README.OpenSource
1[
2 {
3 "Name": "EGL",
4 "License": "MIT License",
5 "License File": "LICENSE",
6 "Version Number": "1.5",
7 "Owner": "lizheng2@huawei.com",
8 "Upstream URL": "https://github.com/KhronosGroup/EGL-Registry.git",
9 "Description": "EGL is an interface between Khronos rendering APIs such as OpenGL ES or OpenVG and the underlying native platform window system."
10 }
11]
12
README.md
1# EGL-Registry
2
3The EGL-Registry repository contains the EGL API and Extension Registry,
4including specifications, reference pages and reference cards, and the
5enumerant registry. It is also used as a backing store for the web view of
6the registry at https://www.khronos.org/registry/egl/ ; commits to the
7master branch of this repository will be reflected there.
8
9In the past, the EGL registry was maintained in a public Subversion
10repository. The history in that repository has not been imported to github,
11but it is still available at
12https://cvs.khronos.org/svn/repos/registry/trunk/public/egl/ .
13
14Interesting files in this repository include:
15
16* index.php - toplevel index page for the web view. This relies on PHP
17 include files found elsewhere on www.khronos.org and so is not very useful
18 in isolation.
19* registry.tcl - extension number registry. Documents the names and index
20 numbers assigned to EGL extension specifications.
21* api/egl.xml - extension enumerant and API registry. Defines the EGL API,
22 including extensions, and is used to generate headers. Documents the EGL
23 enumerant ranges assigned to different vendors.
24* api/EGL/ and api/KHR/ - header files used by an EGL implementation.
25 EGL/eglext.h and EGL/egl.h are generated from egl.xml. The other headers
26 are handcoded and express OS and window system (platform) dependencies.
27* extensions/ - EGL extension specifications, grouped into vendor-specific
28 subdirectories.
29* sdk/ - EGL reference pages and reference cards. There are separate sets
30 for each API version.
31* specs/ - EGL specification documents.
32
33## Reserving EGL Enumerant Ranges
34
35EGL enumerants are documented in api/egl.xml . New ranges can be allocated
36by proposing a pull request to master modifying this file, following the
37existing examples. Allocate ranges starting at the lowest free values
38available (search for "Reservable for future use"). Ranges are not
39officially allocated until your pull request is *accepted* into master. At
40that point you can use values from your assigned range for API extensions.
41
42
43## Adding Extension Specifications
44
45Extension specification documents can be added by proposing a pull request
46to master, adding the specification .txt file and related changes under
47extensions/\<vendor\>/filename.txt. Your pull request must also:
48
49* Allocate an extension number in registry.tcl (follow the existing
50 ```<extension>``` examples, search for "Next free extension number", and use
51 the lowest available extension number).
52* Include that extension number in the extension specification document.
53* Define the interfaces introduced by this extension in api/egl.xml,
54 following the examples of existing extensions. If you have difficulty
55 doing this, consult the registry schema documentation in the GL registry
56 at www.khronos.org/registry/gl/; you may also create Issues in the
57 EGL-Registry repository to request help.
58* Verify that the EGL headers regenerate properly after applying your XML
59 changes. In the api/ directory, you must be able to do the following without
60 errors:
61```
62 # Validate XML changes
63 make validate
64 # Verify headers build and are legal C
65 make clobber
66 make
67 make tests
68```
69* Finally, add a link from the extensions section of index.php to the
70 extension document, using the specified extension number, so it shows up
71 in the web view (this could in principle be generated automatically from
72 registry.tcl / egl.xml, but isn't at present).
73
74Sometimes extension text files contain inappropriate UTF-8 characters. They
75should be restricted to the ASCII subset of UTF-8 at present. They can be
76removed using the iconv Linux command-line tool via
77
78 iconv -c -f utf-8 -t ascii filename.txt
79
80(see internal Bugzilla issue 16141 for more).
81
82We may transition to an asciidoc-based extension specification format at
83some point.
84
85
86## Build Tools
87
88This section is not complete (see https://github.com/KhronosGroup/EGL-Registry/issues/92).
89
90To validate the XML and build the headers you will need at least GNU make,
91'jing' for the 'make validate' step (https://relaxng.org/jclark/jing.html),
92and Python 3.5 and the lxml.etree Python library
93(https://pypi.org/project/lxml/) for the 'make' step. The 'make tests' step
94requires whatever the C and C++ compilers configured for GNU make are,
95usually gcc and g++.
96
97All of these components are available prepackaged for major Linux
98distributions and for the Windows 10 Debian WSL.
99
100
101