Fix texcoord export.

examples/obj_sticher/obj_writer.cc

@@ -99,14 +99,14 @@ bool WriteObj(const std::string& filename, std::vector<tinyobj::shape_t> shapes)
     }
     if (shapes[i].mesh.normals.size() > 0) has_vn = true;
 
-    // texcoord
+    // facevarying texcoord
     if (shapes[i].mesh.texcoords.size() > 0) {
       for (size_t k = 0; k < shapes[i].mesh.indices.size() / 3; k++) {
         for (int j = 0; j < 3; j++) {
           int idx = shapes[i].mesh.indices[3*k+j];
           fprintf(fp, "vt %f %f %f\n",
-            shapes[i].mesh.texcoords[3*idx+0],
-            shapes[i].mesh.texcoords[3*idx+1]);
+            shapes[i].mesh.texcoords[2*idx+0],
+            shapes[i].mesh.texcoords[2*idx+1]);
         }
       }
     }