144 lines
4.9 KiB
Plaintext
144 lines
4.9 KiB
Plaintext
// Copyright (c) 2014-2019 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_display_swapchain.txt[]
|
|
|
|
*Last Modified Date*::
|
|
2017-03-13
|
|
*IP Status*::
|
|
No known IP claims.
|
|
*Contributors*::
|
|
- James Jones, NVIDIA
|
|
- Jeff Vigil, Qualcomm
|
|
- Jesse Hall, Google
|
|
|
|
This extension provides an API to create a swapchain directly on a device's
|
|
display without any underlying window system.
|
|
|
|
=== New Object Types
|
|
|
|
None
|
|
|
|
=== New Enum Constants
|
|
|
|
* Extending elink:VkStructureType:
|
|
** ename:VK_STRUCTURE_TYPE_DISPLAY_PRESENT_INFO_KHR
|
|
* Extending elink:VkResult:
|
|
** ename:VK_ERROR_INCOMPATIBLE_DISPLAY_KHR
|
|
|
|
=== New Enums
|
|
|
|
None
|
|
|
|
=== New Structures
|
|
|
|
* slink:VkDisplayPresentInfoKHR
|
|
|
|
=== New Functions
|
|
|
|
* flink:vkCreateSharedSwapchainsKHR
|
|
|
|
=== Issues
|
|
|
|
1) Should swapchains sharing images each hold a reference to the images, or
|
|
should it be up to the application to destroy the swapchains and images in
|
|
an order that avoids the need for reference counting?
|
|
|
|
*RESOLVED*: Take a reference.
|
|
The lifetime of presentable images is already complex enough.
|
|
|
|
2) Should the pname:srcRect/pname:dstRect parameters be specified as part of
|
|
the present command, or at swapchain creation time?
|
|
|
|
*RESOLVED*: As part of the presentation command.
|
|
This allows moving and scaling the image on the screen without the need to
|
|
respecify the mode or create a new swapchain and presentable images.
|
|
|
|
3) Should pname:srcRect/pname:dstRect be specified as rects, or separate
|
|
offset/extent values?
|
|
|
|
*RESOLVED*: As rects.
|
|
Specifying them separately might make it easier for hardware to expose
|
|
support for one but not the other, but in such cases applications must just
|
|
take care to obey the reported capabilities and not use non-zero offsets or
|
|
extents that require scaling, as appropriate.
|
|
|
|
4) How can applications create multiple swapchains that use the same images?
|
|
|
|
*RESOLVED*: By calling flink:vkCreateSharedSwapchainsKHR.
|
|
|
|
An earlier resolution used flink:vkCreateSwapchainKHR, chaining multiple
|
|
slink:VkSwapchainCreateInfoKHR structures through pname:pNext.
|
|
In order to allow each swapchain to also allow other extension structs, a
|
|
level of indirection was used: slink:VkSwapchainCreateInfoKHR::pname:pNext
|
|
pointed to a different structure, which had both an pname:sType/pname:pNext
|
|
for additional extensions, and also had a pointer to the next
|
|
slink:VkSwapchainCreateInfoKHR structure.
|
|
The number of swapchains to be created could only be found by walking this
|
|
linked list of alternating structures, and the pname:pSwapchains out
|
|
parameter was reinterpreted to be an array of slink:VkSwapchainKHR handles.
|
|
|
|
Another option considered was a method to specify a "`shared`" swapchain
|
|
when creating a new swapchain, such that groups of swapchains using the same
|
|
images could be built up one at a time.
|
|
This was deemed unusable because drivers need to know all of the displays an
|
|
image will be used on when determining which internal formats and layouts to
|
|
use for that image.
|
|
|
|
=== Examples
|
|
|
|
[NOTE]
|
|
.Note
|
|
====
|
|
The example code for the `<<VK_KHR_display>>` and `VK_KHR_display_swapchain`
|
|
extensions was removed from the appendix after revision 1.0.43.
|
|
The display swapchain creation example code was ported to the cube demo that
|
|
is shipped with the official Khronos SDK, and is being kept up-to-date in
|
|
that location (see:
|
|
https://github.com/KhronosGroup/Vulkan-Tools/blob/master/cube/cube.c).
|
|
====
|
|
|
|
=== Version History
|
|
|
|
* Revision 1, 2015-07-29 (James Jones)
|
|
- Initial draft
|
|
|
|
* Revision 2, 2015-08-21 (Ian Elliott)
|
|
- Renamed this extension and all of its enumerations, types, functions,
|
|
etc.
|
|
This makes it compliant with the proposed standard for Vulkan
|
|
extensions.
|
|
- Switched from "revision" to "version", including use of the
|
|
VK_MAKE_VERSION macro in the header file.
|
|
|
|
* Revision 3, 2015-09-01 (James Jones)
|
|
- Restore single-field revision number.
|
|
|
|
* Revision 4, 2015-09-08 (James Jones)
|
|
- Allow creating multiple swap chains that share the same images using a
|
|
single call to vkCreateSwapChainKHR().
|
|
|
|
* Revision 5, 2015-09-10 (Alon Or-bach)
|
|
- Removed underscores from SWAP_CHAIN in two enums.
|
|
|
|
* Revision 6, 2015-10-02 (James Jones)
|
|
- Added support for smart panels/buffered displays.
|
|
|
|
* Revision 7, 2015-10-26 (Ian Elliott)
|
|
- Renamed from VK_EXT_KHR_display_swapchain to VK_KHR_display_swapchain.
|
|
|
|
* Revision 8, 2015-11-03 (Daniel Rakos)
|
|
- Updated sample code based on the changes to VK_KHR_swapchain.
|
|
|
|
* Revision 9, 2015-11-10 (Jesse Hall)
|
|
- Replaced VkDisplaySwapchainCreateInfoKHR with
|
|
vkCreateSharedSwapchainsKHR, changing resolution of issue #4.
|
|
|
|
* Revision 10, 2017-03-13 (James Jones)
|
|
- Closed all remaining issues.
|
|
The specification and implementations have been shipping with the
|
|
proposed resolutions for some time now.
|
|
- Removed the sample code and noted it has been integrated into the
|
|
official Vulkan SDK cube demo.
|