OpenGL extension IBM.cull_vertex
This module customises the behaviour of the OpenGL.raw.GL.IBM.cull_vertex to provide a more Python-friendly API
Overview (from the spec)
IBM_cull_vertex provides a subset of the vertex culling functionality found in EXT_cull_vertex without providing a guarantee that faces will be culled because of it. EXT_cull_vertex is a technically superior solution, but the vertex culling aspect of IBM_cull_vertex provides generally useful function cheaply (without imposing the mandated culling found in EXT_cull_vertex).
The official definition of this extension is available here: