Make loading of obj files into TriangleMesh possible.

src/libslic3r/Format/OBJ.cpp

@@ -15,39 +15,41 @@
 
 namespace Slic3r {
 
-bool load_obj(const char *path, Model *model, const char *object_name_in)
+bool load_obj(const char *path, TriangleMesh *meshptr)
 {
+    if(meshptr == nullptr) return false;
+    
     // Parse the OBJ file.
     ObjParser::ObjData data;
     if (! ObjParser::objparse(path, data)) {
-//    die "Failed to parse $file\n" if !-e $path;
+        //    die "Failed to parse $file\n" if !-e $path;
         return false;
     }
-
+    
     // Count the faces and verify, that all faces are triangular.
     size_t num_faces = 0;
-	size_t num_quads = 0;
+    size_t num_quads = 0;
     for (size_t i = 0; i < data.vertices.size(); ) {
         size_t j = i;
         for (; j < data.vertices.size() && data.vertices[j].coordIdx != -1; ++ j) ;
         if (i == j)
             continue;
-		size_t face_vertices = j - i;
-		if (face_vertices != 3 && face_vertices != 4) {
+        size_t face_vertices = j - i;
+        if (face_vertices != 3 && face_vertices != 4) {
             // Non-triangular and non-quad faces are not supported as of now.
             return false;
         }
-		if (face_vertices == 4)
-			++ num_quads;
-		++ num_faces;
+        if (face_vertices == 4)
+            ++ num_quads;
+        ++ num_faces;
         i = j + 1;
     }
-
+    
     // Convert ObjData into STL.
-    TriangleMesh mesh;
+    TriangleMesh &mesh = *meshptr;
     stl_file &stl = mesh.stl;
     stl.stats.type = inmemory;
-    stl.stats.number_of_facets = int(num_faces + num_quads);
+    stl.stats.number_of_facets = uint32_t(num_faces + num_quads);
     stl.stats.original_num_facets = int(num_faces + num_quads);
     // stl_allocate clears all the allocated data to zero, all normals are set to zeros as well.
     stl_allocate(&stl);
@@ -68,14 +70,14 @@ bool load_obj(const char *path, Model *model, const char *object_name_in)
                 ++ num_normals;
             }
         }
-		if (data.vertices[i].coordIdx != -1) {
-			// This is a quad. Produce the other triangle.
-			stl_facet &facet2 = stl.facet_start[i_face++];
+        if (data.vertices[i].coordIdx != -1) {
+            // This is a quad. Produce the other triangle.
+            stl_facet &facet2 = stl.facet_start[i_face++];
             facet2.vertex[0] = facet.vertex[0];
             facet2.vertex[1] = facet.vertex[2];
-			const ObjParser::ObjVertex &vertex = data.vertices[i++];
-			memcpy(facet2.vertex[2].data(), &data.coordinates[vertex.coordIdx * 4], 3 * sizeof(float));
-			if (vertex.normalIdx != -1) {
+            const ObjParser::ObjVertex &vertex = data.vertices[i++];
+            memcpy(facet2.vertex[2].data(), &data.coordinates[vertex.coordIdx * 4], 3 * sizeof(float));
+            if (vertex.normalIdx != -1) {
                 normal(0) += data.normals[vertex.normalIdx*3];
                 normal(1) += data.normals[vertex.normalIdx*3+1];
                 normal(2) += data.normals[vertex.normalIdx*3+2];
@@ -96,25 +98,37 @@ bool load_obj(const char *path, Model *model, const char *object_name_in)
             if (len > EPSILON)
                 facet.normal = normal / len;
         }
-	}
+    }
     stl_get_size(&stl);
     mesh.repair();
     if (mesh.facets_count() == 0) {
-        // die "This STL file couldn't be read because it's empty.\n"
+        // die "This OBJ file couldn't be read because it's empty.\n"
         return false;
     }
-
-    std::string  object_name;
-    if (object_name_in == nullptr) {
-        const char *last_slash = strrchr(path, DIR_SEPARATOR);
-        object_name.assign((last_slash == nullptr) ? path : last_slash + 1);
-    } else
-       object_name.assign(object_name_in);
-
-    model->add_object(object_name.c_str(), path, std::move(mesh));
+    
     return true;
 }
 
+bool load_obj(const char *path, Model *model, const char *object_name_in)
+{
+    TriangleMesh mesh;
+    
+    bool ret = load_obj(path, &mesh);
+    
+    if (ret) {
+        std::string  object_name;
+        if (object_name_in == nullptr) {
+            const char *last_slash = strrchr(path, DIR_SEPARATOR);
+            object_name.assign((last_slash == nullptr) ? path : last_slash + 1);
+        } else
+           object_name.assign(object_name_in);
+    
+        model->add_object(object_name.c_str(), path, std::move(mesh));
+    }
+    
+    return ret;
+}
+
 bool store_obj(const char *path, TriangleMesh *mesh)
 {
     //FIXME returning false even if write failed.

src/libslic3r/Format/OBJ.hpp

@@ -5,8 +5,10 @@ namespace Slic3r {
 
 class TriangleMesh;
 class Model;
+class ModelObject;
 
 // Load an OBJ file into a provided model.
+extern bool load_obj(const char *path, TriangleMesh *mesh);
 extern bool load_obj(const char *path, Model *model, const char *object_name = nullptr);
 
 extern bool store_obj(const char *path, TriangleMesh *mesh);