[mesh] Mesh: Fix .gltf and add.glb mesh export

Author: gregoire-dl

src/aliceVision/mesh/Mesh.cpp

@@ -44,10 +44,14 @@ std::string EFileType_enumToString(const EFileType meshFileType)
             return "obj";
         case EFileType::FBX:
             return "fbx";
-        case EFileType::STL:
-            return "stl";
         case EFileType::GLTF:
             return "gltf";
+        case EFileType::GLB:
+            return "glb";
+        case EFileType::STL:
+            return "stl";
+        case EFileType::PLY:
+            return "ply";
     }
     throw std::out_of_range("Unrecognized EMeshFileType");
 }
@@ -61,10 +65,15 @@ EFileType EFileType_stringToEnum(const std::string& meshFileType)
         return EFileType::OBJ;
     if (m == "fbx")
         return EFileType::FBX;
-    if (m == "stl")
-        return EFileType::STL;
     if (m == "gltf")
         return EFileType::GLTF;
+    if (m == "glb")
+        return EFileType::GLB;
+    if (m == "stl")
+        return EFileType::STL;
+    if (m == "ply")
+        return EFileType::PLY;
+
     throw std::out_of_range("Invalid mesh file type " + meshFileType);
 }
 
@@ -81,26 +90,42 @@ void Mesh::save(const std::string& filepath)
     const std::string fileTypeStr = std::filesystem::path(filepath).extension().string().substr(1);
     const EFileType fileType = mesh::EFileType_stringToEnum(fileTypeStr);
 
-    ALICEVISION_LOG_INFO("Save " << fileTypeStr << " mesh file");
+    ALICEVISION_LOG_INFO("Saving " << fileTypeStr << " mesh file using Assimp.");
 
+    // Assimp scene setup
+    // create scene and root node
     aiScene scene;
+    scene.mRootNode = new aiNode();
 
-    scene.mRootNode = new aiNode;
-
+    // create default material
+    scene.mMaterials = new aiMaterial*[1];
+    scene.mMaterials[0] = new aiMaterial();
+    scene.mNumMaterials = 1;
+    
+    // create mesh
     scene.mMeshes = new aiMesh*[1];
+    scene.mMeshes[0] = new aiMesh();
     scene.mNumMeshes = 1;
+
+    // link mesh to root node
     scene.mRootNode->mMeshes = new unsigned int[1];
+    scene.mRootNode->mMeshes[0] = 0;
     scene.mRootNode->mNumMeshes = 1;
+    
+    // fill mesh data
+    aiMesh* aimesh = scene.mMeshes[0];
 
-    scene.mMaterials = new aiMaterial*[1];
-    scene.mNumMaterials = 1;
-    scene.mMaterials[0] = new aiMaterial;
+    // set default material index
+    aimesh->mMaterialIndex = 0;  
 
-    scene.mRootNode->mMeshes[0] = 0;
-    scene.mMeshes[0] = new aiMesh;
-    aiMesh* aimesh = scene.mMeshes[0];
-    aimesh->mMaterialIndex = 0;
+    if (fileType == EFileType::GLTF || fileType == EFileType::GLB) 
+    {
+        // set primitive types to triangles, required for gltf and glb export
+        // for other file types, primitive types is unspecified to avoid normal generation 
+        aimesh->mPrimitiveTypes = aiPrimitiveType_TRIANGLE; 
+    }
 
+    // fill mesh vertices
     aimesh->mNumVertices = pts.size();
     aimesh->mVertices = new aiVector3D[pts.size()];
 
@@ -114,6 +139,7 @@ void Mesh::save(const std::string& filepath)
         ++index;
     }
 
+    // fill mesh faces
     aimesh->mNumFaces = tris.size();
     aimesh->mFaces = new aiFace[tris.size()];
 
@@ -128,31 +154,57 @@ void Mesh::save(const std::string& filepath)
         }
     }
 
-    std::string formatId = fileTypeStr;
+    // exporter setup
+    std::string pFormatId = fileTypeStr;
     unsigned int pPreprocessing = 0u;
-    // If gltf, use gltf 2.0
-    if (fileType == EFileType::GLTF)
+
+    if (fileType == EFileType::GLTF || fileType == EFileType::GLB)
     {
-        formatId = "gltf2";
+        if (fileType == EFileType::GLTF)
+        {
+            // gltf file, use gltf 2.0
+            pFormatId = "gltf2";
+        }
+        else
+        {
+            // glb file, use glb 2.0
+            pFormatId = "glb2";
+        }
+
         // gen normals in order to have correct shading in Qt 3D Scene
         // but cause problems with assimp importer
         pPreprocessing |= aiProcess_GenNormals;
     }
-    // If obj, do not use material
     else if (fileType == EFileType::OBJ)
     {
-        formatId = "objnomtl";
+        // obj file, do not use material
+        pFormatId = "objnomtl";
     }
 
+    // export mesh
     Assimp::Exporter exporter;
-    exporter.Export(&scene, formatId, filepath, pPreprocessing);
+    const aiReturn ret = exporter.Export(&scene, pFormatId, filepath, pPreprocessing);
 
-    ALICEVISION_LOG_INFO("Save mesh to " << fileTypeStr << " done.");
+    // log mesh information
+    ALICEVISION_LOG_DEBUG("Mesh information:" << std::endl
+                          << "\t- # vertices: " << pts.size() << std::endl
+                          << "\t- # triangles: " << tris.size() << std::endl
+                          << "\t- # UVs: " << uvCoords.size() << std::endl
+                          << "\t- # normals: " << normals.size());
 
-    ALICEVISION_LOG_DEBUG("Vertices: " << pts.size());
-    ALICEVISION_LOG_DEBUG("Triangles: " << tris.size());
-    ALICEVISION_LOG_DEBUG("UVs: " << uvCoords.size());
-    ALICEVISION_LOG_DEBUG("Normals: " << normals.size());
+    // check for errors
+    if (ret != AI_SUCCESS)
+    {
+        if (ret == AI_OUTOFMEMORY)
+        {
+            ALICEVISION_LOG_ERROR("Assimp exporter ran out of memory while exporting mesh to " << filepath);
+        }
+
+        ALICEVISION_THROW_ERROR("Assimp exporter failed to export mesh to " << filepath << ", error: " << exporter.GetErrorString());
+        return;
+    }
+    
+    ALICEVISION_LOG_INFO("Mesh saved.");
 }
 
 bool Mesh::loadFromBin(const std::string& binFilepath)

src/aliceVision/mesh/Mesh.hpp

@@ -50,7 +50,9 @@ enum class EFileType
     OBJ = 0,
     FBX,
     GLTF,
-    STL
+    GLB,
+    STL,
+    PLY
 };
 
 EFileType EFileType_stringToEnum(const std::string& filetype);