This folder contains the files required for building the Windows Vulkan
Runtime Installer Package.

To build the Installer:

    1. Install Nullsoft Install System version 3.0b1 or greater. (Available
       from http://nsis.sourceforge.net/Download.)

    2. Build Vulkan LoaderAndTools as described in ../BUILD.md.

    3. Edit the InstallerRT.nsi file in this folder and modify the following
       lines to match the version of the Windows Vulkan Runtime you wish to
       build:

          !define VERSION_ABI_MAJOR
          !define VERSION_API_MAJOR
          !define VERSION_MINOR
          !define VERSION_PATCH
          !define VERSION_BUILDNO
          !define PUBLISHER

    4. Right click on the InstallerRT.nsi file and select "Compile NSIS Script".
       The Windows Vulkan Runtime Installer package file will be created in
       this folder. The name of the installer file is
       VulkanRT-<version>-Installer.exe.


Some notes on the behavior of the Windows Vulkan Runtime Installer:

   o  When VulkanRT-<version>-Installer.exe is run on a 64-bit version
      of Windows, it will install both the 32 and 64 bit versions of
      the Vulkan runtime.  When it is run on a 32-bit version of
      Windows, it will install the 32 bit version of the Vulkan runtime.

   o  The VulkanRT-<version>-Installer.exe created with the above steps
      can be run in silent mode by using the /S command line option when
      invoking the installer.

   o  If the Vulkan Runtime is already installed on the system,
      subsequent installs of the same version of the Vulkan Runtime
      will be installed to the same folder to which it is was
      previously installed.

   o  The Vulkan Runtime Installer uses "counted" installs. If the
      same version of the Vulkan Runtime is installed multiple times
      on a system, the Vulkan Runtime must be uninstalled the same
      number of times before it is completely removed from the system.

   o  If the Vulkan Runtime is already installed on a system and a
      different version is subsequently installed, both versions will
      then co-exist on the system. The Vulkan Runtime Installer does
      not remove prior versions of the Vulkan Runtime when a newer
      version is installed.

   o  The Vulkan Runtime can be uninstalled from Control Panel ->
      Programs and Features. It can also be uninstalled by running
      UninstallVulkanRT.exe in the install folder. The uninstall can
      be run in silent mode by using the /S command line option
      when invoking the uninstaller. The location of the the
      UninstallVulkanRT.exe can be found in the registry value
      HKLM\Software\Microsoft\Windows\CurrentVersion\Uninstall\
      VulkanRT<version>\UninstallString

   o  The Vulkan Runtime Installer installs the Vulkan loader as
      C:\Windows\System32\vulkan-<version>.dll. It then compares all
      versions of the loader in C:\Windows\System32 that have the
      same VERSION_ABI_MAJOR as the version being installed. It selects
      the most recent one of these loader files and copies it to
      C:\Windows\System32\vulkan-<VERSION_ABI_MAJOR>.dll.  For example,
      during the install of Vulkan Runtime version 2.0.1.1, the
      following files might be present in C:\Windows\System32:

           vulkan-1-1-0-2-3.dll
           vulkan-1-2-0-1-0.dll
           vulkan-1-2-0-1-1.dll

     [Note that the first "1" in the above files is VERSION_ABI_MAJOR.
     The other numbers identify the release version.] The installer
     will copy the most recent one of these files (in this case
     vulkan-1-2-0-1-1.dll) to vulkan-1.dll. This is repeated for
     C:\Windows\SYSWOW64 on 64-bit Windows systems to set up the
     32-bit loader.

   o The Vulkan Runtime Installer returns the following exit codes:
         0 - Success
        10 - Failure
      If the Installer returns an error code of 10, the Installer
      will have attempted to uninstall whatever it installed
      before it detected an error.

   o The Vulkan Runtime Uninstaller returns the following exit codes:
         0 - Success
         3 - Success, reboot required
        10 - Failure
      If the Uninstaller returns an error code of 10, it will have
      simply exited when the failure was detected and will
      not have attempted to do further uninstall work.