KTX uses the the CMake build system. Depending on your platform and how you configure it, it will create project/build files (e.g. an Xcode project, a Visual Studio solution or Make files) that allow you to build the software and more (See CMake generators).
KTX consist of the following parts
- The
libktx
main library - Command line tools (for Linux / macOS / Windows)
- Load test applications (for OpenGL® 3, OpenGLES® or Vulkan®)
- Documentation
Supported platforms (please see their specific requirements first)
The minimal way to a build is to clone this repository and run the following in a terminal
# Navigate to the root of your KTX-Software clone (replace with
# your actual path)
cd /path/to/KTX-Software
# This generates build/project files in the sub-folder `build`
cmake . -B build
# Compile the project
cmake --build build
This creates the libktx
library and the command line tools. To create the complete project generate the project like this:
cmake . -B build -D KTX_FEATURE_LOADTEST_APPS=ON -D KTX_FEATURE_DOC=ON
If you need the library to be static, add -D BUILD_SHARED_LIBS=OFF
to the CMake configure command (always disabled on iOS and Emscripten).
Note:
When linking to the static library, make sure to define
KHRONOS_STATIC
before including KTX header files. This is especially important on Windows.
If you want to run the CTS tests (recommended only during KTX development)
add -D KTX_FEATURE_TOOLS_CTS=ON
to the CMake configure command and fetch
the CTS submodule. For more information see Conformance Test Suite.
If you want the Basis Universal encoders in libktx
to use OpenCL
add -D BASISU_SUPPORT_OPENCL=ON
to the CMake configure command.
Note:
There is very little advantage to using OpenCL in the context of
libktx
. It is disabled in the default build configuration.
Note:
When building from a source
tar.gz
and not from the git repository directly, it is recommended to set the variableKTX_GIT_VERSION_FULL
to the associated git tag (e.gv4.3.2
)cmake . -G Ninja -B build -DKTX_GIT_VERSION_FULL=v4.3.2
Use with caution.
You need to install the following
- CMake
- gcc and g++ from the GNU Compiler Collection
- GNU Make or Ninja (recommended)
- Doxygen and dot (only if generating documentation)
To build libktx
such that the Basis Universal encoders will use
OpenCL you need
- OpenCL headers
- OpenCL driver
On Ubuntu and Debian these can be installed via
sudo apt install build-essential cmake libzstd-dev ninja-build doxygen graphviz opencl-c-headers mesa-opencl-icd
mesa-opencl-icd
should be replaced by the appropriate package for your GPU.
On Fedora and RedHat these can be installed via
sudo dnf install make automake gcc gcc-c++ kernel-devel cmake libzstd-devel ninja-build doxygen graphviz mesa-libOpenCL
To build the load test applications you also need to install the following
- SDL2 development library
- assimp development library
- OpenGL development libraries
- Vulkan development libraries
- Vulkan SDK
- zlib development library
On Ubuntu and Debian these can be installed via
sudo apt install libsdl2-dev libgl1-mesa-glx libgl1-mesa-dev libvulkan1 libvulkan-dev libassimp-dev
On Fedora and RedHat these can be installed via
sudo dnf install SDL2-devel mesa-libGL mesa-libGL-devel mesa-vulkan-drivers assimp-devel
KTX requires glslc
, which comes with Vulkan SDK (in sub-
folder x86_64/bin/glslc
). Make sure the complete path to the tool is in
in your environment's PATH
variable. If you've followed Vulkan SDK
install instructions for your platform this should already be set up. You
can test it by running
# Should output version number.
glslc --version
# If it fails, try this then repeat the above.
export PATH=$PATH:/path/to/vulkansdk/x86_64/bin
You should be able then to build like this
# First either configure a debug build of libktx and the tools
cmake . -G Ninja -B build
# ...or alternatively a release build including all targets
cmake . -G Ninja -B build -DCMAKE_BUILD_TYPE=Release -D KTX_FEATURE_LOADTEST_APPS=ON -D KTX_FEATURE_DOC=ON
# Compile the project
cmake --build build
You need to install the following
- CMake
- Xcode or, if using a different build system, the Xcode command line tools.
- Doxygen and dot (only if generating documentation)
To build the load test applications you also need to install
- vcpkg (which will automatically install the actual dependencies: SDL2 and assimp)
- Vulkan SDK
Other dependencies (like OpenGL) come with Xcode.
For the load test applications you must also set these environment variables:
VCPKG_ROOT
to the location where you installed vcpkg.VULKAN_SDK
to themacOS
folder in your VulkanSDK installation. This can be set with the command. /path/to/your/vulkansdk/setenv.sh
.
Note: If using the CMake GUI or Xcode IDE you must ensure
VULKAN_SDK
is made available to them.
Note:
VULKAN_SDK
is essential when bulding for iOS. When building for macOS it is not necessary if you selected System Global Installation when installing the SDK.
Note: the
iphoneos
orMacOSX
SDK version gets hardwired into the generated projects. After installing an Xcode update that has the SDK for a new version of iOS, builds will fail. The only way to remedy this is to delete the CMake cache and reconfigure and regenerate from scratch. Use of aCMakeUserPresets.json
file to capture unchanging settings is recommended.
To build for macOS:
# This creates an Xcode project at `build/mac/KTX-Software.xcodeproj`
# containing the libktx and tools targets.
mkdir build
cmake -G Xcode -B build/mac
# If you want to build the load test apps as well, set the
# `KTX_FEATURE_LOADTEST_APPS` and `CMAKE_TOOLCHAIN_FILE`
# parameters. vcpkg will automatically install the dependencies.
cmake -GXcode -Bbuild/mac -D KTX_FEATURE_LOADTEST_APPS=ON -D CMAKE_TOOLCHAIN_FILE=$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake
# Compile the project
cmake --build build/mac
Macs are either based on Intel or the newer Apple Silicon architecture. By default CMake configures to build for your host's platform, whichever it is. If you want to cross compile universal binaries (that support both platforms), add the parameter -DCMAKE_OSX_ARCHITECTURES="\$(ARCHS_STANDARD)"
to cmake.
Known limitations:
- Intel Macs have support for SSE, but if you're building universal binaries, you have to disable SSE or the build will fail
Example how to build universal binaries
# Configure universal binaries and disable SSE
cmake -G Xcode -B build-macos-universal -D CMAKE_OSX_ARCHITECTURES="\$(ARCHS_STANDARD)" -D BASISU_SUPPORT_SSE=OFF
# Build
cmake --build build-macos-universal
# Easy way to check if the resulting binaries are universal
file build-macos-universal/Debug/libktx.dylib
# outputs:
# build-macos-universal/Debug/libktx.dylib: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit dynamically linked shared library x86_64] [arm64]
# build-macos-universal/Debug/libktx.dylib (for architecture x86_64): Mach-O 64-bit dynamically linked shared library x86_64
# build-macos-universal/Debug/libktx.dylib (for architecture arm64): Mach-O 64-bit dynamically linked shared library arm64
file build-macos-universal/Debug/ktx
# outputs:
# build-macos-universal/Debug/ktx: Mach-O universal binary with 2 architectures: [x86_64:Mach-O 64-bit executable x86_64] [arm64:Mach-O 64-bit executable arm64]
# build-macos-universal/Debug/ktx (for architecture x86_64): Mach-O 64-bit executable x86_64
# build-macos-universal/Debug/ktx (for architecture arm64): Mach-O 64-bit executable arm64
To explicity build for one or the other architecture use
-D CMAKE_OSX_ARCHITECTURES=arm64
or -D CMAKE_OSX_ARCHITECTURES=x86_64
To sign the applications you need to set the following CMake variables:
Name | Value |
---|---|
XCODE_CODE_SIGN_IDENTITY | Owner* of the Developer ID Application certificate to use for signing. |
XCODE_DEVELOPMENT_TEAM | Development team of the certificate owner. |
To sign the installation package you need to set the following variables:
Name | Value |
---|---|
PRODUCTBUILD_IDENTITY_NAME | Owner* of the Developer ID Installer certificate to use for signing. |
PRODUCTBUILD_KEYCHAIN_PATH | Path to the keychain file with the certificate. Blank if its in the default keychain. |
To build for iOS:
# This creates an Xcode project at `build/ios/KTX-Software.xcodeproj`
# containing the libktx targets.
mkdir build # if it does not exist
cmake -G Xcode -B build/ios -D CMAKE_SYSTEM_NAME=iOS
# This creates a project to build the load test apps as well.
cmake -G Xcode -B build/ios -D KTX_FEATURE_LOADTEST_APPS=ON -D CMAKE_TOOLCHAIN_FILE=$VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake
# Compile the project
cmake --build build -- -sdk iphoneos
If using the CMake GUI, when it asks you to specify the generator for the project, you need to check Specify options for cross-compiling and on the next screen make sure Operating System is set to iOS
.
To sign the applications you need to set the following CMake variables:
Name | Value |
---|---|
XCODE_CODE_SIGN_IDENTITY | Owner* of the Apple Development certificate to use for signing. |
XCODE_DEVELOPMENT_TEAM | Development team used to create the Provisioning Profile. This may not be the same as the team of the Apple Development certificate owner. |
XCODE_PROVISIONING_PROFILE | Name of the profile to use. |
* Owner is what is formally known as the Subject Name of a certificate. It is the string displayed by the Keychain Access app in the list of installed certificates and shown as the value of the Common Name field of the Subject Name section of the details shown after double-clicking the certificate.
There are two ways to build the Web version of the software: using Docker or using your own Emscripten installation.
Install Docker Desktop which is available for GNU/Linux, macOS and Windows.
In the repo root run
scripts/build_wasm_docker.sh
This will build both Debug and Release configurations and will include the load test application. Builds are done with the official Emscripten Docker image. Output will be written to the folders build/web-{debug,release}
.
If you are using Windows you will need a Unix-like shell such as the one with Git for Windows or one in Windows Subsystem for Linux (WSL) to run this script.
Install Emscripten and follow the install instructions closely. After you've set up your emscripten environment in a terminal, run the following:
Debug:
# Configure
emcmake cmake -B build-web-debug . -D CMAKE_BUILD_TYPE=Debug
# Build
cmake --build build-web-debug --config Debug
Release:
# Configure
emcmake cmake -B build-web .
# Build
cmake --build build-web
To include the load test application into the build add -DKTX_FEATURE_LOADTEST_APPS=ON
to either of the above configuration steps.
Web builds create three additional targets:
ktx_js
(libktx javascript wrapper - with write support)ktx_js_read
(libktx_read javascript wrapper - read-only)msc_basis_transcoder_js
(transcoder wrapper)
Note: The libktx wrappers do not use the transcoder wrapper. They directly uses the underlying c++ transcoder.
You need to install the following
To build the load test applications you also need to install
- vcpkg (which will automatically install the actual dependencies: SDL2 and assimp)
- Vulkan SDK
For the load test applications you must also set these environment variables:
VCPKG_ROOT
to the location where you installed vcpkg.VULKAN_SDK
to the location where you installed VulkanSDK. Normally this is set during installation of the SDK.
Additional requirement for the OpenGL ES version of the load tests application
CMake can create solutions for Microsoft Visual Studio (2019 and 2022 are supported by KTX).
Note: x86 (32-bit) Windows is not supported.
To build for Windows
# This creates a solution at `build/KTX-Software.sln`
# containing the libktx and tools targets.
cmake -B build .
# If you want to build the load test apps as well, set the
# `KTX_FEATURE_LOADTEST_APPS` and `CMAKE_TOOLCHAIN_FILE`
# parameters. vcpkg will automatically install the dependencies.
cmake -B build . -D KTX_FEATURE_LOADTEST_APPS=ON -D CMAKE_TOOLCHAIN_FILE=$env:VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake
# Compile the project
cmake --build build
To configure for Universal Windows Platform (Windows Store) you have to
- Set the platform to
x64
,ARM
orARM64
(depending on your target device/platform) - Set the system name to
WindowsStore
- Provide a system version (e.g.
10.0
)
Note: Support is currently limited to
ktx
andlibktx_read
(no tools, tests or load tests apps)
Example UWP configuration
cmake . -A ARM64 -B build_uwp_arm64 -D CMAKE_SYSTEM_NAME:String=WindowsStore -D CMAKE_SYSTEM_VERSION:String="10.0"
# Build `ktx.dll` only
cmake -B build_uwp_arm64 --target ktx
A bash
shell is needed by the mkversion
script used during the build. If you installed your git
via the
Git for Windows package you are good to go.
Alternatives are
Windows Subsystem for Linux plus a Linux distribution or Cygwin. A contribution of a PowerShell equivalent script will be welcomed.
The NSIS compiler is needed if you intend to build packages.
CMake can include OpenGL ES versions of the KTX loader tests in the generated solution. To build and run these you need to install an OpenGL ES emulator. See below.
To sign applications and the NSIS installer you need to import your certificate to an Azure Key Vault or to the Current User or Local Machine certificate store.
The latter can be done interactively with Windows' commands certmgr
and
certlm
respectively. You need to set the following CMake variables to
turn on signing:
Name | Value |
---|---|
CODE_SIGN_KEY_VAULT | Where the signing certificate is stored. One of Azure, Machine, User. |
CODE_SIGN_TIMESTAMP_URL | URL of the timestamp server to use. Usually provided by the issuer of your certificate. Timestamping is required as it keeps the signatures valid even after certificate expiration. |
The following additional variables must be set if using Azure:
Name | Value |
---|---|
AZURE_KEY_VAULT_CERTIFICATE | Name of the certificate in Azure Key Vault. |
AZURE_KEY_VAULT_CLIENT_ID | Id of an application (Client) registered with Azure that has permission to access the certificate. |
AZURE_KEY_VAULT_CLIENT_SECRET | Secret to authenticate access to the Client. |
AZURE_KEY_VAULT_TENANT_ID | Id of the Azure Active Directory (Tenant) holding the Client. |
AZURE_KEY_VAULT_URL | URL of the key vault |
If using a local certificate store the following variables must be set instead:
Name | Value |
---|---|
LOCAL_KEY_VAULT_SIGNING_IDENTITY | Subject Name of code signing certificate. Displayed in 'Issued To' field of cert{lm,mgr}. Overriden by LOCAL_KEY_VAULT_CERTIFICATE_THUMBPRINT. |
LOCAL_KEY_VAULT_CERTIFICATE_THUMBPRINT | Thumbprint of the certificate to use. Use this instead of LOCAL_KEY_VAULT_SIGNING_IDENTITY when you have multiple certificates with the same identity. |
The es1loadtests
and es3loadtests
targets on Windows require an
OpenGL ES emulator.
Imagination Technologies PowerVR.
emulator is recommended. Any of the other major emulators listed below could also be used:
If you want to run the es1loadtests
you will need to use
Imagination Technologies' PowerVR emulator as that alone supports OpenGL ES
1.1. You must set the CMake configuration variable OPENGL_ES_EMULATOR
to the directory containing the .lib files of your chosen emulator and ensure the .dlls are in your $env:PATH
or co-located with es1loadtests
.
*You will need to build ANGLE yourself.
To build libktx
such that the Basis Universal encoders will use
OpenCL you need an OpenCL driver, which is typically included in the driver for your GPU, and an OpenCL SDK. If no SDK is present, the build will use the headers and library that are included in this repo.
Support is currently limited to libktx and libktx_read (no tools, tests or loadtest apps)
Requirements:
The path to the NDK, a CMake toolchain file (that comes with the NDK), the desired Android ABI and minimum API level have to be provided when configuring with CMake (see Android NDK CMake guide for more details/settings). Example:
export ANDROID_NDK=/path/to/Android_NDK #This is the location of Android NDK
# Configure
cmake . -B "build-android" \
-DANDROID_PLATFORM=android-24 \ # API level 24 equals Android 7.0
-DANDROID_ABI="arm64-v8a" \ # target platform
-DANDROID_NDK="$ANDROID_NDK" \
-DCMAKE_TOOLCHAIN_FILE="$ANDROID_NDK/build/cmake/android.toolchain.cmake" \ # Toolchain file in a subfolder of the NDK
-DBASISU_SUPPORT_SSE=OFF # Disable SSE
# Build
cmake --build "build-android"
Note: SSE has to be disabled currently (for ABIs x86 and x86_64) due to an issue.
The submodule of CTS Repository is optional and
only required for running the CTS tests during KTX development. If the CTS test suit is desired it
can be fetched during cloning with the additional --recurse-submodules
git clone flag:
git clone --recurse-submodules git@github.com:KhronosGroup/KTX-Software.git
If the repository was already cloned or whenever the submodule ref changes the submodule has to be updated with:
git submodule update --init --recursive tests/cts
(For more information on submodules see the git documentation.)
Once the submodule is fetched the CTS tests can be enabled with the KTX_FEATURE_TOOLS_CTS
cmake option during cmake configuration. Please note that for KTX_FEATURE_TOOLS_CTS
to take
effect both KTX_FEATURE_TESTS
and KTX_FEATURE_TOOLS
has to be also enabled.
The CTS integrates into ctest
so running ctest
will also execute the CTS tests too.
The test cases can be limited to the CTS tests with ctest -R ktxToolsTest
.
Example for development workflow with CTS testing:
# Git clone and submodule fetch
git clone git@github.com:KhronosGroup/KTX-Software.git
cd KTX-Software/
git submodule update --init --recursive tests/cts
# Configure
mkdir build
cmake -B build . -DKTX_FEATURE_DOC=ON -DBUILD_SHARED_LIBS=OFF -DKTX_FEATURE_TOOLS_CTS=ON -DKTX_FEATURE_TESTS=ON -DKTX_FEATURE_TOOLS_CTS=ON
# Build everything (depending on workflow its better to build the specific target like 'ktxtools'):
cmake --build build --target all
# Run every test case:
ctest --test-dir build
# Run only the CTS test cases:
ctest --test-dir build -R ktxToolsTest
To create and update CTS test cases and about their specific features and usages see the CTS documentation.
All but a few project developers can ignore this section. The files discussed here only need to be re-generated when formats are added to Vulkan or errors are discovered. These will be rare occurrences.
The following files related to the the VkFormat enum are generated from vulkan_core.h
:
- lib/vkformat_check.c
- lib/vkformat_enum.h
- lib/vkformat_list.inl
- lib/vkformat_str.c
- lib/vkformat_typesize.c
- lib/dfd/dfd2vk.inl
- lib/dfd/vk2dfd.inl
- interface/java_binding/src/main/java/org/khronos/ktxVkFormat.java
- interface/python_binding/pyktx/vk_format.py
- interface/js_binding/vk_format.inl
The following files are generated from the mapping database in the KTX-Specification repo by generate_format_switches.rb
:
- lib/vkFormat2glFormat.inl
- lib/vkFormat2glInternalFormat.inl
- lib/vkFormat2glType.inl
All are generated by the mkvk
target which is only configured if KTX_GENERATE_VK_FILES
is set to ON
at the time of CMake configuration. Since this setting is labelled Advanced it will not be visible in the CMake GUI unless Advanced
is set.
Configuring this target adds some dependencies which are discussed below.
Needed if you are regenerating source files.
Standard on GNU/Linux and macOS. Available on Windows as part of Git for
Windows, WSL (Windows Subsystem for Linux) or Cygwin. Note that no CMake
AWK_EXECUTABLE
cache variable is used because awk is standard on GNU/Linux
and macOS and on Windows awk tends to be available when bash is and there
the awk script is invoked via bash.
Needed for the script that creates the version numbers from git describe
output. Also needed if you are regenerating source files.
Standard on GNU/Linux and macOS. Available on Windows as part of Git for Windows, WSL (Windows Subsystem for Linux) or Cygwin.
This package manager is needed to install the SDL2 and assimp dependencies of the KTX load test applications on macOS and Windows. Since KTX-Software uses vcpkg's manifest mode, installation of the dependencies is automatic.
Clone the vcpkg repo and run its bootstrap:
cd /place/to/clone/vcpkg
git clone https://github.com/microsoft/vcpkg
cd vcpkg
./bootstrap-vcpkg.sh -disableMetrics
# On Windows use ./bootstrap-vcpkg.bat
For more information see the
vcpkg with CMake
Getting Started guide. Ignore all but the installation instructions. Set the
environment variable VCPKG_ROOT
to where you have installed vcpkg and set
CMAKE_TOOLCHAIN_FILE
to $VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake
when
using CMake to configure your project.
Simple Direct Media Layer. Needed if you want to build the KTX load tests.
On GNU/Linux install libsdl2-dev
using your package manager. On iOS, macOS
and Windows it will be automatically installed by vcpkg. Libraries installed by other package managers are typically not redistributable or
bundle-able.
Canonical source is at https://github.com/libsdl-org/SDL/tree/SDL2.
Open Asset Import Library. Needed if you want to build the KTX load tests.
On GNU/Linux install libassimp-dev
using your package manager. On
iOS. macOS and Windows it will be automatically installed by vcpkg.
Canonical source is at https://github.com/assimp/assimp.
Needed if you want to build the KTX Vulkan load tests, vkloadtests
. The minimum required version is 1.3.283.0.
Download the Vulkan SDK from Lunar G.
For Ubuntu (20.04 and 22.04) install packages are available. See Getting Started - Ubuntu for detailed instructions.
For other GNU/Linux distributions a .tar.gz
file is available. See
Getting Started - Tarball for detailed instructions.
For Windows install the Vulkan SDK via the installer.
For iOS and macOS, install the Vulkan SDK by downloading the macOS installer and double-clicking install in the mounted .dmg
. This SDK contains MoltenVK (Vulkan Portability on Metal) for both iOS and macOS.
Needed if you want to generate libktx, ktxtools and other documentation.
You need a minimum of version 1.8.14 to generate the documentation correctly.
You can download binaries and also find instructions for building it from source
at Doxygen downloads. Make
sure the directory containing the doxygen
executable is in your $PATH
.
Needed if you want Doxygen to generate include dependency, inverse include dependency, inheritance and other graphs in the generated documentation.
You can download binaries from Graphviz downloads.
Optional. If not present documentation will be generated minus graphs.
Needed if you want to enable the Basis Universal encoders to use OpenCL when building libktx.
On GNU/Linux and Windows you need to install an OpenCL SDK and OpenCL driver. Drivers are standard on macOS & iOS and Xcode includes the SDK. On GNU/Linux the SDK can be installed using your package manager. On Windows, the place from which to download the SDK depends on your GPU vendor. In both cases, the GPU driver typically includes an OpenCL driver.
If you are building pyktx, review the requirements in the pyktx README.
Needed if you are regenerating source files.
On GNU/Linux install perl
using your package manager. On macOS Perl is still
included as of macOS Sonoma. In future you may need to install an additional
package. On Windows, you need a Perl that writes Windows line endings (CRLF).
Strawberry Perl via Chocolatey is recommended.
choco install strawberryperl
Needed if you are regenerating source files.
Ruby version 3 or later is required. On GNU/Linux install ruby
using your
package manager. On macOS install using a package manager such as Brew or with
RVM (Ruby Version Manager). Note that Ruby is included in the Xcode command line tools but as of Xcode 15.3 is still version
2.6. On Windows use RubyInstaller.
Needed if you are regenerating source files.
git clone https://github.com/KhronosGroup/KTX-Specification
to a peer
directory of your KTX-Software workarea or set the value of the
KTX_SPECIFICATION
CMake cache variable to the location of your specification
clone.
The KTX repository is transitioning to enforcing a set of formatting guides, checked during CI. The tool used for this is ClangFormat. To minimize friction, it is advised that one configure their environment to run ClangFormat in an automated fashion, minimally before committing to source control, ideally on every save.
Set the editor.formatOnSave
option and use one of the C/C++ formatting extensions available, most notably ms-vscode.cpptools or llvm-vs-code-extensions.vscode-clangd.
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