Merge pull request #3069 from ms-maxvollmer/GLTF2_guarantee_rootnode_fix

GLTF2: Fixed behavior of glTF2Importer::ImportNodes

code/glTF2/glTF2Importer.cpp

@@ -952,8 +952,8 @@ aiNode *ImportNode(aiScene *pScene, glTF2::Asset &r, std::vector<unsigned int> &
 
 void glTF2Importer::ImportNodes(glTF2::Asset &r) {
 	if (!r.scene) {
-        return;
-    }
+		throw DeadlyImportError("GLTF: No scene");
+	}
 
 	std::vector<Ref<Node>> rootNodes = r.scene->nodes;
 
@@ -970,6 +970,8 @@ void glTF2Importer::ImportNodes(glTF2::Asset &r) {
 			root->mChildren[root->mNumChildren++] = node;
 		}
 		mScene->mRootNode = root;
+	} else {
+		mScene->mRootNode = new aiNode("ROOT");
 	}
 }
 

test/models/glTF2/TestNoRootNode/NoScene.gltf

@@ -0,0 +1,6 @@
+{
+    "asset": {
+        "version": "2.0"
+    },
+    "scene": 0
+}

test/models/glTF2/TestNoRootNode/SceneWithoutNodes.gltf

@@ -0,0 +1,10 @@
+{
+    "asset": {
+        "version": "2.0"
+    },
+    "scene": 0,
+    "scenes": [
+        {
+        }
+    ]
+}

test/unit/utglTF2ImportExport.cpp

@@ -490,3 +490,16 @@ TEST_F(utglTF2ImportExport, texcoords) {
     EXPECT_EQ(aiGetMaterialInteger(material, AI_MATKEY_GLTF_TEXTURE_TEXCOORD(aiTextureType_UNKNOWN, 0), &uvIndex), aiReturn_SUCCESS);
     EXPECT_EQ(uvIndex, 1);
 }
+
+TEST_F(utglTF2ImportExport, norootnode_noscene) {
+    Assimp::Importer importer;
+    const aiScene* scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/glTF2/TestNoRootNode/NoScene.gltf", aiProcess_ValidateDataStructure);
+    ASSERT_EQ(scene, nullptr);
+}
+
+TEST_F(utglTF2ImportExport, norootnode_scenewithoutnodes) {
+    Assimp::Importer importer;
+    const aiScene* scene = importer.ReadFile(ASSIMP_TEST_MODELS_DIR "/glTF2/TestNoRootNode/SceneWithoutNodes.gltf", aiProcess_ValidateDataStructure);
+    ASSERT_NE(scene, nullptr);
+    ASSERT_NE(scene->mRootNode, nullptr);
+}