Latest revision as of 10:54, 28 September 2024

The following table lists libraries and other third party (3p) dependencies used in constructing the Second Life Viewer.

Most of these (all the open source ones) should be available as prebuilds packaged by and for use with Autobuild.

Generic Layout (Single-branch, 2024 Style)

3p packages should vendor upstream contents using git submodules unless a source git repository for the source dependency is not available. A typical 3p package layout looks like this:

.
├── [vendor submodule]/ - Git submodule containing upstream source
├── .github/            - CI/CD and repository configuration
├── autobuild.xml       - Autobuild manifest
├── build-cmd.sh        - Script used to build the repository
├── LICENSE             - Repository licensing
└── README.md           - Repository readme

Contributor Instructions

The general workflow for contributing changes to a 3p library looks like this:

Fork the repository and make changes. Be sure to test your work locally.
Create a PR (Be sure to follow PR Etiquette and our Code of Conduct)
Have this PR reviewed and merged
Done! The maintainer should cut a new version as appropriate using the workflow described below.

Maintainer Instructions

A properly versioned and promoted release of 3p-zlib-ng

If you are a 3p package maintainer you will want to follow these instructions to review and release new versions:

Review PRs quickly, and merge them directly into the default branch once approved
Cut a new release by using Github's Releases feature:
1. Navigate to Repository -> Releases and click "Draft new Release"
2. Click Choose a tag and create a new tag using the vUPSTREAM-rRELEASE format described below
3. Click Generate release notes and edit them as appropriate. Keep the title of the release equal to the version being used.
4. Click Publish release

After the release is published, CI/CD should be triggered by the addition of the new tag, and provide a nice set of packages and instructions for consumers to use.

Version format

3p packages should be released using the following version schema:

Format

  vUPSTREAM-rRELEASE

  Example: v1.0.0-r2 (Second vendored release of v1.0.0 of this library)

  UPSTREAM - Upstream package version. ex. 1.0.0 or 6.7
  RELEASE - Vendored release number, ex. 1, 2

Patches

By convention, patches should be kept in a patches/* directory and applied to the upstream source during build. You can use the following utility function, declared in your build-cmd.sh script to help:

apply_patch()
{
    local patch="$1"
    local path="$2"
    echo "Applying $patch..."
    git apply --check --reverse --directory="$path" "$patch" || git apply --directory="$path" "$patch"
}

Patch helper from 3p-boost

Differences from old style (vendor branch)

Originally, 3p libraries were maintained using a separate vendor and default branch. Repositories using this style should be migrated to new single-branch format. Benefits of using a single-branch are:

Simpler PR process (Make PR against default, merge it. Done.)
Faster release process, which means quicker integration for package consumers
Easier integration with GitHub functionality such as Automatic Release Notes
More explicit maintenance of patches makes delta from upstreams clearer and simpler to understand

List of third party libraries

Library	Repository	License	Upstream Home	Description
apr_suite	3p-apr	Apache License	http://apr.apache.org/	"A set of C functions which provide a portable and consistent interface into operating system - or simply widely useful - functionality. We primarily use it for threading and socket i/o. This is actually three packages, apr, apr-util and apr-iconv."
boost	3p-boost	Boost License	http://www.boost.org/	A set of portable C++ libraries which provide a wide set of functionality. Used primarily for tokenization.
curl	3p-curl	BSD-style^B	http://curl.haxx.se/libcurl/	Handles moving data across the net in many different protocols. Used to GET/POST/PUT/DELETE web resources.
expat	3p-expat	MIT License	https://github.com/libexpat/libexpat	XML parser.
freetype	3p-freetype	Freetype License and Others	http://www.freetype.org/	Font engine.
glh_linear	3p-glh_linear			nVidia NVParse SDK: platform-independent C++ Apple OpenGL helper library
gstreamer	3p-gstreamer	Open	http://gstreamer.freedesktop.org
havok		Commercial
jpeglib	3p-jpeglib	Open	http://www.ijg.org/	JPEG decoder library.
kdu	3p-kdu-private^LL	Commercial	http://www.kakadusoftware.com	Kakadu (KDU) JPEG-2000 decoder library.
libpng	3p-libpng	Open	http://www.libpng.org/pub/png/libpng.html	PNG image library.
libxml2	3p-libxml2	MIT License
ndofdev	3p-libndofdev	BSD-style^B		Provides joystick driver support (mac and win) for the 3DConnexion SpaceNavigator.
ogg_vorbis	3p-ogvorbis	BSD-style^B	http://xiph.org/ogg/	Audio codec and playback.
openal	3p-openal-soft	GPL	http://connect.creativelabs.com/openal/default.aspx	3D Spatial audio
openjpeg	3p-openjpeg	BSD-style^B	http://www.openjpeg.org/	An open-source JPEG-2000 library; a slower alternative to Kadaku. Used in the open source release
openssl	3p-openssl	Apache License	http://www.openssl.org/	Provides encryption for sensitive actions such as user login
sdl	3p-sdl2	zlib License	http://www.libsdl.org/index.php	The Simple DirectMedia Layer libraries are used for handling input and basic window/GL setup on the Linux client.
slvoice		Commercial		This is the Vivox provided executable (renamed SLVoice)
tut	3p-tut	BSD-style^B	http://tut-framework.sourceforge.net/	Unit test framework based on the use of c++ meta template programming. Used to test LL libraries.
xmlrpc_epi	3p-xmlrpc-epi	Epinions, Inc License	http://xmlrpc-epi.sourceforge.net/	XML-RPC protocol utility
zlib-ng	3p-zlib-ng	zlib License	http://www.zlib.net/	zlib is a lossless data-compression library which is used for a variety of network i/o and file compression.

Redistribution

Some files in the SL installation can't be freely redistributed. This means it's not possible to simply package and offer for download a modified viewer: some files must not be redistributed.

This page documents the licenses and redistribution requirements of various files used by the viewer.

Windows

These are the files that need to be shipped with the Windows version

Runtime

Microsoft components. It's not yet known whether they're redistributable.

dbghelp.dll: Redistributable
msvcp71.dll: C++ Runtime Library, redistributable -viewer now using msvcp80.dll when compiled with VC2005
msvcr71.dll: C Runtime Library, Redistributable -viewer now using msvcr80.dll when compiled with VC2005

FONTS

Meta font software files

From the Readme.txt

The Meta font software files contained in this folder are the
copyrighted property of FSI FontShop International ("FSI") and are
licensed by FSI solely for use by Linden Research, Inc. and by
residents or users of Second Life in the Second Life environment,
subject to the Second Life Terms of Service.  These Meta font software
files may not be copied by residents or developers of Second Life or
used by them for any other purpose whatsoever.

MtBkLfRg.ttf
MtBdLfRg.ttf

NOTE 1: These files must be replaced for an true open source build.

NOTE 2: At least starting with Viewer 6, Linden Lab has replaced the 'Meta' font with Bitstream's DejaVu, which is released under a very permissible license; Viewer 7 additionally added TwemojiSVG.ttf, which is presumably the (huge) Twitter Unicode emoji color OpenType-SVG font for Linux/MacOS/Windows (where SVG images are encoded as if they were font glyphs), released under a Creative Commons 4.0 Attrbution license, and which, in turn, is based on the Twitter Emoji font, also released under the same license.

AFAIK, the only viewer which still contains the two Meta fonts is the Cool VL Viewer — since it still pulls some code from the original SL Viewer 1 — but these are never used on the compiled application itself.

Kakadu

JPEG2000 library. Not redistributable. OpenJPEG is an alternative library that is redistributable

llkdu.dll

Starting with Viewer 2.5, llkdu.dll has been phased out. The libkdu.a and kdu.lib are still not redistributable but can be built from the toolkit provided by Kakadu under a license. How to build a viewer with such a library is documented in KDU Implementation.

OpenSSL

SSL library. Redistributable.

libeay32.dll
ssleay32.dll

Vivox

Vivox is the component that provides the voice functionality.

SLVoice.exe: Voice daemon. Not redistributable
SLVoiceAgent: Exact purpose unknown. Not redistributable
alut.dll: OpenAL, by Creative Labs. Redistributable.
ortp.dll: oRTP project, LGPL. Redistributable.
srtp.dll: Secure RTP?
vivoxsdk.dll: Vivox Communications API. Not redistributable
wrap_oal.dll: OpenAL32 by Creative Labs. Redistributable.

Unknown Libraries

The purpose and licensing of these files is not known:

tntk.dll: Probably Vivox related -see Voice/Technical for other info on ViVox files

Difference between revisions of "Third Party Libraries"