`obj` parsing doesn't know the file name, but `mtllib` is relative to that file about tinyobjloader-c HOT 4 OPEN

457c457
<     const char *p = (const char *) memchr(s, 0, n);
---
>     const char *p = memchr(s, 0, n);
1208,1212d1207
< int tinyobj_parse_obj_with_filename(tinyobj_attrib_t *attrib, tinyobj_shape_t **shapes,
<                       size_t *num_shapes, tinyobj_material_t **materials_out,
<                       size_t *num_materials_out, const char *buf, size_t len,
<                       const char *filename, unsigned int flags);
< 
1217,1223d1211
<   return tinyobj_parse_obj_with_filename(attrib, shapes, num_shapes, materials_out, num_materials_out, buf, len, NULL, flags);
< }
< 
< int tinyobj_parse_obj_with_filename(tinyobj_attrib_t *attrib, tinyobj_shape_t **shapes,
<                       size_t *num_shapes, tinyobj_material_t **materials_out,
<                       size_t *num_materials_out, const char *buf, size_t len,
<                       const char *filename, unsigned int flags) {
1329c1317
<     char *relative_filename = my_strndup(commands[mtllib_line_index].mtllib_name,
---
>     char *filename = my_strndup(commands[mtllib_line_index].mtllib_name,
1331,1341d1318
<     char buffer[1024];
<     int filename_len = strlen(filename);
<     memcpy(buffer, filename, filename_len);
<     char *sentinel = buffer + filename_len;
<     while (buffer < sentinel && *sentinel != '/')
<         sentinel--;
<     if (*sentinel == '/')
<         sentinel++;
<     int rel_len = commands[mtllib_line_index].mtllib_name_len;
<     memcpy(sentinel, relative_filename, rel_len);
<     sentinel[rel_len] = 0;
1343c1320
<     int ret = tinyobj_parse_and_index_mtl_file(&materials, &num_materials, buffer, &material_table);
---
>     int ret = tinyobj_parse_and_index_mtl_file(&materials, &num_materials, filename, &material_table);
1347c1324
<       fprintf(stderr, "TINYOBJ: Failed to parse material file '%s': %d\n", buffer, ret);
---
>       fprintf(stderr, "TINYOBJ: Failed to parse material file '%s': %d\n", filename, ret);
1350c1327
<     TINYOBJ_FREE(relative_filename);
---
>     TINYOBJ_FREE(filename);
1381a1359,1372
>         /* @todo
>            if (commands[t][i].material_name &&
>            commands[t][i].material_name_len > 0) {
>            std::string material_name(commands[t][i].material_name,
>            commands[t][i].material_name_len);
> 
>            if (material_map.find(material_name) != material_map.end()) {
>            material_id = material_map[material_name];
>            } else {
>         // Assign invalid material ID
>         material_id = -1;
>         }
>         }
>         */