- Qt 5.15
- Qt 3D
- C++ Classes
- QComputeCommand
- Qt 5.15.11 Reference Documentation

# QComputeCommand Class

class Qt3DRender::QComputeCommand

QComponent to issue work for the compute shader on GPU. More...

Header: | #include <QComputeCommand>
qmake: | QT += 3drender
Since: | Qt 5.7
Instantiated By: | ComputeCommand
Inherits: | Qt3DCore::QComponent

This class was introduced in Qt 5.7.

- List of all members, including inherited members

## Properties

- runType : RunType
- workGroupX : int
- workGroupY : int
- workGroupZ : int

## Public Functions

| QComputeCommand(Qt3DCore::QNode *parent = nullptr)
RunType | runType() const
int | workGroupX() const
int | workGroupY() const
int | workGroupZ() const

## Public Slots

void | setRunType(RunType runType)
void | setWorkGroupX(int workGroupX)
void | setWorkGroupY(int workGroupY)
void | setWorkGroupZ(int workGroupZ)
void | trigger(int workGroupX, int workGroupY, int workGroupZ, int frameCount = 1)
void | trigger(int frameCount = 1)

## Signals

void | runTypeChanged()
void | workGroupXChanged()
void | workGroupYChanged()
void | workGroupZChanged()

## Detailed Description

A Qt3DRender::QComputeCommand is used to issue work for the compute shader. The compute shader is specified in the QMaterial component of the same entity the QComputeCommand is added to. The workGroupX, workGroupY and workGroupZ properties specify the work group sizes for the compute shader invocation. Qt3DRender::QDispatchCompute node needs to be present in the FrameGraph to actually issue the commands.

Note: If the rendering policy is set to Qt3DRender::QRenderSettings::OnDemand and there are no changes to the scene, the ComputeCommand will not be invoked repeatedly. The Qt3DRender::QRenderSettings::Always render policy must be set for the ComputeCommand to be repeatedly invoked if there are no other changes to the scene that triggers rendering a new frame.

## Property Documentation

### runType : RunType

Specifies whether the compute command should be performed every frame or manually triggered.

If set to Continuous, Compute command is executed everyframe. This is the default.

If set to Manual CompouteCommand is executed for a given number of frames and then the component disables itself.

Access functions:

RunType | runType() const
void | setRunType(RunType runType)

Notifier signal:

void | runTypeChanged()

### workGroupX : int

Specifies X workgroup size.

Access functions:

int | workGroupX() const
void | setWorkGroupX(int workGroupX)

Notifier signal:

void | workGroupXChanged()

### workGroupY : int

Specifies Y workgroup size.

Access functions:

int | workGroupY() const
void | setWorkGroupY(int workGroupY)

Notifier signal:

void | workGroupYChanged()

### workGroupZ : int

Specifies Z workgroup size.

Access functions:

int | workGroupZ() const
void | setWorkGroupZ(int workGroupZ)

Notifier signal:

void | workGroupZChanged()

## Member Function Documentation

### QComputeCommand::QComputeCommand(Qt3DCore::QNode *parent = nullptr)

The constructor creates a new Qt3DRender::QComputeCommand instance with the specified parent.

### `[slot]` void QComputeCommand::setWorkGroupX(int workGroupX)

Sets the workgroup for the first dimension to workGroupX.

Note: Setter function for property workGroupX.

See also workGroupX().

### `[slot]` void QComputeCommand::setWorkGroupY(int workGroupY)

Sets the workgroup for the second dimension to workGroupY.

Note: Setter function for property workGroupY.

See also workGroupY().

### `[slot]` void QComputeCommand::setWorkGroupZ(int workGroupZ)

Sets the workgroup for the third dimension to workGroupZ.

Note: Setter function for property workGroupZ.

See also workGroupZ().

### `[slot]` void QComputeCommand::trigger(int workGroupX, int workGroupY, int workGroupZ, int frameCount = 1)

When the run type is set to Manual, calling trigger will make the compute command be executed for the next frameCount frames. Upon completion of the execution, the enabled property will be set to false. The size of the workgroup previously set will be overridden with workGroupX, workGroupY, workGroupZ.

### `[slot]` void QComputeCommand::trigger(int frameCount = 1)

When the run type is set to Manual, calling trigger will make the compute command be executed for the next frameCount frames. Upon completion of the execution, the enabled property will be set to false.