C Specification
To copy query statuses and numerical results directly to buffer memory, call:
// Provided by VK_KHR_device_address_commands
void vkCmdCopyQueryPoolResultsToMemoryKHR(
VkCommandBuffer commandBuffer,
VkQueryPool queryPool,
uint32_t firstQuery,
uint32_t queryCount,
const VkStridedDeviceAddressRangeKHR* pDstRange,
VkAddressCommandFlagsKHR dstFlags,
VkQueryResultFlags queryResultFlags);Parameters
-
commandBufferis the command buffer into which this command will be recorded. -
queryPoolis the query pool managing the queries containing the desired results. -
firstQueryis the initial query index. -
queryCountis the number of queries.firstQueryandqueryCounttogether define a range of queries. -
pDstRangeis a pointer to a VkStridedDeviceAddressRangeKHR describing a range of memory addressed with a stride that will receive the results of the copy command. -
dstFlagsis a VkAddressCommandFlagsKHR value defining the flags for the destination address range. -
queryResultFlagsis a bitmask of VkQueryResultFlagBits specifying how and when results are returned.
Description
Any results written for a query are written according to a layout dependent on the query type.
Results for any query in queryPool identified by firstQuery and
queryCount that is available are copied to pDstRange.
If VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set, results for all
queries in queryPool identified by firstQuery and
queryCount are copied to pDstRange, along with an extra
availability value written directly after the results of each query and
interpreted as an unsigned integer.
A value of zero indicates that the results are not yet available, otherwise
the query is complete and results are available.
If VK_QUERY_RESULT_WITH_STATUS_BIT_KHR is set, results for all queries
in queryPool identified by firstQuery and queryCount are
copied to pDstRange, along with an extra status value written directly
after the results of each query and interpreted as a signed integer.
A value of zero indicates that the results are not yet available.
Positive values indicate that the operations within the query completed
successfully, and the query results are valid.
Negative values indicate that the operations within the query completed
unsuccessfully.
VkQueryResultStatusKHR defines specific meaning for values returned here, though implementations are free to return other values.
If the status value written is negative, indicating that the operations within the query completed unsuccessfully, then all other results written by this command are undefined unless otherwise specified for any of the results of the used query type.
Results for any available query written by this command are final and represent the final result of the query. If VK_QUERY_RESULT_PARTIAL_BIT is set, then for any query that is unavailable, an intermediate result between zero and the final result value is written for that query. Otherwise, any result written by this command is undefined.
If VK_QUERY_RESULT_64_BIT is set, results and availability
or status
values for all queries are written as an array of 64-bit values.
If the queryPool was created with
VK_QUERY_TYPE_PERFORMANCE_QUERY_KHR, results for each query are
written as an array of the type indicated by
VkPerformanceCounterKHR::storage for the counter being queried.
Otherwise, results and availability
or status
values are written as an array of 32-bit values.
If an unsigned integer query’s value overflows the result type, the value
may either wrap or saturate.
If the maintenance7 feature is enabled, for
an unsigned integer query, the 32-bit result value must be equal to the 32
least significant bits of the equivalent 64-bit result value.
If a signed integer query’s value overflows the result type, the value is
undefined.
If a floating-point query’s value is not representable as the result type,
the value is undefined.
This command defines an execution dependency between other query commands that reference the same query.
The first synchronization scope
includes all commands which reference the queries in queryPool
indicated by query that occur earlier in
submission order.
If flags does not include VK_QUERY_RESULT_WAIT_BIT,
vkCmdEndQueryIndexedEXT,
vkCmdWriteTimestamp2,
vkCmdEndQuery, and vkCmdWriteTimestamp are excluded from this
scope.
The second synchronization scope
includes all commands which reference the queries in queryPool
indicated by query that occur later in
submission order.
The operation of this command happens after the first scope and happens before the second scope.
vkCmdCopyQueryPoolResultsToMemoryKHR is considered to be a transfer
operation, and its writes to buffer memory must be synchronized using
VK_PIPELINE_STAGE_TRANSFER_BIT and VK_ACCESS_TRANSFER_WRITE_BIT
before using the results.
Document Notes
For more information, see the Vulkan Specification.
This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.