= Vulkan^(R)^ Specification Build Instructions and Notes
:toc2:
:toclevels: 2

ifdef::env-github[]
:note-caption: :information_source:
endif::[]

[[intro]]
== Introduction

This README describes how to build the Vulkan API specification,
reference pages, and\or other related targets.

It documents how to set up your build environment, build steps and
targets, and contains some troubleshooting advice.

[[building]]
== Building The Spec

First, clone the Khronos Github repository containing the Vulkan
specification to your local Linux, Windows, or Mac PC.
The repository is located at https://github.com/KhronosGroup/Vulkan-Docs/.

Next, install all the necessary build tools (see <<depends,Software
Dependencies>> below).

Finally, go to the root directory of your local repository clone, and do

    $ make html

which builds an HTML5 specification output for the core Vulkan 1.1
specification, with no extensions included.

    $ ./makeAllExts all

builds the spec targets `html`, `pdf`, `styleguide`, `registry`,
`manhtmlpages`, and `allchecks`, with *all* registered extensions included.

[NOTE]
.Note
====
  * `make all` takes a long time to run, and generates outputs that are
    irrelevant for most users.
    Usually `make html` is used to update the HTML target, which is all
    that's needed for quick review of changes made.
  * The default `make` options build a Vulkan 1.1 specification with no
    optional extensions.
  * The `validusage` target is not built as part of `make all`, due to it
    needing to be built with all extensions enabled.
    Building this target will fail otherwise.
====

These targets generate a variety of output documents in the directory
specified by the Makefile variable `$(OUTDIR)` (by default, `out/`).
The checked-in file `out/index.html` links to all these
targets, or they can individually be found as follows:

Vulkan^(R)^ Specification::
  * `html` -- Single-file HTML5 in `$(OUTDIR)/html/vkspec.html`, and KaTeX
    dependency in $(OUTDIR)/katex
  * `chunked` -- Chunked HTML5 in `$(OUTDIR)/html/chap?.html`
  * `pdf` -- PDF in `$(OUTDIR)/pdf/vkspec.pdf`
"`styleguide`" (Vulkan^(R)^ Documentation and Extensions: Procedures and Conventions)::
  * `styleguide` -- Single-file HTML5 in `$(OUTDIR)/styleguide.html`
XML Registry schema document::
  * `registry` -- Single-file HTML5 in `$(OUTDIR)/registry.html`
<<building-diff,Diff spec>>::
  * `diff_html` -- Single-file HTML5 in `$(OUTDIR)/html/diff.html`
<<refpages,Reference pages>>::
  * `manhtmlpages` -- File-per-entry-point HTML in `$(OUTDIR)/man/html/*`.
    Must be built with all extensions enabled (using `makeAllExts`).
<<validation-scripts,Validator output>>::
  * None at present. The `allchecks` target writes to standard output unless
    the underlying script is given additional options.
Valid usage database::
  * `validusage` - json database of all valid usage statements in the
     specification. Must be built with `./makeAllExts` (for now).
     Output in `$(OUTDIR)/validation/validusage.json`.
     A validated schema for the output of this is stored in
     `$(CURDIR)/config/vu-to-json/vu_schema.json`

Once you have the basic build working, an appropriate parallelization option
to make, such as

----
make -j 8
----

may significantly speed up the reference page builds.

If you encounter problems refer to the <<troubleshooting>> section.

[[building-versions]]
=== Building Specifications For Different API Versions

The `Makefile` defaults to building a Vulkan 1.1 specification.
This is controlled by Asciidoctor attributes passed in the Makefile variable
`$(VERSIONS)`
To instead build a Vulkan 1.0 specification, pass

----
VERSIONS="VK_VERSION_1_0"
----

on the `make` command line.


[[building-extensions]]
=== Building With Extensions Included

Extensions are defined in the same source as the core Specification, but
are only conditionally included in the output.
http://asciidoctor.org/docs/user-manual/#attributes[Asciidoctor attributes]
of the same name as the extension are used to define whether the extension
is included or not -- defining such an attribute will cause the output to
include the text for that extension.

When building the specification, the extensions included are those specified
as a space-separated list of extension names (e.g. `VK_KHR_surface`) in the
Makefile variable `$(EXTENSIONS)`, usually set on the make command line.
When changing the list of extensions, it is critical to remove all generated
files using the `clean_generated` Makefile target, as the contents of
generated files depends on `$(EXTENSIONS)`.
There are several helper scripts which clean these files and then build one
or more specified targets for specified extensions:

  * `makeExt` -- generate outputs with one or more extensions enabled.
    Usage is `makeExt extension-names target(s)`, where `extension-names` is
    a space-separated list of extension names, such as
    `VK_EXT_debug_report`.
    If more than one extension is specified, `extension-names` must be
    quoted on the command line.
  * `makeKHR` -- generate outputs with all Khronos (`VK_KHR_*`) extensions
    enabled.
    Usage is `makeKHR target(s)`.
  * `makeAllExts` -- generate outputs with all Vulkan extensions enabled.
    Usage is `makeAllExts target(s)`.

The `target(s)` passed to these scripts are arbitrary `make` options, and
can be used to set Makefile variables and options, as well as specify actual
build targets; you can, for example, do:

----
$ ./makeAllExts -j 8 VERSIONS="VK_VERSION_1_0" html
----

The Makefile variable `$(APITITLE)` defines an additional string which is
appended to the specification title.
When building with extensions enabled, this should be set to something like
`(with extension VK_extension_name)`.
The `makeExt`, `makeKHR`, and `makeAllExts` scripts already do this.

The reference pages (the `manhtmlpages` target) must be built using
`makeAllExts`; there are markup and scripting issues which will probably
cause any more restricted set of refpages to fail to build.


[[building-diff]]
==== Building A Highlighted Extension Diff

The `diff_html` target in the makefile can be used to generate a version of
the specification which highlights changes made to the specification by the
inclusion of a particular set of extensions.

Extensions in the Makefile variable `$(EXTENSIONS)` define the base
extensions to be enabled by the specification, and these will not be
highlighted in the output.
Extensions in the Makefile variable `$(DIFFEXTENSIONS)` define the set of
extensions whose changes to the text will be highlighted when they are
enabled.
Any extensions in both variables will be treated as if they were only
included in `$(DIFFEXTENSIONS)`.
`$(DIFFEXTENSIONS)` can be set when using the `make*` scripts described
above.

In the resulting HTML document, content that has been added by one of the
extensions will be highlighted with a lime background, and content that was
removed will be highlighted with a pink background.
Each section has an anchor of `#differenceN`, with an arrow (=>) at the end
of each section which links to the next difference section.
The first diff section is `#difference1`.

[NOTE]
.Note
====
This output is not without errors.
It may instead result in visible `+++[.added]##content##+++` and
`+++[.removed]##content##+++`, and so also highlights not being rendered.
But such visible markup still correctly encapsulates the modified content.
====

[[building-test]]
=== Alternate and Test Builds

If you are just testing Asciidoctor formatting, macros, stylesheets, etc.,
you may want to edit `vkspec.txt` to just include your test code.
The asciidoctor HTML build is very fast, even for the whole Specification,
but PDF builds take several minutes.


=== Images Used In The Specification

All images used in the specification are in the `images/` directory in the
SVG format, and were created with Inkscape.
We recommend using Inkscape to modify or create new images, as we've had
problems using SVG files created by some other tools; especially in the PDF
builds.

[[validation-scripts]]
=== Validation Scripts

The `allchecks` Makefile target runs a Python script that looks for markup
errors, missing interfaces, macro misuse, and inconsistencies in the
specification text.
This script is necessarily heuristic, since it's dealing with lots of
hand-written material, but it identifies many problems and can suggest
solutions.
This script is also run as part of the CI tests in the internal Khronos
gitlab repository.


[[macros]]
== Our Asciidoctor Macros

We use a bunch of custom macros in the reference pages and API spec
Asciidoctor sources.
The validator scripts rely on these macros as part of their sanity checks,
and you should use the macros whenever referring to an API command, struct,
token, or enum name, so the documents are semantically tagged and more
easily verifiable.

The supported macros are defined in the `config/spec-macros/extension.rb`
asciidoctor extension script.

The tags used are described in the
link:https://www.khronos.org/registry/vulkan/specs/1.1/styleguide.html[style
guide] (generated from `styleguide.txt`).

We (may) eventually tool up the spec and ref pages to the point that
anywhere there's a type or token referred to, clicking on (or perhaps
hovering over) it in the HTML view will take reader to the definition of
that type/token.
That will take some more plumbing work to tag the stuff in the autogenerated
include files, and do something sensible in the spec (e.g. resolve links to
internal references).

Most of these macros deeply need more intuitive names.


[[refpages]]
== Reference Pages

The reference pages are extracted from the API Specification source, which
has been tagged to help identify boundaries of language talking about
different commands, structures, enumerants, and other types.
A set of Python scripts extract and lightly massage the relevant tagged
language into corresponding ref page.
Pages without corresponding content in the API spec are generated
automatically, when possible (e.g. for `Vk*FlagBits` pages).

If for some reason you want to regenerate the ref page sources from scratch
yourself, you can do so by

----
rm man/apispec.txt
make apispec.txt
----

The `genRef.py` script will generate many warnings, but most are just
reminders that some pages are automatically generated.
If everything is working correctly, all the `man/*.txt` files will be
regenerated, but their contents will not change.

If you add new API features to the Specification in a branch, make sure that
the commands have the required tagging and that ref pages are generated for
them, and build properly.


[[styles]]
== Our stylesheets

We use an HTML stylesheet `config/khronos.css` derived from the
http://asciidoctor.org/docs/produce-custom-themes-using-asciidoctor-stylesheet-factory/[Asciidoctor
stylesheet factory] "`colony`" theme, with the default Arial font family
replaced by the sans-serif https://en.wikipedia.org/wiki/Noto_fonts[Noto
font family].


=== Marking Normative Language

// editing-note: Chapter should probably be merged with styleguide to reduce size

Normative language is marked as *bold*, and also with the [purple]#purple#
role for HTML output.
It can be used to mark entire paragraphs or spans of words.
In addition, the normative terminology macros, such as `must:` and `may:`
and `cannot:`, always use this role.

The formatting of normative language depends on the stylesheet.
Currently it just comes out in purple.
We may add a way to disable this formatting at build time.


[[equations]]
== Imbedding Equations

// editing-note: Chapter should probably be merged with styleguide to reduce size

Where possible, equations should be written using straight asciidoc markup
with the _eq_ role.
This covers many common equations and is faster than the alternatives.
A variety of mathematical symbols are defined using attributes in the
included `config/attribs.txt`.
These symbols are defined using attribute names the same as the comparable
LaTeX macro names, where possible.

For more complex equations, such as multi-case statements, matrices, and
complex fractions, equations should be written using the `latexmath:` inline
and block macros.
The contents of the `latexmath:` blocks should be LaTeX math notation.
LaTeX math markup delimiters are now inserted by the asciidoctor toolchain.

LaTeX math is passed through unmodified to all HTML output forms, which is
subsequently rendered with the KaTeX engine when the HTML is loaded.
A local copy of the KaTeX release is kept in `katex/` and
copied to the HTML output directory during spec generation.
Math is processed into SVGs via asciidoctor-mathematical for PDF output.

The following caveats apply:

  * The special characters `<` , `>` , and `&` can currently be used only in
    +++[latexmath]+++ block macros, not in +++latexmath:[]+++ inline macros.
    Instead use `\lt`, `\leq`, `\gt`, and `\geq` for `<`, `<=`, `>`, and
    `>=` respectively.
    `&` is an alignment construct for multiline equations, and should only
    appear in block macros anyway.
  * AMSmath environments (e.g. `pass:[\begin{equation*}]`,
    `pass:[{align*}]`, etc.) cannot be used in KaTeX at present, and have
    been replaced with constructs supported by KaTeX such as
    `pass:[{aligned}]`.
  * Arbitrary LaTeX constructs cannot be used.
    KaTeX and asciidoctor-mathematical are only equation renderers, not full
    LaTeX engines.
    Imbedding LaTeX like `\Large` or `pass:[\hbox{\tt\small VK\_FOO}]` may
    not work in any of the backends, and should be avoided.

See the
link:https://www.khronos.org/registry/vulkan/specs/1.1/styleguide.html#writing-latexmath["`style guide`"]
(Vulkan Documentation and Extensions) document for more details of supported
LaTeX math constructs.


[[anchors]]
== Asciidoc Anchors And Xrefs

// editing-note: Chapter should probably be merged with styleguide to reduce size

In the API spec, sections can have anchors (labels) applied with the
following syntax.
In general the anchor should immediately precede the chapter or section
title and should use the form `pass:[[[chapter-section-label]]]`.
For example,

For example, in chapter `synchronization.txt`:

----
[[synchronization-primitives]]
Synchronization Primitives
----

Cross-references to those anchors can then be generated with, for example,

----
See the <<synchronization-primitives>> section for discussion of fences,
semaphores, and events.
----

You can also add anchors on arbitrary paragraphs, using a similar naming
scheme.

Anything whose definition comes from one of the autogenerated API include
files (`.txt` files in the directories `basetypes`, `enums`, `flags`,
`funcpointers`, `handles`, `protos`, and `structs`) has a corresponding
anchor whose name is the name of the function, struct, etc.
being defined.
Therefore you can say something like:

----
Fences are used with the +++<<vkQueueSubmit>>+++ command...
----

// editing-note: why would I though. There are xlink: macros for that.


[[depends]]
== Software Dependencies

This section describes the software components used by the Vulkan spec
toolchain.

Before building the Vulkan spec, you must install the following tools.
Minimum versions known to be working are shown. Later versions will probably
work at least as well.

  * GNU make (`make` version: 4.0.8-1; older versions probably OK)
  * Python 3 (`python`, version: 3.4.2)
  * Ruby (`ruby`, version: 2.5.3)
  ** The Ruby development package (`ruby-dev`) may also be required in some
     environments.
  * Git command-line client (`git`, version: 2.1.4).
    The build can progress without a git client, but branch/commit
    information will be omitted from the build.
    Any version supporting the following operations should work:
  ** `git symbolic-ref --short HEAD`
  ** `git log -1 --format="%H"`
  * Ghostscript (`ghostscript`, version: 9.10).
    This is for the PDF build, and it can still progress without it.
    Ghostscript is used to optimize the size of the PDF, so it will be order
    of magnitude smaller if it is included.
  * The following dependencies are required only if building the
    `chunked` target (chunked HTML output).
  ** Node (`nodejs`, version: 8.11.1)
  *** Node Package Manager (`npm`, version: 5.8.0), for installing Lunr
  ** Lunr (`lunr`, version: 2.3.6), installed with npm.
     One of the lunr files, `lunr.js`, is also incorporated into this
     repository under `config/chunkindex/lunr.js`, so it will always be
     available at spec load time. It is possible that there will be
     incompatibilities between the installed version of lunr used to build
     the index, and the copy of `lunr.js` included with the repository. If
     so, update the repository copy of the file from your lunr distribution,
     or install the specific lunr version 2.3.6 corresponding to the
     repository copy.
  *** Ensure that the installed `lunr` package is found by `node` at
      runtime. This may require setting the environment variable NODE_PATH
      to the path where `lunr` is installed. This path will probably be
      `/usr/lib/node_modules`, if you install `nodejs` and `npm` from
      deb.nodesource.com .

The following Ruby Gems and platform package dependencies must also be
installed.
This process is described in more detail for individual platforms and
environment managers below.
Please read the remainder of this document (other than platform-specific
parts you don't use) completely before trying to install.

  * Asciidoctor (`asciidoctor`, version: 1.5.8)
  * Coderay (`coderay`, version 1.1.2)
  * JSON Schema (`json-schema`, version 2.8.1)
  * Asciidoctor Diagram (`asciidoctor-diagram`, version: 1.5.11)
  * Asciidoctor PDF (`asciidoctor-pdf`, version: 1.5.0.alpha16)
  * Asciidoctor Mathematical (`asciidoctor-mathematical`, version 0.2.2)
  * https://github.com/asciidoctor/asciidoctor-mathematical#dependencies[Dependencies
    for `asciidoctor-mathematical`] (There are a lot of these!)
  * KaTeX distribution (version 0.7.0 from https://github.com/Khan/KaTeX.
    This is cached under `katex/`, and need not be installed from github.
  * If generating the chunked HTML target:
  ** `asciidoctor-chunker` installed according to
     https://github.com/wshito/asciidoctor-chunker[the chunker README].
  ** `Roswell` (version 18.10.10.95 from
     https://github.com/roswell/roswell/releases)

.Note
[NOTE]
====
Older versions of these packages may work, but are not recommended.
In particular, the latest versions of `asciidoctor-pdf` and
`asciidoctor-mathematical` often solve problems we've encountered in older
versions.
====

Only the `asciidoctor` and `coderay` gems are needed for the HTML `make`
targets.
Rest is needed for the PDF builds.

`json-schema` is only required in order to validate the output of the valid
usage extraction scripts to a JSON file.
If not installed, validation will be skipped when the JSON is built.

[NOTE]
.Note
====
While it's easier to install just the toolchain components for HTML builds,
people submitting MRs with substantial changes to the Specification are
responsible for verifying that their branches build *both* `html` and `pdf`
targets.
====

Platform-specific toolchain instructions follow:

  * Microsoft Windows
  ** <<depends-ubuntu,Ubuntu / Windows 10>>
  ** <<depends-mingw,MinGW>> (PDF builds not tested)
  ** <<depends-cygwin,Cygwin>>
  * <<depends-osx,Mac OS X>>
  * <<depends-linux,Linux (Debian, Ubuntu, etc.)>>


[[depends-windows]]
=== Windows (General)

Most of the dependencies on Linux packages are light enough that it's
possible to build the spec natively in Windows, but it means bypassing the
makefile and calling functions directly.
Considering how easy it is to get an Unix subsystem or VM on Windows, this
is not recommended.
It is unlikely a direct path will become supported in the future.

Three options for Windows users are described below: Ubuntu / Windows 10
(best, as long as you're running Windows 10), MinGW, and Cygwin.


[[depends-ubuntu]]
==== Ubuntu / Windows 10

At the time of writing Ubuntu Subsystem is provided in 18.04 LTS and
16.04 LTS versions.
These versions are perfectly suitable for building this repo.

You can install Ubuntu Subsystem as described in the official documentation:
https://docs.microsoft.com/en-us/windows/wsl/install-win10

The distro image is not kept up-to-date, so it is recommended to run:

----
sudo apt update
sudo apt full-upgrade
----

Rest is identical to <<depends-linux,Linux instructions>>.


[[depends-mingw]]
==== MinGW

MinGW can be obtained here: http://www.mingw.org/

Once the installer has run its initial setup, following the
http://www.mingw.org/wiki/Getting_Started[instructions on the website], you
should install the `mingw-developer-tools`, `mingw-base` and `msys-base`
packages.
The `msys-base` package allows you to use a bash terminal from windows with
whatever is normally in your path on Windows, as well as the unix tools
installed by MinGW.

In the native Windows environment, you should also install the following
native packages:

  * Python 3.x (https://www.python.org/downloads/)
  * Ruby 2.x (https://rubyinstaller.org/)
  * Git command-line client (https://git-scm.com/download)

Once this is setup, and the necessary <<depends-gems,Ruby Gems>> are
installed, launch the `msys` bash shell, and navigate to the spec Makefile.
From there, you'll need to set `PYTHON=` to the location of your python
executable for version 3.x before your make command - but otherwise
everything other than pdf builds should just work.

NOTE: Building the PDF spec via this path has not yet been tested but *may*
be possible - liblasem is the main issue and it looks like there is now a
mingw32 build of it available.


[[depends-cygwin]]
==== Cygwin

When installing Cygwin, you should install the following packages via
`setup`:

----
// "curl" is only used to download fonts, can be done in another way
autoconf
bison
cmake
curl
flex
gcc-core
gcc-g++
ghostscript
git
libbz2-devel
libcairo-devel
libcairo2
libffi-devel
libgdk_pixbuf2.0-devel
libiconv
libiconv-devel
liblasem0.4-devel
libpango1.0-devel
libpango1.0_0
libxml2
libxml2-devel
make
python3
ruby
ruby-devel
----

NOTE: Native versions of some of these packages are usable, but care should
be taken for incompatibilities with various parts of cygwin - e.g. paths.
Ruby in particular is unable to resolve Windows paths correctly via the
native version.
Python and Git for Windows can be used, though for Python you'll need to set
the path to it via the PYTHON environment variable, before calling make.

When it comes to installing the mathematical ruby gem, there are two things
that will require tweaking to get it working.
Firstly, instead of:

----
MATHEMATICAL_SKIP_STRDUP=1 gem install asciidoctor-mathematical
----

You should use

----
MATHEMATICAL_USE_SYSTEM_LASEM=1 gem install asciidoctor-mathematical
----

The latter causes it to use the lasem package already installed, rather than
trying to build a fresh one.

Recent versions of some gems break the installation process and/or pdf build
on some systems. If the above doesn't work, try:

----
MATHEMATICAL_USE_SYSTEM_LASEM=1 gem install mathematical -v 1.6.7
gem install ruby-enum -v 0.7.0
gem install asciidoctor-mathematical
----

The mathematical gem also looks for "liblasem" rather than "liblasem0.4" as
installed by the lasem0.4-devel package, so it is necessary to add a symlink
to your /lib directory using:

----
ln -s /lib/liblasem-0.4.dll.a /lib/liblasem.dll.a
----

<<Ruby Gems>> are not installed to a location that is in your path normally.
Gems are installed to `~/bin/` - you should add this to your path before
calling make:

    export PATH=~/bin:$PATH

Finally, you'll need to manually install fonts for lasem via the following
commands:

----
mkdir /usr/share/fonts/truetype cd /usr/share/fonts/truetype
curl -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmex10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmmi10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmr10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmsy10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/esint10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/eufm10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/msam10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/msbm10.ttf
----

[[depends-linux]]
=== Linux (Debian, Ubuntu, etc.)

System dependencies can be installed via apt:

----
sudo apt install build-essential python3 git cmake bison flex \
    libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev \
    libpango1.0-dev fonts-lyx ghostscript libreadline-dev
----

[NOTE]
.Note
====
On Ubuntu versions prior to 18.04 LTS, you will probably need to use the
`ttf-lyx` package instead of `fonts-lyx`.
====

These instructions are for the Ubuntu installation and are generally
applicable to native Linux environments that use Debian packages, although
the exact list of packages to install may differ.
Other distributions using different package managers, such as RPM (Fedora)
and Yum (SuSE) will have different requirements.

Ruby can also be installed as a system package:

----
sudo apt install ruby ruby-dev
----

Ruby packages are often well out of date, so using <<ruby-env,alternative
ruby environments>> such as `rbenv` or `rvm` might be preferable.

Once the Ruby environment is set up, install the required
<<depends-gems,Ruby Gems>>.

If you will need to generate the chunked HTML target, install the
<<depends-chunker, Asciidoctor-chunker>> dependencies as described below.


[[depends-osx]]
=== Mac OS X

Mac OS X should work in the same way as for Ubuntu by using the Homebrew
package manager, with the exception that you can simply install the ruby
package via `brew` rather than using a ruby-specific version manager.

You'll likely also need to install additional fonts for the PDF build via
mathematical, which you can do with:

----
cd ~/Library/Fonts
curl -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmex10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmmi10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmr10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmsy10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/esint10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/eufm10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/msam10.ttf \
     -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/msbm10.ttf
----

Then install the required <<depends-gems,Ruby Gems>>.


[[depends-gems]]
=== Ruby Gems

The following ruby gems can be installed directly via the `gem install`
command, once the platform is set up:

----
gem install --no-rdoc --no-ri asciidoctor coderay json-schema asciidoctor-mathematical asciidoctor-diagram
gem install --no-rdoc --no-ri --pre asciidoctor-pdf
----

Depending on Ruby environment `gem` may require `sudo`.

It may significantly speed up installation if you skip documentation build
by passing `--no-rdoc --no-ri` arguments.

It may be beneficial to use updated packages via:

----
gem update --no-rdoc --no-ri
gem clean
----


[[depends-chunker]]
=== Asciidoctor-chunker and Index Generation

To generate the `chunked` HTML target, you must install
https://github.com/wshito/asciidoctor-chunker[`asciidoctor-chunker`] and
the underlying https://github.com/roswell/roswell/releases[`Roswell`]
compiler and related dependencies. These projects do not seem to support
standard software repositories and packaging (e.g. RPM, .deb, etc.), so
you will need to follow the
https://github.com/wshito/asciidoctor-chunker[How to Install] directions
for asciidoctor-chunker.

Note that both Roswell and asciidoctor-chunker are installed outside the
scope of the Vulkan Specification repository (in system directories, and
in your home directory, respectively).

You must also install these Javascript dependencies to generate the
index, partly as system packages, and partly with npm. Note that npm is not
packaged for Debian 9, thus it's installed from deb.nodesource.com following
https://linuxize.com/post/how-to-install-node-js-on-debian-9/

----
curl -sL https://deb.nodesource.com/setup_8.x | sudo bash -
# nodejs also installs npm
sudo apt install nodejs
sudo npm install -g lunr@2.3.6
setenv NODE_PATH /usr/lib/node_modules
----

[[troubleshooting]]
== Troubleshooting

This section goes over known problems and solutions for toolchain
installation or for build.

If you get arbitrary build errors it can't hurt to first try resolve it by
cleaning the tree:

----
make clean
git clean -dxf
----


=== STEM SVG Errors

If you happen to have `_` or other Asciidoctor formating characters in your
path, then PDF build using `asciidoctor-mathematical` may fail with:

----
asciidoctor: WARNING: image to embed not found or not readable: whatever/<em>stuff/Vulkan-Docs/out/equations_temp/stem-d3355033150173c1d397e342237db405.svg
----

See https://github.com/asciidoctor/asciidoctor-mathematical/issues/43.

You simply need to have the repository cloned in a simpler path.


=== Ghostscript Errors

Ghostscript optimization of the PDF may produce:

----
   **** Error reading a content stream. The page may be incomplete.
               Output may be incorrect.
   **** Error: File did not complete the page properly and may be damaged.
               Output may be incorrect.
----

Usually, it is just a problem with the Asciidoc sources (e.g. silent failure
to render content that does not fit in the page; such as SVG equations where
there is no line break opportunity).


=== Ruby Gem Versioning Errors

Sometimes, when updating ruby gem packages incompatibilities arise.
It is resoleved by identifying the offending packages and downgrading them:

----
$ gem uninstall package_name
$ gem install package_name --version good_version_number
----

If you already have the gem dependencies previously installed, if there are
new versions, then updating to them instead might help:

----
$ gem update --no-rdoc --no-ri
----

*ruby-enum*

We have seen this PDF build error:
----
Failed to load AsciiDoc document - wrong constant name default (NameError)
----

It should not be occurring with updated packages.
Make sure you are using `ruby-enum 0.7.1` or later, and `mathematical 1.6.8`
or later.
If you are forced to use earlier versions, see
https://github.com/gjtorikian/mathematical/issues/69 for a report of a
related versioning problem.

*prawn*

Make sure you are using prawn 2.2.1 or later, and prawn-templates 0.0.5 or
later. Incompatibilities between `asciidoctor-pdf` and earlier versions of
these gems affects the PDF build. See
https://github.com/KhronosGroup/Vulkan-Docs/issues/476


=== asciidoctor-mathematical gem native extension errors

Installing `mathematical` gem builds `lasem` and `mtex2MML` native binaries.
The <<depends,Dependencies>> we list should be sufficient for the install to
build those native extensions successfully.

If you encounter problems, it is possible to use those binaries from
preinstalled locations.
See https://github.com/gjtorikian/mathematical#troubleshooting.


=== Asciidoctor include errors

If you get errors like:

----
asciidoctor: ERROR: chapters/???.txt: line 189: include file not found: ???/Vulkan-Docs/api/protos/???.txt
----

you probably forgot to call `make clean_generated` as stated in the
<<building-extensions>> chapter.

=== Asciidoctor-chunker memory exhaustion

If you get errors like:

----
ASCIIDOCTOR-CHUNKER: Processing Chap 17 ....
Heap exhausted during garbage collection: 224 bytes available, 288 requested.
...
GC control variables:
   *GC-INHIBIT* = true
   *GC-PENDING* = true
   *STOP-FOR-GC-PENDING* = false
fatal error encountered in SBCL pid 31086(tid 0x7f4816866700):
Heap exhausted, game over.
----

try specifying a larger dynamic space size, something bigger than 2000:

----
$ ROSWELLOPTS="dynamic-space-size=2500" ./makeAllExts html chunked
----

[[ruby-env]]
== Alternative Ruby environments

The default `ruby` packages on Linux distro may be out of date.
Through the default `ruby` package, Ubuntu 18.04 provides ruby 2.5, and
Ubuntu 16.10 provides ruby 2.3.
Those system packages seem to be sufficient to build this repo.

But there are better options; either https://rvm.io[rvm] or
https://github.com/rbenv/rbenv[rbenv] is recommended to install an updated
version of Ruby environment.

[NOTE]
.Note
====
  * If you are new to Ruby, you should *completely remove* (through the
    package manager, e.g. `sudo apt purge *packagename*`) all existing
    Ruby and asciidoctor infrastructure on your machine before trying to use
    rvm or rbenv for the first time.
    `dpkg -l | egrep 'asciidoctor|ruby|rbenv|rvm'` will give you a list of
    candidate package names to remove.
  ** If you already have a favorite Ruby package manager, ignore this
     advice, and just install the required OS packages and gems.
  * In addition, `rvm` and `rbenv` are *mutually incompatible*.
    They both rely on inserting shims and `$PATH` modifications in your bash
    shell.
    If you already have one of these installed and are familiar with it,
    it's probably best to stay with that one.
    One of the editors, who is new to Ruby, found `rbenv` far more
    comprehensible than `rvm`.
    The other editor likes `rvm` better.
  ** Neither `rvm` nor `rbenv` work, out of the box, when invoked from
     non-Bash shells like `tcsh`.
     This can be hacked up by setting the right environment variables and
     `PATH` additions based on a bash environment.
  * Most of the tools on Bash for Windows are quite happy with Windows line
    endings (`CR LF`), but bash scripts expect Unix line endings (`LF`).
    The file `.gitattributes` at the top of the vulkan tree forces such
    scripts to be checked out with the proper line endings on non-Linux
    platforms.
    If you add new scripts whose names don't end in `.sh`, they should be
    included in `.gitattributes` as well.
====


[[depends-ubuntu-rbenv]]
===== Ubuntu/Windows 10 Using Rbenv

Rbenv is a lighter-weight Ruby environment manager with less functionality
than rvm.
Its primary task is to manage different Ruby versions, while rvm has
additional functionality such as managing "`gemsets`" that is irrelevant to
our needs.

A complete installation script for the toolchain on Ubuntu for Windows,
developed on an essentially out-of-the-box environment, follows.
If you try this, don't try to execute the entire thing at once.
Do each step separately in case of errors we didn't encounter.

----
# Install packages needed by `ruby_build` and by toolchain components.
# See https://github.com/rbenv/ruby-build/wiki and
# https://github.com/asciidoctor/asciidoctor-mathematical#dependencies

sudo apt-get install autoconf bison build-essential libssl-dev \
    libyaml-dev libreadline6-dev zlib1g-dev libncurses5-dev \
    libffi-dev libgdbm3 libgdbm-dev cmake libxml2 \
    libxml2-dev flex pkg-config libglib2.0-dev \
    libcairo-dev libpango1.0-dev libgdk-pixbuf2.0-dev \
    libpangocairo-1.0 libreadline-dev

# Install rbenv from https://github.com/rbenv/rbenv
git clone https://github.com/rbenv/rbenv.git ~/.rbenv

# Set path to shim layers in .bashrc
echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> .bashrc

~/.rbenv/bin/rbenv init

# Set .rbenv environment variables in .bashrc
echo 'eval "$(rbenv init -)"' >> .bashrc

# Restart your shell (e.g. open a new terminal window). Note that
# you do not need to use the `-l` option, since the modifications
# were made to .bashrc rather than .bash_profile. If successful,
# `type rbenv` should print 'rbenv is a function' followed by code.

# Install `ruby_build` plugin from https://github.com/rbenv/ruby-build

git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build

# Install Ruby 2.5.3 (current as of this writing; earlier may work)
# Setting RUBY_CONFIGURE_OPTS dramatically cuts the install time, see
# https://github.com/rbenv/ruby-build/issues/1054#issuecomment-276934761
RUBY_CONFIGURE_OPTS=--disable-install-doc
export RUBY_CONFIGURE_OPTS
rbenv install 2.5.3

# Configure rbenv globally to always use Ruby 2.5.3.
echo "2.5.3" > ~/.rbenv/version

# Finally, install toolchain components.
# asciidoctor-mathematical also takes in excess of 20 min. to build!
# The same RUBY_CONFIGURE_OPTS advice above may apply here as well.

gem install --no-rdoc --no-ri asciidoctor coderay json-schema asciidoctor-mathematical asciidoctor-diagram
gem install --no-rdoc --no-ri --pre asciidoctor-pdf
----


[[depends-ubuntu-rvm]]
===== Ubuntu/Windows 10 Using RVM

Here are (sparser) instructions for using rvm to setup version 2.3.x:

----
gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
\curl -sSL https://get.rvm.io | bash -s stable --ruby
source ~/.rvm/scripts/rvm
rvm install ruby-2.3
rvm use ruby-2.3
----

NOTE: Windows 10 Bash will need to be launched with the "-l" option
appended, so that it runs a login shell; otherwise RVM won't function
correctly on future launches.


[[history]]
== Revision History

  * 2018-12-04 - Update Rbenv and ruby gem installation instructions and
    package dependencies for Linux and Ubuntu/Windows 10.
  * 2018-10-25 - Update Troubleshooting, and Windows and Linux build. Plus
    random editing.
  * 2018-03-13 - Rename to BUILD.adoc and update for new directory
    structure.
  * 2018-03-05 - Update README for Vulkan 1.1 release.
  * 2017-03-20 - Add description of prawn versioning problem and how to fix
    it.
  * 2017-03-06 - Add description of ruby-enum versioning problem and how to
    fix it.
  * 2017-02-13 - Move some comments here from ../../../README.md. Tweak
    asciidoctor markup to more clearly delineate shell command blocks.
  * 2017-02-10 - Add more Ruby installation guidelines and reflow the
    document in accordance with the style guide.
  * 2017-01-31 - Add rbenv instructions and update the README elsewhere.
  * 2017-01-16 - Modified dependencies for Asciidoctor
  * 2017-01-06 - Replace MathJax with KaTeX.
  * 2016-08-25 - Update for the single-branch model.
  * 2016-07-10 - Update for current state of spec and ref page generation.
  * 2015-11-11 - Add new can: etc.
    macros and DBLATEXPREFIX variable.
  * 2015-09-21 - Convert document to asciidoc and rename to README.md in the
    hope the gitlab browser will render it in some fashion.
  * 2015-09-21 - Add descriptions of LaTeX and MathJax math support for all
    output formats.
  * 2015-09-02 - Added Cygwin package info.
  * 2015-09-02 - Initial version documenting macros, required toolchain
    components and versions, etc.
