vkCmdCopyQueryPoolResults

To copy query statuses and numerical results directly to buffer memory, call:

void vkCmdCopyQueryPoolResults(
    VkCommandBuffer commandBuffer,
    VkQueryPool queryPool,
    uint32_t firstQuery,
    uint32_t queryCount,
    VkBuffer dstBuffer,
    VkDeviceSize dstOffset,
    VkDeviceSize stride,
    VkQueryResultFlags flags);

• commandBuffer is the command buffer into which this command will be recorded.
• queryPool is the query pool managing the queries containing the desired results.
• firstQuery is the initial query index.
• queryCount is the number of queries. firstQuery and queryCount together define a range of queries.
• dstBuffer is a VkBuffer object that will receive the results of the copy command.
• dstOffset is an offset into dstBuffer.
• stride is the stride in bytes between results for individual queries within dstBuffer. The required size of the backing memory for dstBuffer is determined as described above for vkGetQueryPoolResults.
• flags is a bitmask of VkQueryResultFlagBits specifying how and when results are returned.

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 dstBuffer.

If VK_QUERY_RESULT_WITH_AVAILABILITY_BIT is set, results for all queries in queryPool identified by firstQuery and queryCount are copied to dstBuffer, 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 dstBuffer, 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.

vkCmdCopyQueryPoolResults 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.