Merge pull request #624 from krOoze/update_readme_wubutu

Update Ubuntu subsystem build instructions

BUILD.adoc

@@ -2,74 +2,82 @@
 :toc2:
 :toclevels: 2
 
+ifdef::env-github[]
+:note-caption: :information_source:
+endif::[]
 
 [[intro]]
 == Introduction
 
-This README describes important stuff for getting the Vulkan API
+This README describes how to build the Vulkan API specification,
-specification and reference pages building properly.
+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
+specification to your local Linux, Windows, or Mac PC.
-located at https://github.com/KhronosGroup/Vulkan-Docs/ .
+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
+Finally, go to the root directory of your local repository clone, and do
 
     $ make html
 
-builds an HTML5 specification output.
+which builds an HTML5 specification output.
 
     $ make all
 
-builds the spec targets `html`, `pdf`, `styleguide`, `manhtml`, `manpdf`,
+builds the spec targets `html`, `pdf`, `styleguide`, `registry`, `manhtml`,
-`manhtmlpages`, `checkinc`, and `checklinks`.
+`manpdf`, `manhtmlpages`, `checkinc`, and `checklinks`.
 
 [NOTE]
-.Notes
+.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 verification and viewing of changes.
+    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
+    needing to be built with all extensions enabled.
-    will fail otherwise.
+    Building this target will fail otherwise.
 ====
 
 These targets generate a variety of output documents in the directory
-specified by the Makefile variable `$(OUTDIR)` (by default, `out`).
+specified by the Makefile variable `$(OUTDIR)` (by default, `out/`).
 The checked-in file `out/index.html` links to all these
 targets, or they can individually be found as follows:
 
-  * API spec:
+Vulkan^(R)^ Specification::
-  ** `html` - HTML5 in `$(OUTDIR)/html/vkspec.html`
+  * `html` -- Single-file HTML5 in `$(OUTDIR)/html/vkspec.html`, and KaTeX
-  ** `pdf` - PDF in `$(OUTDIR)/pdf/vkspec.pdf`
+    dependency in $(OUTDIR)/katex
-  * "`Vulkan Documentation and Extensions`" guide:
+  * `pdf` -- PDF in `$(OUTDIR)/pdf/vkspec.pdf`
-  ** `styleguide` - Single-file HTML5 in `$(OUTDIR)/styleguide.html`
+"`styleguide`" (Vulkan^(R)^ Documentation and Extensions: Procedures and Conventions)::
-  * Diff spec:
+  * `styleguide` -- Single-file HTML5 in `$(OUTDIR)/styleguide.html`
-  ** `diff_html` - Single-file HTML5 in `$(OUTDIR)/html/diff.html`
+XML Registry schema document::
-  * Reference pages:
+  * `registry` -- Single-file HTML5 in `$(OUTDIR)/registry.html`
-  ** `manhtml` - Single-file HTML in `$(OUTDIR)/apispec.html`
+<<building-diff,Diff spec>>::
-  ** `manpdf` - Single-file PDF in `$(OUTDIR)/apispec.html`
+  * `diff_html` -- Single-file HTML5 in `$(OUTDIR)/html/diff.html`
-  ** `manhtmlpages` - File-per-entry-point HTML in `$(OUTDIR)/man/html/*`
+<<refpages,Reference pages>>::
-  * Validator output:
+  * `manhtml` -- Single-file HTML in `$(OUTDIR)/apispec.html`
-  ** `checkinc` - List of commands, structs, etc.
+  * `manpdf` -- Single-file PDF in `$(OUTDIR)/apispec.pdf`
+  * `manhtmlpages` -- File-per-entry-point HTML in `$(OUTDIR)/man/html/*`
+<<validation-scripts,Validator output>>::
+  * `checkinc` -- List of commands, structs, etc.
      missing from the API spec in `$(OUTDIR)/checks/notInSpec.txt`
-  ** `checklinks` - Validator script output for API spec in
+  * `checklinks` -- Validator script output for API spec in
     `$(OUTDIR)/checks/specErrs.txt` and for reference pages in
     `$(OUTDIR)/checks/manErrs.txt`
-  * Valid usage database:
+Valid usage database::
-  ** `validusage` - json database of all valid usage statements in the
+  * `validusage` - json database of all valid usage statements in the
-     specification. Must be built with ./makeAllExts (for now).
+     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`
@@ -83,23 +91,13 @@ make -j 8
 
 may significantly speed up the reference page builds.
 
-
+If you encounter problems refer to the <<troubleshooting>> section.
-[[build-bugs]]
-=== Asciidoctor Build Errors
-
-If you see an error like this from the `pdf` target:
-
-    /home/jon/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/ruby-enum-0.7.1/lib/ruby-enum/enum.rb:34:in `const_set': asciidoctor: FAILED: /home/tree/git/vulkan/vkspec.txt: Failed to load AsciiDoc document - wrong constant name default (NameError)
-
-then try <<ruby-enum-downgrade,downgrading ruby-enum>>
-as described below
-
 
 [[building-versions]]
 === Building Specifications For Different API Versions
 
 The `Makefile` defaults to building a Vulkan 1.1 specification.
-This is controlled by asciidoc attributes passed in the Makefile variable
+This is controlled by Asciidoctor attributes passed in the Makefile variable
 `$(VERSIONS)`
 To instead build a Vulkan 1.0 specification, pass
 
@@ -115,39 +113,45 @@ on the `make` command line.
 
 Extensions are defined in the same source as the core Specification, but
 are only conditionally included in the output.
-Asciidoctor http://asciidoctor.org/docs/user-manual/#attributes[attributes]
+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
+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 `$(EXTENSIONS)`, normally set on the make command line.
+Makefile variable `$(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.
+  * `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
+  * `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.
+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` and `makeKHR` scripts already do this.
+The `makeExt`, `makeKHR`, and `makeAllExts` scripts already do this.
 
 
 [[building-diff]]
@@ -171,29 +175,37 @@ 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
+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".
+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 asciidoc formatting, macros, stylesheets, etc., you
+If you are just testing Asciidoctor formatting, macros, stylesheets, etc.,
-may want to edit `vkspec.txt` to just include your test code.
+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 SVG
+All images used in the specification are in the `images/` directory in the
-format, and were created with Inkscape.
+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
+problems using SVG files created by some other tools; especially in the PDF
 builds.
 
-
+[[validation-scripts]]
 === Validation Scripts
 
 [NOTE]
@@ -204,7 +216,7 @@ work properly at present due to numerous changes in the macro and
 conditional markup used in the specification sources.
 ====
 
-There are a several Makefile targets which look for inconsistencies and
+There are several Makefile targets which look for inconsistencies and
 missing material between the specification and ref pages, and the canonical
 description of the API in `vk.xml` :
 
@@ -214,16 +226,13 @@ description of the API in `vk.xml` :
 
 They are necessarily heuristic since they're dealing with lots of
 hand-written material.
-To use them you'll also need to install:
-
-  * `python3`
 
 The `checkinc` target uses Unix filters to determine which autogenerated API
 include files are used (and not used) in the spec.
-It generates several output files, but the only one you're likely to care
+It generates `notInSpec.txt` report.
-about is `actual.only`.
+This contains a list of the include files which are *not* referenced
-This is a list of the include files which are *not* referenced anywhere in
+anywhere in the spec, and probably correspond to undocumented material in
-the spec, and probably correspond to undocumented material in the spec.
+the spec.
 
 The `checklinks` target validates the various internal tagged links in the
 man pages and spec (e.g. the `fname:vkFuncBlah`, `sname:VkStructBlah`, etc.)
@@ -234,10 +243,10 @@ found.
 
 
 [[macros]]
-== Our Asciidoc Macros
+== Our Asciidoctor Macros
 
-We use a bunch of custom macros in the reference pages and API spec asciidoc
+We use a bunch of custom macros in the reference pages and API spec
-sources.
+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
@@ -246,12 +255,14 @@ easily verifiable.
 The supported macros are defined in the `config/vulkan-macros/extension.rb`
 asciidoctor extension script.
 
-The tags used are described in the style guide (`styleguide.txt`).
+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 and be taken to the definition of that
+hovering over) it in the HTML view will take reader to the definition of
-type/token.
+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).
@@ -300,11 +311,13 @@ 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
+In addition, the normative terminology macros, such as `must:` and `may:`
-cannot:, always use this role.
+and `cannot:`, always use this role.
 
 The formatting of normative language depends on the stylesheet.
 Currently it just comes out in purple.
@@ -314,6 +327,8 @@ 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.
@@ -323,9 +338,9 @@ 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
+complex fractions, equations should be written using the `latexmath:` inline
 and block macros.
-The contents of the latexmath: blocks should be LaTeX math notation.
+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
@@ -342,26 +357,31 @@ The following caveats apply:
     `>=` 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*}],
+  * AMSmath environments (e.g. `pass:[\begin{equation*}]`,
-    etc.) cannot be used in KaTeX at present, and have been replaced with
+    `pass:[{align*}]`, etc.) cannot be used in KaTeX at present, and have
-    constructs supported by KaTeX such as pass:[{aligned}].
+    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
+    Imbedding LaTeX like `\Large` or `pass:[\hbox{\tt\small VK\_FOO}]` may
-    work in any of the backends, and should be avoided.
+    not work in any of the backends, and should be avoided.
 
-See the "`Vulkan Documentation and Extensions`" document for more details of
+See the
-supported LaTeX math constructs.
+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 '+++[[chapter-section-label]]+++'.
+title and should use the form `pass:[[[chapter-section-label]]]`.
 For example,
 
 For example, in chapter `synchronization.txt`:
@@ -392,6 +412,7 @@ 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
@@ -403,21 +424,21 @@ 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)
+  * GNU make (`make` version: 4.0.8-1; older versions probably OK)
-  * Python 3 (python, version: 3.4.2)
+  * Python 3 (`python`, version: 3.4.2)
-  * Ruby (ruby, version: 2.3.3)
+  * Ruby (`ruby`, version: 2.3.3)
-  ** The Ruby development package (ruby-dev) may also be required in some
+  ** The Ruby development package (`ruby-dev`) may also be required in some
      environments.
-  * Git command-line client (git, version: 2.1.4).
+  * 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).
+  * 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 will be a lot
+    Ghostscript is used to optimize the size of the PDF, so it will be order
-    smaller if it is included.
+    of magnitude smaller if it is included.
 
 The following Ruby Gems and platform package dependencies must also be
 installed.
@@ -426,28 +447,28 @@ 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: 1.5.6.1)
+  * Asciidoctor (`asciidoctor`, version: 1.5.6.1)
-  * Coderay (coderay, version 1.1.2)
+  * Coderay (`coderay`, version 1.1.2)
-  * JSON Schema (json-schema, version 2.8.0)
+  * JSON Schema (`json-schema`, version 2.8.0)
-  * Asciidoctor PDF (asciidoctor-pdf, version: 1.5.0.alpha16)
+  * Asciidoctor PDF (`asciidoctor-pdf`, version: 1.5.0.alpha16)
-  * Asciidoctor Mathematical (asciidoctor-mathematical, version 0.2.2)
+  * 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!)
+    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
+    This is cached under `katex/`, and need not be installed from github.
-    installed from github.
 
 .Note
 [NOTE]
 ====
 Older versions of these packages may work, but are not recommended.
-In particular, the latest versions of asciidoctor-pdf and
+In particular, the latest versions of `asciidoctor-pdf` and
-asciidoctor-mathematical contain important patches working around issues
+`asciidoctor-mathematical` contain important patches working around issues
 we've discovered, and those patches may not be present in earlier versions.
 ====
 
-Only the `asciidoctor` and `coderay` gems are needed if you don't intend to
+Only the `asciidoctor` and `coderay` gems are needed for the HTML `make`
-build PDF versions of the spec and supporting documents.
+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.
@@ -478,166 +499,32 @@ Platform-specific toolchain instructions follow:
 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.
-This might be solved in future.
+Considering how easy it is to get an Unix subsystem or VM on Windows, this
-For now, there are three options for Windows users: Ubuntu / Windows 10,
+is not recommended and it is unlikely a direct path will become supported in
+the future.
+
+There are three supported options for Windows users: Ubuntu / Windows 10,
 MinGW, or Cygwin.
 
 
 [[depends-ubuntu]]
 ==== Ubuntu / Windows 10
 
-When using the "`Ubuntu Subsystem`" for Windows 10, most dependencies can be
+At the time of writing Ubuntu Subsystem is provided in 18.04 LTS and
-installed via apt-get:
+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-get -qq -y install build-essential python3 git cmake bison flex \
+sudo apt update
-    libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev \
+sudo apt full-upgrade
-    libpango1.0-dev ttf-lyx gtk-doc-tools ghostscript
 ----
 
-The default ruby packages on Ubuntu are fairly out of date.
+Rest is identical to <<depends-linux,Linux instructions>>.
-Ubuntu only provides `ruby` and `ruby2.0` - the latter is multiple revisions
-behind the current stable branch, and would require wrangling to get the
-makefile working with it.
-
-Luckily, there are better options; either https://rvm.io[rvm] or
-https://github.com/rbenv/rbenv[rbenv] is recommended to install a more
-recent version.
-
-[NOTE]
-.Note
-====
-
-  * If you are new to Ruby, you should *completely remove* (through the
-    package manager, e.g. `sudo apt-get remove *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 in the 1.0
-    branch 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
-
-# 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 2.3.3
-# This takes in excess of 20 min. to build!
-# https://github.com/rbenv/ruby-build/issues/1054#issuecomment-276934761
-# suggests:
-# "You can speed up Ruby installs by avoiding generating ri/RDoc
-# documentation for them:
-# RUBY_CONFIGURE_OPTS=--disable-install-doc rbenv install 2.3.3
-# We have not tried this.
-
-rbenv install 2.3.3
-
-# Configure rbenv globally to always use Ruby 2.3.3.
-echo "2.3.3" > ~/.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 asciidoctor coderay json-schema
-gem install --pre asciidoctor-pdf
-MATHEMATICAL_SKIP_STRDUP=1 gem install asciidoctor-mathematical
-----
-
-
-[[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.
-
-
-[[depends-ubuntu-sys]]
-===== Ubuntu 16.04 using system Ruby
-
-The Ubuntu 16.04.1 default Ruby install (version 2.3.1) seems to be
-up-to-date enough to run all the required gems, but also needs the
-`ruby-dev` package installed through the package manager.
-
-In addition, the library
-`/var/lib/gems/2.3.0/gems/mathematical-1.6.7/ext/mathematical/lib/liblasem.so`
-has to be copied or linked into a directory where the loader can find it.
-This requirement appears to be due to a problem with the
-asciidoctor-mathematical build process.
 
 
 [[depends-mingw]]
@@ -768,6 +655,34 @@ 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/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
+----
+
+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>>.
 
 [[depends-osx]]
 === Mac OS X
@@ -794,23 +709,6 @@ curl -LO http://mirrors.ctan.org/fonts/cm/ps-type1/bakoma/ttf/cmex10.ttf \
 Then install the required <<depends-gems,Ruby Gems>>.
 
 
-[[depends-linux]]
-=== Linux (Debian, Ubuntu, etc.)
-
-The instructions for the <<depends-ubuntu,Ubuntu / Windows 10>> installation
-are generally applicable to native Linux environments using Debian packages,
-such as Debian and Ubuntu, 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.
-
-Using `rbenv` or `rvm` is neccessary, since the system Ruby packages are
-often well out of date.
-
-Once the environment manager, Ruby, and `ruby_build` have been installed,
-install the required <<depends-gems,Ruby Gems>>.
-
-
 [[depends-gems]]
 === Ruby Gems
 
@@ -818,35 +716,271 @@ The following ruby gems can be installed directly via the `gem install`
 command, once the platform is set up:
 
 ----
-gem install rake asciidoctor coderay json-schema
+gem install asciidoctor coderay json-schema
 
 # Required only for pdf builds
-MATHEMATICAL_SKIP_STRDUP=1 gem install asciidoctor-mathematical
+gem install asciidoctor-mathematical
 gem install --pre asciidoctor-pdf
 ----
 
-[[ruby-enum-downgrade]]
+Depending on Ruby environment `gem` may require `sudo`.
-==== Ruby Gem Versioning Errors
+
+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
+gem clean
+----
+
+[[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
+----
 
 *ruby-enum*
 
-Make sure you are using ruby-enum 0.7.1 or later, and mathematical 1.6.8 or
+We have seen this PDF build error:
-later. If you are forced to use earlier versions, see
+----
+Failed to load AsciiDoc document - wrong constant name default (NameError)
+----
+
+It should not be occuring 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
+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.
+
+
+[[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
+
+# 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 2.3.3
+# This takes in excess of 20 min. to build!
+# https://github.com/rbenv/ruby-build/issues/1054#issuecomment-276934761
+# suggests:
+# "You can speed up Ruby installs by avoiding generating ri/RDoc
+# documentation for them:
+# RUBY_CONFIGURE_OPTS=--disable-install-doc rbenv install 2.3.3
+# We have not tried this.
+
+rbenv install 2.3.3
+
+# Configure rbenv globally to always use Ruby 2.3.3.
+echo "2.3.3" > ~/.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 asciidoctor coderay json-schema
+gem install --pre asciidoctor-pdf
+MATHEMATICAL_SKIP_STRDUP=1 gem install asciidoctor-mathematical
+----
+
+
+[[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
 
+  * 2018-10-25 - 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.