QRhiBufferBackedIndirectCommandBuffer Class Reference

#include <qrhi_p.h>

Inheritance diagram for QRhiBufferBackedIndirectCommandBuffer:

Collaboration diagram for QRhiBufferBackedIndirectCommandBuffer:

Public Member Functions
	QRhiBufferBackedIndirectCommandBuffer (QRhiImplementation *rhi, Type type, quint32 maxCommandCount)
	\variable QRhiIndirectCommandBufferBuildInfo::topology
	~QRhiBufferBackedIndirectCommandBuffer ()
void	destroy () override
	Releases (or requests deferred releasing of) the underlying native graphics resources.
bool	create () override
	Creates the corresponding native objects.
void	enqueueUpload (QRhiResourceUpdateBatch *u)
void	execute (QRhiCommandBuffer *cb, quint32 firstCommand, quint32 commandCount)
void	build (const QRhiIndirectCommandBufferBuildInfo &info)
Public Member Functions inherited from QRhiIndirectCommandBuffer
QRhiResource::Type	resourceType () const override
Type	type () const
void	setType (Type t)
	Sets the command type t.
quint32	maxCommandCount () const
void	setMaxCommandCount (quint32 count)
	Sets the capacity, the maximum number of commands, to count.
void	clear ()
	Discards all commands recorded so far.
void	draw (quint32 vertexCount, quint32 instanceCount=1, quint32 firstVertex=0, quint32 firstInstance=0)
	Records a non-indexed draw command with vertexCount, instanceCount, firstVertex, and firstInstance.
void	drawIndexed (quint32 indexCount, quint32 instanceCount=1, quint32 firstIndex=0, qint32 vertexOffset=0, quint32 firstInstance=0)
	Records an indexed draw command with indexCount, instanceCount, firstIndex, vertexOffset, and firstInstance.
quint32	recordedCommandCount () const
bool	isGpuBuilt () const
quint32	commandCount () const
Public Member Functions inherited from QRhiResource
virtual	~QRhiResource ()
	Destructor.
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
bool	valid = false
QRhiBuffer *	buffer = nullptr
quint64	uploadedGeneration = 0
QRhiIndirectCommandBufferBuildInfo	buildInfo

Additional Inherited Members
Public Types inherited from QRhiIndirectCommandBuffer
enum	Type { Draws , IndexedDraws }
	Specifies the kind of commands an indirect command buffer holds. More...
Public Types inherited from QRhiResource
enum	Type {   Buffer , Texture , Sampler , RenderBuffer ,   RenderPassDescriptor , SwapChainRenderTarget , TextureRenderTarget , ShaderResourceBindings ,   GraphicsPipeline , SwapChain , ComputePipeline , CommandBuffer ,   ShadingRateMap , IndirectCommandBuffer }
	Specifies type of the resource. More...
Protected Member Functions inherited from QRhiIndirectCommandBuffer
	QRhiIndirectCommandBuffer (QRhiImplementation *rhi, Type type_, quint32 maxCommandCount_)
Protected Member Functions inherited from QRhiResource
	QRhiResource (QRhiImplementation *rhi)
Protected Attributes inherited from QRhiIndirectCommandBuffer
Type	m_type
quint32	m_maxCommandCount
QByteArray	m_data
quint32	m_commandCount = 0
quint64	m_generation = 0
bool	m_gpuBuilt = false
quint32	m_gpuBuiltCommandCount = 0
Protected Attributes inherited from QRhiResource
QRhiImplementation *	m_rhi = nullptr
quint64	m_id
QByteArray	m_objectName

Detailed Description

Definition at line 304 of file qrhi_p.h.

Constructor & Destructor Documentation

QRhiBufferBackedIndirectCommandBuffer()

QRhiBufferBackedIndirectCommandBuffer::QRhiBufferBackedIndirectCommandBuffer	(	QRhiImplementation *	rhi,
		Type	type,
		quint32	maxCommandCount )

\variable QRhiIndirectCommandBufferBuildInfo::topology

The topology the commands will be drawn with. Must match the topology of the graphics pipeline that is set when QRhiCommandBuffer::executeIndirect() is called. Some backends need it in order to build their native indirect command buffer, and it is not available to them outside of a render pass.

\variable QRhiIndirectCommandBufferBuildInfo::sourceBuffer

The buffer holding the QRhiIndirectDrawCommand or QRhiIndexedIndirectDrawCommand entries. Must have IndirectBuffer usage.

Its size is not used to work out how many commands there are, see commandCount.

\variable QRhiIndirectCommandBufferBuildInfo::sourceBufferOffset

\variable QRhiIndirectCommandBufferBuildInfo::commandCount

The number of commands to take from sourceBuffer. This is what QRhiIndirectCommandBuffer::commandCount() reports afterwards, and so how many draws QRhiCommandBuffer::executeIndirect() issues by default.

0 means QRhiIndirectCommandBuffer::maxCommandCount(). It does not mean "as many as fit in sourceBuffer": a buffer written by the GPU can be larger than the number of commands in it, so no count is ever derived from its size. A value above QRhiIndirectCommandBuffer::maxCommandCount() is clamped to it, with a warning.

Note

Specifying countBuffer changes what this value means: it stops being the number of commands and becomes the maximum number of commands, with the device-side count in countBuffer deciding the actual number. Without a countBuffer, exactly this many commands are executed.

\variable QRhiIndirectCommandBufferBuildInfo::stride

The byte distance between two commands in sourceBuffer. 0 means the size of the corresponding command struct.

\variable QRhiIndirectCommandBufferBuildInfo::countBuffer

An optional buffer whose first quint32 holds the number of commands to execute. Requires QRhi::DrawIndirectCount.

Note

Setting this turns commandCount into an upper bound. The device-side value is clamped to it, so a count buffer can only ever reduce the number of draws, never raise it.

\variable QRhiIndirectCommandBufferBuildInfo::countBufferOffset

\variable QRhiIndirectCommandBufferBuildInfo::indexBuffer

The index buffer the commands index into. Required for IndexedDraws.

\variable QRhiIndirectCommandBufferBuildInfo::indexBufferOffset

\variable QRhiIndirectCommandBufferBuildInfo::indexFormat

Definition at line 9093 of file qrhi.cpp.

References QRhiBufferBackedIndirectCommandBuffer().

Referenced by QRhiBufferBackedIndirectCommandBuffer().

Here is the call graph for this function:

Here is the caller graph for this function:

~QRhiBufferBackedIndirectCommandBuffer()

QRhiBufferBackedIndirectCommandBuffer::~QRhiBufferBackedIndirectCommandBuffer

(

)

Definition at line 9100 of file qrhi.cpp.

References destroy().

Here is the call graph for this function:

Member Function Documentation

build()

void QRhiBufferBackedIndirectCommandBuffer::build

(

const QRhiIndirectCommandBufferBuildInfo &

info

)

Definition at line 9170 of file qrhi.cpp.

create()

bool QRhiBufferBackedIndirectCommandBuffer::create ( )

overridevirtual

Creates the corresponding native objects.

Fails when maxCommandCount() is 0.

A given QRhiIndirectCommandBuffer takes its commands either from draw() and drawIndexed() followed by QRhiResourceUpdateBatch::commitIndirectCommandBuffer(), or from QRhiCommandBuffer::buildIndirect(), but not from both. Moving to the latter is one-way: clear() does not undo it, and neither does a subsequent commitIndirectCommandBuffer(); isGpuBuilt() stays true and the commands keep coming from the buffer. Call create() again to get an indirect command buffer that is populated from the CPU once more.

Note

Like with every other QRhi resource, destroy() gives up the contents, and so create() starts from an empty indirect command buffer: recordedCommandCount() is 0 afterwards. Setting a different type() or maxCommandCount() and calling create() again therefore needs the commands to be recorded again as well.

Returns

true when successful, false when a graphics operation failed.

Implements QRhiIndirectCommandBuffer.

Definition at line 9128 of file qrhi.cpp.

References destroy(), and valid.

Here is the call graph for this function:

destroy()

void QRhiBufferBackedIndirectCommandBuffer::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 9105 of file qrhi.cpp.

References buffer, and valid.

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

Here is the caller graph for this function:

enqueueUpload()

void QRhiBufferBackedIndirectCommandBuffer::enqueueUpload

(

QRhiResourceUpdateBatch *

u

)

Definition at line 9147 of file qrhi.cpp.

References buffer.

execute()

void QRhiBufferBackedIndirectCommandBuffer::execute	(	QRhiCommandBuffer *	cb,
		quint32	firstCommand,
		quint32	commandCount )

Definition at line 9183 of file qrhi.cpp.

References buffer.

Member Data Documentation

buffer

QRhiBuffer* QRhiBufferBackedIndirectCommandBuffer::buffer = nullptr

Definition at line 320 of file qrhi_p.h.

Referenced by testing.tools.encode_pdf_filter._Ascii85DecodePdfStream::close(), testing.tools.encode_pdf_filter._FlateDecodePdfStream::close(), testing.tools.encode_pdf_filter._PdfStream::close(), destroy(), enqueueUpload(), execute(), testing.tools.encode_pdf_filter._FlateDecodePdfStream::flush(), testing.tools.encode_pdf_filter._PdfStream::flush(), testing.tools.encode_pdf_filter._SinkPdfStream::getbuffer(), testing.tools.encode_pdf_filter._FlateDecodePdfStream::write(), testing.tools.encode_pdf_filter._PdfStream::write(), and testing.tools.encode_pdf_filter._PngIdatPdfStream::write().

buildInfo

QRhiIndirectCommandBufferBuildInfo QRhiBufferBackedIndirectCommandBuffer::buildInfo

Definition at line 322 of file qrhi_p.h.

uploadedGeneration

quint64 QRhiBufferBackedIndirectCommandBuffer::uploadedGeneration = 0

Definition at line 321 of file qrhi_p.h.

valid

bool QRhiBufferBackedIndirectCommandBuffer::valid = false

Definition at line 319 of file qrhi_p.h.

Referenced by create(), and destroy().

---

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

• qtbase/src/gui/rhi/qrhi_p.h (11180da797955b8d19490bba7b885f4a0de2e9c2)
• qtbase/src/gui/rhi/qrhi.cpp (11180da797955b8d19490bba7b885f4a0de2e9c2)