Parse multiple group names. Fixes #146

models/cube.obj

@@ -13,6 +13,7 @@ v 2.000000 2.000000 0.000000
 g front cube
 usemtl white
 f 1 2 3 4
+# two white spaces between 'back' and 'cube'
 g back  cube
 # expects white material
 f 8 7 6 5

tests/tester.cc

@@ -807,6 +807,24 @@ TEST_CASE("line-primitive", "[line]") {
   REQUIRE(6 == shapes[0].path.indices.size());
 }
 
+TEST_CASE("multiple-group-names", "[group]") {
+  tinyobj::attrib_t attrib;
+  std::vector<tinyobj::shape_t> shapes;
+  std::vector<tinyobj::material_t> materials;
+
+  std::string err;
+  bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, "../models/cube.obj", gMtlBasePath);
+
+  if (!err.empty()) {
+    std::cerr << "[group] " << err << std::endl;
+  }
+
+  REQUIRE(true == ret);
+  REQUIRE(6 == shapes.size());
+  REQUIRE(0 == shapes[0].name.compare("front cube"));
+  REQUIRE(0 == shapes[1].name.compare("back cube")); // multiple whitespaces are aggregated as single white space.
+}
+
 // Fuzzer test.
 // Just check if it does not crash.
 // Disable by default since Windows filesystem can't create filename of afl testdata

tiny_obj_loader.h

@@ -23,6 +23,7 @@ THE SOFTWARE.
 */
 
 //
+// version 1.2.2 : Parse multiple group names.
 // version 1.2.1 : Added initial support for line('l') primitive(PR #178)
 // version 1.2.0 : Hardened implementation(#175)
 // version 1.1.1 : Support smoothing groups(#162)
@@ -1790,10 +1791,13 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
 
   shape_t shape;
 
+  size_t line_num = 0;
   std::string linebuf;
   while (inStream->peek() != -1) {
     safeGetline(*inStream, linebuf);
 
+    line_num++;
+
     // Trim newline '\r\n' or '\n'
     if (linebuf.size() > 0) {
       if (linebuf[linebuf.size() - 1] == '\n')
@@ -2001,7 +2005,6 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
       faceGroup.clear();
 
       std::vector<std::string> names;
-      names.reserve(2);
 
       while (!IS_NEW_LINE(token[0])) {
         std::string str = parseString(&token);
@@ -2009,14 +2012,32 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
         token += strspn(token, " \t\r");  // skip tag
       }
 
-      assert(names.size() > 0);
+      // names[0] must be 'g'
 
-      // names[0] must be 'g', so skip the 0th element.
-      if (names.size() > 1) {
-        name = names[1];
-      } else {
+      if (names.size() < 2) {
+        // 'g' with empty names
+        if (err) {
+          std::stringstream ss;
+          ss << "WARN: Empty group name. line: " << line_num << "\n";
+          (*err) += ss.str();
           name = "";
         }
+      } else {
+
+        std::stringstream ss;
+        ss << names[1];
+
+        // tinyobjloader does not support multiple groups for a primitive.
+        // Currently we concatinate multiple group names with a space to get
+        // single group name.
+
+        for (size_t i = 2; i < names.size(); i++) {
+          ss << " " << names[i];
+        }
+
+        name = ss.str();
+
+      }
 
       continue;
     }
@@ -2169,7 +2190,6 @@ bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
   std::vector<material_t> materials;
   std::vector<std::string> names;
   names.reserve(2);
-  std::string name;
   std::vector<const char *> names_out;
 
   std::string linebuf;
@@ -2346,13 +2366,6 @@ bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
 
       assert(names.size() > 0);
 
-      // names[0] must be 'g', so skip the 0th element.
-      if (names.size() > 1) {
-        name = names[1];
-      } else {
-        name.clear();
-      }
-
       if (callback.group_cb) {
         if (names.size() > 1) {
           // create const char* array.