Vulkan-Docs/chapters/VK_NVX_device_generated_com.../generation.txt

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== Indirect Commands Generation
[open,refpage='vkCmdReserveSpaceForCommandsNVX',desc='Perform a reservation of command buffer space',type='protos']
--
Command space for generated commands recorded into a secondary command
buffer must: be reserved by calling:
include::../../api/protos/vkCmdReserveSpaceForCommandsNVX.txt[]
* pname:commandBuffer is the secondary command buffer in which the space
for device-generated commands is reserved.
* pname:pProcessCommandsInfo is a pointer to an instance of the
slink:vkCmdReserveSpaceForCommandsNVX structure containing parameters
affecting the reservation of command buffer space.
.Valid Usage
****
* [[VUID-vkCmdReserveSpaceForCommandsNVX-commandBuffer-01329]]
The provided pname:commandBuffer must: not have had a prior space
reservation since its creation or the last reset.
* [[VUID-vkCmdReserveSpaceForCommandsNVX-commandBuffer-01330]]
The state of the pname:commandBuffer must: be legal to execute all
commands within the sequence provided by the
pname:indirectCommandsLayout member of pname:pProcessCommandsInfo.
****
include::../../validity/protos/vkCmdReserveSpaceForCommandsNVX.txt[]
--
[open,refpage='VkCmdReserveSpaceForCommandsInfoNVX',desc='Structure specifying parameters for the reservation of command buffer space',type='structs']
--
include::../../api/structs/VkCmdReserveSpaceForCommandsInfoNVX.txt[]
* pname:sType is the type of this structure.
* pname:pNext is `NULL` or a pointer to an extension-specific structure.
* pname:objectTable is the slink:VkObjectTableNVX to be used for the
generation process.
Only registered objects at the time
flink:vkCmdReserveSpaceForCommandsNVX is called, will be taken into
account for the reservation.
* pname:indirectCommandsLayout is the slink:VkIndirectCommandsLayoutNVX
that must: also be used at generation time.
* pname:maxSequencesCount is the maximum number of sequences for which
command buffer space will be reserved.
include::../../validity/structs/VkCmdReserveSpaceForCommandsInfoNVX.txt[]
--
The generated commands will behave as if they were recorded within the call
to fname:vkCmdReserveSpaceForCommandsNVX, that means they can inherit state
defined in the command buffer prior this call.
However, given the stateless nature of the generated sequences, they will
not affect commands after the reserved space.
Treat the state that can: be affected by the provided
sname:VkIndirectCommandsLayoutNVX as undefined:.
[open,refpage='vkCmdProcessCommandsNVX',desc='Performs the generation of commands on the device',type='protos']
--
The actual generation on the device is handled with:
include::../../api/protos/vkCmdProcessCommandsNVX.txt[]
* pname:commandBuffer is the primary command buffer in which the
generation process takes space.
* pname:pProcessCommandsInfo is a pointer to an instance of the
slink:VkCmdProcessCommandsInfoNVX structure containing parameters
affecting the processing of commands.
include::../../validity/protos/vkCmdProcessCommandsNVX.txt[]
--
[open,refpage='VkCmdProcessCommandsInfoNVX',desc='Structure specifying parameters for the generation of commands',type='structs']
--
include::../../api/structs/VkCmdProcessCommandsInfoNVX.txt[]
* pname:sType is the type of this structure.
* pname:pNext is `NULL` or a pointer to an extension-specific structure.
* pname:objectTable is the slink:VkObjectTableNVX to be used for the
generation process.
Only registered objects at the time
flink:vkCmdReserveSpaceForCommandsNVX is called, will be taken into
account for the reservation.
* pname:indirectCommandsLayout is the slink:VkIndirectCommandsLayoutNVX
that provides the command sequence to generate.
* pname:indirectCommandsTokenCount defines the number of input tokens
used.
* pname:pIndirectCommandsTokens provides an array of
slink:VkIndirectCommandsTokenNVX that reference the input data for each
token command.
* pname:maxSequencesCount is the maximum number of sequences for which
command buffer space will be reserved.
If pname:sequencesCountBuffer is dlink:VK_NULL_HANDLE, this is also the
actual number of sequences generated.
* pname:targetCommandBuffer can: be the secondary slink:VkCommandBuffer in
which the commands should be recorded.
If pname:targetCommandBuffer is `NULL` an implicit reservation as well
as execution takes place on the processing sname:VkCommandBuffer.
* pname:sequencesCountBuffer can: be slink:VkBuffer from which the actual
amount of sequences is sourced from as ftext:uint32_t value.
* pname:sequencesCountOffset is the byte offset into
pname:sequencesCountBuffer where the count value is stored.
* pname:sequencesIndexBuffer must: be set if
pname:indirectCommandsLayout's
ename:VK_INDIRECT_COMMANDS_LAYOUT_USAGE_INDEXED_SEQUENCES_BIT is set and
provides the used sequence indices as ftext:uint32_t array.
Otherwise it must: be dlink:VK_NULL_HANDLE.
* pname:sequencesIndexOffset is the byte offset into
pname:sequencesIndexBuffer where the index values start.
.Valid Usage
****
* [[VUID-VkCmdProcessCommandsInfoNVX-objectTable-01331]]
The provided pname:objectTable must: include all objects referenced by
the generation process.
* [[VUID-VkCmdProcessCommandsInfoNVX-indirectCommandsTokenCount-01332]]
pname:indirectCommandsTokenCount must: match the
pname:indirectCommandsLayout's pname:tokenCount.
* [[VUID-VkCmdProcessCommandsInfoNVX-tokenType-01333]]
The pname:tokenType member of each entry in the
pname:pIndirectCommandsTokens array must: match the values used at
creation time of pname:indirectCommandsLayout
* [[VUID-VkCmdProcessCommandsInfoNVX-targetCommandBuffer-01334]]
If pname:targetCommandBuffer is provided, it must: have reserved command
space.
* [[VUID-VkCmdProcessCommandsInfoNVX-targetCommandBuffer-01335]]
If pname:targetCommandBuffer is provided, the pname:objectTable must:
match the reservation's objectTable and must: have had all referenced
objects registered at reservation time.
* [[VUID-VkCmdProcessCommandsInfoNVX-targetCommandBuffer-01336]]
If pname:targetCommandBuffer is provided, the
pname:indirectCommandsLayout must: match the reservation's
indirectCommandsLayout.
* [[VUID-VkCmdProcessCommandsInfoNVX-targetCommandBuffer-01337]]
If pname:targetCommandBuffer is provided, the pname:maxSequencesCount
must: not exceed the reservation's maxSequencesCount.
* [[VUID-VkCmdProcessCommandsInfoNVX-sequencesCountBuffer-01338]]
If pname:sequencesCountBuffer is used, its usage flag must: have
ename:VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT bit set.
* [[VUID-VkCmdProcessCommandsInfoNVX-sequencesCountBuffer-01339]]
If pname:sequencesCountBuffer is used, pname:sequencesCountOffset must:
be aligned to
sname:VkDeviceGeneratedCommandsLimitsNVX::pname:minSequenceCountBufferOffsetAlignment.
* [[VUID-VkCmdProcessCommandsInfoNVX-sequencesIndexBuffer-01340]]
If pname:sequencesIndexBuffer is used, its usage flag must: have
ename:VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT bit set.
* [[VUID-VkCmdProcessCommandsInfoNVX-sequencesIndexBuffer-01341]]
If pname:sequencesIndexBuffer is used, pname:sequencesIndexOffset must:
be aligned to
sname:VkDeviceGeneratedCommandsLimitsNVX::pname:minSequenceIndexBufferOffsetAlignment.
****
include::../../validity/structs/VkCmdProcessCommandsInfoNVX.txt[]
--
Referencing the functions defined in <<indirectmdslayout>>,
fname:vkCmdProcessCommandsNVX behaves as:
[source,c]
---------------------------------------------------
// For targetCommandBuffers the existing reservedSpace is reset & overwritten.
VkCommandBuffer cmd = targetCommandBuffer ?
targetCommandBuffer.reservedSpace :
commandBuffer;
uint32_t sequencesCount = sequencesCountBuffer ?
min(maxSequencesCount, sequencesCountBuffer.load_uint32(sequencesCountOffset) :
maxSequencesCount;
cmdProcessAllSequences(cmd, objectTable,
indirectCommandsLayout, pIndirectCommandsTokens,
sequencesCount,
sequencesIndexBuffer, sequencesIndexOffset);
// The stateful commands within indirectCommandsLayout will not
// affect the state of subsequent commands in the target
// command buffer (cmd)
---------------------------------------------------
[NOTE]
.Note
====
It is important to note that the state that may be affected through
generated commands must: be considered undefined: for the commands following
them.
It is not possible to setup generated state and provoking work that uses
this state outside of the generated sequence.
====