Vertex coords are saved as s16 instead of f32 inside DynOS .bin files,
causing unintended overflow for vertex coords outside of the range
[-32768, +32767]. The format cannot be changed without breaking all
existing DynOS models, so, when writing a .bin file, a sentinel value
is added at the top of the vertex buffer for buffers that need f32
coords. If that sentinel is detected during the reading process,
the next vertex coords will be read as f32 instead of s16.