From b85714b4cf15f51e928d62e043014056e95e0629 Mon Sep 17 00:00:00 2001
From: Syoyo Fujita <syoyo@lighttransport.com>
Date: Fri, 23 Feb 2018 20:25:13 +0900
Subject: [PATCH] Skip parsing incomplete or invalid face definition(e.g. `f`
 definition only contains 1 or 2 indices).

---
 models/invalid-face-definition.mtl | 24 ++++++++++++++++++++++++
 models/invalid-face-definition.obj | 18 ++++++++++++++++++
 tests/tester.cc                    | 18 ++++++++++++++++++
 tiny_obj_loader.h                  |  5 +++++
 4 files changed, 65 insertions(+)
 create mode 100644 models/invalid-face-definition.mtl
 create mode 100644 models/invalid-face-definition.obj

diff --git a/models/invalid-face-definition.mtl b/models/invalid-face-definition.mtl
new file mode 100644
index 0000000..d3a1c7a
--- /dev/null
+++ b/models/invalid-face-definition.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
diff --git a/models/invalid-face-definition.obj b/models/invalid-face-definition.obj
new file mode 100644
index 0000000..73ca678
--- /dev/null
+++ b/models/invalid-face-definition.obj
@@ -0,0 +1,18 @@
+mtllib invalid-face-definition.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
+f 1
+g back cube
+# expects white material
+f 8 7
diff --git a/tests/tester.cc b/tests/tester.cc
index d5d83c6..e3bc006 100644
--- a/tests/tester.cc
+++ b/tests/tester.cc
@@ -751,6 +751,24 @@ TEST_CASE("smoothing-group", "[Issue162]") {
 
 }
 
+TEST_CASE("invalid-face-definition", "[face]") {
+  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/invalid-face-definition.obj", gMtlBasePath);
+
+  
+  if (!err.empty()) {
+    std::cerr << "[face] " << err << std::endl;
+  }
+
+  REQUIRE(true == ret);
+  REQUIRE(1 == shapes.size());
+  REQUIRE(0 == shapes[0].mesh.indices.size());
+}
+
 #if 0
 int
 main(
diff --git a/tiny_obj_loader.h b/tiny_obj_loader.h
index ac1421e..a876842 100644
--- a/tiny_obj_loader.h
+++ b/tiny_obj_loader.h
@@ -1023,6 +1023,11 @@ static bool exportFaceGroupToShape(shape_t *shape,
   for (size_t i = 0; i < faceGroup.size(); i++) {
     const face_t &face = faceGroup[i];
 
+    if (face.vertex_indices.size() < 3) {
+      // Face must have 3+ vertices.
+      continue;
+    }
+
     vertex_index_t i0 = face.vertex_indices[0];
     vertex_index_t i1(-1);
     vertex_index_t i2 = face.vertex_indices[1];