Fix mtllib reloading: load a mtl file only once

li-plus · li-plus · commit bd36e2c8ef90 · 2021-12-25T13:10:51.000+08:00
diff --git a/tiny_obj_loader.h b/tiny_obj_loader.h
@@ -2445,6 +2445,7 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
   std::string name;
 
   // material
+  std::map<std::string, std::map<std::string, int> > material_maps;
   std::map<std::string, int> material_map;
   int material = -1;
 
@@ -2735,10 +2736,21 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
         } else {
           bool found = false;
           for (size_t s = 0; s < filenames.size(); s++) {
+            std::map<std::string, std::map<std::string, int> >::const_iterator
+                material_map_it = material_maps.find(filenames[s]);
+            if (material_map_it != material_maps.end()) {
+              found = true;
+              material_map = material_map_it->second;
+              continue;
+            }
+
             std::string warn_mtl;
             std::string err_mtl;
             bool ok = (*readMatFn)(filenames[s].c_str(), materials,
                                    &material_map, &warn_mtl, &err_mtl);
+            material_maps.insert(
+                std::pair<std::string, std::map<std::string, int> >(
+                    filenames[s], material_map));
             if (warn && (!warn_mtl.empty())) {
               (*warn) += warn_mtl;
             }
@@ -2993,6 +3005,7 @@ bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
   std::stringstream errss;
 
   // material
+  std::map<std::string, std::map<std::string, int> > material_maps;
   std::map<std::string, int> material_map;
   int material_id = -1;  // -1 = invalid
 
@@ -3138,10 +3151,21 @@ bool LoadObjWithCallback(std::istream &inStream, const callback_t &callback,
         } else {
           bool found = false;
           for (size_t s = 0; s < filenames.size(); s++) {
+            std::map<std::string, std::map<std::string, int> >::const_iterator
+                material_map_it = material_maps.find(filenames[s]);
+            if (material_map_it != material_maps.end()) {
+              found = true;
+              material_map = material_map_it->second;
+              continue;
+            }
+
             std::string warn_mtl;
             std::string err_mtl;
             bool ok = (*readMatFn)(filenames[s].c_str(), &materials,
                                    &material_map, &warn_mtl, &err_mtl);
+            material_maps.insert(
+                std::pair<std::string, std::map<std::string, int> >(
+                    filenames[s], material_map));
 
             if (warn && (!warn_mtl.empty())) {
               (*warn) += warn_mtl;  // This should be warn message.
