Importing .obj Files in OpenSCAD (#4542)

Add OBJ import.

CMakeLists.txt

@@ -661,6 +661,7 @@ set(CORE_SOURCES
   src/io/import_3mf.cc
   src/io/import_amf.cc
   src/io/import_stl.cc
+  src/io/import_obj.cc
   src/io/import_off.cc
   src/io/import_svg.cc
   src/io/import_json.cc

src/core/ImportNode.cc

@@ -91,6 +91,7 @@ static std::shared_ptr<AbstractNode> do_import(const ModuleInstantiation *inst,
     else if (ext == ".3mf") actualtype = ImportType::_3MF;
     else if (ext == ".amf") actualtype = ImportType::AMF;
     else if (ext == ".svg") actualtype = ImportType::SVG;
+    else if (ext == ".obj") actualtype = ImportType::OBJ;
   }
 
   auto node = std::make_shared<ImportNode>(inst, actualtype);
@@ -192,6 +193,10 @@ const Geometry *ImportNode::createGeometry() const
     g = import_off(this->filename, loc);
     break;
   }
+  case ImportType::OBJ: {
+    g = import_obj(this->filename, loc);
+    break;
+  }
   case ImportType::SVG: {
     g = import_svg(this->fn, this->fs, this->fa, this->filename, this->id, this->layer, this->dpi, this->center, loc);
     break;

src/core/ImportNode.h

@@ -14,6 +14,7 @@ enum class ImportType {
   SVG,
   DXF,
   NEF3,
+  OBJ,
 };
 
 class ImportNode : public LeafNode

src/gui/MainWindow.cc

@@ -269,6 +269,7 @@ MainWindow::MainWindow(const QStringList& filenames)
   const QString surfaceStatement = "surface(\"%1\");\n";
   const QString importFunction = "data = import(\"%1\");\n";
   knownFileExtensions["stl"] = importStatement;
+  knownFileExtensions["obj"] = importStatement;
   knownFileExtensions["3mf"] = importStatement;
   knownFileExtensions["off"] = importStatement;
   knownFileExtensions["dxf"] = importStatement;

src/io/import.h

@@ -6,6 +6,7 @@
 #include "AST.h"
 
 class PolySet *import_stl(const std::string& filename, const Location& loc);
+class PolySet *import_obj(const std::string& filename, const Location& loc);
 
 PolySet *import_off(const std::string& filename, const Location& loc);
 

src/io/import_obj.cc

@@ -0,0 +1,85 @@
+#include "import.h"
+#include "PolySet.h"
+#include <fstream>
+#include <vector>
+#include <boost/regex.hpp>
+#include <boost/lexical_cast.hpp>
+#include <boost/algorithm/string.hpp>
+#include <boost/algorithm/string/split.hpp>
+
+PolySet *import_obj(const std::string& filename, const Location& loc) {
+  std::unique_ptr<PolySet> p = std::make_unique<PolySet>(3);
+
+
+  std::ifstream f(filename.c_str(), std::ios::in | std::ios::binary );
+  if (!f.good()) {
+    LOG(message_group::Warning, Location::NONE, "",
+        "Can't open import file '%1$s', import() at line %2$d",
+        filename, loc.firstLine());
+    return p.release();
+  }
+  std::vector<Vector3d> pts;
+  boost::regex ex_comment(R"(^\s*#)");
+  boost::regex ex_v( R"(^\s*v\s+([^\s]+)\s+([^\s]+)\s+([^\s]+)\s*$)");
+  boost::regex ex_f( R"(^\s*f\s+(.*)$)");
+  boost::regex ex_vt( R"(^\s*vt)");
+  boost::regex ex_vn( R"(^\s*vn)");
+  boost::regex ex_mtllib( R"(^\s*mtllib)");
+  boost::regex ex_usemtl( R"(^\s*usemtl)");
+  boost::regex ex_o( R"(^\s*o)");
+  boost::regex ex_s( R"(^\s*s)");
+  boost::regex ex_g( R"(^\s*g)");
+  int lineno = 1;
+  std::string line;
+
+  auto AsciiError = [&](const auto& errstr){
+    LOG(message_group::Error, loc, "",
+    "OBJ File line %1$s, %2$s line '%3$s' importing file '%4$s'",
+    lineno, errstr, line, filename);
+  };
+
+  while (!f.eof()) {
+    lineno++;
+    std::getline(f, line);
+    boost::trim(line);
+
+    boost::smatch results;
+    if (line.length() == 0 || boost::regex_search(line, ex_comment)) {
+      continue;
+    } else if (boost::regex_search(line, results, ex_v) && results.size() >= 4) {
+      try {
+	Vector3d v;
+        for (int i = 0; i < 3; i++) {
+          v[i]= boost::lexical_cast<double>(results[i + 1]); 
+        }
+        pts.push_back(v);
+      } catch (const boost::bad_lexical_cast& blc) {
+        AsciiError("can't parse vertex");
+        return new PolySet(3);
+      }
+    } else if (boost::regex_search(line, results, ex_f) && results.size() >= 2) {
+      p->append_poly();
+      std::string args=results[1];
+      std::vector<std::string> words;
+      boost::split(words, results[1], boost::is_any_of(" \t"));
+      for (const std::string& word : words) {
+	int ind=boost::lexical_cast<int>(word);
+        if(ind >= 1 && ind  <= pts.size())
+          p->append_vertex(pts[ind-1][0], pts[ind-1][1], pts[ind-1][2]);
+        else
+          LOG(message_group::Warning, Location::NONE, "", "Index %1$d out of range in Line %2$d", filename, lineno);
+      }
+
+    } else if (boost::regex_search(line, results, ex_vt)) { // ignore texture coords
+    } else if (boost::regex_search(line, results, ex_vn)) { // ignore normal coords
+    } else if (boost::regex_search(line, results, ex_mtllib)) { // ignore material lib
+    } else if (boost::regex_search(line, results, ex_usemtl)) { // ignore usemtl
+    } else if (boost::regex_search(line, results, ex_o)) { // ignore object name
+    } else if (boost::regex_search(line, results, ex_s)) { // ignore smooting
+    } else if (boost::regex_search(line, results, ex_g)) { // ignore group name
+    } else {
+      LOG(message_group::Warning, Location::NONE, "", "Unrecognized Line  %1$s in line Line %2$d", line, lineno);
+    }
+  }
+  return p.release();
+}

tests/CMakeLists.txt

@@ -708,6 +708,7 @@ list(APPEND CGALSTLSANITYTEST_FILES ${TEST_SCAD_DIR}/misc/normal-nan.scad)
 list(APPEND EXPORT_STL_TEST_FILES ${TEST_SCAD_DIR}/stl/stl-export.scad)
 
 list(APPEND EXPORT_OBJ_TEST_FILES ${TEST_SCAD_DIR}/obj/obj-export.scad)
+list(APPEND EXPORT_OBJ_TEST_FILES ${TEST_SCAD_DIR}/obj/obj-import-export.scad)
 
 list(APPEND EXPORT_3MF_TEST_FILES ${TEST_SCAD_DIR}/3mf/3mf-export.scad)
 

tests/data/obj/dodecahedron.obj

@@ -0,0 +1,61 @@
+# Author: Guenther Sohler, create_dod.py
+# Date:	2023-03-08
+
+g Dodecahedron
+
+v -0.57735 -0.57735 0.57735
+v 0.934172 0.356822 0
+v 0.934172 -0.356822 0
+v -0.934172 0.356822 0
+v -0.934172 -0.356822 0
+v 0 0.934172 0.356822
+v 0 0.934172 -0.356822
+v 0.356822 0 -0.934172
+v -0.356822 0 -0.934172
+v 0 -0.934172 -0.356822
+v 0 -0.934172 0.356822
+v 0.356822 0 0.934172
+v -0.356822 0 0.934172
+v 0.57735 0.57735 -0.57735
+v 0.57735 0.57735 0.57735
+v -0.57735 0.57735 -0.57735
+v -0.57735 0.57735 0.57735
+v 0.57735 -0.57735 -0.57735
+v 0.57735 -0.57735 0.57735
+v -0.57735 -0.57735 -0.57735
+f 19 3 2
+f 12 19 2
+f 15 12 2
+f 8 14 2
+f 18 8 2
+f 3 18 2
+f 20 5 4
+f 9 20 4
+f 16 9 4
+f 13 17 4
+f 1 13 4
+f 5 1 4
+f 7 16 4
+f 6 7 4
+f 17 6 4
+f 6 15 2
+f 7 6 2
+f 14 7 2
+f 10 18 3
+f 11 10 3
+f 19 11 3
+f 11 1 5
+f 10 11 5
+f 20 10 5
+f 20 9 8
+f 10 20 8
+f 18 10 8
+f 9 16 7
+f 8 9 7
+f 14 8 7
+f 12 15 6
+f 13 12 6
+f 17 13 6
+f 13 1 11
+f 12 13 11
+f 19 12 11

tests/data/scad/obj/obj-import-export.scad

@@ -0,0 +1 @@
+import("../../obj/dodecahedron.obj");

tests/regression/objexport/obj-import-export-expected.obj

@@ -0,0 +1,57 @@
+# OpenSCAD obj exporter
+v 0.57735 -0.57735 0.57735
+v 0.934172 -0.356822 0
+v 0.934172 0.356822 0
+v 0.356822 0 0.934172
+v 0.57735 0.57735 0.57735
+v 0.356822 0 -0.934172
+v 0.57735 0.57735 -0.57735
+v 0.57735 -0.57735 -0.57735
+v -0.57735 -0.57735 -0.57735
+v -0.934172 -0.356822 0
+v -0.934172 0.356822 0
+v -0.356822 0 -0.934172
+v -0.57735 0.57735 -0.57735
+v -0.356822 0 0.934172
+v -0.57735 0.57735 0.57735
+v -0.57735 -0.57735 0.57735
+v 0 0.934172 -0.356822
+v 0 0.934172 0.356822
+v 0 -0.934172 -0.356822
+v 0 -0.934172 0.356822
+f  1 2 3
+f  4 1 3
+f  5 4 3
+f  6 7 3
+f  8 6 3
+f  2 8 3
+f  9 10 11
+f  12 9 11
+f  13 12 11
+f  14 15 11
+f  16 14 11
+f  10 16 11
+f  17 13 11
+f  18 17 11
+f  15 18 11
+f  18 5 3
+f  17 18 3
+f  7 17 3
+f  19 8 2
+f  20 19 2
+f  1 20 2
+f  20 16 10
+f  19 20 10
+f  9 19 10
+f  9 12 6
+f  19 9 6
+f  8 19 6
+f  12 13 17
+f  6 12 17
+f  7 6 17
+f  4 5 18
+f  14 4 18
+f  15 14 18
+f  14 16 20
+f  4 14 20
+f  1 4 20