim->mAnimMeshes[i]);
+                    Mesh::Primitive::Target& target = targets[i];
+
+                    if (target.position.size() > 0) {
+                        aiVector3D *positionDiff == nullptr;
+                        target.position[0]->ExtractData(positionDiff);
+                        for(int vertexId = 0; vertexId < aim->mNumVertices; vertexId++) {
+                            aiAnimMesh.mVertices[vertexId] += positionDiff[vertexId];
+                        }
+                        delete [] positionDiff;
+                    }
+                    if (target.normal.size() > 0) {
+                        aiVector3D *normalDiff == nullptr;
+                        target.normal[0]->ExtractData(normalDiff);
+                        for(int vertexId = 0; vertexId < aim->mNumVertices; vertexId++) {
+                            aiAnimMesh.mNormals[vertexId] += normalDiff[vertexId];
+                        }
+                        delete [] normalDiff;
+                    }
+                    if (target.tangent.size() > 0) {
+                        Tangent *tangent = nullptr;
+                        attr.tangent[0]->ExtractData(tangent);
+
+                        aiVector3D *tangentDiff = nullptr;
+                        target.tangent[0]->ExtractData(tangentDiff);
+
+                        for (unsigned int vertexId = 0; vertexId < aim->mNumVertices; ++vertexId) {
+                            tangent[vertexId].xyz += tangentDiff[vertexId];
+                            aiAnimMesh.mTangents[vertexId] = tangent[vertexId];
+                            aiAnimMesh.mBitangents[vertexId] = (aiAnimMesh.mNormals[vertexId] ^ tangent[vertexId].xyz) * tangent[vertexId].w;
+                        }
+                        delete [] tangent;
+                        delete [] tangentDiff;
+                    }
+                    if (mesh.weights.size() > i) {
+                        aiAnimMesh.mWeight = mesh.weights[i];
+                    }
+                }
+            }
+
 
             if (prim.indices) {
                 aiFace* faces = 0;