TinyOBJ

Provides a Ruby interface around TinyOBJ.

Installation

Add this line to your application's Gemfile:

gem 'tiny_obj'

And then execute:

$ bundle

Or install it yourself as:

$ gem install tiny_obj

Usage

    require 'tiny_obj'
    obj = TinyOBJ.load("path/to/file.obj") # finds materials in /path/to
    obj = TinyOBJ.load("path/to/file.obj", "path/to/materials/dir")

    hash = obj.to_hash
    #=> hash is a hash containing :materials, :vertices, :shapes, and other
    #   goodness.

Converting the OBJ into a hash is convenient but not performant. If you are dealing with a large object, you may wish to fill a buffer with data without having to convert it into Ruby hashes, arrays and numbers. You can do that with TinyOBJ#fill_buffers. Below is a complete example, which uses Fiddle to allocate the buffer.

Note that using Fiddle is not required (but is convenient since it ships with Ruby). Only knowing the memory address of the buffer is necessary. Be aware that using the wrong address or not a real (or adequately-sized) buffer can lead to undefined behavior and program crashes.

vertex_stride = Fiddle::SIZEOF_FLOAT * (
                  3 + # 3 floats for each position (x, y, z)
                  3 + # 3 floats for each normal (x, y, z)
                  2   # 2 floats for each texture coord (u, v)
                )

index_stride  = 2 # each index will be one uint16, or two 8-bit bytes
vertex_buffer = Fiddle::Pointer.malloc(@obj.num_distinct_vertices * vertex_stride)
index_buffer  = Fiddle::Pointer.malloc(@obj.num_indices           * index_stride)

@obj.fill_buffers(positions:     vertex_buffer,
                  normals:       vertex_buffer + Fiddle::SIZEOF_FLOAT * 3,
                  texcoords:     vertex_buffer + Fiddle::SIZEOF_FLOAT * 6,
                  indices:       index_buffer,
                  vertex_stride: vertex_stride,
                  index_stride:  index_stride,
                  index_type:    :uint16)

# vertex_buffer now contains interleaved vertex data, and
# index_buffer now contains index data.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/sinisterchipmunk/tinyobj-ruby.

License

The gem is available as open source under the terms of the MIT License.