The Hacker's Guide to BRL-CAD
=============================

Please read this document if you are contributing to BRL-CAD.

BRL-CAD is a relatively large package with a long history and
heritage.  Many people have contributed over the years, and there
continues to be room for involvement and improvement in just about
every aspect of the package.  As such, contributions to BRL-CAD are
very welcome and appreciated.

For the sake of code consistency, project coherency, and the long-term
evolution of BRL-CAD, there are guidelines for getting involved.
Contributors are strongly encouraged to follow these guidelines and to
likewise ensure that other contributors similarly follow the
guidelines.  There are simply too many religious wars over what
usually come down to personal preferences and familiarity that are
distractions from making productive progress.

These guidelines apply to all developers, documentation writers,
testers, porters, graphic designers, web designers, and anyone else
that is directly contributing to BRL-CAD.  As all contributors are
also directly assisting in the development of BRL-CAD as a package,
this guide often simply refers to contributors as developers.

Although BRL-CAD was originally developed and supported primarily by
the U.S. Army Research Laboratory and its affiliates, it is now a true
Open Source project with contributions coming in to the project from
around the world.  The U.S. Army Research Laboratory continues to
support and contribute to BRL-CAD, but now the project is primarily
driven by a team of core developers and the BRL-CAD open source
community.  Contact the BRL-CAD developers for more information.


TABLE OF CONTENTS
-----------------
  Introduction
  Table of Contents
  Getting Started
  How to Contribute
  Source Code Languages
  Filesystem Organization
  Coding Style & Standards
  Documentation
  Testing
  Patch Submission Guidelines
  Bugs & Unexpected Behavior
  Commit Access
  Contributor Responsibilities
  Version Numbers & Compatibility
  Making a Release
  Getting Help


GETTING STARTED
---------------

As there are many ways to get started with BRL-CAD, one of the most
important steps for new contributors to do is get involved in the
discussions and communicate with the BRL-CAD developers.  There are
mailing lists, on-line forums, and an IRC channel dedicated to BRL-CAD
development and project communication.  All contributors are
encouraged to participate in any of the available communication
channels:

* Internet Relay Chat

  The primary and generally preferred mechanism for interactive
  developer discussions is via Internet Relay Chat (IRC).  Several of
  the core developers and core contributors of BRL-CAD hang out in
  #brlcad on the Freenode network.  With most any IRC client, you
  should be able to join #brlcad on irc.freenode.net, port 6667.  See
  http://freenode.net and http://irchelp.org for more information

* E-mail Mailing Lists

  There are several mailing lists available for interaction, e.g. the
  http://sourceforge.net/mail/?group_id=105292 "brlcad-devel" mailing
  list.  More involved contributors may also be interested in joining
  the "brlcad-commits" and "brlcad-tracker" mailing lists.

* On-line Forums

  Discussion forums are available on the project site at
  http://sourceforge.net/forum/?group_id=105292 for both developers
  and users.  Of particular interest to developers is, of course, the
  "Developers" forum where all contributors are incouraged to
  participate.


HOW TO CONTRIBUTE
-----------------

BRL-CAD's open source management structure is best described as a
meritocracy.  Roughly stated, this basically means that the power to
make decisions lies directly with the individuals that have ability or
merit with respect to BRL-CAD.  An individual's ability and merit is
basically a function of their past and present contributions to the
project.  Those who constructively contribute, frequently interact,
and remain highly involved have more say than those who do not.

As BRL-CAD is comprised of a rather large code base with extensive
existing documentation and web resources, there are many many places
where one may begin to get involved with the project.  More than
likely, there is some new goal you already have in mind, be it a new
geometry converter, support for a different image type, a fix to some
bug, an update to existing documentation, a new web page, or something
else entirely.  Regardless of the goal or contribution, it is highly
encouraged that you interact with the existing developers and discuss
your intentions.  This is particularly important if you would like to
see your modification added to BRL-CAD and you do not yet have
contributor access.  When in doubt, working on resolving existing
bugs, improving performance, documentation, and writing tests are
perfect places to begin.

For many, it can be overwhelming at just how much there is.  To a
certain extent, you will need to familiarize yourself with the basic
existing infrastructure before significantly changing or adding a
completely new feature.  There is documentation available in the
source distribution's doc/ directory, throughout the source hierarchy
in manpages, on the website, and potentially in the documentation
tracker at http://sourceforge.net/docman/?group_id=105292 covering a
wide variety of topics.  Consult the existing documentation, sources,
and developers to become more familiar with what already exists.

See the PATCH SUBMISSION GUIDELINES section below for details on
preparing and providing contributions.


SYSTEM ARCHITECTURE
-------------------

At a glance, BRL-CAD consists of about a dozen libraries and over 400
executable binaries.  The package has been designed from the ground up
adopting a UNIX methodology, providing many tools that may often be
used in harmony in order to complete a task at hand.  These tools
include geometry and image converters, image and signal processing
tools, various raytrace applications, geometry manipulators, and more.

One of the firm design intents of the architecture is to be as
cross-platform and portable as is realistically and reasonably
possible.  As such, BRL-CAD maintains support for many legacy systems
and devices provided that maintaining such support is not a
significant burden on developer resources.  Whether it is a burden or
not is of course a potentially subjective matter.  As a general
guideline, there needs to be a strong compelling motivation to
actually remove any functionality.  Code posterity, readability, and
complexity are generally not sufficient reasons.  This applies to
sections of code that are no longer being used, might not compile, or
might even have major issues (bugs).  This applies to bundled 3rd
party libraries, compilation environments, compiler support, and
language constructs.

In correlation with a long-standing heritage of support is a design
intent to maintain verifiable repeatable results throughout the
package, in particular in the raytrace library.  BRL-CAD includes
scripts that will compare a given compilation against the performance
of one of the very first systems to support BRL-CAD: a VAX 11/780
running BSD.  As the BRL-CAD Benchmark is a metric of the raytrace
application itself, the performance results are a very useful metric
for weighing the relative computational strength of a given platform.
The mathematically intensive computations exercise the processing
unit, system memory, various levels of data and instruction cache, the
operating system, and compiler optimization capabilities.

To support what has evolved to be a relatively large software package,
there are a variety of support libraries and interfaces that have
aided to encapsulate and simplify application programming.  At the
heart of BRL-CAD is a Constructive Solid Geometry (CSG) raytrace
library.  BRL-CAD has its own database format for storing geometry to
disk which includes both binary and text file format representations.
The raytrace library utilizes a suite of other libraries that provide
other basic application functionality.

LIBRARIES
---------

librt: The BRL-CAD Ray-Trace library is a performance and
accuracy-oriented ray intersection, geometric analysis, and geometry
representation library that supports a wide variety of geometric
forms.  Geometry can be grouped into combinations and regions using
CSG boolean operations.

libbu: The BRL-CAD Utility library contains a wide variety of routines
for memory allocation, threading, string handling, argument support,
linked lists, and more.

libbn: The BRL-CAD Numerics library provides many floating-point math
manipulation routines for vector and matrix math, a polynomial
equation solver, noise functions, random number generators, complex
number support, and more as well.

libcursor: The cursor library is a lightweight cursor manipulation
library similar to curses but with less overhead.

libdm: The display manager library contains the logic for generalizing
a drawable context.  This includes the ability to output
drawing/plotting instructions to a variety of devices such as X11,
Postscript, OpenGL, plot files, textfiles, and more.  There is
generally structured order to data going to a display manager (like
the wireframe in the geometry editor).

libfb: The framebuffer library is an interface for managing a graphics
context that consists of pixel data.  This library supports multiple
devices directly, providing a generic device-independent method of
using a frame buffer or files containing frame buffer images.

libfft: The Fast-Fourier Transform library is a signal processing
library for performing FFTs or inverse FFTs efficiently.

libmultispectral: The multispectral optics library is a separate
compilation mode of the optics library where support for additional
bands of energy are added.  By providing a defined spectrum of energy,
the raytrace library will produce different signal analyses for a
given set of geometry.

liboptical: The optical library is the basis for BRL-CAD's shaders.
This includes shaders such as the Phong and Cook-Torrence lighting
models, as well as various visual effects such as texturing, marble,
wood graining, air, gravel, grass, clouds, fire, and more.

liborle: The "old" run-length encoding library that will decode and
encode University of Utah Raster Toolkit format Run-Length Encoded
data.

libpkg: The "Package" library is a network communications library that
supports multiplexing and demultiplexing synchronous and asynchronous
messages across stream connections.  The library supports a
client-server communication model.

librtserver: The ray-trace server library is a thin interface over
librt that simplifies the process of applying individual ray
intersection tests against a given set of geometry.  The library
supports communication with a BRL-CAD geometry repository and
multithreaded ray dispatch.

libsysv: The System 5 compatibility library exists to support legacy
systems that lack functionality required by BRL-CAD.  This library is
deprecated and should generally not be used for new development.

libtclcad: The Tcl-CAD library is a thin interface that assists in the
binding of an image to a Tk graphics context.

libtermio: The terminal I/O library is a TTY control library for
managing a terminal interface.

libwdb: The "write database" library provides a simple interface for
the generation of BRL-CAD geometry files supporting a majority of the
various primitives available as well as combination/region support.
The library is a write-only interface (librt is necessary to read &
write) and is useful for procedural geometry.


FILESYSTEM ORGANIZATION
-----------------------

Included below is a sample (not comprehensive) of how some of the
sources are organized in the source distribution.  For the directories
under src/, see the src/README file for more details on subdirectories
not covered here.

bench/
	The BRL-CAD Benchmark Suite
db/
	Example geometry databases
doc/
	Documentation
include/
	Public headers
m4/
	Autoconf compilation resource files
misc/
	Anything not categorized or is sufficently en masse
pix/
	Sample raytrace images, includes benchmark reference images
regress/
	Scripts and resources for regression testing
sh/
	Utility scripts, used primarily by the build system
src/
	Sources, see src/README for more details
src/conv/
	Various geometry converters
src/conv/iges/
	IGES converter
src/fb/
	Tools for displaying data to or reading from framebuffers
src/fbserv/
	Framebuffer server
src/java/
	Java geometry server interface to librt
src/libbn/
	BRL-CAD numerics library
src/libbu
	BRL-CAD utility library
src/libfb/
	BRL-CAD Framebuffer library
src/libfft/
	Fast Fourier transform library
src/libpkg/
	Network "package" library
src/librt/
	BRL-CAD Ray-trace library
src/libwdb/
	Write database library
src/mged/
	Multi-device geometry editor
src/other/
	External frameworks (Tcl/Tk, libpng, zlib, etc)
src/proc-db/
	Procedural geometry tools, create models programmatically
src/remrt/
	Distributed raytrace support
src/rt/
	Raytracers, various
src/util/
	Various image processing utilities


SOURCE CODE LANGUAGES
---------------------

The vast majority of BRL-CAD is written in ANSI C with the intent to
be strictly conformant to the C standard.  A majority of the MGED
geometry editor is written in a combination of C, Tcl/Tk, and Incr
Tcl/Tk.  The BRL-CAD Benchmark, build system, and utility scripts are
written in what should be POSIX-compliant Bourne Shell Script.  An
initial implementation of a BRL-CAD Geometry Server is written in PHP.

With release 7.0, BRL-CAD has moved forward and worked toward making
all of BRL-CAD C code conform strictly with the ANSI/ISO standard for
C language compilation (ISO/IEC 9899:1990).  Support for older
compilers and older K&R-based system facilities is being migrated to
the build system declarations and preprocessor defines.

There is currently not a unified C++ interface to any of the libraries
nor any tools written in C++ in BRL-CAD at this time, though several
of both have been written over the years for various purposes.  While
C++ as an implementation language of new tools and new library
interfaces is not prohibitied, the mixing of C++ semantics and C++
code (including simple // style comments) in the existing C files is
not allowed.  As new interfaces are developed, new contributors become
involved, and C++ code integration becomes more prevalent, the
contributor guidelines will become reinforced with more details.


CODING STYLE & STANDARDS
------------------------

For anyone who plans on contributing code, the following conventions
should be followed.  Contributions that do not conform are likely to
be ridiculed and rejected until they do.  ;-)

Violations of these rules in the existing code are not excuses to
follow suit.  If code is seen that doesn't conform, it may and should
be fixed.

Code Organization:

Code that is potentially useful to another application, or that may be
abstracted in such a way that it is useful to other applications,
should be put in a library and not in application directories.

C files use the .c extension.  Header files use the .h extension.  C++
files use the .cxx extension.  PHP files use the .php extension.
Tcl/Tk files use the .tcl/.tk extensions.  POSIX Bourne-style shell
scripts use the .sh extension.

Source files go into the src/ directory on the top level, into a
corresponding directory for the category of binary or library that it
belongs to.  Documentation files go into the doc/ directory on the top
level, with the exception of manual pages that should be colocated
with any corresponding source files.

Header files private to a library go into that library's directory.
Public header files go intp the include/ directory on the top level.
Public header files should not include any headers that are private.
Headers should include any other headers that they require for correct
parsing (this is an on-going clean-up effort).  Public header files
should not include the common header.

Headers should be included in a particular order.  That order is
generally as follows:

  - any single "interface" header [optional]
  - the common header (unless the interface header includes it)
  - system headers
  - public headers
  - private headers

Applications may optionally provide an interface header that defines
common structures applicable to most or all files being compiled for
that application.  That interface header will generally be the first
file to be included, as it usually includes the common header and
system headers.  The common header should always be included before
any system header.  Standard C system headers should be included
before library system headers.  Headers should be written to be
self-contained, not requiring other headers to be necessarily included
before they may be used.  If another header is necessary for a header
to function correctly, it should include it.

Language Compliance:

Features of C that conform to the ISO/IEC 9899-1990 C standard (C90)
are generally the baseline for strict language conformance.  As
BRL-CAD used to be K&R syntax conformant, there remains on-going
effort to ensure a full conversion to a standards compliant ISO C
implementation.

Code Conventions:

Globals variables, global structures, and other public data containers
are highly discouraged - globals are often the easy way around a hard
coding problem but more often complicate refactoring and restructuring
in the future.  Try to find another solution unless there is a very
compelling and good reason for their use.

Functions should always specify a return type, including functions
that return int or void.  ANSI C prototypes should be used to declare
functions, not K&R function prototypes.

There are several functions whose functionality are either wrapped or
implemented in a cross-platform manner by libbu.  This includes
functions related to memory allocation, command option parsing,
logging routines, and more.  The following functions and global
variables should be utilized instead of the standard C facility:

  bu_malloc() instead of malloc()
  bu_free() instead of free()
  bu_log() instead of printf()
  bu_bomb() instead of abort()
  bu_getopt() instead of getopt()
  bu_opterr instead of opterr
  bu_optind instead of optind
  bu_optopt instead of optopt
  bu_optarg instead of optarg

The code should strive to achieve conformance with the GNU coding
standard with a few exceptions.  One such exception is NOT utilizing
the GNU indentation style, but instead utilizing the K&R indentation
style (also commonly recognized as the primary Java coding style as
published by Sun) is utilized for brace placement indentation, and
most code formatting convention.  The following examples should be
strictly adhered to, if only for the sake of being consistent.

1) Whitespace

Indents are 4 characters, tabs are 8 characters.  There should be an
emacs and vi local variables block setting at the end of each file to
adopt, enforce, and otherwise remind this convention.  The following
lines should be in all C source and header files at the end of the
file:

/*
 * Local Variables:
 * mode: C
 * tab-width: 8
 * c-basic-offset: 4
 * indent-tabs-mode: t
 * End:
 * ex: shiftwidth=4 tabstop=8
 */

A similar block can be used on source and script files in other
languages (such as Tcl, Shell, Perl, etc).  See the local variable
footer script in sh/footer.sh to automatically set/update files.

Space around operators.
  a = (b + c) * d;  /* ok */

No space around parentheses.
  while (1) { ...   /* ok */

Commas and semicolons are followed by whitespace.
  int main(int argc, char *argv[]); /* ok */
  for (i = 0; i < max; i++) { ...   /* ok */

2) Braces

Opening braces should be on the same line as their statement, close
braces should line up with that same statement.  This is intently not
the GNU or BSD indent style, but rather the K&R style (see
http://en.wikipedia.org/wiki/Indent_style for details).

  for (i = 0; i < 100; i++) {
    if (i % 10 == 0) {
      j += 1;
    } else {
      j -= 1;
    }
  }

3) Names

Prefer mixed-case names over underscore-separated ones. (this one is
less important, as there are vast quantities of both in the code)
Variable names should start with a lowercase letter.
  double localVariable; /* ok */
  double LocalVariable; /* bad (looks like class or constructor) */
  double _localVar;     /* bad (looks like member variable)      */

Variables are not to be "decorated" to show their type (i.e. do not
use Hungarian notation or variations thereof) with a slight exception
for pointers on occasion.  The name should use a concise, meaningful
name that is not cryptic (typing a descriptive name is preferred over
someone else hunting down what was meant).
  char *name;    /* ok  */
  char *pName;   /* discouraged for new code, but okay */
  char *fooPtr;  /* bad */
  char *lpszFoo; /* bad */

Constants should be all upper-case with word boundaries optionally
separated by underscores.
  static const int MAX_READ = 2;  /* ok  */
  static const int arraySize = 8; /* bad */

4) Debugging

Compilation preprocessor defines should never change the size of
structures.
  struct Foo {
  #ifdef DEBUG_CODE  // bad
    int _magic;
  #endif
  };

5) Comments

"//" style comments are not allowed in C source files.  This is mainly
to cause fewer compilation and portability issues when porting to
older systems where such support is frequently not available in the C
compiler.  Comment blocks should utilize an asterisk at the beginning
of each new line.

/* This is a
 * comment block.
 */

GNU Build System:

The GNU Autotools build system (e.g. autoconf defines) should be used
extensively to test for availability of system services such as
standard header files, available libraries, and data types.  No
assumptions should be made regarding the availability of any
particular header, function, datatype, or other resource.  After
running the configure script, there will be an autogenerated
include/brlcad_config.h file that contains many preprocessor
directives and type declarations that may be used where needed.

Generic platform checks (e.g. #ifdef unix, #ifdef _WIN32) are highly
discouraged and should generally not be used.  Replace those checks
with tests for the actual facility being utilized instead.

The Windows platform utilizes its own manually-generated configure
results header (include/config_win.h) that has to be manually updated
if new tests are added to the configure.ac template.

Only the BRL-CAD sources should include and utilize the common.h
header.  They should not include brlcad_config.h or config_win.h
directly.  If used, the common.h header should be listed before any
system headers.


DOCUMENTATION
-------------

BRL-CAD has extensive documentation in various formats and presently
maintained in various locations.  It is an on-going desire and goal of
the project to have all documentation located along with the source
code in CVS.

In line with that goal and where beneficial, a large portion of the
tutorial documentation is being converted to the Docbook XML format.
Having the tutorial documentation in the Docbook XML format allows for
easier maintenances, better export conversion support, and
representation in a textual format that may be revision controlled and
tracked.

Documenting Source Code:

The source code should always be reasonably documented, this almost
goes without saying for any body of code that is to maintain some
longevity.  Determining just how much documentation is sufficient and
how much is too much is generally resolved over time, but it should
generally be looked at from the perspective of "If I look at this code
in a couple years from now, what would help me remember or understand
it better?"  and add documentation accordingly.

All public library functions and most private or application functions
should be appropriately documented using Doxygen/Javadoc style
comments.  Without getting into the advanced details, this minimally
means that you need to add an additional asterisk to a comment that
precedes your functions:

/** Computes the answer to the meaning of life, the universe, and
 *  everything.
 */
int the_answer() { return 42; };


TESTING
-------

The need for a more formal testing plan has become more of a pressing
issue as the size of BRL-CAD continues to grow.  As such, more
importance on various forms of testing is becoming necessary.

While specific plans for unit and black box testing are not yet
finalized, the Corredor Automation Test Suite will be used to assist
in performing cross-platform build tests, regression tests, and
various integration and operability tests.

A debug build may be specified via:

./configure --enable-debug

A profile build may be specified via:

./configure --enable-profiling

Verbose compilation warnings may be enabled:

./configure --enable-warnings

To perform a run of the benchmark suite to validate raytrace behavior:

make benchmark

To perform a run of the test suite:

make test


PATCH SUBMISSION GUIDELINES
---------------------------

To contribute to BRL-CAD, begin by submitting modifications to the
patches section at http://sf.net/projects/brlcad/.  Patches in the
universal diff format (diff -u) are generally preferred when modifying
existing source or other text files.  Otherwise, contributors are
welcome to submit their changes in full to the patches tracker as
compressed file attachments.

All text patches should be submitted in the unified diff format where
it's feasible to create one either using CVS or using the unmodified
original file.  This is generally the "-u" option to diff, and is also
supported by the CVS diff command:

cvs diff -u > my_patch.diff

Where possible, diffs should be generated against the latest CVS
version available to make it easier to review and patch the changes
in.  If a modification involves the addition or removal of files,
those files should be provided separately with instructions on where
they belong (or what should be removed).  If CVS cannot be used,
please provide the complete release and build number of the files you
worked with.

ANY MODIFICATIONS THAT ARE PROVIDED MUST NOT MODIFY OR CONFLICT WITH
THE EXISTING "COPYING" FILE DISTRIBUTION REQUIREMENTS.  This means
that library modifications must be LGPL-compatible and changes to
applications must be GPL-compatible.  Similarly, GPL libraries may NOT
be used or otherwised linked against BRL-CAD.  Contributors are asked
to only provide patches that may legally be incorporated into BRL-CAD
under the existing distribution provisions described in the COPYING
file.

Patches that are difficult to apply are difficult to accept.


BUGS & UNEXPECTED BEHAVIOR
--------------------------

When a bug or unexpected behavior is encountered that cannot be
quickly fixed, it minimally needs to be documented.  If you are
already a BRL-CAD contributor, this means either making a comment in
the BUGS file or by making a formal report to the SourceForge bug
tracker at:

http://sourceforge.net/tracker/?atid=640802&group_id=105292&func=browse

If the bug is complicated, will require significant discussion or
collaboration, cannot be fixed any time soon, or if you do not have
commit access, the issue should be reported to the SourceForge bug
tracker.  The issues listed in BUGS are not necessarily listed in bug
tracker, and vice-versa.  The BUGS file is merely maintained as a
convenience notepad of long and short term issues for the developers
only.


COMMIT ACCESS
-------------

Details on the particulars of how to interact with CVS are described
in the doc/cvspolicy.txt document.  In brief, BRL-CAD has a STABLE
branch in CVS that should always compile and run with expected
behavior on all supported platforms.  On the contrary, while the CVS
HEAD is generally always expected to compile, more flexibility is
allowed for resolution of cross-platform build issues and on-going
development.  Read the aforementioned CVS policy document for more
details.

Commit access is evaluated on a person-to-person basis at the
discretion of existing contributors.  If you would like to have commit
access, there is usually no need to ask.  Getting involved with the
other contributors and making patches will generally result in
automatic consideration for commit access.  If you have to ask for it,
you probably won't get it.

Those with commit access have a responsibility to ensure that other
developers are following the guidelines that have been described in
this developer's guide within reasonable expectations.  A basic rule
of thumb is: don't break anything.

While the testing process will strive to ensure consistent behavior as
changes are made, the responsibility still remains with the individual
contributors to ensure that everything still compiles and runs as it
should.  At any given time, BRL-CAD should compile on all of the
primary platforms and (minimally) pass the BRL-CAD Benchmark
successfully.  If changes are made that are not exercised by the
Benchmark suite, testing should be manually performed in a manner that
exercises those particular changes.


CONTRIBUTOR RESPONSIBILITIES
----------------------------

Contributors of BRL-CAD that are granted commit access are expected to
uphold standards of conduct and adhere to conventions and procedures
outlines in this guide.  All contributors are directly supporting the
on-going development of BRL-CAD by being granted commit access.  As
such, these individuals are also considered "developers" whether they
are modifying source code or not, and have similar obligations.  To
summarize some of the expected responsibilities:

1) Developers are expected to uphold the quality, functionality,
maintainability, and portability of the source code at all times.

2) Bugs, typos, and compilation errors are to be expected as part of
the process of active software development and documentation, but it
is ultimately unacceptible to allow them to persist.  If it is
discovered that a recent modification introduces a new problem, such
as causing a compilation portability failure, then it is the
responsibility of the contributor that introduced the change to assist
in resolving the issue promptly.  It is the responsibility of all
developers to address issues as they are encountered regardless of who
introduces the problem.

3) Contributors making commits to the repository are required to
uphold the legal conventions and requirements overviewed in the
COPYING file.  This includes the implicit assignment of copyright to
the U.S. Government on all contributed code unless otherwise
explicitly arranged as well as the usage of appropriate license
headers in all files where expected.

4) It is expected that developers will adhere to the coding style
conventions and filesystem organization outlined in this developer's
guide.  This includes the utilization of the specified coding style as
well as the prescribed K&R indentation convention.

5) Contributors are expected to communicate with other contributors
and to avoid code or file territorialism.  All contributors are
expected and encouraged to fix problems as they are found regardless
of where in the package they are located.  Care should of course be
taken to ensure that fixing in a bug in a section of code does not
introduce other issues, especially for unfamiliar code.


VERSION NUMBERS & COMPATIBILITY
-------------------------------

The BRL-CAD version number is in the configure.ac file.  The README,
ChangeLog, HISTORY files as well as a variety of documents in the doc/
directory may also make references to version numbers.

Starting with release 7.0.0, BRL-CAD has adopted a three-digit version
number convention for identifying and tracking future releases.  This
number follows a common convention where the three numbers represent:

	{MAJOR_VERSION}.{MINOR_VERSION}.{PATCH_VERSION}

All "development" builds use an odd number for the minor version.  All
"release" builds use an even number for the minor version.

The MAJOR_VERSION should only increment when it is deemed that a
significant amount of major changes have accumulated, new features
have been added, or enough significant backwards incompatibilities
were added to make a release warrant a major version increment.  In
general, releases of BRL-CAD that differ in the MAJOR_VERSION are not
considered compatible with each other.

The MINOR_VERSION is updated more frequently and serves the dual role
as previously mentioned of easily identifying a build as a public
release.  A minor version update is generally issued after significant
development activity (generally several months of activity) has been
tested and deemed sufficiently stable.  When a stable release is made,
it may (but not necessarily) be tagged as a maintenance branch in CVS
(see doc/cvspolicy.txt) with patch releases being performed on that
branch.

The PATCH_VERSION may and should be updated as frequently as is
necessary.  Every public maintenance release should increment the
patch version.  Every development version modification that is
backwards incompatible in some manner should increment the patch
version number.


MAKING A RELEASE
----------------

BRL-CAD uses a monthly iteration development cycle.  If there have
been significant changes since the previous iteration, the
contributors are expected to "settle down" around the last couple days
of the month so that the source code may be verified, tested, and
released.  Major changes to the source code and documentation should
not occur during these last couple days of the iteration, only minor
bug and build fixes.  A release should then be made within the first
few days of the next month's iteration.  Repeat, rinse, recycle.

In addition to the monthly iteration release, additional releases may
be made on an as-needed basis.  This is particularly relevant for
emergency bug-fix releases and in response to security issues.  The
December/January timeframe is considered a single iteration with only
one iteration release necessarily being made in that timeframe.

When making a release, certain public repositories, mailing lists, and
news outlets require updating and notification.  Especially when the
major or minor version of BRL-CAD is going to be updated, it is very
important to follow and ensure that the following steps have been
successfully performed:

0) All code is committed to CVS.

1) Verify that the NEWS file includes a comment for all relevant and
significant items added since the previous release.

2) All existing manual pages and the TODO file are updated with the
latest changes.

3) Update or verify the version numbers minimally in configure.ac,
NEWS, README, and include/config_win.h (see VERSION NUMBERS &
COMPATIBILITY section) and commit the changes to the source
repository.

4) Update the ChangeLog with entries since the last release; commit
the updated ChangeLog.  Use the YYYY-MM-DD of the previous release.
Get the date from the NEWS file.

    rcs2log -h users.sourceforge.net -r "-d>YYYY-MM-DD" > ChangeLog

5) A "./configure && make" completes successfully on all platforms.

6) Perform a "make distcheck" successfully.  This will ensure that a
proper source distribution tarball may be generated and that a build
should compile properly regardless of the existence of the GNU Build
System tools (autoconf, automake, etc).

7) Tag the release using the format "rel-MAJOR-MINOR-PATCH".  See the
doc/cvspolicy.txt document for details.  e.g. cvs tag rel-7-2-4

8) Export a tagged version of the sources (required so that RCS ids
are correct):  cvs export -r rel-MAJOR-MINOR-PATCH brlcad

9) Perform another "make distcheck" on the exported/updated sources
(preferably on Mac OS X) to generate the distributable compressed
source tarballs.

10) Verify that the source distribution tarballs may be expanded; and
that they build, run, and that the file permissions are correct.

11) Use one of the source distribution tarballs to generate
platform-specific builds.  Test the build:  make test && make bench

12) Post the source and platform-specific binary distributions to
SourceForge (i.e. upload them via ftp to upload.sf.net's incoming
directory and select them on the sf.net File Release System).

13) Increment and commit the next BRL-CAD release numbers to CVS;
update the configure.ac, README, include/config_win.h, and NEWS
immediately to a developer version (odd minor or patch version number,
e.g. 7.4.1).

14) If appropriate, notify and/or update the following information
outlets with the details of the new release:

      News on the BRL-CAD website
      http://brlcad.org/
	with news details

      SourceForge Project News
      http://sf.net/projects/brlcad/
	with news details

      BRL-CAD News & Users mailing lists
      brlcad-news@lists.sourceforge.net
      brlcad-users@lists.sourceforge.net
	with news details

      CAD on Linux mailing list
      cad-linux@freelists.org
	with news details

      Freshmeat  (anyone can submit update)
      http://freshmeat.net/projects/BRL-CAD/
	short without news details (sentance format)

      Versiontracker  (only 'brlcad' can update)
      http://www.versiontracker.com/dyn/moreinfo/macosx/26289
      http://www.versiontracker.com/dyn/moreinfo/win/64903
	short without news details (list format)

      upFront.ezine (if major)
      Ralph Grabowski
      ralphg@upfrontezine.com
	with news details

      CADinfo.NET (if major)
      copyboy@cadinfo.net
	with news details

      TenLinks Daily (if major)
      http://www.tenlinks.com/NEWS/tl_daily/submit_news.htm
      news@tenlinks.com
	with news details

      Slashdot (if major)
      http://slashdot.org
	short without news details

      Government Computer News (if major)
      Joab Jackson
      jjackson@gcn.com
	short without news details

15) Sit back and enjoy a beverage for a job well done.


GETTING HELP
------------

See the GETTING STARTED section above.  Basically, communicate with
the existing developers.  There is an IRC channel, e-mail mailing
lists, and on-line forums dedicated to developer discussions.
