diff --git a/src/external/tinyobj_loader_c.h b/src/external/tinyobj_loader_c.h
index 6d34d25f..502a55a7 100644
--- a/src/external/tinyobj_loader_c.h
+++ b/src/external/tinyobj_loader_c.h
@@ -746,7 +746,7 @@ static int tinyobj_parse_and_index_mtl_file(tinyobj_material_t **materials_out,
   (*materials_out) = NULL;
   (*num_materials_out) = 0;
 
-  fp = fopen(filename, "r");
+  fp = fopen(filename, "rt");
   if (!fp) {
     fprintf(stderr, "TINYOBJ: Error reading file '%s': %s (%d)\n", filename, strerror(errno), errno);
     return TINYOBJ_ERROR_FILE_OPERATION;