moltenvk/README.md
Bill Hollings fbf2af58a0 Fixes and consolidation of external library header references.
All external library header references consistently include framework references.
Cleanup references to external library headers that are no longer required.
Simplify and consolidate external library header paths in Xcode projects.
Add MVK_EXCLUDE_SPIRV_TOOLS build option to avoid use of SPIRV-Tools library.
Remove all other references to headers within SPIRV-Tools library.
2019-05-28 17:19:43 -04:00

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16 KiB
Markdown

<a class="site-logo" href="https://github.com/KhronosGroup/MoltenVK" title="MoltenVK">
<img src="Docs/images/MoltenVK-Logo-Banner.png" alt="MoltenVK" style="width:256px;height:auto">
</a>
MoltenVK
========
Copyright (c) 2014-2019 [The Brenwill Workshop Ltd.](http://www.brenwill.com)
*This document is written in [Markdown](http://en.wikipedia.org/wiki/Markdown) format.
For best results, use a Markdown reader.*
[![Build Status](https://travis-ci.org/KhronosGroup/MoltenVK.svg?branch=master)](https://travis-ci.org/KhronosGroup/MoltenVK)
Table of Contents
-----------------
- [Developing Vulkan Applications on macOS and iOS](#developing_vulkan)
- [Introduction to **MoltenVK**](#intro)
- [Fetching **MoltenVK** Source Code](#install)
- [Building **MoltenVK**](#building)
- [Running the **MoltenVK** Demo Applications](#demos)
- [Using **MoltenVK** in Your Application](#using)
- [**MoltenVK** and *Vulkan* Compliance](#compliance)
- [Reporting Issues](#issues)
- [Contributing to **MoltenVK** Development](#contributing)
<a name="developing_vulkan"></a>
Developing Vulkan Applications for macOS and iOS
------------------------------------------------
The recommended method for developing a *Vulkan* application for *macOS* is to use the
[*Vulkan SDK*](https://vulkan.lunarg.com/sdk/home).
The *Vulkan SDK* includes a **MoltenVK** runtime library for *macOS*. *Vulkan* is a layered
architecture that allows applications to add additional functionality without modifying the
application itself. The *Validation Layers* included in the *Vulkan SDK* are an essential debugging
tool for application developers because they identify inappropriate use of the *Vulkan API*.
If you are developing a *Vulkan* application for *macOS*, it is highly recommended that you use the
[*Vulkan SDK*](https://vulkan.lunarg.com/sdk/home) and the **MoltenVK** library included in it.
If you are developing a *Vulkan* application for *iOS*, or are developing a *Vulkan* application for
*macOS* and want to use a different **MoltenVK** runtime library than provided in the *macOS Vulkan SDK*,
you can use this document to learn how to build a **MoltenVK** runtime library from source code.
To learn how to integrate the **MoltenVK** runtime library into a game or application,
see the [`MoltenVK_Runtime_UserGuide.md `](Docs/MoltenVK_Runtime_UserGuide.md)
document in the `Docs` directory.
<a name="intro"></a>
Introduction to MoltenVK
------------------------
**MoltenVK** is a driver-level implementation of the [*Vulkan 1.0*](https://www.khronos.org/vulkan)
graphics and compute API, that runs on Apple's [*Metal*](https://developer.apple.com/metal)
graphics and compute framework on both *iOS* and *macOS*.
**MoltenVK** allows you to use the *Vulkan* graphics and compute API to develop modern,
cross-platform, high-performance graphical games and applications, and to run them across
many platforms, including both *iOS* and *macOS*.
*Metal* uses a different shading language, the *Metal Shading Language (MSL)*, than
*Vulkan*, which uses *SPIR-V*. **MoltenVK** automatically converts your *SPIR-V* shaders
to their *MSL* equivalents.
To provide *Vulkan* capability to the *iOS* and *macOS* platforms, **MoltenVK** uses *Apple's*
publicly available API's, including *Metal*. **MoltenVK** does **_not_** use any private or
undocumented API calls or features, so your app will be compatible with all standard distribution
channels, including *Apple's App Store*.
The **MoltenVK** runtime package contains two products:
- **MoltenVK** is a driver-level implementation of the [*Vulkan 1.0*](https://www.khronos.org/vulkan)
graphics and compute API.
- **MoltenVKShaderConverter** converts *SPIR-V* shader code to *Metal Shading Language (MSL)*
shader code, and converts *GLSL* shader source code to *SPIR-V* shader code and/or
*Metal Shading Language (MSL)* shader code. The *SPIR-V* converter is included in the
**MoltenVK** runtime to automatically convert *SPIR-V* shaders to their *MSL* equivalents.
In addition, both the *SPIR-V* and *GLSL* converters can be be packaged into a stand-alone
command-line *macOS* tool for converting shaders at development time.
<a name="install"></a>
Fetching **MoltenVK** Source Code
---------------------------------
To fetch **MoltenVK** source code, clone this `MoltenVK` repository, and then run the
`fetchDependencies` script to retrieve and build several external open-source libraries
on which **MoltenVK** relies:
1. Ensure you have `cmake` and `python3` installed:
brew install cmake
brew install python
For faster dependency builds, you can also optionally install `ninja`:
brew install ninja
2. Clone the `MoltenVK` repository:
git clone https://github.com/KhronosGroup/MoltenVK.git
3. Retrieve and build the external libraries:
cd MoltenVK
./fetchDependencies
For more information about the external open-source libraries used by **MoltenVK**,
see the [`ExternalRevisions/README.md`](ExternalRevisions/README.md) document.
<a name="building"></a>
Building **MoltenVK**
-------------------
During building, **MoltenVK** references the latest *Apple SDK* frameworks. To access these frameworks,
and to avoid build errors, be sure to use the latest publicly available version of *Xcode*.
>***Note:*** To support `IOSurfaces` on *iOS*, **MoltenVK**, and any app that uses **MoltenVK**,
must be built with a minimum **iOS Deployment Target** (aka `IPHONEOS_DEPLOYMENT_TARGET `) build
setting of `iOS 11.0` or greater.
Once built, the **MoltenVK** libraries can be run on *iOS* or *macOS* devices that support *Metal*.
- At runtime, **MoltenVK** requires at least *macOS 10.11* or *iOS 9* (or *iOS 11* if using `IOSurfaces`).
- Information on *macOS* devices that are compatible with *Metal* can be found in
[this article](http://www.idownloadblog.com/2015/06/22/how-to-find-mac-el-capitan-metal-compatible).
- Information on *iOS* devices that are compatible with *Metal* can be found in
[this article](https://developer.apple.com/library/content/documentation/DeviceInformation/Reference/iOSDeviceCompatibility/HardwareGPUInformation/HardwareGPUInformation.html).
The `MoltenVKPackaging.xcodeproj` *Xcode* project contains targets and schemes to build
and package the entire **MoltenVK** runtime distribution package, or to build individual
**MoltenVK** or **MoltenVKShaderConverter** components.
To build a **MoltenVK** runtime distribution package, suitable for testing and integrating into an app,
open `MoltenVKPackaging.xcodeproj` in *Xcode*, and use one of the following *Xcode Schemes*, depending
on whether you want a **_Release_** or **_Debug_** configuration, and whether you want to build for both
the *iOS* and *macOS* platforms, or just one platform (in **_Release_** configuration):
- **MoltenVK Package**
- **MoltenVK Package (Debug)**
- **MoltenVK Package (iOS only)**
- **MoltenVK Package (macOS only)**
Each of these`MoltenVKPackaging.xcodeproj` *Xcode* project *Schemes* puts the resulting packages in the
`Package` directory, creating it if necessary. This directory contains separate `Release` and `Debug`
directories, holding the most recent **_Release_** and **_Debug_** builds, respectively.
A separate `Latest` directory links to the most recent build, regardless of whether it was a **_Release_**
or **_Debug_** build. Effectively, the `Package/Latest` directory points to whichever of the `Package/Release`
or `Package/Debug` directories was most recently updated.
With this packaging structure, you can follow the [instructions below](#using) to link your application
to the **MoltenVK** libraries and frameworks in the `Package/Latest` directory, to provide the flexibility
to test your app with either a **_Debug_** build, or a higher-performance **_Release_** build.
### Building from the Command Line
If you prefer to build **MoltenVK** from the command line, or to include the activity in a larger build script,
you can do so using the following command within the `MoltenVK` repository folder, and identifying one of the
*Xcode Schemes* from the list above. For example, the following command will build **MoltenVK** in the
**_Release_** configuration for both *macOS* and *iOS*:
xcodebuild -quiet -project MoltenVKPackaging.xcodeproj -scheme "MoltenVK Package" build
Alternately, you can use the basic `Makefile` in the `MoltenVK` repository folder to build **MoltenVK**
in the **_Release_** configuration from the command line. The following `make` targets are provided:
make
make all
make macos
make ios
make clean
make install
The `install` target will copy the most recently built *macOS* `MoltenVK.framework` into
the `/Library/Frameworks` folder of your computer. Since `/Library/Frameworks` is protected,
you will generally need to run it as `sudo make install` and enter your password.
The default `make` command with no arguments is the same as `make all`.
The `make` targets all require that *Xcode* is installed on your system.
Building from the command line creates the same `Package` folder structure described above when building
from within *Xcode*.
### Building Within a Larger External Build Environment
If you build **MoltenVK** as part of a larger build environment, that does not use the scripts or *Xcode*
projects provided by **MoltenVK**, you may be interested in certain build options designed to allow you to
customize the use of **MoltenVK** within your custom build environment. These options are not available
in the default **MoltenVK** build environment described in the previous sections.
- `MoltenVKShaderConverter` uses the `SPIRV-Tools` external library to log SPIR-V code for diagnostics.
If this is not useful to you, you can define the `MVK_EXCLUDE_SPIRV_TOOLS` when building the
`MoltenVKShaderConverter` code base, and **MoltenVK** will not attempt to use code from the `SPIRV-Tools`
repository. In this way, you will not need to retrieve or build the `SPIRV-Tools` repository, or link to
a `SPIRV-Tools` external library.
<a name="demos"></a>
Running the **MoltenVK** Demo Applications
------------------------------------------
Once you have compiled and built the **MoltenVK** runtime distribution package from this **MoltenVK** repository,
as described in the [Building **MoltenVK**](#building) section, you can explore how **MoltenVK** provides *Vulkan*
support on *iOS* and *macOS* by investigating and running the demo applications that are included in **MoltenVK**.
The **MoltenVK** demo apps are located in the `Demos` folder. Each demo app is available as an *Xcode* project.
To review and run the included demo apps, open the `Demos/Demos.xcworkspace` workspace in *Xcode*.
Please read the [`Demos/README.md`](Demos/README.md) document for a description of each demo app, and instructions
on running the demo apps. Several of the demo apps allow you to explore a variety of *Vulkan* features by modifying
*Xcode* build settings. Additional demos can be downloaded and built from external repositories, as described in the
[`Demos/README.md`](Demos/README.md) document
<a name="using"></a>
Using **MoltenVK** in Your Application
--------------------------------------
Once you have compiled and built the **MoltenVK** runtime distribution package from this **MoltenVK** repository,
as described in the [Building **MoltenVK**](#building) section, follow the instructions in the Installation
section of the [`Docs/MoltenVK_Runtime_UserGuide.md`](Docs/MoltenVK_Runtime_UserGuide.md#install) document
in the `Docs` directory, to link the **MoltenVK** libraries and frameworks to your application.
The runtime distribution package in the `Package/Latest` directory is a stand-alone package, and you can copy
the contents of that directory out of this **MoltenVK** repository into your own application building environment.
<a name="compliance"></a>
**MoltenVK** and *Vulkan* Compliance
------------------------------------
**MoltenVK** is designed to be a *Vulkan 1.0* driver that runs on *macOS* and *iOS* platforms by mapping *Vulkan*
capability to native *Metal* capability.
The fundamental design and development goal of **MoltenVK** is to provide this capability in a way that
is both maximally compliant with the *Vulkan 1.0* specification, and maximally performant.
Such compliance and performance is inherently affected by the capability available through *Metal*, as the
native driver on *macOS* and *iOS* platforms. *Vulkan* compliance may fall into one of the following categories:
- Direct mapping between *Vulkan* capabilities and *Metal* capabilities. Within **MoltenVK**, almost all capability
is the result of this type of direct mapping.
- Synthesized compliance through alternate implementation. A very small amount of capability is provided using
this mechanism, such as via an extra render or compute shader stage.
- Non-compliance. This appears where the capabilities of *Vulkan* and *Metal* are sufficiently different, that
there is no practical, or reasonably performant, mechanism to implement a *Vulkan* capability in *Metal*.
Because of design differences between *Vulkan* and *Metal*, a very small amount of capability falls into this
category, and at present **MoltenVK** is **_not_** fully compliant with the *Vulkan* specification. A list of
known limitations is documented in the [`MoltenVK_Runtime_UserGuide.md`](Docs/MoltenVK_Runtime_UserGuide.md#limitations)
document in the `Docs` directory.
The **MoltenVK** development team welcomes you to [post Issues](https://github.com/KhronosGroup/MoltenVK/issues)
of non-compliance, and engage in discussions about how compliance can be improved, and non-compliant features can
be implemented or worked around.
**MoltenVK** is a key component of the [*Khronos Vulkan Portability Initiative*](https://www.khronos.org/vulkan/portability-initiative),
whose intention is to provide specifications, resources, and tools to allow developers to understand and design
their *Vulkan* apps for maximum cross-platform compatibility and portability, including on platforms, such as
*macOS* and *iOS*, where a native *Vulkan* driver is not available.
<a name="issues"></a>
Reporting Issues
----------------
- If you encounter an issue with the behaviour of **MoltenVK**, you can report it in the
[*MoltenVK Issues List*](https://github.com/KhronosGroup/MoltenVK/issues).
- If you encounter an issue with the *Vulkan SDK*, including the *Validation Layers*, you can report it in the
[*Vulkan SDK Issues List*](https://vulkan.lunarg.com/issue/home).
<a name="contributing"></a>
Contributing to **MoltenVK** Development
----------------------------------------
As a public open-source project, **MoltenVK** benefits from code contributions from a wide range of developers,
and we encourage you to get involved and contribute code to this **MoltenVK** repository.
To contribute your code, submit a [Pull Request](https://github.com/KhronosGroup/MoltenVK/pulls)
to this repository. The first time you do this, you will be asked to agree to the **MoltenVK**
[Contributor License Agreement](https://cla-assistant.io/KhronosGroup/MoltenVK).
### Licensing
**MoltenVK** is licensed under the Apache 2.0 license. All new source code files should include a
copyright header at the top, containing your authorship copyright and the Apache 2.0 licensing stub.
You may copy the text from an existing source code file as a template.
The Apache 2.0 license guarantees that code in the **MoltenVK** repository is free of Intellectual Property
encumbrances. In submitting code to this repository, you are agreeing that the code is free of any Intellectual
Property claims.
### Code Formatting
When contributing code, please honour the code formatting style found in existing **MoltenVK** source code.
In future, this will formally be enforced using `clang-format`.