Add smooting group test .obj with two squares.

Bump version.

README.md

@@ -98,6 +98,7 @@ TinyObjLoader is successfully used in ...
 * PBR material extension for .MTL. Its proposed here: http://exocortex.com/blog/extending_wavefront_mtl_to_support_pbr
 * Callback API for custom loading.
 * Double precision support(for HPC application).
+* Smoothing group
 
 
 ## TODO
@@ -105,8 +106,6 @@ TinyObjLoader is successfully used in ...
 * [ ] Fix obj_sticker example.
 * [ ] More unit test codes.
 * [x] Texture options
-* [ ] Normal vector generation
-  * [ ] Support smoothing groups
 
 ## License
 

examples/obj_sticher/obj_writer.cc

@@ -172,5 +172,3 @@ bool WriteObj(const std::string& filename, const std::vector<tinyobj::shape_t>&
 
   return ret;
 }
-
-

examples/viewer/viewer.cc

@@ -37,11 +37,11 @@ extern "C" {
 #include <windows.h>
 
 #ifdef max
- #undef max
+#undef max
 #endif
 
 #ifdef min
- #undef min
+#undef min
 #endif
 
 #include <mmsystem.h>
@@ -143,15 +143,15 @@ float eye[3], lookat[3], up[3];
 
 GLFWwindow* window;
 
-static std::string GetBaseDir(const std::string &filepath) {
+static std::string GetBaseDir(const std::string& filepath) {
   if (filepath.find_last_of("/\\") != std::string::npos)
     return filepath.substr(0, filepath.find_last_of("/\\"));
   return "";
 }
 
-static bool FileExists(const std::string &abs_filename) {
+static bool FileExists(const std::string& abs_filename) {
   bool ret;
-  FILE *fp = fopen(abs_filename.c_str(), "rb");
+  FILE* fp = fopen(abs_filename.c_str(), "rb");
   if (fp) {
     ret = true;
     fclose(fp);
@@ -191,14 +191,106 @@ static void CalcNormal(float N[3], float v0[3], float v1[3], float v2[3]) {
 
     N[0] /= len;
     N[1] /= len;
+    N[2] /= len;
   }
 }
 
+namespace  // Local utility functions
+{
+struct vec3 {
+  float v[3];
+  vec3() {
+    v[0] = 0.0f;
+    v[1] = 0.0f;
+    v[2] = 0.0f;
+  }
+};
+
+void normalizeVector(vec3 &v) {
+  float len2 = v.v[0] * v.v[0] + v.v[1] * v.v[1] + v.v[2] * v.v[2];
+  if (len2 > 0.0f) {
+    float len = sqrtf(len2);
+
+    v.v[0] /= len;
+    v.v[1] /= len;
+    v.v[2] /= len;
+  }
+}
+
+// Check if `mesh_t` contains smoothing group id.
+bool hasSmoothingGroup(const tinyobj::shape_t& shape)
+{
+  for (size_t i = 0; i < shape.mesh.smoothing_group_ids.size(); i++) {
+    if (shape.mesh.smoothing_group_ids[i] > 0) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void computeSmoothingNormals(const tinyobj::attrib_t& attrib, const tinyobj::shape_t& shape,
+                             std::map<int, vec3>& smoothVertexNormals) {
+  smoothVertexNormals.clear();
+  std::map<int, vec3>::iterator iter;
+
+  for (size_t f = 0; f < shape.mesh.indices.size() / 3; f++) {
+    // Get the three indexes of the face (all faces are triangular)
+    tinyobj::index_t idx0 = shape.mesh.indices[3 * f + 0];
+    tinyobj::index_t idx1 = shape.mesh.indices[3 * f + 1];
+    tinyobj::index_t idx2 = shape.mesh.indices[3 * f + 2];
+
+    // Get the three vertex indexes and coordinates
+    int vi[3];      // indexes
+    float v[3][3];  // coordinates
+
+    for (int k = 0; k < 3; k++) {
+      vi[0] = idx0.vertex_index;
+      vi[1] = idx1.vertex_index;
+      vi[2] = idx2.vertex_index;
+      assert(vi[0] >= 0);
+      assert(vi[1] >= 0);
+      assert(vi[2] >= 0);
+
+      v[0][k] = attrib.vertices[3 * vi[0] + k];
+      v[1][k] = attrib.vertices[3 * vi[1] + k];
+      v[2][k] = attrib.vertices[3 * vi[2] + k];
+    }
+
+    // Compute the normal of the face
+    float normal[3];
+    CalcNormal(normal, v[0], v[1], v[2]);
+
+    // Add the normal to the three vertexes
+    for (size_t i = 0; i < 3; ++i) {
+      iter = smoothVertexNormals.find(vi[i]);
+      if (iter != smoothVertexNormals.end()) {
+        // add
+        iter->second.v[0] += normal[0];
+        iter->second.v[1] += normal[1];
+        iter->second.v[2] += normal[2];
+      } else {
+        smoothVertexNormals[vi[i]].v[0] = normal[0];
+        smoothVertexNormals[vi[i]].v[1] = normal[1];
+        smoothVertexNormals[vi[i]].v[2] = normal[2];
+      }
+    }
+
+  }  // f
+
+  // Normalize the normals, that is, make them unit vectors
+  for (iter = smoothVertexNormals.begin(); iter != smoothVertexNormals.end();
+       iter++) {
+    normalizeVector(iter->second);
+  }
+
+}  // computeSmoothingNormals
+}  // namespace
+
 static bool LoadObjAndConvert(float bmin[3], float bmax[3],
-                       std::vector<DrawObject>* drawObjects,
-                       std::vector<tinyobj::material_t>& materials,
-                       std::map<std::string, GLuint>& textures,
-                       const char* filename) {
+                              std::vector<DrawObject>* drawObjects,
+                              std::vector<tinyobj::material_t>& materials,
+                              std::map<std::string, GLuint>& textures,
+                              const char* filename) {
   tinyobj::attrib_t attrib;
   std::vector<tinyobj::shape_t> shapes;
 
@@ -217,8 +309,8 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
 #endif
 
   std::string err;
-  bool ret =
-      tinyobj::LoadObj(&attrib, &shapes, &materials, &err, filename, base_dir.c_str());
+  bool ret = tinyobj::LoadObj(&attrib, &shapes, &materials, &err, filename,
+                              base_dir.c_str());
   if (!err.empty()) {
     std::cerr << err << std::endl;
   }
@@ -242,56 +334,62 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
   materials.push_back(tinyobj::material_t());
 
   for (size_t i = 0; i < materials.size(); i++) {
-    printf("material[%d].diffuse_texname = %s\n", int(i), materials[i].diffuse_texname.c_str());
+    printf("material[%d].diffuse_texname = %s\n", int(i),
+           materials[i].diffuse_texname.c_str());
   }
 
   // Load diffuse textures
   {
-      for (size_t m = 0; m < materials.size(); m++) {
-          tinyobj::material_t* mp = &materials[m];
-          
-          if (mp->diffuse_texname.length() > 0) {
-              // Only load the texture if it is not already loaded
-              if (textures.find(mp->diffuse_texname) == textures.end()) {
-                  GLuint texture_id;
-                  int w, h;
-                  int comp;
+    for (size_t m = 0; m < materials.size(); m++) {
+      tinyobj::material_t* mp = &materials[m];
 
-                  std::string texture_filename = mp->diffuse_texname;
-                  if (!FileExists(texture_filename)) {
-                    // Append base dir.
-                    texture_filename = base_dir + mp->diffuse_texname;
-                    if (!FileExists(texture_filename)) {
-                      std::cerr << "Unable to find file: " << mp->diffuse_texname << std::endl;
-                      exit(1);
-                    }
-                  }
-                  
-                  unsigned char* image = stbi_load(texture_filename.c_str(), &w, &h, &comp, STBI_default);
-                  if (!image) {
-                      std::cerr << "Unable to load texture: " << texture_filename << std::endl;
-                      exit(1);
-                  }
-                  std::cout << "Loaded texture: " << texture_filename << ", w = " << w << ", h = " << h << ", comp = " << comp << std::endl;
+      if (mp->diffuse_texname.length() > 0) {
+        // Only load the texture if it is not already loaded
+        if (textures.find(mp->diffuse_texname) == textures.end()) {
+          GLuint texture_id;
+          int w, h;
+          int comp;
 
-                  glGenTextures(1, &texture_id);
-                  glBindTexture(GL_TEXTURE_2D, texture_id);
-                  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
-                  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-                  if (comp == 3) {
-                      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
-                  }
-                  else if (comp == 4) {
-                      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, image);
-                  } else {
-                      assert(0); // TODO
-                  }
-                  glBindTexture(GL_TEXTURE_2D, 0);
-                  stbi_image_free(image);
-                  textures.insert(std::make_pair(mp->diffuse_texname, texture_id));
-              }
+          std::string texture_filename = mp->diffuse_texname;
+          if (!FileExists(texture_filename)) {
+            // Append base dir.
+            texture_filename = base_dir + mp->diffuse_texname;
+            if (!FileExists(texture_filename)) {
+              std::cerr << "Unable to find file: " << mp->diffuse_texname
+                        << std::endl;
+              exit(1);
+            }
           }
+
+          unsigned char* image =
+              stbi_load(texture_filename.c_str(), &w, &h, &comp, STBI_default);
+          if (!image) {
+            std::cerr << "Unable to load texture: " << texture_filename
+                      << std::endl;
+            exit(1);
+          }
+          std::cout << "Loaded texture: " << texture_filename << ", w = " << w
+                    << ", h = " << h << ", comp = " << comp << std::endl;
+
+          glGenTextures(1, &texture_id);
+          glBindTexture(GL_TEXTURE_2D, texture_id);
+          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+          glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+          if (comp == 3) {
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, w, h, 0, GL_RGB,
+                         GL_UNSIGNED_BYTE, image);
+          } else if (comp == 4) {
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA,
+                         GL_UNSIGNED_BYTE, image);
+          } else {
+            assert(0);  // TODO
+          }
+          glBindTexture(GL_TEXTURE_2D, 0);
+          stbi_image_free(image);
+          textures.insert(std::make_pair(mp->diffuse_texname, texture_id));
+        }
       }
+    }
   }
 
   bmin[0] = bmin[1] = bmin[2] = std::numeric_limits<float>::max();
@@ -301,30 +399,55 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
     for (size_t s = 0; s < shapes.size(); s++) {
       DrawObject o;
       std::vector<float> buffer;  // pos(3float), normal(3float), color(3float)
+
+      // Check for smoothing group and compute smoothing normals
+      std::map<int, vec3> smoothVertexNormals;
+      if (hasSmoothingGroup(shapes[s]) > 0) {
+        std::cout << "Compute smoothingNormal for shape [" << s << "]" << std::endl;
+        computeSmoothingNormals(attrib, shapes[s], smoothVertexNormals);
+      }
+
       for (size_t f = 0; f < shapes[s].mesh.indices.size() / 3; f++) {
         tinyobj::index_t idx0 = shapes[s].mesh.indices[3 * f + 0];
         tinyobj::index_t idx1 = shapes[s].mesh.indices[3 * f + 1];
         tinyobj::index_t idx2 = shapes[s].mesh.indices[3 * f + 2];
-        
+
         int current_material_id = shapes[s].mesh.material_ids[f];
 
-        if ((current_material_id < 0) || (current_material_id >= static_cast<int>(materials.size()))) {
+        if ((current_material_id < 0) ||
+            (current_material_id >= static_cast<int>(materials.size()))) {
           // Invaid material ID. Use default material.
-          current_material_id = materials.size() - 1; // Default material is added to the last item in `materials`.
+          current_material_id =
+              materials.size() -
+              1;  // Default material is added to the last item in `materials`.
         }
-        //if (current_material_id >= materials.size()) {
-        //    std::cerr << "Invalid material index: " << current_material_id << std::endl;
+        // if (current_material_id >= materials.size()) {
+        //    std::cerr << "Invalid material index: " << current_material_id <<
+        //    std::endl;
         //}
         //
         float diffuse[3];
         for (size_t i = 0; i < 3; i++) {
-            diffuse[i] = materials[current_material_id].diffuse[i];
+          diffuse[i] = materials[current_material_id].diffuse[i];
         }
         float tc[3][2];
         if (attrib.texcoords.size() > 0) {
-            assert(attrib.texcoords.size() > 2 * idx0.texcoord_index + 1);
-            assert(attrib.texcoords.size() > 2 * idx1.texcoord_index + 1);
-            assert(attrib.texcoords.size() > 2 * idx2.texcoord_index + 1);
+          if ((idx0.texcoord_index < 0) || (idx1.texcoord_index < 0) ||
+              (idx2.texcoord_index < 0)) {
+            // face does not contain valid uv index.
+            tc[0][0] = 0.0f;
+            tc[0][1] = 0.0f;
+            tc[1][0] = 0.0f;
+            tc[1][1] = 0.0f;
+            tc[2][0] = 0.0f;
+            tc[2][1] = 0.0f;
+          } else {
+            assert(attrib.texcoords.size() >
+                   size_t(2 * idx0.texcoord_index + 1));
+            assert(attrib.texcoords.size() >
+                   size_t(2 * idx1.texcoord_index + 1));
+            assert(attrib.texcoords.size() >
+                   size_t(2 * idx2.texcoord_index + 1));
 
             // Flip Y coord.
             tc[0][0] = attrib.texcoords[2 * idx0.texcoord_index];
@@ -333,13 +456,14 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
             tc[1][1] = 1.0f - attrib.texcoords[2 * idx1.texcoord_index + 1];
             tc[2][0] = attrib.texcoords[2 * idx2.texcoord_index];
             tc[2][1] = 1.0f - attrib.texcoords[2 * idx2.texcoord_index + 1];
+          }
         } else {
-            tc[0][0] = 0.0f;
-            tc[0][1] = 0.0f;
-            tc[1][0] = 0.0f;
-            tc[1][1] = 0.0f;
-            tc[2][0] = 0.0f;
-            tc[2][1] = 0.0f;
+          tc[0][0] = 0.0f;
+          tc[0][1] = 0.0f;
+          tc[1][0] = 0.0f;
+          tc[1][1] = 0.0f;
+          tc[2][0] = 0.0f;
+          tc[2][1] = 0.0f;
         }
 
         float v[3][3];
@@ -363,27 +487,63 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
         }
 
         float n[3][3];
-        if (attrib.normals.size() > 0) {
-          int f0 = idx0.normal_index;
-          int f1 = idx1.normal_index;
-          int f2 = idx2.normal_index;
-          assert(f0 >= 0);
-          assert(f1 >= 0);
-          assert(f2 >= 0);
-          for (int k = 0; k < 3; k++) {
-            n[0][k] = attrib.normals[3 * f0 + k];
-            n[1][k] = attrib.normals[3 * f1 + k];
-            n[2][k] = attrib.normals[3 * f2 + k];
+        {
+          bool invalid_normal_index = false;
+          if (attrib.normals.size() > 0) {
+            int nf0 = idx0.normal_index;
+            int nf1 = idx1.normal_index;
+            int nf2 = idx2.normal_index;
+
+            if ((nf0 < 0) || (nf1 < 0) || (nf2 < 0)) {
+              // normal index is missing from this face.
+              invalid_normal_index = true;
+            } else {
+              for (int k = 0; k < 3; k++) {
+                assert(size_t(3 * nf0 + k) < attrib.normals.size());
+                assert(size_t(3 * nf1 + k) < attrib.normals.size());
+                assert(size_t(3 * nf2 + k) < attrib.normals.size());
+                n[0][k] = attrib.normals[3 * nf0 + k];
+                n[1][k] = attrib.normals[3 * nf1 + k];
+                n[2][k] = attrib.normals[3 * nf2 + k];
+              }
+            }
+          } else {
+            invalid_normal_index = true;
+          }
+
+          if (invalid_normal_index && !smoothVertexNormals.empty()) {
+            // Use smoothing normals
+            int f0 = idx0.vertex_index;
+            int f1 = idx1.vertex_index;
+            int f2 = idx2.vertex_index;
+
+            if (f0 >= 0 && f1 >= 0 && f2 >= 0) {
+              n[0][0] = smoothVertexNormals[f0].v[0];
+              n[0][1] = smoothVertexNormals[f0].v[1];
+              n[0][2] = smoothVertexNormals[f0].v[2];
+
+              n[1][0] = smoothVertexNormals[f1].v[0];
+              n[1][1] = smoothVertexNormals[f1].v[1];
+              n[1][2] = smoothVertexNormals[f1].v[2];
+
+              n[2][0] = smoothVertexNormals[f2].v[0];
+              n[2][1] = smoothVertexNormals[f2].v[1];
+              n[2][2] = smoothVertexNormals[f2].v[2];
+
+              invalid_normal_index = false;
+            }
+          }
+
+          if (invalid_normal_index) {
+            // compute geometric normal
+            CalcNormal(n[0], v[0], v[1], v[2]);
+            n[1][0] = n[0][0];
+            n[1][1] = n[0][1];
+            n[1][2] = n[0][2];
+            n[2][0] = n[0][0];
+            n[2][1] = n[0][1];
+            n[2][2] = n[0][2];
           }
-        } else {
-          // compute geometric normal
-          CalcNormal(n[0], v[0], v[1], v[2]);
-          n[1][0] = n[0][0];
-          n[1][1] = n[0][1];
-          n[1][2] = n[0][2];
-          n[2][0] = n[0][0];
-          n[2][1] = n[0][1];
-          n[2][2] = n[0][2];
         }
 
         for (int k = 0; k < 3; k++) {
@@ -396,11 +556,9 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
           // Combine normal and diffuse to get color.
           float normal_factor = 0.2;
           float diffuse_factor = 1 - normal_factor;
-          float c[3] = {
-              n[k][0] * normal_factor + diffuse[0] * diffuse_factor,
-              n[k][1] * normal_factor + diffuse[1] * diffuse_factor,
-              n[k][2] * normal_factor + diffuse[2] * diffuse_factor
-          };
+          float c[3] = {n[k][0] * normal_factor + diffuse[0] * diffuse_factor,
+                        n[k][1] * normal_factor + diffuse[1] * diffuse_factor,
+                        n[k][2] * normal_factor + diffuse[2] * diffuse_factor};
           float len2 = c[0] * c[0] + c[1] * c[1] + c[2] * c[2];
           if (len2 > 0.0f) {
             float len = sqrtf(len2);
@@ -412,7 +570,7 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
           buffer.push_back(c[0] * 0.5 + 0.5);
           buffer.push_back(c[1] * 0.5 + 0.5);
           buffer.push_back(c[2] * 0.5 + 0.5);
-          
+
           buffer.push_back(tc[k][0]);
           buffer.push_back(tc[k][1]);
         }
@@ -422,19 +580,22 @@ static bool LoadObjAndConvert(float bmin[3], float bmax[3],
       o.numTriangles = 0;
 
       // OpenGL viewer does not support texturing with per-face material.
-      if (shapes[s].mesh.material_ids.size() > 0 && shapes[s].mesh.material_ids.size() > s) {
-          o.material_id = shapes[s].mesh.material_ids[0]; // use the material ID of the first face.
+      if (shapes[s].mesh.material_ids.size() > 0 &&
+          shapes[s].mesh.material_ids.size() > s) {
+        o.material_id = shapes[s].mesh.material_ids[0];  // use the material ID
+                                                         // of the first face.
       } else {
-          o.material_id = materials.size() - 1; // = ID for default material.
+        o.material_id = materials.size() - 1;  // = ID for default material.
       }
       printf("shape[%d] material_id %d\n", int(s), int(o.material_id));
-          
+
       if (buffer.size() > 0) {
         glGenBuffers(1, &o.vb_id);
         glBindBuffer(GL_ARRAY_BUFFER, o.vb_id);
-        glBufferData(GL_ARRAY_BUFFER, buffer.size() * sizeof(float), &buffer.at(0),
-                     GL_STATIC_DRAW);
-        o.numTriangles = buffer.size() / (3 + 3 + 3 + 2) / 3; // 3:vtx, 3:normal, 3:col, 2:texcoord
+        glBufferData(GL_ARRAY_BUFFER, buffer.size() * sizeof(float),
+                     &buffer.at(0), GL_STATIC_DRAW);
+        o.numTriangles = buffer.size() / (3 + 3 + 3 + 2) /
+                         3;  // 3:vtx, 3:normal, 3:col, 2:texcoord
 
         printf("shape[%d] # of triangles = %d\n", static_cast<int>(s),
                o.numTriangles);
@@ -467,7 +628,7 @@ static void reshapeFunc(GLFWwindow* window, int w, int h) {
 }
 
 static void keyboardFunc(GLFWwindow* window, int key, int scancode, int action,
-                  int mods) {
+                         int mods) {
   (void)window;
   (void)scancode;
   (void)mods;
@@ -549,7 +710,9 @@ static void motionFunc(GLFWwindow* window, double mouse_x, double mouse_y) {
   prevMouseY = mouse_y;
 }
 
-static void Draw(const std::vector<DrawObject>& drawObjects, std::vector<tinyobj::material_t>& materials, std::map<std::string, GLuint>& textures) {
+static void Draw(const std::vector<DrawObject>& drawObjects,
+                 std::vector<tinyobj::material_t>& materials,
+                 std::map<std::string, GLuint>& textures) {
   glPolygonMode(GL_FRONT, GL_FILL);
   glPolygonMode(GL_BACK, GL_FILL);
 
@@ -572,7 +735,7 @@ static void Draw(const std::vector<DrawObject>& drawObjects, std::vector<tinyobj
     if ((o.material_id < materials.size())) {
       std::string diffuse_texname = materials[o.material_id].diffuse_texname;
       if (textures.find(diffuse_texname) != textures.end()) {
-          glBindTexture(GL_TEXTURE_2D, textures[diffuse_texname]);
+        glBindTexture(GL_TEXTURE_2D, textures[diffuse_texname]);
       }
     }
     glVertexPointer(3, GL_FLOAT, stride, (const void*)0);
@@ -668,7 +831,8 @@ int main(int argc, char** argv) {
   float bmin[3], bmax[3];
   std::vector<tinyobj::material_t> materials;
   std::map<std::string, GLuint> textures;
-  if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, materials, textures, argv[1])) {
+  if (false == LoadObjAndConvert(bmin, bmax, &gDrawObjects, materials, textures,
+                                 argv[1])) {
     return -1;
   }
 

experimental/tinyobj_loader_opt.h

@@ -1440,7 +1440,9 @@ bool parseObj(attrib_t *attrib, std::vector<shape_t> *shapes,
     // std::cout << "mtllib :" << material_filename << std::endl;
 
     auto t1 = std::chrono::high_resolution_clock::now();
-
+	if (material_filename.back() == '\r') {
+			material_filename.pop_back();
+	}
     std::ifstream ifs(material_filename);
     if (ifs.good()) {
       LoadMtl(&material_map, materials, &ifs);
@@ -1516,13 +1518,13 @@ bool parseObj(attrib_t *attrib, std::vector<shape_t> *shapes,
     StackVector<std::thread, 16> workers;
 
     for (size_t t = 0; t < num_threads; t++) {
-      int material_id = -1;  // -1 = default unknown material.
       workers->push_back(std::thread([&, t]() {
         size_t v_count = v_offsets[t];
         size_t n_count = n_offsets[t];
         size_t t_count = t_offsets[t];
         size_t f_count = f_offsets[t];
         size_t face_count = face_offsets[t];
+		int material_id = -1;  // -1 = default unknown material.
 
         for (size_t i = 0; i < commands[t].size(); i++) {
           if (commands[t][i].type == COMMAND_EMPTY) {
@@ -1579,7 +1581,19 @@ bool parseObj(attrib_t *attrib, std::vector<shape_t> *shapes,
     for (size_t t = 0; t < workers->size(); t++) {
       workers[t].join();
     }
-
+	if(material_map.size()>1&& num_threads>1) {
+			for (size_t t = 0; t < num_threads; t++) {
+				size_t face_count = face_offsets[t];
+				if (-1 == attrib->material_ids[face_count]) {
+					int prev_material_id = attrib->material_ids[face_count - 1];
+					size_t max_face_offset = (t == num_threads - 1) ? attrib->material_ids.size() : face_offsets[t + 1];
+					for (int i = face_count; i<max_face_offset; ++i) {
+						if (attrib->material_ids[i] != -1) break;
+						attrib->material_ids[i] = prev_material_id;
+					}
+				}
+			}
+	}
     auto t_end = std::chrono::high_resolution_clock::now();
     ms_merge = t_end - t_start;
   }

loader_example.cc

@@ -29,6 +29,13 @@ extern "C" {
 #endif
 #endif
 
+#ifdef __clang__
+#pragma clang diagnostic push
+#if __has_warning("-Wzero-as-null-pointer-constant")
+#pragma clang diagnostic ignored "-Wzero-as-null-pointer-constant"
+#endif
+#endif
+
 class timerutil {
  public:
 #ifdef _WIN32
@@ -361,7 +368,7 @@ static bool TestStreamLoadObj() {
     virtual ~MaterialStringStreamReader() {}
     virtual bool operator()(const std::string& matId,
                             std::vector<material_t>* materials,
-                            std::map<unsigned int, int>* matMap,
+                            std::map<std::string, int>* matMap,
                             std::string* err) {
       (void)matId;
       std::string warning;

models/issue-161-inconsistent-f.obj

@@ -0,0 +1,37 @@
+o cube
+mtllib cube.mtl
+
+v -0.500000 -0.500000 0.500000
+v 0.500000 -0.500000 0.500000
+v -0.500000 0.500000 0.500000
+v 0.500000 0.500000 0.500000
+v -0.500000 0.500000 -0.500000
+v 0.500000 0.500000 -0.500000
+v -0.500000 -0.500000 -0.500000
+v 0.500000 -0.500000 -0.500000
+
+vt 0.000000 0.000000
+vt 1.000000 0.000000
+vt 0.000000 1.000000
+vt 1.000000 1.000000
+
+g cube
+usemtl cube
+s 1
+f 1/1 2/2 3/3
+f 3/3 2/2 4/4
+s 2
+f 3/1 4/2 5/3
+f 5/3 4/2 6/4
+s 3
+f 5/4 6/3 7/2
+f 7/2 6/3 8/1
+s 4
+f 7/1 8/2 1/3
+f 1/3 8/2 2/4
+s 5
+f 2/1 8/2 4/3
+f 4/3 8/2 6/4
+s 6
+f 7/1 1/2 5/3
+f 5 1 3

models/issue-162-smoothing-group.mtl

@@ -0,0 +1,23 @@
+newmtl test1
+  Ns 10.0000
+  Ni 1.5000
+  d 1.0000
+  Tr 0.0000
+  Tf 1.0000 1.0000 1.0000 
+  illum 2
+  Ka 0.0000 0.0000 0.0000
+  Kd 0.5 0.2 0.2
+  Ks 0.0000 0.0000 0.0000
+  Ke 0.0000 0.0000 0.0000
+
+ newmtl test2
+  Ns 10.0000
+  Ni 1.5000
+  d 1.0000
+  Tr 0.0000
+  Tf 1.0000 1.0000 1.0000 
+  illum 2
+  Ka 0.0000 0.0000 0.0000
+  Kd 0.2 0.5 0.2
+  Ks 0.0000 0.0000 0.0000
+  Ke 0.0000 0.0000 0.0000

models/issue-162-smoothing-group.obj

@@ -0,0 +1,51 @@
+
+# cube.obj
+#
+
+mtllib issue-162-smoothing-group.mtl
+
+v -0.500000 -0.500000 0.500000
+v 0.500000 -0.500000 0.500000
+v -0.500000 0.500000 0.500000
+v 0.500000 0.500000 0.500000
+v -0.500000 0.500000 -0.500000
+v 0.500000 0.500000 -0.500000
+v -0.500000 -0.500000 -0.500000
+v 0.500000 -0.500000 -0.500000
+
+vt 0.000000 0.000000
+vt 1.000000 0.000000
+vt 0.000000 1.000000
+vt 1.000000 1.000000
+
+vn 0.000000 0.000000 1.000000
+vn 0.000000 1.000000 0.000000
+vn 0.000000 0.000000 -1.000000
+vn 0.000000 -1.000000 0.000000
+vn 1.000000 0.000000 0.000000
+vn -1.000000 0.000000 0.000000
+
+usemtl test1
+g test1
+s 1
+f 1/1/1 2/2/1 3/3/1
+f 3/3/1 2/2/1 4/4/1
+
+usemtl test2
+g test2
+
+s off
+f 3/1/2 4/2/2 5/3/2
+f 5/3/2 4/2/2 6/4/2
+s 3
+f 5/4/3 6/3/3 7/2/3
+f 7/2/3 6/3/3 8/1/3
+s 4
+f 7/1/4 8/2/4 1/3/4
+f 1/3/4 8/2/4 2/4/4
+s 0
+f 2/1/5 8/2/5 4/3/5
+f 4/3/5 8/2/5 6/4/5
+s 6
+f 7/1/6 1/2/6 5/3/6
+f 5/3/6 1/2/6 3/4/6

models/smoothing-group-two-squares.obj

@@ -0,0 +1,22 @@
+# from tinyobjloader issue #29
+
+v 0.000000 2.000000 0.000000
+v 0.000000 0.000000 0.000000
+v 2.000000 0.000000 0.000000
+v 2.000000 2.000000 0.000000
+v 4.000000 0.000000 -3.255298
+v 4.000000 2.000000 -3.255298
+#vn 0.000000 0.000000 1.000000
+#vn 0.000000 0.000000 1.000000
+#vn 0.276597 0.000000 0.960986
+#vn 0.276597 0.000000 0.960986
+#vn 0.531611 0.000000 0.846988
+#vn 0.531611 0.000000 0.846988
+# 6 vertices
+
+# 6 normals
+
+g all
+s 1
+f 1//1 2//2 3//3 4//4
+f 4//4 3//3 5//5

models/smoothing-normal.mtl

@@ -0,0 +1,24 @@
+newmtl white
+Ka 0 0 0
+Kd 1 1 1
+Ks 0 0 0
+
+newmtl red
+Ka 0 0 0
+Kd 1 0 0
+Ks 0 0 0
+
+newmtl green
+Ka 0 0 0
+Kd 0 1 0
+Ks 0 0 0
+
+newmtl blue
+Ka 0 0 0
+Kd 0 0 1
+Ks 0 0 0
+
+newmtl light
+Ka 20 20 20
+Kd 1 1 1
+Ks 0 0 0

models/smoothing-normal.obj

@@ -0,0 +1,35 @@
+mtllib smoothing-normal.mtl
+
+v 0.000000 2.000000 2.000000
+v 0.000000 0.000000 2.000000
+v 2.000000 0.000000 2.000000
+v 2.000000 2.000000 2.000000
+v 0.000000 2.000000 0.000000
+v 0.000000 0.000000 0.000000
+v 2.000000 0.000000 0.000000
+v 2.000000 2.000000 0.000000
+# 8 vertices
+
+g front cube
+usemtl white
+s 1
+f 1 2 3 4
+#g bottom cube
+#usemtl white
+s 1
+f 2 6 7 3
+
+g back cube
+# expects white material
+s off
+f 8 7 6 5
+#g right cube
+#usemtl red
+#f 4 3 7 8
+#g top cube
+#usemtl white
+#f 5 1 4 8
+#g left cube
+#usemtl green
+#f 5 6 2 1
+# 6 elements

tests/tester.cc

@@ -303,7 +303,7 @@ std::string matStream(
             virtual bool operator() (
               const std::string& matId,
               std::vector<material_t>* materials,
-              std::map<unsigned int, int>* matMap,
+              std::map<std::string, int>* matMap,
               std::string* err)
             {
                 (void)matId;
@@ -717,6 +717,40 @@ TEST_CASE("texture-name-whitespace", "[Issue145]") {
 
 }
 
+TEST_CASE("smoothing-group", "[Issue162]") {
+  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/issue-162-smoothing-group.obj", gMtlBasePath);
+
+  
+  if (!err.empty()) {
+    std::cerr << "[Issue162] " << err << std::endl;
+  }
+
+  REQUIRE(true == ret);
+  REQUIRE(2 == shapes.size());
+
+  REQUIRE(2 == shapes[0].mesh.smoothing_group_ids.size());
+  REQUIRE(1 == shapes[0].mesh.smoothing_group_ids[0]);
+  REQUIRE(1 == shapes[0].mesh.smoothing_group_ids[1]);
+
+  REQUIRE(10 == shapes[1].mesh.smoothing_group_ids.size());
+  REQUIRE(0 == shapes[1].mesh.smoothing_group_ids[0]);
+  REQUIRE(0 == shapes[1].mesh.smoothing_group_ids[1]);
+  REQUIRE(3 == shapes[1].mesh.smoothing_group_ids[2]);
+  REQUIRE(3 == shapes[1].mesh.smoothing_group_ids[3]);
+  REQUIRE(4 == shapes[1].mesh.smoothing_group_ids[4]);
+  REQUIRE(4 == shapes[1].mesh.smoothing_group_ids[5]);
+  REQUIRE(0 == shapes[1].mesh.smoothing_group_ids[6]);
+  REQUIRE(0 == shapes[1].mesh.smoothing_group_ids[7]);
+  REQUIRE(6 == shapes[1].mesh.smoothing_group_ids[8]);
+  REQUIRE(6 == shapes[1].mesh.smoothing_group_ids[9]);
+
+}
+
 #if 0
 int
 main(