QNullBuffer Struct Reference

#include <qrhinull_p.h>

Inheritance diagram for QNullBuffer:

Collaboration diagram for QNullBuffer:

Public Member Functions
	QNullBuffer (QRhiImplementation *rhi, Type type, UsageFlags usage, quint32 size)
	~QNullBuffer ()
void	destroy () override
	Releases (or requests deferred releasing of) the underlying native graphics resources.
bool	create () override
	Creates the corresponding native graphics resources.
char *	beginFullDynamicBufferUpdateForCurrentFrame () override
Public Member Functions inherited from QRhiBuffer
QRhiResource::Type	resourceType () const override
Type	type () const
void	setType (Type t)
	Sets the buffer's type to t.
UsageFlags	usage () const
void	setUsage (UsageFlags u)
	Sets the buffer's usage flags to u.
quint32	size () const
void	setSize (quint32 sz)
	Sets the size of the buffer in bytes.
virtual bool	create ()=0
	Creates the corresponding native graphics resources.
virtual NativeBuffer	nativeBuffer ()
virtual char *	beginFullDynamicBufferUpdateForCurrentFrame ()
virtual void	endFullDynamicBufferUpdateForCurrentFrame ()
	To be called when the entire contents of the buffer data has been updated in the memory block returned from beginFullDynamicBufferUpdateForCurrentFrame().
Public Member Functions inherited from QRhiResource
virtual	~QRhiResource ()
	Destructor.
virtual Type	resourceType () const =0
virtual void	destroy ()=0
	Releases (or requests deferred releasing of) the underlying native graphics resources.
void	deleteLater ()
	When called without a frame being recorded, this function is equivalent to deleting the object.
QByteArray	name () const
void	setName (const QByteArray &name)
	Sets a name for the object.
quint64	globalResourceId () const
QRhi *	rhi () const

Public Attributes
char *	data = nullptr

Additional Inherited Members
Public Types inherited from QRhiBuffer
enum	Type { Immutable , Static , Dynamic }
	Specifies storage type of buffer resource. More...
enum	UsageFlag { VertexBuffer = 1 << 0 , IndexBuffer = 1 << 1 , UniformBuffer = 1 << 2 , StorageBuffer = 1 << 3 }
	Flag values to specify how the buffer is going to be used. More...
Public Types inherited from QRhiResource
enum	Type {   Buffer , Texture , Sampler , RenderBuffer ,   RenderPassDescriptor , SwapChainRenderTarget , TextureRenderTarget , ShaderResourceBindings ,   GraphicsPipeline , SwapChain , ComputePipeline , CommandBuffer }
	Specifies type of the resource. More...
Protected Member Functions inherited from QRhiBuffer
	QRhiBuffer (QRhiImplementation *rhi, Type type_, UsageFlags usage_, quint32 size_)
	\variable QRhiBuffer::NativeBuffer::objects
Protected Member Functions inherited from QRhiResource
	QRhiResource (QRhiImplementation *rhi)
Protected Attributes inherited from QRhiBuffer
Type	m_type
UsageFlags	m_usage
quint32	m_size
Protected Attributes inherited from QRhiResource
QRhiImplementation *	m_rhi = nullptr
quint64	m_id
QByteArray	m_objectName

Detailed Description

Definition at line 22 of file qrhinull_p.h.

Constructor & Destructor Documentation

QNullBuffer()

QNullBuffer::QNullBuffer	(	QRhiImplementation *	rhi,
		Type	type,
		UsageFlags	usage,
		quint32	size
	)

Definition at line 564 of file qrhinull.cpp.

~QNullBuffer()

QNullBuffer::~QNullBuffer

(

)

Definition at line 569 of file qrhinull.cpp.

References destroy().

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Member Function Documentation

beginFullDynamicBufferUpdateForCurrentFrame()

char * QNullBuffer::beginFullDynamicBufferUpdateForCurrentFrame ( )

overridevirtual

Returns

a pointer to a memory block with the host visible buffer data.

This is a shortcut for medium-to-large dynamic uniform buffers that have their entire contents (or at least all regions that are read by the shaders in the current frame) changed {in every frame} and the QRhiResourceUpdateBatch-based update mechanism is seen too heavy due to the amount of data copying involved.

The call to this function must be eventually followed by a call to endFullDynamicUniformBufferUpdateForCurrentFrame(), before recording any render or compute pass that relies on this buffer.

Warning

Updating data via this method is not compatible with QRhiResourceUpdateBatch-based updates and readbacks. Unexpected behavior may occur when attempting to combine the two update models for the same buffer. Similarly, the data updated this direct way may not be visible to \l{QRhiResourceUpdateBatch::readBackBuffer()}{readBackBuffer operations}, depending on the backend.

When updating buffer data via this method, the update must be done in every frame, otherwise backends that perform double or triple buffering of resources may end up in unexpected behavior.

Partial updates are not possible with this approach since some backends may choose a strategy where the previous contents of the buffer is lost upon calling this function. Data must be written to all regions that are read by shaders in the frame currently being prepared.

This function can only be called when recording a frame, so between QRhi::beginFrame() and QRhi::endFrame().

This function can only be called on Dynamic buffers.

Reimplemented from QRhiBuffer.

Definition at line 598 of file qrhinull.cpp.

References data, QRhiBuffer::Dynamic, QRhiBuffer::m_type, and Q_ASSERT.

create()

bool QNullBuffer::create ( )

overridevirtual

Creates the corresponding native graphics resources.

If there are already resources present due to an earlier create() with no corresponding destroy(), then destroy() is called implicitly first.

Returns

true when successful, false when a graphics operation failed. Regardless of the return value, calling destroy() is always safe.

Implements QRhiBuffer.

Definition at line 584 of file qrhinull.cpp.

References destroy(), QRhiBuffer::m_size, and QRHI_RES_RHI.

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destroy()

void QNullBuffer::destroy ( )

overridevirtual

Releases (or requests deferred releasing of) the underlying native graphics resources.

Safe to call multiple times, subsequent invocations will be a no-op then.

Once destroy() is called, the QRhiResource instance can be reused, by calling create() again. That will then result in creating new native graphics resources underneath.

Note

Resources referenced by commands for the current frame should not be released until the frame is submitted by QRhi::endFrame().

The QRhiResource destructor also performs the same task, so calling this function is not necessary before deleting a QRhiResource.

See also

deleteLater()

Implements QRhiResource.

Definition at line 574 of file qrhinull.cpp.

References data, and QRHI_RES_RHI.

Referenced by ~QNullBuffer(), and create().

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Member Data Documentation

data

char* QNullBuffer::data = nullptr

Definition at line 30 of file qrhinull_p.h.

Referenced by beginFullDynamicBufferUpdateForCurrentFrame(), destroy(), and QRhiNull::resourceUpdate().

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The documentation for this struct was generated from the following files:

• qtbase/src/gui/rhi/qrhinull_p.h
• qtbase/src/gui/rhi/qrhinull.cpp