Class GOOGLEDisplayTiming
VK_KHR_swapchain
extension to obtain information about the presentation engine’s display, to obtain timing information about each present, and to schedule a present to happen no earlier than a desired time. An application can use this to minimize various visual anomalies (e.g. stuttering).
Traditional game and real-time animation applications need to correctly position their geometry for when the presentable image will be presented to the user. To accomplish this, applications need various timing information about the presentation engine’s display. They need to know when presentable images were actually presented, and when they could have been presented. Applications also need to tell the presentation engine to display an image no sooner than a given time. This allows the application to avoid stuttering, so the animation looks smooth to the user.
This extension treats variable-refresh-rate (VRR) displays as if they are fixed-refresh-rate (FRR) displays.
Examples
Note
The example code for the this extension (like the VK_KHR_surface
and VK_GOOGLE_display_timing
extensions) is contained in 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 ).
VK_GOOGLE_display_timing
- Name String
VK_GOOGLE_display_timing
- Extension Type
- Device extension
- Registered Extension Number
- 93
- Revision
- 1
- Extension and Version Dependencies
VK_KHR_swapchain
- Contact
- Ian Elliott ianelliottus
Other Extension Metadata
- Last Modified Date
- 2017-02-14
- IP Status
- No known IP claims.
- Contributors
- Ian Elliott, Google
- Jesse Hall, Google
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Field Summary
Modifier and TypeFieldDescriptionstatic final String
The extension name.static final int
The extension specification version.static final int
ExtendsVkStructureType
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Method Summary
Modifier and TypeMethodDescriptionstatic int
nvkGetPastPresentationTimingGOOGLE
(VkDevice device, long swapchain, long pPresentationTimingCount, long pPresentationTimings) Unsafe version of:GetPastPresentationTimingGOOGLE
static int
nvkGetRefreshCycleDurationGOOGLE
(VkDevice device, long swapchain, long pDisplayTimingProperties) Unsafe version of:GetRefreshCycleDurationGOOGLE
static int
vkGetPastPresentationTimingGOOGLE
(VkDevice device, long swapchain, int[] pPresentationTimingCount, VkPastPresentationTimingGOOGLE.Buffer pPresentationTimings) Array version of:GetPastPresentationTimingGOOGLE
static int
vkGetPastPresentationTimingGOOGLE
(VkDevice device, long swapchain, IntBuffer pPresentationTimingCount, VkPastPresentationTimingGOOGLE.Buffer pPresentationTimings) Obtain timing of a previously-presented image.static int
vkGetRefreshCycleDurationGOOGLE
(VkDevice device, long swapchain, VkRefreshCycleDurationGOOGLE pDisplayTimingProperties) Obtain the RC duration of the PE’s display.
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Field Details
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VK_GOOGLE_DISPLAY_TIMING_SPEC_VERSION
public static final int VK_GOOGLE_DISPLAY_TIMING_SPEC_VERSIONThe extension specification version.- See Also:
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VK_GOOGLE_DISPLAY_TIMING_EXTENSION_NAME
The extension name.- See Also:
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VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLE
public static final int VK_STRUCTURE_TYPE_PRESENT_TIMES_INFO_GOOGLEExtendsVkStructureType
.- See Also:
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Method Details
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nvkGetRefreshCycleDurationGOOGLE
public static int nvkGetRefreshCycleDurationGOOGLE(VkDevice device, long swapchain, long pDisplayTimingProperties) Unsafe version of:GetRefreshCycleDurationGOOGLE
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vkGetRefreshCycleDurationGOOGLE
public static int vkGetRefreshCycleDurationGOOGLE(VkDevice device, long swapchain, VkRefreshCycleDurationGOOGLE pDisplayTimingProperties) Obtain the RC duration of the PE’s display.C Specification
To query the duration of a refresh cycle (RC) for the presentation engine’s display, call:
VkResult vkGetRefreshCycleDurationGOOGLE( VkDevice device, VkSwapchainKHR swapchain, VkRefreshCycleDurationGOOGLE* pDisplayTimingProperties);
Valid Usage (Implicit)
device
must be a validVkDevice
handleswapchain
must be a validVkSwapchainKHR
handlepDisplayTimingProperties
must be a valid pointer to aVkRefreshCycleDurationGOOGLE
structureswapchain
must have been created, allocated, or retrieved fromdevice
Host Synchronization
- Host access to
swapchain
must be externally synchronized
Return Codes
- On success, this command returns
- On failure, this command returns
See Also
- Parameters:
device
- the device associated withswapchain
.swapchain
- the swapchain to obtain the refresh duration for.pDisplayTimingProperties
- a pointer to aVkRefreshCycleDurationGOOGLE
structure.
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nvkGetPastPresentationTimingGOOGLE
public static int nvkGetPastPresentationTimingGOOGLE(VkDevice device, long swapchain, long pPresentationTimingCount, long pPresentationTimings) Unsafe version of:GetPastPresentationTimingGOOGLE
- Parameters:
pPresentationTimingCount
- a pointer to an integer related to the number ofVkPastPresentationTimingGOOGLE
structures to query, as described below.
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vkGetPastPresentationTimingGOOGLE
public static int vkGetPastPresentationTimingGOOGLE(VkDevice device, long swapchain, IntBuffer pPresentationTimingCount, @Nullable VkPastPresentationTimingGOOGLE.Buffer pPresentationTimings) Obtain timing of a previously-presented image.C Specification
The implementation will maintain a limited amount of history of timing information about previous presents. Because of the asynchronous nature of the presentation engine, the timing information for a given
QueuePresentKHR
command will become available some time later. These time values can be asynchronously queried, and will be returned if available. All time values are in nanoseconds, relative to a monotonically-increasing clock (e.g.CLOCK_MONOTONIC
(see clock_gettime(2)) on Android and Linux).To asynchronously query the presentation engine, for newly-available timing information about one or more previous presents to a given swapchain, call:
VkResult vkGetPastPresentationTimingGOOGLE( VkDevice device, VkSwapchainKHR swapchain, uint32_t* pPresentationTimingCount, VkPastPresentationTimingGOOGLE* pPresentationTimings);
Description
If
pPresentationTimings
isNULL
, then the number of newly-available timing records for the givenswapchain
is returned inpPresentationTimingCount
. Otherwise,pPresentationTimingCount
must point to a variable set by the user to the number of elements in thepPresentationTimings
array, and on return the variable is overwritten with the number of structures actually written topPresentationTimings
. If the value ofpPresentationTimingCount
is less than the number of newly-available timing records, at mostpPresentationTimingCount
structures will be written, andINCOMPLETE
will be returned instead ofSUCCESS
, to indicate that not all the available timing records were returned.Valid Usage (Implicit)
device
must be a validVkDevice
handleswapchain
must be a validVkSwapchainKHR
handlepPresentationTimingCount
must be a valid pointer to auint32_t
value- If the value referenced by
pPresentationTimingCount
is not 0, andpPresentationTimings
is notNULL
,pPresentationTimings
must be a valid pointer to an array ofpPresentationTimingCount
VkPastPresentationTimingGOOGLE
structures swapchain
must have been created, allocated, or retrieved fromdevice
Host Synchronization
- Host access to
swapchain
must be externally synchronized
Return Codes
- On success, this command returns
- On failure, this command returns
See Also
- Parameters:
device
- the device associated withswapchain
.swapchain
- the swapchain to obtain presentation timing information duration for.pPresentationTimingCount
- a pointer to an integer related to the number ofVkPastPresentationTimingGOOGLE
structures to query, as described below.pPresentationTimings
- eitherNULL
or a pointer to an array ofVkPastPresentationTimingGOOGLE
structures.
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vkGetPastPresentationTimingGOOGLE
public static int vkGetPastPresentationTimingGOOGLE(VkDevice device, long swapchain, int[] pPresentationTimingCount, @Nullable VkPastPresentationTimingGOOGLE.Buffer pPresentationTimings) Array version of:GetPastPresentationTimingGOOGLE
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