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Fast C OBJ parser
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Arseny Kapoulkine 66f467de8f Fix 32-bit integer overflow issues 
When an array reached a size that would require >4GB allocation, the
argument to realloc would overflow during multiplication, resulting in a
very small allocation and a subsequent out of bounds access.

This change fixes that and also adjusts capacity calculation so that it
doesn't overflow 32-bit range until it's basically impossible not to.

This is not perfect - in particular, on 32-bit systems there's a risk of
size_t overflow that remains, however because we grow in 1.5x
increments, realistically an attempt to grow a 2GB allocation to the
next increment would fail before that. We can also technically overflow
capacity even after the adjustment, but that requires 3+B elements which
effectively means an .obj file on the scale of hundreds of gigabytes, at
which point maybe a streaming parser would be more practical.
2023-06-08 20:35:25 -07:00
test Merge all face/index arrays together 2019-06-11 07:35:30 -07:00
.gitignore Add .gitignore file 2019-05-19 09:51:43 +01:00
CMakeLists.txt Update CMake file so it can be used with FetchContent in other projects 2021-08-01 14:06:21 +01:00
fast_obj.c Add fast_obj.c to allow compilation as standalone library if required 2020-05-23 16:25:05 +01:00
fast_obj.h Fix 32-bit integer overflow issues 2023-06-08 20:35:25 -07:00
LICENSE Initial commit 2018-07-29 13:31:09 +01:00
README.md Attempt to clarify use of dummy entry in position/normal/texture coordinate arrays 2020-02-29 15:01:22 +00:00

README.md

fast_obj

Because the world needs another OBJ loader. Single header library, should compile without warnings in both C89 or C++. Much faster (5-10x) than other libraries tested.

To use:

 fastObjMesh* mesh = fast_obj_read("path/to/objfile.obj");

 ...do stuff with mesh...

 fast_obj_destroy(mesh);

Note that valid indices in the fastObjMesh::indices array start from 1. A dummy position, normal and texture coordinate are added to the corresponding fastObjMesh arrays at element 0 and then an index of 0 is used to indicate that attribute is not present at the vertex. This means that users can avoid the need to test for non-present data if required as the vertices will still reference a valid entry in the mesh arrays.

A simple test app is provided to compare speed against tinyobjloader and check output matches.