Abstract class defining common features of hardware buffers. More...

#include <OgreHardwareBuffer.h>

Inheritance diagram for Ogre::HardwareBuffer:

[legend]

Public Types
enum	LockOptions { HBL_NORMAL , HBL_DISCARD , HBL_READ_ONLY , HBL_NO_OVERWRITE , HBL_WRITE_ONLY }
	Locking options. More...

enum	Usage { HBU_STATIC = 1 , HBU_DYNAMIC = 2 , HBU_WRITE_ONLY = 4 , HBU_DISCARDABLE = 8 , HBU_STATIC_WRITE_ONLY = 5 , HBU_DYNAMIC_WRITE_ONLY = 6 , HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE = 14 }
	Enums describing buffer usage; not mutually exclusive. More...

Public Member Functions
	HardwareBuffer (Usage usage, bool systemMemory, bool useShadowBuffer)
	Constructor, to be called by HardwareBufferManager only. More...

virtual	~HardwareBuffer ()

virtual void	_updateFromShadow (void)
	Updates the real buffer from the shadow buffer, if required. More...

virtual void	copyData (HardwareBuffer &srcBuffer)
	Copy all data from another buffer into this one. More...

virtual void	copyData (HardwareBuffer &srcBuffer, size_t srcOffset, size_t dstOffset, size_t length, bool discardWholeBuffer=false)
	Copy data from another buffer into this one. More...

size_t	getSizeInBytes (void) const
	Returns the size of this buffer in bytes. More...

Usage	getUsage (void) const
	Returns the Usage flags with which this buffer was created. More...

bool	hasShadowBuffer (void) const
	Returns whether this buffer has a system memory shadow for quicker reading. More...

bool	isLocked (void) const
	Returns whether or not this buffer is currently locked. More...

bool	isSystemMemory (void) const
	Returns whether this buffer is held in system memory. More...

void *	lock (LockOptions options)
	Lock the entire buffer for (potentially) reading / writing. More...

virtual void *	lock (size_t offset, size_t length, LockOptions options)
	Lock the buffer for (potentially) reading / writing. More...

void	operator delete (void *ptr)

void	operator delete (void ptr, const char , int, const char *)

void	operator delete (void ptr, void )

void	operator delete[] (void *ptr)

void	operator delete[] (void ptr, const char , int, const char *)

void *	operator new (size_t sz)

void *	operator new (size_t sz, const char file, int line, const char func)
	operator new, with debug line info More...

void *	operator new (size_t sz, void *ptr)
	placement operator new More...

void *	operator new[] (size_t sz)

void *	operator new[] (size_t sz, const char file, int line, const char func)
	array operator new, with debug line info More...

virtual void	readData (size_t offset, size_t length, void *pDest)=0
	Reads data from the buffer and places it in the memory pointed to by pDest. More...

void	suppressHardwareUpdate (bool suppress)
	Pass true to suppress hardware upload of shadow buffer changes. More...

virtual void	unlock (void)
	Releases the lock on this buffer. More...

virtual void	writeData (size_t offset, size_t length, const void *pSource, bool discardWholeBuffer=false)=0
	Writes data to the buffer from an area of system memory; note that you must ensure that your buffer is big enough. More...

Protected Member Functions
virtual void *	lockImpl (size_t offset, size_t length, LockOptions options)=0
	Internal implementation of lock() More...

virtual void	unlockImpl (void)=0
	Internal implementation of unlock() More...

Protected Attributes
bool	mIsLocked

size_t	mLockSize

size_t	mLockStart

HardwareBuffer *	mShadowBuffer

bool	mShadowUpdated

size_t	mSizeInBytes

bool	mSuppressHardwareUpdate

bool	mSystemMemory

Usage	mUsage

bool	mUseShadowBuffer

Detailed Description

Abstract class defining common features of hardware buffers.

Remarks: A 'hardware buffer' is any area of memory held outside of core system ram, and in our case refers mostly to video ram, although in theory this class could be used with other memory areas such as sound card memory, custom coprocessor memory etc.

: This reflects the fact that memory held outside of main system RAM must be interacted with in a more formal fashion in order to promote cooperative and optimal usage of the buffers between the various processing units which manipulate them.

: This abstract class defines the core interface which is common to all buffers, whether it be vertex buffers, index buffers, texture memory or framebuffer memory etc.

: Buffers have the ability to be 'shadowed' in system memory, this is because the kinds of access allowed on hardware buffers is not always as flexible as that allowed for areas of system memory - for example it is often either impossible, or extremely undesirable from a performance standpoint to read from a hardware buffer; when writing to hardware buffers, you should also write every byte and do it sequentially. In situations where this is too restrictive, it is possible to create a hardware, write-only buffer (the most efficient kind) and to back it with a system memory 'shadow' copy which can be read and updated arbitrarily. Ogre handles synchronising this buffer with the real hardware buffer (which should still be created with the HBU_DYNAMIC flag if you intend to update it very frequently). Whilst this approach does have it's own costs, such as increased memory overhead, these costs can often be outweighed by the performance benefits of using a more hardware efficient buffer. You should look for the 'useShadowBuffer' parameter on the creation methods used to create the buffer of the type you require (see HardwareBufferManager) to enable this feature.

Definition at line 74 of file OgreHardwareBuffer.h.

Member Enumeration Documentation

◆ LockOptions

enum Ogre::HardwareBuffer::LockOptions

Locking options.

Enumerator
HBL_NORMAL	Normal mode, ie allows read/write and contents are preserved.
HBL_DISCARD	Discards the entire buffer while locking; this allows optimisation to be performed because synchronisation issues are relaxed. Only allowed on buffers created with the HBU_DYNAMIC flag.
HBL_READ_ONLY	Lock the buffer for reading only. Not allowed in buffers which are created with HBU_WRITE_ONLY. Mandatory on static buffers, i.e. those created without the HBU_DYNAMIC flag.
HBL_NO_OVERWRITE	As HBL_DISCARD, except the application guarantees not to overwrite any region of the buffer which has already been used in this frame, can allow some optimisation on some APIs.
HBL_WRITE_ONLY	Lock the buffer for writing only.

Definition at line 121 of file OgreHardwareBuffer.h.

◆ Usage

enum Ogre::HardwareBuffer::Usage

Enums describing buffer usage; not mutually exclusive.

Enumerator
HBU_STATIC	Static buffer which the application rarely modifies once created. Modifying the contents of this buffer will involve a performance hit.
HBU_DYNAMIC	Indicates the application would like to modify this buffer with the CPU fairly often. Buffers created with this flag will typically end up in AGP memory rather than video memory.
HBU_WRITE_ONLY	Indicates the application will never read the contents of the buffer back, it will only ever write data. Locking a buffer with this flag will ALWAYS return a pointer to new, blank memory rather than the memory associated with the contents of the buffer; this avoids DMA stalls because you can write to a new memory area while the previous one is being used.
HBU_DISCARDABLE	Indicates that the application will be refilling the contents of the buffer regularly (not just updating, but generating the contents from scratch), and therefore does not mind if the contents of the buffer are lost somehow and need to be recreated. This allows and additional level of optimisation on the buffer. This option only really makes sense when combined with HBU_DYNAMIC_WRITE_ONLY.
HBU_STATIC_WRITE_ONLY	Combination of HBU_STATIC and HBU_WRITE_ONLY.
HBU_DYNAMIC_WRITE_ONLY	Combination of HBU_DYNAMIC and HBU_WRITE_ONLY. If you use this, strongly consider using HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE instead if you update the entire contents of the buffer very regularly.
HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE	Combination of HBU_DYNAMIC, HBU_WRITE_ONLY and HBU_DISCARDABLE.

Definition at line 79 of file OgreHardwareBuffer.h.

Constructor & Destructor Documentation

◆ HardwareBuffer()

Ogre::HardwareBuffer::HardwareBuffer	(	Usage	usage,
		bool	systemMemory,
		bool	useShadowBuffer
	)

Constructor, to be called by HardwareBufferManager only.

Definition at line 161 of file OgreHardwareBuffer.h.

◆ ~HardwareBuffer()

virtual Ogre::HardwareBuffer::~HardwareBuffer ( )

virtual

Definition at line 176 of file OgreHardwareBuffer.h.

Member Function Documentation

◆ _updateFromShadow()

virtual void Ogre::HardwareBuffer::_updateFromShadow ( void )

virtual

Updates the real buffer from the shadow buffer, if required.

Definition at line 305 of file OgreHardwareBuffer.h.

References lockImpl(), and unlockImpl().

◆ copyData() [1/2]

virtual void Ogre::HardwareBuffer::copyData ( HardwareBuffer & srcBuffer )

virtual

Copy all data from another buffer into this one.

Remarks: Normally these buffers should be of identical size, but if they're not, the routine will use the smallest of the two sizes.

Definition at line 298 of file OgreHardwareBuffer.h.

References getSizeInBytes().

◆ copyData() [2/2]

virtual void Ogre::HardwareBuffer::copyData	(	HardwareBuffer &	srcBuffer,
		size_t	srcOffset,
		size_t	dstOffset,
		size_t	length,
		bool	discardWholeBuffer = `false`
	)

virtual

Copy data from another buffer into this one.

Remarks: Note that the source buffer must not be created with the usage HBU_WRITE_ONLY otherwise this will fail.

Parameters

srcBuffer	The buffer from which to read the copied data
srcOffset	Offset in the source buffer at which to start reading
dstOffset	Offset in the destination buffer to start writing
length	Length of the data to copy, in bytes.
discardWholeBuffer	If true, will discard the entire contents of this buffer before copying

Definition at line 284 of file OgreHardwareBuffer.h.

References lock(), and unlock().

◆ getSizeInBytes()

size_t Ogre::HardwareBuffer::getSizeInBytes ( void ) const

Returns the size of this buffer in bytes.

Definition at line 330 of file OgreHardwareBuffer.h.

Referenced by copyData().

◆ getUsage()

Usage Ogre::HardwareBuffer::getUsage ( void ) const

Returns the Usage flags with which this buffer was created.

Definition at line 332 of file OgreHardwareBuffer.h.

◆ hasShadowBuffer()

bool Ogre::HardwareBuffer::hasShadowBuffer ( void ) const

Returns whether this buffer has a system memory shadow for quicker reading.

Definition at line 336 of file OgreHardwareBuffer.h.

◆ isLocked()

bool Ogre::HardwareBuffer::isLocked ( void ) const

Returns whether or not this buffer is currently locked.

Definition at line 338 of file OgreHardwareBuffer.h.

References isLocked().

Referenced by isLocked(), and unlock().

◆ isSystemMemory()

bool Ogre::HardwareBuffer::isSystemMemory ( void ) const

Returns whether this buffer is held in system memory.

Definition at line 334 of file OgreHardwareBuffer.h.

◆ lock() [1/2]

void* Ogre::HardwareBuffer::lock ( LockOptions options )

Lock the entire buffer for (potentially) reading / writing.

Parameters

options Locking options

Returns: Pointer to the locked memory

Definition at line 220 of file OgreHardwareBuffer.h.

◆ lock() [2/2]

virtual void* Ogre::HardwareBuffer::lock	(	size_t	offset,
		size_t	length,
		LockOptions	options
	)

virtual

Lock the buffer for (potentially) reading / writing.

Parameters

offset	The byte offset from the start of the buffer to lock
length	The size of the area to lock, in bytes
options	Locking options

Returns: Pointer to the locked memory

Reimplemented in Ogre::HardwarePixelBuffer, Ogre::DefaultHardwareCounterBuffer, Ogre::DefaultHardwareUniformBuffer, Ogre::DefaultHardwareIndexBuffer, and Ogre::DefaultHardwareVertexBuffer.

Definition at line 183 of file OgreHardwareBuffer.h.

References Ogre::Exception::ERR_INVALIDPARAMS, lock(), and OGRE_EXCEPT.

Referenced by copyData(), and lock().

◆ lockImpl()

virtual void* Ogre::HardwareBuffer::lockImpl	(	size_t	offset,
		size_t	length,
		LockOptions	options
	)

protectedpure virtual

Internal implementation of lock()

Implemented in Ogre::HardwarePixelBuffer, Ogre::DefaultHardwareCounterBuffer, Ogre::DefaultHardwareUniformBuffer, Ogre::DefaultHardwareIndexBuffer, and Ogre::DefaultHardwareVertexBuffer.

Referenced by _updateFromShadow().

◆ operator delete() [1/3]

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete ( void * ptr )

inherited

Definition at line 96 of file OgreMemoryAllocatedObject.h.

◆ operator delete() [2/3]

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete	(	void *	ptr,
		const char *	,
		int	,
		const char *
	)

inherited

Definition at line 108 of file OgreMemoryAllocatedObject.h.

◆ operator delete() [3/3]

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete	(	void *	ptr,
		void *
	)

inherited

Definition at line 102 of file OgreMemoryAllocatedObject.h.

◆ operator delete[]() [1/2]

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete[] ( void * ptr )

inherited

Definition at line 113 of file OgreMemoryAllocatedObject.h.

◆ operator delete[]() [2/2]

template<class Alloc >

void Ogre::AllocatedObject< Alloc >::operator delete[]	(	void *	ptr,
		const char *	,
		int	,
		const char *
	)

inherited

Definition at line 119 of file OgreMemoryAllocatedObject.h.

◆ operator new() [1/3]

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new ( size_t sz )

inherited

Definition at line 73 of file OgreMemoryAllocatedObject.h.

◆ operator new() [2/3]

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new	(	size_t	sz,
		const char *	file,
		int	line,
		const char *	func
	)

inherited

operator new, with debug line info

Definition at line 68 of file OgreMemoryAllocatedObject.h.

◆ operator new() [3/3]

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new	(	size_t	sz,
		void *	ptr
	)

inherited

placement operator new

Definition at line 79 of file OgreMemoryAllocatedObject.h.

◆ operator new[]() [1/2]

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new[] ( size_t sz )

inherited

Definition at line 91 of file OgreMemoryAllocatedObject.h.

◆ operator new[]() [2/2]

template<class Alloc >

void* Ogre::AllocatedObject< Alloc >::operator new[]	(	size_t	sz,
		const char *	file,
		int	line,
		const char *	func
	)

inherited

array operator new, with debug line info

Definition at line 86 of file OgreMemoryAllocatedObject.h.

◆ readData()

virtual void Ogre::HardwareBuffer::readData	(	size_t	offset,
		size_t	length,
		void *	pDest
	)

pure virtual

Reads data from the buffer and places it in the memory pointed to by pDest.

Parameters

offset	The byte offset from the start of the buffer to read
length	The size of the area to read, in bytes
pDest	The area of memory in which to place the data, must be large enough to accommodate the data!

Implemented in Ogre::HardwarePixelBuffer, Ogre::DefaultHardwareCounterBuffer, Ogre::DefaultHardwareUniformBuffer, Ogre::DefaultHardwareIndexBuffer, and Ogre::DefaultHardwareVertexBuffer.

◆ suppressHardwareUpdate()

void Ogre::HardwareBuffer::suppressHardwareUpdate ( bool suppress )

Pass true to suppress hardware upload of shadow buffer changes.

Definition at line 342 of file OgreHardwareBuffer.h.

◆ unlock()

virtual void Ogre::HardwareBuffer::unlock ( void )

virtual

Releases the lock on this buffer.

Remarks: Locking and unlocking a buffer can, in some rare circumstances such as switching video modes whilst the buffer is locked, corrupt the contents of a buffer. This is pretty rare, but if it occurs, this method will throw an exception, meaning you must re-upload the data.

: Note that using the 'read' and 'write' forms of updating the buffer does not suffer from this problem, so if you want to be 100% sure your data will not be lost, use the 'read' and 'write' forms instead.

Reimplemented in Ogre::DefaultHardwareCounterBuffer, Ogre::DefaultHardwareUniformBuffer, Ogre::DefaultHardwareIndexBuffer, and Ogre::DefaultHardwareVertexBuffer.

Definition at line 236 of file OgreHardwareBuffer.h.

References isLocked(), and unlock().

Referenced by copyData(), and unlock().

◆ unlockImpl()

virtual void Ogre::HardwareBuffer::unlockImpl ( void )

protectedpure virtual

Internal implementation of unlock()

Implemented in Ogre::DefaultHardwareCounterBuffer, Ogre::DefaultHardwareUniformBuffer, Ogre::DefaultHardwareIndexBuffer, and Ogre::DefaultHardwareVertexBuffer.

Referenced by _updateFromShadow().

◆ writeData()

virtual void Ogre::HardwareBuffer::writeData	(	size_t	offset,
		size_t	length,
		const void *	pSource,
		bool	discardWholeBuffer = `false`
	)

pure virtual

Writes data to the buffer from an area of system memory; note that you must ensure that your buffer is big enough.

Parameters

offset	The byte offset from the start of the buffer to start writing
length	The size of the data to write to, in bytes
pSource	The source of the data to be written
discardWholeBuffer	If true, this allows the driver to discard the entire buffer when writing, such that DMA stalls can be avoided; use if you can.

Implemented in Ogre::HardwarePixelBuffer, Ogre::DefaultHardwareCounterBuffer, Ogre::DefaultHardwareUniformBuffer, Ogre::DefaultHardwareIndexBuffer, and Ogre::DefaultHardwareVertexBuffer.

Member Data Documentation

◆ mIsLocked

bool Ogre::HardwareBuffer::mIsLocked

protected

Definition at line 145 of file OgreHardwareBuffer.h.

◆ mLockSize

size_t Ogre::HardwareBuffer::mLockSize

protected

Definition at line 147 of file OgreHardwareBuffer.h.

◆ mLockStart

size_t Ogre::HardwareBuffer::mLockStart

protected

Definition at line 146 of file OgreHardwareBuffer.h.

◆ mShadowBuffer

HardwareBuffer* Ogre::HardwareBuffer::mShadowBuffer

protected

Definition at line 150 of file OgreHardwareBuffer.h.

◆ mShadowUpdated

bool Ogre::HardwareBuffer::mShadowUpdated

protected

Definition at line 151 of file OgreHardwareBuffer.h.

◆ mSizeInBytes

size_t Ogre::HardwareBuffer::mSizeInBytes

protected

Definition at line 143 of file OgreHardwareBuffer.h.

◆ mSuppressHardwareUpdate

bool Ogre::HardwareBuffer::mSuppressHardwareUpdate

protected

Definition at line 152 of file OgreHardwareBuffer.h.

◆ mSystemMemory

bool Ogre::HardwareBuffer::mSystemMemory

protected

Definition at line 148 of file OgreHardwareBuffer.h.

◆ mUsage

Usage Ogre::HardwareBuffer::mUsage

protected

Definition at line 144 of file OgreHardwareBuffer.h.

◆ mUseShadowBuffer

bool Ogre::HardwareBuffer::mUseShadowBuffer

protected

Definition at line 149 of file OgreHardwareBuffer.h.

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

OgreHardwareBuffer.h

Public Types

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Member Enumeration Documentation

◆ LockOptions

◆ Usage

Constructor & Destructor Documentation

◆ HardwareBuffer()

◆ ~HardwareBuffer()

Member Function Documentation

◆ _updateFromShadow()

◆ copyData() [1/2]

◆ copyData() [2/2]

◆ getSizeInBytes()

◆ getUsage()

◆ hasShadowBuffer()

◆ isLocked()

◆ isSystemMemory()

◆ lock() [1/2]

◆ lock() [2/2]

◆ lockImpl()

◆ operator delete() [1/3]

◆ operator delete() [2/3]

◆ operator delete() [3/3]

◆ operator delete[]() [1/2]

◆ operator delete[]() [2/2]

◆ operator new() [1/3]

◆ operator new() [2/3]

◆ operator new() [3/3]

◆ operator new[]() [1/2]

◆ operator new[]() [2/2]

◆ readData()

◆ suppressHardwareUpdate()

◆ unlock()

◆ unlockImpl()

◆ writeData()

Member Data Documentation

◆ mIsLocked

◆ mLockSize

◆ mLockStart

◆ mShadowBuffer

◆ mShadowUpdated

◆ mSizeInBytes

◆ mSuppressHardwareUpdate

◆ mSystemMemory

◆ mUsage

◆ mUseShadowBuffer