Vulkan-Docs/doc/specs/vulkan
Jon Leech ce60b9c887 Change log for March 7, 2018 Vulkan 1.1.70 spec update:
* Vulkan 1.1 initial release. Bump API patch number and header version
    number to 70 for this update. The patch number will be used for both
    Vulkan 1.1 and Vulkan 1.0 updates, and continues to increment
    continuously from the previous Vulkan 1.0.69 update.

    NOTE: We are not publishing an updated 1.0.70 specification, or 1.1
    reference pages, along with 1.1.70. There are still minor issues to work
    out with those build targets. However, we will soon generate all three
    types of documents as part of the regular spec update cycle.

    NOTE: The GitHub KhronosGroup/Vulkan-Docs repository now maintains the
    current specification in the `master` branch. The `1.0` branch is out of
    date and will not be maintained, since we will be generating both 1.1
    and 1.0 specifications from the `master` branch in the future.

Github Issues:

  * Clarify how mapped memory ranges are flushed in
    flink:vkFlushMappedMemoryRanges (public issue 127).
  * Specify that <<synchronization-pipeline-stages, Pipeline Stages>> are a
    list of tasks that each command performs, rather than necessarily being
    discrete pieces of hardware that one task flows through. Add a
    "`synchronization command`" pipeline type which all synchronization
    command execute (it's just TOP + BOTTOM), with an explanatory note
    (public issue 554).

Internal Issues:

  * Regenerate all images used in the spec in Inkscape with a consistent
    look-and-feel, and adjust image size attributes so they're all legible,
    and not too large with respect to the spec body text (internal issue
    701).
  * Document in the <<extensions,extensions>> appendix and in the style
    guide that `KHX` extensions are no longer supported or used in the
    Vulkan 1.1 timeframe (internal issue 714).
  * Remove the leftover equations_temp directory after PDF build completes
    (internal issue 925).
  * Update the <<credits, Credits (Informative)>> appendix to include
    contributors to Vulkan 1.1, and to list them according to the API
    version(s) they contributed to (internal issue 987).
  * Add a NOTE to the introduction explaining that interfaces defined by
    extensions which were promoted to Vulkan 1.1 are now expressed as
    aliases of the Vulkan 1.1 type (internal issue 991).
  * Instrument spec source conditionals so spec can be built with 1.1
    features, extensions promoted to 1.1, or both (internal issues 992,
    998).
  * Modify the XML schema and tools to support explicit aliasing of types,
    structures, and commands, and use this to express the promotion of 1.0
    extensions to 1.1 core features, by making the extension interfaces
    aliases of the core features they were promoted to. Mark up promoted
    interfaces to allow still generating 1.0 + extension specifications
    (internal issue 991).
  * Platform names, along with corresponding preprocessor symbols to enable
    extensions specific to those platforms, are now reserved in vk.xml using
    the <platform> tag. Update the registry schema and schema specification
    to match (internal issue 1011).
  * Updated the <<textures-texel-replacement, Texel Replacement>> section to
    clarify that reads from invalid texels for image resources result in
    undefined values (internal issue 1014).
  * Modify description of patch version so it continues to increment across
    minor version changes (internal issue 1033).
  * Clarify and unify language describing physical device-level core and
    extension functionality in the <<fundamentals-validusage-extensions,
    Valid Usage for Extensions>>, <<fundamentals-validusage-versions, Valid
    Usage for Newer Core Versions>>, <<initialization-functionpointers
    Command Function Pointers>>, <<initialization-phys-dev-extensions,
    Extending Physical Device From Device Extensions>>
    <<extended-functionality-instance-extensions-and-devices, Instance
    Extensions and Device Extensions>> sections and for
    flink:vkGetPhysicalDeviceImageFormatProperties2. This documents that
    instance-level functionality is tied to the loader, and independent of
    the ICD; physical device-level functionality is tied to the ICD, and
    associated with device extensions; physical devices are treated more
    uniformly between core and extensions; and instance and physical
    versions can be different (internal issue 1048).
  * Updated the <<commandbuffers-lifecycle, Command Buffer Lifecycle>>
    section to clarify the ability for pending command buffers to transition
    to the invalid state after submission, and add a command buffer
    lifecycle diagram (internal issue 1050).
  * Clarify that some flink:VkDescriptorUpdateTemplateCreateInfo parameters
    are ignored when push descriptors are not supported (internal issue
    1054).
  * Specify that flink:vkCreateImage will return an error if the image is
    too large, in a NOTE in the slink:VkImageFormatProperties description
    (internal issue 1078).
  * Remove near-duplicate NOTEs about when to query function pointers
    dynamically in the <<initialization, Initialization>> chapter and
    replace by extending the NOTE in the <<fundamentals-abi, Application
    Binary Interface>> section (internal issue 1085).
  * Restore missing references to "`Sparse Resource Features`" in the
    flink:VkBufferCreateFlagBits description (internal issue 1086).
  * Tidy up definitions of descriptor types in the `GL_KHR_vulkan_glsl`
    specification, the <<descriptorsets, Resource Descriptors>> section and
    its subsections, and the <<interfaces-resources-descset, Descriptor Set
    Interface>> for consistency, reduction of duplicate information, and
    removal of GLSL correspondance/examples (internal issue 1090).
  * Correctly describe code:PrimitiveId as an Input for tessellation control
    and evaluation shaders, not an Output (internal issue 1109).
  * Relax the requirements on chroma offsets for nearest filtering in
    <<textures-implict-reconstruction, Implicit Reconstruction>> (internal
    issue 1116).

Other Issues:

  * Clarify the intended relationship between specification language and
    certain terms defined in the Khronos Intellectual Property Rights
    policy. Specific changes include:
  ** Rewrote IP/Copyright preamble and introduction to better agree with
     normative language both as laid out in the introduction, and the
     Khronos IPR policy.
  ** Added notion of fully informative sections, which are now tagged with
     "`(Informative)`" in their titles.
  ** Removed non-normative uses of the phrase "`not required`"
  ** Clarified the distinction between terms "`optional`" and "`not
     required:`" as they relate to the IPR Policy, and updated specification
     text to use terms consistent with the intent.
  ** Reduced additions to RFC 2119, and ensured the specification agreed
     with the leaner language.
  ** Removed the terms "`hardware`", "`software`", "`CPU`", and "`GPU`" from
     normative text.
  ** Moved several paragraphs that should not have been normative to
     informative notes.
  ** Clarified a number of definitions in the Glossary.
  ** Updated the document writing guide to match new terminology changes.
  * Explicitly state in the <<fundamentals-objectmodel-lifetime-acquire,
    application memory lifetime>> language that that for objects other than
    descriptor sets, a slink:VkDescriptorSetLayout object used in the
    creation of another object (such as slink:VkPipelineLayout or
    slink:VkDescriptorUpdateTemplateKHR) is only in use during the creation
    of that object and can be safely destroyed afterwards.
  * Updated the <<textures-scale-factor, Scale Factor Operation>> section to
    use the ratio of anisotropy, rather than the integer sample rate, to
    perform the LOD calculation. The spec still allows use of the sample
    rate as the value used to calculate the LOD, but no longer requires it.
  * Update `vulkan_ext.c` to include all platform-related definitions from
    the Vulkan platform headers, following the split of the headers into
    platform-specific and non-platform-specific files.
  * Fix bogus anchor name in the <<commandbuffers, Command Buffers>> chapter
    which accidentally duplicated an anchor in the pipelines chapter. There
    were no reference to this anchor, fortunately.
  * Add valid usage statement for slink:VkWriteDescriptorSet and
    slink:VkCopyDescriptorSet requiring that the slink:VkDescriptorSetLayout
    used to allocate the source and destination sets must not have been
    destroyed at the time flink:vkUpdateDescriptorSets is called.
  * Document mapping of subgroup barrier functions to SPIR-V, and clarify a
    place where subgroupBarrier sounds like it's execution-only in the
    standalone `GL_KHR_shader_subgroup` specification.
  * Use an HTML stylesheet derived from the Asciidoctor `colony` theme, with
    the default Arial font family replaced by the sans-serif Noto font
    family.
  * Numerous minor updates to README.adoc, build scripts, Makefiles, and
    registry and style guide specifications to support Vulkan 1.1 outputs,
    use them as defaults, and remove mention of `KHX` extensions, which are
    no longer supported.

New Extensions:

  * `VK_EXT_vertex_attrib_divisor`
2018-03-07 04:18:52 -08:00
..
appendices Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
chapters Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
config Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
images Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
katex Change log for January 23, 2017 Vulkan 1.0.39 spec update: 2017-01-17 20:11:25 -08:00
man Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
scripts Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
style Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
Makefile Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
README.adoc Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
checkLinks.py Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
copyright-ccby.txt Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
copyright-spec.txt Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
fixupRef.py Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
genRef.py Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
genRelease Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
genspec.py Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
installRelease Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
makeAllExts Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
makeExt Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
makeKHR Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
promote.py Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
refDesc.py Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
refPageNotes.md Change log for July 10, 2016 Vulkan 1.0.20 spec update: 2016-07-10 18:13:41 -07:00
reflib.py Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
reflow.py Change log for January 5, 2018 Vulkan 1.0.67 spec update: 2018-01-05 17:39:15 -08:00
reflow_count.py Change log for February 19, 2018 Vulkan 1.0.69 spec update: 2018-02-19 15:19:38 -08:00
registry.txt Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
sandboxCopy Change log for February 10, 2017 Vulkan 1.0.40 spec update: 2017-02-10 20:37:39 -08:00
styleguide.txt Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00
vkspec.txt Change log for March 7, 2018 Vulkan 1.1.70 spec update: 2018-03-07 04:18:52 -08:00

README.adoc

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


[[intro]]
== Introduction

This README describes important stuff for getting the Vulkan API
specification and reference pages building properly.


[[building]]
== Building The Spec

Once you have all the right tools installed (see <<depends,Software
Dependencies>> below), go to `...path-to-git-repo/doc/specs/vulkan` .

    $ make html

builds an HTML5 specification output.

    $ make all

builds the spec targets `html`, `pdf`, `styleguide`, `manhtml`, `manpdf`,
`manhtmlpages`, `checkinc`, and `checklinks`.

[NOTE]
.Notes
====
  * `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.
  * 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/1.0`).
The checked-in file `../../../out/1.0/index.html` links to all these
targets, or they can individually be found as follows:

  * API spec:
  ** `html` - HTML5 in `$(OUTDIR)/html/vkspec.html`
  ** `pdf` - PDF in `$(OUTDIR)/pdf/vkspec.pdf`
  * "`Vulkan Documentation and Extensions`" guide:
  ** `styleguide` - Single-file HTML5 in `$(OUTDIR)/styleguide.html`
  * Diff spec:
  ** `diff_html` - Single-file HTML5 in `$(OUTDIR)/html/diff.html`
  * Reference pages:
  ** `manhtml` - Single-file HTML in `$(OUTDIR)/apispec.html`
  ** `manpdf` - Single-file PDF in `$(OUTDIR)/apispec.html`
  ** `manhtmlpages` - File-per-entry-point HTML in `$(OUTDIR)/man/html/*`
  * Validator output:
  ** `checkinc` - List of commands, structs, etc.
     missing from the API spec in `$(OUTDIR)/checks/notInSpec.txt`
  ** `checklinks` - Validator script output for API spec in
     `$(OUTDIR)/checks/specErrs.txt` and for reference pages in
     `$(OUTDIR)/checks/manErrs.txt`
  * 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.


[[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/doc/specs/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
`$(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.
Asciidoctor http://asciidoctor.org/docs/user-manual/#attributes[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 `$(EXTENSIONS)`, normally set on the make command line.
When changing the list of extensions, it is critical to remove all generated
files using the `clean_generated` Makefile target, as the contents of
generated files depends on `$(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)`.

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.

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.


[[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".


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

If you are just testing asciidoc 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 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

[NOTE]
.Note
====
The validation scripts have not been kept up to date, and probably don't
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
missing material between the specification and ref pages, and the canonical
description of the API in `vk.xml` :

  * `checkinc`
  * `checklinks`
  * `allchecks` - both `checkinc` and `checklinks`

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
about is `actual.only`.
This is a list of the include files which are *not* referenced anywhere in
the spec, and probably correspond to undocumented material in 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.)
against the canonical description of the API in `vk.xml`.
It generates two output files, `manErrs.txt` and `specErrs.txt`, which
report problematic tags and the filenames/lines on which those tags were
found.


[[macros]]
== Our Asciidoc Macros

We use a bunch of custom macros in the reference pages and API spec asciidoc
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/vulkan-macros/extension.rb`
asciidoctor extension script.

The tags used are described in the style guide (`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
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 pages 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

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

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 `doc/specs/vulkan/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 "`Vulkan Documentation and Extensions`" document for more details of
supported LaTeX math constructs.


[[anchors]]
== Asciidoc Anchors And Xrefs

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]]+++'.
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...
----


[[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:

  * GNU make (make version: 4.0.8-1; older versions probably OK)
  * Python 3 (python, version: 3.4.2)
  * Ruby (ruby, version: 2.3.3)
  ** 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 will be a lot
    smaller if it is included.

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: 1.5.6.1)
  * Coderay (coderay, version 1.1.2)
  * JSON Schema (json-schema, version 2.8.0)
  * 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 `doc/specs/vulkan/katex/`, and need not be
    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
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
build PDF versions of the spec and supporting documents.

`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.
This might be solved in future.
For now, there are three 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
installed via apt-get:

----
sudo apt-get -qq -y install build-essential python3 git cmake bison flex \
    libffi-dev libxml2-dev libgdk-pixbuf2.0-dev libcairo2-dev \
    libpango1.0-dev ttf-lyx gtk-doc-tools ghostscript
----

The default ruby packages on Ubuntu are fairly out of date.
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]]
==== 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-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-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

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

# Required only for pdf builds
MATHEMATICAL_SKIP_STRDUP=1 gem install asciidoctor-mathematical
gem install --pre asciidoctor-pdf
----

[[ruby-enum-downgrade]]
==== Ruby Gem Versioning Errors

*ruby-enum*

As of 2017-03-06, there appears to be a problem with the ruby-enum version
0.7.1 gem which breaks the PDF build. Make sure you are using ruby-enum
0.7.0, as follows:

    gem uninstall ruby-enum
    gem install -v 0.7.0 ruby-enum

Hopefully this will soon be fixed. See
https://github.com/gjtorikian/mathematical/issues/69 for a report of this
problem.


*prawn*

As of 2017-03-20, there are incompatibilities between asciidoctor-pdf and
certain versions of prawn and prawn-templates affecting the PDF build. Make
sure to update to prawn 2.2.1 and prawn-templates 0.0.5. See

https://github.com/KhronosGroup/Vulkan-Docs/issues/476


[[history]]
== Revision History

  * 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.