// Copyright (c) 2014-2017 Khronos Group. This work is licensed under a
// Creative Commons Attribution 4.0 International License; see
// http://creativecommons.org/licenses/by/4.0/

include::meta/VK_KHR_xlib_surface.txt[]

*Last Modified Date*::
    2015-11-28
*IP Status*::
    No known IP claims.
*Contributors*::
  - Patrick Doane, Blizzard
  - Jason Ekstrand, Intel
  - Ian Elliott, LunarG
  - Courtney Goeltzenleuchter, LunarG
  - Jesse Hall, Google
  - James Jones, NVIDIA
  - Antoine Labour, Google
  - Jon Leech, Khronos
  - David Mao, AMD
  - Norbert Nopper, Freescale
  - Alon Or-bach, Samsung
  - Daniel Rakos, AMD
  - Graham Sellers, AMD
  - Ray Smith, ARM
  - Jeff Vigil, Qualcomm
  - Chia-I Wu, LunarG

The +VK_KHR_xlib_surface+ extension is an instance extension.
It provides a mechanism to create a slink:VkSurfaceKHR object (defined by
the +VK_KHR_surface+ extension) that refers to an X11 code:Window, using the
Xlib client-side library, as well as a query to determine support for
rendering via Xlib.

=== New Object Types

None

=== New Enum Constants

  * Extending elink:VkStructureType:
  ** ename:VK_STRUCTURE_TYPE_XLIB_SURFACE_CREATE_INFO_KHR

=== New Enums

None

=== New Structures

  * slink:VkXlibSurfaceCreateInfoKHR

=== New Functions

  * flink:vkCreateXlibSurfaceKHR
  * flink:vkGetPhysicalDeviceXlibPresentationSupportKHR

=== Issues

1) Does X11 need a way to query for compatibility between a particular
physical device and a specific screen? This would be a more general query
than flink:vkGetPhysicalDeviceSurfaceSupportKHR : if it returned
ename:VK_TRUE, then the physical device could be assumed to support
presentation to any window on that screen.

*RESOLVED*: Yes, this is needed for toolkits that want to create a
slink:VkDevice before creating a window.
To ensure the query is reliable, it must be made against a particular X
visual rather than the screen in general.

=== Version History

 * Revision 1, 2015-09-23 (Jesse Hall)
   - Initial draft, based on the previous contents of VK_EXT_KHR_swapchain
     (later renamed VK_EXT_KHR_surface).

 * Revision 2, 2015-10-02 (James Jones)
   - Added presentation support query for (Display*, VisualID) pair.
   - Removed "root" parameter from CreateXlibSurfaceKHR(), as it is
     redundant when a window on the same screen is specified as well.
   - Added appropriate X errors.
   - Adjusted wording of issue #1 and added agreed upon resolution.

 * Revision 3, 2015-10-14 (Ian Elliott)
   - Renamed this extension from VK_EXT_KHR_x11_surface to
     VK_EXT_KHR_xlib_surface.

 * Revision 4, 2015-10-26 (Ian Elliott)
   - Renamed from VK_EXT_KHR_xlib_surface to VK_KHR_xlib_surface.

 * Revision 5, 2015-11-03 (Daniel Rakos)
   - Added allocation callbacks to vkCreateXlibSurfaceKHR.

 * Revision 6, 2015-11-28 (Daniel Rakos)
   - Updated the surface create function to take a pCreateInfo structure.