Vulkan-Docs/chapters/dispatch.txt

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// Copyright (c) 2015-2019 Khronos Group. This work is licensed under a
// Creative Commons Attribution 4.0 International License; see
// http://creativecommons.org/licenses/by/4.0/
[[dispatch]]
= Dispatching Commands
_Dispatching commands_ (commands with ftext:Dispatch in the name) provoke
work in a compute pipeline.
Dispatching commands are recorded into a command buffer and when executed by
a queue, will produce work which executes according to the bound compute
pipeline.
A compute pipeline must: be bound to a command buffer before any dispatch
commands are recorded in that command buffer.
[open,refpage='vkCmdDispatch',desc='Dispatch compute work items',type='protos']
--
:refpage: vkCmdDispatch
To record a dispatch, call:
include::{generated}/api/protos/vkCmdDispatch.txt[]
* pname:commandBuffer is the command buffer into which the command will be
recorded.
* pname:groupCountX is the number of local workgroups to dispatch in the X
dimension.
* pname:groupCountY is the number of local workgroups to dispatch in the Y
dimension.
* pname:groupCountZ is the number of local workgroups to dispatch in the Z
dimension.
When the command is executed, a global workgroup consisting of
[eq]#pname:groupCountX {times} pname:groupCountY {times} pname:groupCountZ#
local workgroups is assembled.
.Valid Usage
****
include::{chapters}/commonvalidity/draw_dispatch_common.txt[]
include::{chapters}/commonvalidity/draw_dispatch_nonindirect_common.txt[]
* [[VUID-vkCmdDispatch-groupCountX-00386]]
pname:groupCountX must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[0]
* [[VUID-vkCmdDispatch-groupCountY-00387]]
pname:groupCountY must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[1]
* [[VUID-vkCmdDispatch-groupCountZ-00388]]
pname:groupCountZ must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[2]
****
include::{generated}/validity/protos/vkCmdDispatch.txt[]
--
[open,refpage='vkCmdDispatchIndirect',desc='Dispatch compute work items using indirect parameters',type='protos']
--
:refpage: vkCmdDispatchIndirect
To record an indirect command dispatch, call:
include::{generated}/api/protos/vkCmdDispatchIndirect.txt[]
* pname:commandBuffer is the command buffer into which the command will be
recorded.
* pname:buffer is the buffer containing dispatch parameters.
* pname:offset is the byte offset into pname:buffer where parameters
begin.
fname:vkCmdDispatchIndirect behaves similarly to flink:vkCmdDispatch except
that the parameters are read by the device from a buffer during execution.
The parameters of the dispatch are encoded in a
slink:VkDispatchIndirectCommand structure taken from pname:buffer starting
at pname:offset.
.Valid Usage
****
include::{chapters}/commonvalidity/draw_dispatch_common.txt[]
include::{chapters}/commonvalidity/draw_dispatch_indirect_common.txt[]
* [[VUID-vkCmdDispatchIndirect-offset-00407]]
The sum of pname:offset and the size of sname:VkDispatchIndirectCommand
must: be less than or equal to the size of pname:buffer
****
include::{generated}/validity/protos/vkCmdDispatchIndirect.txt[]
--
[open,refpage='VkDispatchIndirectCommand',desc='Structure specifying a dispatch indirect command',type='structs',xrefs='vkCmdDispatchIndirect']
--
The sname:VkDispatchIndirectCommand structure is defined as:
include::{generated}/api/structs/VkDispatchIndirectCommand.txt[]
* pname:x is the number of local workgroups to dispatch in the X
dimension.
* pname:y is the number of local workgroups to dispatch in the Y
dimension.
* pname:z is the number of local workgroups to dispatch in the Z
dimension.
The members of sname:VkDispatchIndirectCommand have the same meaning as the
corresponding parameters of flink:vkCmdDispatch.
.Valid Usage
****
* [[VUID-VkDispatchIndirectCommand-x-00417]]
pname:x must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[0]
* [[VUID-VkDispatchIndirectCommand-y-00418]]
pname:y must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[1]
* [[VUID-VkDispatchIndirectCommand-z-00419]]
pname:z must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[2]
****
include::{generated}/validity/structs/VkDispatchIndirectCommand.txt[]
--
ifdef::VK_VERSION_1_1,VK_KHR_device_group[]
[open,refpage='vkCmdDispatchBase',desc='Dispatch compute work items',type='protos']
--
:refpage: vkCmdDispatchBase
To record a dispatch using non-zero base values for the components of
code:WorkgroupId, call:
ifdef::VK_VERSION_1_1[]
include::{generated}/api/protos/vkCmdDispatchBase.txt[]
endif::VK_VERSION_1_1[]
ifdef::VK_VERSION_1_1+VK_KHR_device_group[or the equivalent command]
ifdef::VK_KHR_device_group[]
include::{generated}/api/protos/vkCmdDispatchBaseKHR.txt[]
endif::VK_KHR_device_group[]
* pname:commandBuffer is the command buffer into which the command will be
recorded.
* pname:baseGroupX is the start value for the X component of
code:WorkgroupId.
* pname:baseGroupY is the start value for the Y component of
code:WorkgroupId.
* pname:baseGroupZ is the start value for the Z component of
code:WorkgroupId.
* pname:groupCountX is the number of local workgroups to dispatch in the X
dimension.
* pname:groupCountY is the number of local workgroups to dispatch in the Y
dimension.
* pname:groupCountZ is the number of local workgroups to dispatch in the Z
dimension.
When the command is executed, a global workgroup consisting of
[eq]#pname:groupCountX {times} pname:groupCountY {times} pname:groupCountZ#
local workgroups is assembled, with code:WorkgroupId values ranging from
[eq]#[ptext:baseGroup*, ptext:baseGroup* {plus} ptext:groupCount*)# in each
component.
flink:vkCmdDispatch is equivalent to
`vkCmdDispatchBase(0,0,0,groupCountX,groupCountY,groupCountZ)`.
.Valid Usage
****
include::{chapters}/commonvalidity/draw_dispatch_common.txt[]
* [[VUID-vkCmdDispatchBase-baseGroupX-00421]]
pname:baseGroupX must: be less than
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[0]
* [[VUID-vkCmdDispatchBase-baseGroupX-00422]]
pname:baseGroupX must: be less than
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[1]
* [[VUID-vkCmdDispatchBase-baseGroupZ-00423]]
pname:baseGroupZ must: be less than
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[2]
* [[VUID-vkCmdDispatchBase-groupCountX-00424]]
pname:groupCountX must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[0] minus
pname:baseGroupX
* [[VUID-vkCmdDispatchBase-groupCountY-00425]]
pname:groupCountY must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[1] minus
pname:baseGroupY
* [[VUID-vkCmdDispatchBase-groupCountZ-00426]]
pname:groupCountZ must: be less than or equal to
sname:VkPhysicalDeviceLimits::pname:maxComputeWorkGroupCount[2] minus
pname:baseGroupZ
* [[VUID-vkCmdDispatchBase-baseGroupX-00427]]
If any of pname:baseGroupX, pname:baseGroupY, or pname:baseGroupZ are
not zero, then the bound compute pipeline must: have been created with
the ename:VK_PIPELINE_CREATE_DISPATCH_BASE flag.
****
include::{generated}/validity/protos/vkCmdDispatchBase.txt[]
--
endif::VK_VERSION_1_1,VK_KHR_device_group[]