To create a new extension specification, take these steps:

• Request one or more blocks of unused enumerants for GL, GLX, or WGL depending on the needs of your extension, by adding the reservation(s) to the end of gl.xml, glx.xml, and/or wgl.xml.

• Once the pull request modifying the XML files is accepted into main, you have control of those enumerant blocks.

• Create an extension specification, following the model of existing vendor specifications under extensions/vendor/ .

• Obtain whatever degree of review, implementation, and signoff you need from affected parties before declaring the extension complete.

• Add the extension specification under extensions/vendor/extension .

• Modify extensions/registry.py to include the extension, using the next free ARB, GL, and/or ES extension numbers (depending on which API the extension is defined for). Execute the python script nextfree.py in the extensions/ directory to find the next free numbers.

• Once registry.py is updated, 'make' in extensions/ to update the PHP include files which are used to show an index of extensions on the registry website. This requires GNU make and Python 3.

• Add the extension number(s) to the extension specification in the 'Number' block.

• Add the extension interfaces and enumerant assignments to xml/gl.xml, glx.xml, and/or wgl.xml following existing examples. Verify that the relevant extension headers are generated with the correct interfaces by running 'make' in xml/. This requires the lxml Python module.

• Once the pull request adding the extension specification and modifying registry.py is accepted, your extension is registered.

There are some documents under the docs/ directory describing some of the processes for making extensions, but they are largely out of date. They may be updated or removed over time:

• How to create extensions

• Enumerant allocation policies

• Extension specification template

• Extension promotion guidelines

• GLX opcode registry (rarely updated)

• OpenGL Syntax Rules (updated 2006/12/13)

• OpenGL Shading Language Extension Conventions (updated 2006/12/18)

• Extension Specification Example

• ABI - OpenGL ABI for Linux

• api - Header files for all APIs

  • api/ES - Headers for OpenGL ES

  • api/GL - Headers for OpenGL

  • api/SC - Headers for OpenGL SC

  • Note that the OpenGL ES and OpenGL SC headers all depend on the shared khrplatform.h This file is maintained in the EGL Registry.

• docs - Miscellaneous documentation on creating extensions, mostly out of date.

• extensions - Extension specifications for all APIs

  • extensions/registry.py - combined extension registry for all APIs

  • extensions/makeindex.py - create HTML extension indices from registry.py

• index_{es,gl,sc}.php - Index files for the website, linking to specifications, headers, and extensions relevant to each API

• specs - API and Shading Language Specifications for all APIs

  • specs/es - OpenGL ES Specifications

  • specs/gl - OpenGL Specifications

  • specs/sc - OpenGL SC Specifications

• xml - XML API Registry and related tools

Yes, there sure is. The specs/ directory contains over 125 MB of PDFs, including the latest specs for each version of OpenGL and OpenGL ES. While this may be somewhat distressing to people who just want to add a single extension, due to the repository download time, the primary purpose of this repository is to be the backing store for the web registry on khronos.org. Fortunately git is very efficient, so once you’ve done the initial repository clone, updates will be small and quick.