From 3736a5791f63881b3ebe14fbb593099a7dfe7bc1 Mon Sep 17 00:00:00 2001
From: "Adi Shavit @ MacBookPro" <adi.shavit@autodesk.com>
Date: Wed, 27 Jul 2016 10:04:22 +0300
Subject: [PATCH] Fix a crash bug in `LoadObjWithCallback()` when passing a
 nullptr as `MaterialReader *readMatFn`. - This preserves the existing API. If
 `nullptr` is passed then the material file will be ignored. This is useful
 when the user is not interested in the materials. - Note that if `nullptr` is
 not a valid option for this function, then the API needs to be changed to
 take `MaterialReader&`.

---
 tiny_obj_loader.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tiny_obj_loader.h b/tiny_obj_loader.h
index 68f0d7d..0e85632 100644
--- a/tiny_obj_loader.h
+++ b/tiny_obj_loader.h
@@ -1441,6 +1441,7 @@ bool LoadObjWithCallback(void *user_data, const callback_t &callback,
 
     // load mtl
     if ((0 == strncmp(token, "mtllib", 6)) && IS_SPACE((token[6]))) {
+        if (readMatFn) {
             char namebuf[TINYOBJ_SSCANF_BUFFER_SIZE];
             token += 7;
 #ifdef _MSC_VER
@@ -1464,6 +1465,7 @@ bool LoadObjWithCallback(void *user_data, const callback_t &callback,
                 callback.mtllib_cb(user_data, &materials.at(0),
                     static_cast<int>(materials.size()));
             }
+        }
 
       continue;
     }