Vulkan-Docs/chapters/VK_GOOGLE_display_timing/PresentTimeInfo.txt

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[open,refpage='VkPresentTimesInfoGOOGLE',desc='The earliest time each image should be presented',type='structs']
--
When the `<<VK_GOOGLE_display_timing>>` extension is enabled, additional
fields can: be specified that allow an application to specify the earliest
time that an image should be displayed.
This allows an application to avoid stutter that is caused by an image being
displayed earlier than planned.
Such stuttering can occur with both fixed and variable-refresh-rate
displays, because stuttering occurs when the geometry is not correctly
positioned for when the image is displayed.
An application can: instruct the presentation engine that an image should
not be displayed earlier than a specified time by including the
sname:VkPresentTimesInfoGOOGLE structure in the pname:pNext chain of the
sname:VkPresentInfoKHR structure.
The sname:VkPresentTimesInfoGOOGLE structure is defined as:
include::{generated}/api/structs/VkPresentTimesInfoGOOGLE.txt[]
* pname:sType is the type of this structure.
* pname:pNext is `NULL` or a pointer to an extension-specific structure.
* pname:swapchainCount is the number of swapchains being presented to by
this command.
* pname:pTimes is `NULL` or a pointer to an array of
sname:VkPresentTimeGOOGLE elements with pname:swapchainCount entries.
If not `NULL`, each element of pname:pTimes contains the earliest time
to present the image corresponding to the entry in the
sname:VkPresentInfoKHR::pname:pImageIndices array.
.Valid Usage
****
* [[VUID-VkPresentTimesInfoGOOGLE-swapchainCount-01247]]
pname:swapchainCount must: be the same value as
sname:VkPresentInfoKHR::pname:swapchainCount, where
sname:VkPresentInfoKHR is in the pname:pNext chain of this
sname:VkPresentTimesInfoGOOGLE structure.
****
include::{generated}/validity/structs/VkPresentTimesInfoGOOGLE.txt[]
--
[open,refpage='VkPresentTimeGOOGLE',desc='The earliest time image should be presented',type='structs']
--
The sname:VkPresentTimeGOOGLE structure is defined as:
include::{generated}/api/structs/VkPresentTimeGOOGLE.txt[]
* pname:presentID is an application-provided identification value, that
can: be used with the results of
flink:vkGetPastPresentationTimingGOOGLE, in order to uniquely identify
this present.
In order to be useful to the application, it should: be unique within
some period of time that is meaningful to the application.
* pname:desiredPresentTime specifies that the image given should: not be
displayed to the user any earlier than this time.
pname:desiredPresentTime is a time in nanoseconds, relative to a
monotonically-increasing clock (e.g. `CLOCK_MONOTONIC` (see
clock_gettime(2)) on Android and Linux).
A value of zero specifies that the presentation engine may: display the
image at any time.
This is useful when the application desires to provide pname:presentID,
but does not need a specific pname:desiredPresentTime.
--