Add per-face smoothing groupd ids to mesh_t.

Add unit test for smoothing groups.

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

tests/tester.cc

@@ -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(

tiny_obj_loader.h

@@ -225,6 +225,9 @@ typedef struct {
                                                  // face. 3 = polygon, 4 = quad,
                                                  // ... Up to 255.
   std::vector<int> material_ids;                 // per-face material ID
+  std::vector<unsigned int> smoothing_group_ids;  // per-face smoothing group
+                                                  // ID(0 = off. positive value
+                                                  // = group id)
   std::vector<tag_t> tags;                        // SubD tag
 } mesh_t;
 
@@ -384,15 +387,14 @@ struct vertex_index_t {
 // Internal data structure for face representation
 // index + smoothing group.
 struct face_t {
-  int smoothing_group_id; // smoothing group id. 0 = smoothing groupd is off.
+  unsigned int
+      smoothing_group_id;  // smoothing group id. 0 = smoothing groupd is off.
   int pad_;
   std::vector<vertex_index_t> vertex_indices;  // face vertex indices.
 
-  face_t() : smoothing_group_id(0) {
+  face_t() : smoothing_group_id(0) {}
-  }
 };
 
-
 struct tag_sizes {
   tag_sizes() : num_ints(0), num_reals(0), num_strings(0) {}
   int num_ints;
@@ -680,9 +682,10 @@ static inline void parseV(real_t *x, real_t *y, real_t *z, real_t *w,
 }
 
 // Extension: parse vertex with colors(6 items)
-static inline bool parseVertexWithColor(real_t *x, real_t *y, real_t *z, real_t *r,
+static inline bool parseVertexWithColor(real_t *x, real_t *y, real_t *z,
-                          real_t *g, real_t *b,
+                                        real_t *r, real_t *g, real_t *b,
-                          const char **token, const double default_x = 0.0,
+                                        const char **token,
+                                        const double default_x = 0.0,
                                         const double default_y = 0.0,
                                         const double default_z = 0.0) {
   (*x) = parseReal(token, default_x);
@@ -991,22 +994,26 @@ static void InitMaterial(material_t *material) {
 }
 
 // code from https://wrf.ecse.rpi.edu//Research/Short_Notes/pnpoly.html
-static int pnpoly(int nvert, float *vertx, float *verty, float testx, float testy)
+static int pnpoly(int nvert, float *vertx, float *verty, float testx,
-{
+                  float testy) {
   int i, j, c = 0;
   for (i = 0, j = nvert - 1; i < nvert; j = i++) {
     if (((verty[i] > testy) != (verty[j] > testy)) &&
-	 (testx < (vertx[j]-vertx[i]) * (testy-verty[i]) / (verty[j]-verty[i]) + vertx[i]) )
+        (testx <
+         (vertx[j] - vertx[i]) * (testy - verty[i]) / (verty[j] - verty[i]) +
+             vertx[i]))
       c = !c;
   }
   return c;
 }
 
 // TODO(syoyo): refactor function.
-static bool exportFaceGroupToShape(
+static bool exportFaceGroupToShape(shape_t *shape,
-    shape_t *shape, const std::vector<face_t> &faceGroup,
+                                   const std::vector<face_t> &faceGroup,
-    const std::vector<tag_t> &tags, const int material_id,
+                                   const std::vector<tag_t> &tags,
-    const std::string &name, bool triangulate, const std::vector<real_t> &v) {
+                                   const int material_id,
+                                   const std::string &name, bool triangulate,
+                                   const std::vector<real_t> &v) {
   if (faceGroup.empty()) {
     return false;
   }
@@ -1055,8 +1062,7 @@ static bool exportFaceGroupToShape(
           if (cx > cy && cx > cz) {
           } else {
             axes[0] = 0;
-						if( cz > cx && cz > cy )
+            if (cz > cx && cz > cy) axes[1] = 1;
-							axes[1] = 1;
           }
           break;
         }
@@ -1075,7 +1081,8 @@ static bool exportFaceGroupToShape(
         area += (v0x * v1y - v0y * v1x) * 0.5f;
       }
 
-			int maxRounds = 10; // arbitrary max loop count to protect against unexpected errors
+      int maxRounds =
+          10;  // arbitrary max loop count to protect against unexpected errors
 
       face_t remainingFace = face;  // copy
       size_t guess_vert = 0;
@@ -1100,12 +1107,17 @@ static bool exportFaceGroupToShape(
         real_t e1y = vy[2] - vy[1];
         real_t cross = e0x * e1y - e0y * e1x;
         // if an internal angle
-				if( cross * area < 0.0f ) { guess_vert += 1; continue; }
+        if (cross * area < 0.0f) {
+          guess_vert += 1;
+          continue;
+        }
 
         // check all other verts in case they are inside this triangle
         bool overlap = false;
         for (size_t otherVert = 3; otherVert < npolys; ++otherVert) {
-					size_t ovi = size_t(remainingFace.vertex_indices[(guess_vert+otherVert)%npolys].v_idx);
+          size_t ovi = size_t(
+              remainingFace.vertex_indices[(guess_vert + otherVert) % npolys]
+                  .v_idx);
           real_t tx = v[ovi * 3 + axes[0]];
           real_t ty = v[ovi * 3 + axes[1]];
           if (pnpoly(3, vx, vy, tx, ty)) {
@@ -1114,7 +1126,10 @@ static bool exportFaceGroupToShape(
           }
         }
 
-				if( overlap ) { guess_vert += 1; continue; }
+        if (overlap) {
+          guess_vert += 1;
+          continue;
+        }
 
         // this triangle is an ear
         {
@@ -1135,12 +1150,14 @@ static bool exportFaceGroupToShape(
 
           shape->mesh.num_face_vertices.push_back(3);
           shape->mesh.material_ids.push_back(material_id);
+          shape->mesh.smoothing_group_ids.push_back(face.smoothing_group_id);
         }
 
         // remove v1 from the list
         size_t removed_vert_index = (guess_vert + 1) % npolys;
         while (removed_vert_index + 1 < npolys) {
-					remainingFace.vertex_indices[removed_vert_index] = remainingFace.vertex_indices[removed_vert_index+1];
+          remainingFace.vertex_indices[removed_vert_index] =
+              remainingFace.vertex_indices[removed_vert_index + 1];
           removed_vert_index += 1;
         }
         remainingFace.vertex_indices.pop_back();
@@ -1168,6 +1185,7 @@ static bool exportFaceGroupToShape(
 
           shape->mesh.num_face_vertices.push_back(3);
           shape->mesh.material_ids.push_back(material_id);
+          shape->mesh.smoothing_group_ids.push_back(face.smoothing_group_id);
         }
       }
     } else {
@@ -1182,6 +1200,8 @@ static bool exportFaceGroupToShape(
       shape->mesh.num_face_vertices.push_back(
           static_cast<unsigned char>(npolys));
       shape->mesh.material_ids.push_back(material_id);  // per face
+      shape->mesh.smoothing_group_ids.push_back(
+          face.smoothing_group_id);  // per face
     }
   }
 
@@ -1690,7 +1710,6 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
   std::vector<real_t> vt;
   std::vector<real_t> vc;
   std::vector<tag_t> tags;
-  std::vector<int> smoothing_groups;
   std::vector<face_t> faceGroup;
   std::string name;
 
@@ -1699,7 +1718,8 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
   int material = -1;
 
   // smoothing group id
-  int current_smoothing_id = 0;      // Initial value. 0 means no smoothing.
+  unsigned int current_smoothing_id =
+      0;  // Initial value. 0 means no smoothing.
 
   shape_t shape;
 
@@ -1982,11 +2002,12 @@ bool LoadObj(attrib_t *attrib, std::vector<shape_t> *shapes,
         // assume number
         int smGroupId = parseInt(&token);
         if (smGroupId < 0) {
-        // ???
+          // parse error. force set to 0.
-        continue;
+          // FIXME(syoyo): Report warning.
+          current_smoothing_id = 0;
+        } else {
+          current_smoothing_id = static_cast<unsigned int>(smGroupId);
         }
-
-      current_smoothing_id = smGroupId;
       }
 
       continue;