OGRE  1.12.4
Object-Oriented Graphics Rendering Engine
Ogre::HardwarePixelBuffer Class Referenceabstract

Specialisation of HardwareBuffer for a pixel buffer. More...

#include <OgreHardwarePixelBuffer.h>

+ Inheritance diagram for Ogre::HardwarePixelBuffer:

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 = HBU_STATIC | HBU_WRITE_ONLY, HBU_DYNAMIC_WRITE_ONLY = HBU_DYNAMIC | HBU_WRITE_ONLY, HBU_DYNAMIC_WRITE_ONLY_DISCARDABLE = HBU_DYNAMIC_WRITE_ONLY | HBU_DISCARDABLE
}
 Enums describing buffer usage; not mutually exclusive. More...
 

Public Member Functions

 HardwarePixelBuffer (uint32 mWidth, uint32 mHeight, uint32 mDepth, PixelFormat mFormat, HardwareBuffer::Usage usage, bool useSystemMemory, bool useShadowBuffer)
 Should be called by HardwareBufferManager. More...
 
 ~HardwarePixelBuffer ()
 
virtual void _updateFromShadow (void)
 Updates the real buffer from the shadow buffer, if required. More...
 
virtual void blit (const HardwarePixelBufferSharedPtr &src, const Box &srcBox, const Box &dstBox)
 Copies a box from another PixelBuffer to a region of the this PixelBuffer. More...
 
void blit (const HardwarePixelBufferSharedPtr &src)
 Convenience function that blits the entire source pixel buffer to this buffer. More...
 
virtual void blitFromMemory (const PixelBox &src, const Box &dstBox)=0
 Copies a region from normal memory to a region of this pixelbuffer. More...
 
void blitFromMemory (const PixelBox &src)
 Convenience function that blits a pixelbox from memory to the entire buffer. More...
 
virtual void blitToMemory (const Box &srcBox, const PixelBox &dst)=0
 Copies a region of this pixelbuffer to normal memory. More...
 
void blitToMemory (const PixelBox &dst)
 Convenience function that blits this entire buffer to a pixelbox. 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...
 
virtual void copyData (HardwareBuffer &srcBuffer)
 Copy all data from another buffer into this one. More...
 
const PixelBoxgetCurrentLock ()
 Get the current locked region. More...
 
uint32 getDepth () const
 Gets the depth of this buffer. More...
 
PixelFormat getFormat () const
 Gets the native pixel format of this buffer. More...
 
uint32 getHeight () const
 Gets the height of this buffer. More...
 
virtual RenderTexturegetRenderTarget (size_t slice=0)
 Get a render target for this PixelBuffer, or a slice of it. 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...
 
uint32 getWidth () const
 Gets the width of this buffer. 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...
 
virtual const PixelBoxlock (const Box &lockBox, LockOptions options)
 Lock the 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 * lock (LockOptions options)
 
virtual void readData (size_t offset, size_t length, void *pDest)
 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)
 Writes data to the buffer from an area of system memory; note that you must ensure that your buffer is big enough. More...
 

Friends

class RenderTexture
 

Detailed Description

Specialisation of HardwareBuffer for a pixel buffer.

The HardwarePixelbuffer abstracts an 1D, 2D or 3D quantity of pixels stored by the rendering API. The buffer can be located on the card or in main memory depending on its usage. One mipmap level of a texture is an example of a HardwarePixelBuffer.

Member Enumeration Documentation

◆ 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.

This is the least optimal buffer setting.

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.

However, you may read from it’s shadow buffer if you set one up

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 This is the optimal buffer usage setting.

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 This means that you expect to replace the entire contents of the buffer on an extremely regular basis, most likely every frame.

By selecting this option, you free the system up from having to be concerned about losing the existing contents of the buffer at any time, because if it does lose them, you will be replacing them next frame anyway. On some platforms this can make a significant performance difference, so you should try to use this whenever you have a buffer you need to update regularly. Note that if you create a buffer this way, you should use the HBL_DISCARD flag when locking the contents of it for writing.

◆ LockOptions

Locking options.

Enumerator
HBL_NORMAL 

Normal mode, ie allows read/write and contents are preserved.

This kind of lock allows reading and writing from the buffer - it’s also the least optimal because basically you’re telling the card you could be doing anything at all. If you’re not using a shadow buffer, it requires the buffer to be transferred from the card and back again. If you’re using a shadow buffer the effect is minimal.

HBL_DISCARD 

Discards the entire buffer while locking.

This means you are happy for the card to discard the entire current contents of the buffer. Implicitly this means you are not going to read the data - it also means that the card can avoid any stalls if the buffer is currently being rendered from, because it will actually give you an entirely different one. Use this wherever possible when you are locking a buffer which was not created with a shadow buffer. If you are using a shadow buffer it matters less, although with a shadow buffer it’s preferable to lock the entire buffer at once, because that allows the shadow buffer to use HBL_DISCARD when it uploads the updated contents to the real buffer. 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.

This is only useful on buffers with no shadow buffer.

HBL_WRITE_ONLY 

Lock the buffer for writing only.

Constructor & Destructor Documentation

◆ HardwarePixelBuffer()

Ogre::HardwarePixelBuffer::HardwarePixelBuffer ( uint32  mWidth,
uint32  mHeight,
uint32  mDepth,
PixelFormat  mFormat,
HardwareBuffer::Usage  usage,
bool  useSystemMemory,
bool  useShadowBuffer 
)

Should be called by HardwareBufferManager.

◆ ~HardwarePixelBuffer()

Ogre::HardwarePixelBuffer::~HardwarePixelBuffer ( )

Member Function Documentation

◆ lock() [1/3]

virtual const PixelBox& Ogre::HardwarePixelBuffer::lock ( const Box lockBox,
LockOptions  options 
)
virtual

Lock the buffer for (potentially) reading / writing.

Parameters
lockBoxRegion of the buffer to lock
optionsLocking options
Returns
PixelBox containing the locked region, the pitches and the pixel format

◆ lock() [2/3]

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

Lock the buffer for (potentially) reading / writing.

Parameters
offsetThe byte offset from the start of the buffer to lock
lengthThe size of the area to lock, in bytes
optionsLocking options
Returns
Pointer to the locked memory

Reimplemented from Ogre::HardwareBuffer.

◆ getCurrentLock()

const PixelBox& Ogre::HardwarePixelBuffer::getCurrentLock ( )

Get the current locked region.

This is the same value as returned by lock(const Box, LockOptions)

Returns
PixelBox containing the locked region

◆ readData()

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

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

Parameters
offsetThe byte offset from the start of the buffer to read
lengthThe size of the area to read, in bytes
pDestThe area of memory in which to place the data, must be large enough to accommodate the data!

Implements Ogre::HardwareBuffer.

◆ writeData()

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

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

Parameters
offsetThe byte offset from the start of the buffer to start writing
lengthThe size of the data to write to, in bytes
pSourceThe source of the data to be written
discardWholeBufferIf true, this allows the driver to discard the entire buffer when writing, such that DMA stalls can be avoided; use if you can.

Implements Ogre::HardwareBuffer.

◆ blit() [1/2]

virtual void Ogre::HardwarePixelBuffer::blit ( const HardwarePixelBufferSharedPtr src,
const Box srcBox,
const Box dstBox 
)
virtual

Copies a box from another PixelBuffer to a region of the this PixelBuffer.

Parameters
srcSource pixel buffer
srcBoxBox describing the source region in src
dstBoxBox describing the destination region in this buffer
Remarks
The source and destination regions dimensions don't have to match, in which case scaling is done. This scaling is generally done using a bilinear filter in hardware, but it is faster to pass the source image in the right dimensions.
Note
Only call this function when both buffers are unlocked.

Reimplemented in Ogre::D3D9HardwarePixelBuffer, Ogre::GLES2TextureBuffer, Ogre::GLTextureBuffer, Ogre::D3D11HardwarePixelBuffer, and Ogre::GL3PlusTextureBuffer.

◆ blit() [2/2]

void Ogre::HardwarePixelBuffer::blit ( const HardwarePixelBufferSharedPtr src)

Convenience function that blits the entire source pixel buffer to this buffer.

If source and destination dimensions don't match, scaling is done.

Parameters
srcPixelBox containing the source pixels and format in memory
Note
Only call this function when the buffer is unlocked.

◆ blitFromMemory() [1/2]

virtual void Ogre::HardwarePixelBuffer::blitFromMemory ( const PixelBox src,
const Box dstBox 
)
pure virtual

Copies a region from normal memory to a region of this pixelbuffer.

The source image can be in any pixel format supported by OGRE, and in any size.

Parameters
srcPixelBox containing the source pixels and format in memory
dstBoxBox describing the destination region in this buffer
Remarks
The source and destination regions dimensions don't have to match, in which case scaling is done. This scaling is generally done using a bilinear filter in hardware, but it is faster to pass the source image in the right dimensions.
Note
Only call this function when the buffer is unlocked.

Implemented in Ogre::D3D9HardwarePixelBuffer, Ogre::D3D11HardwarePixelBuffer, Ogre::GLES2TextureBuffer, Ogre::GLTextureBuffer, Ogre::GL3PlusTextureBuffer, Ogre::GL3PlusHardwarePixelBuffer, Ogre::GLES2HardwarePixelBuffer, and Ogre::GLHardwarePixelBuffer.

◆ blitFromMemory() [2/2]

void Ogre::HardwarePixelBuffer::blitFromMemory ( const PixelBox src)
inline

Convenience function that blits a pixelbox from memory to the entire buffer.

The source image is scaled as needed.

Parameters
srcPixelBox containing the source pixels and format in memory
Note
Only call this function when the buffer is unlocked.

◆ blitToMemory() [1/2]

virtual void Ogre::HardwarePixelBuffer::blitToMemory ( const Box srcBox,
const PixelBox dst 
)
pure virtual

Copies a region of this pixelbuffer to normal memory.

Parameters
srcBoxBox describing the source region of this buffer
dstPixelBox describing the destination pixels and format in memory
Remarks
The source and destination regions don't have to match, in which case scaling is done.
Note
Only call this function when the buffer is unlocked.

Implemented in Ogre::D3D9HardwarePixelBuffer, Ogre::D3D11HardwarePixelBuffer, Ogre::GL3PlusHardwarePixelBuffer, Ogre::GLES2HardwarePixelBuffer, and Ogre::GLHardwarePixelBuffer.

◆ blitToMemory() [2/2]

void Ogre::HardwarePixelBuffer::blitToMemory ( const PixelBox dst)
inline

Convenience function that blits this entire buffer to a pixelbox.

The image is scaled as needed.

Parameters
dstPixelBox describing the destination pixels and format in memory
Note
Only call this function when the buffer is unlocked.

◆ getRenderTarget()

virtual RenderTexture* Ogre::HardwarePixelBuffer::getRenderTarget ( size_t  slice = 0)
virtual

Get a render target for this PixelBuffer, or a slice of it.

The texture this was acquired from must have TU_RENDERTARGET set, otherwise it is possible to render to it and this method will throw an ERR_RENDERSYSTEM exception.

Parameters
sliceWhich slice
Returns
A pointer to the render target. This pointer has the lifespan of this PixelBuffer.

Reimplemented in Ogre::D3D9HardwarePixelBuffer, Ogre::D3D11HardwarePixelBuffer, Ogre::GLES2TextureBuffer, Ogre::GLTextureBuffer, and Ogre::GL3PlusTextureBuffer.

◆ getWidth()

uint32 Ogre::HardwarePixelBuffer::getWidth ( ) const
inline

Gets the width of this buffer.

◆ getHeight()

uint32 Ogre::HardwarePixelBuffer::getHeight ( ) const
inline

Gets the height of this buffer.

◆ getDepth()

uint32 Ogre::HardwarePixelBuffer::getDepth ( ) const
inline

Gets the depth of this buffer.

◆ getFormat()

PixelFormat Ogre::HardwarePixelBuffer::getFormat ( ) const
inline

Gets the native pixel format of this buffer.

◆ lock() [3/3]

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

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

◆ unlock()

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

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, Ogre::DefaultHardwareVertexBuffer, Ogre::D3D11HardwareUniformBuffer, Ogre::D3D11HardwareVertexBuffer, and Ogre::D3D11HardwareIndexBuffer.

Referenced by Ogre::HardwareBuffer::copyData(), and Ogre::Lod0Stripifier::~Lod0Stripifier().

◆ copyData() [1/2]

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

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
srcBufferThe buffer from which to read the copied data
srcOffsetOffset in the source buffer at which to start reading
dstOffsetOffset in the destination buffer to start writing
lengthLength of the data to copy, in bytes.
discardWholeBufferIf true, will discard the entire contents of this buffer before copying

Reimplemented in Ogre::D3D11HardwareBuffer, Ogre::GLES2HardwareIndexBuffer, Ogre::GLES2HardwareVertexBuffer, Ogre::GL3PlusHardwareShaderStorageBuffer, Ogre::GL3PlusHardwareUniformBuffer, Ogre::GLES2HardwareUniformBuffer, Ogre::GL3PlusHardwareCounterBuffer, Ogre::GL3PlusHardwareVertexBuffer, Ogre::GL3PlusHardwareIndexBuffer, Ogre::D3D11HardwareUniformBuffer, Ogre::D3D11HardwareVertexBuffer, and Ogre::D3D11HardwareIndexBuffer.

References Ogre::HardwareBuffer::lock(), and Ogre::HardwareBuffer::unlock().

◆ copyData() [2/2]

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

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.

References Ogre::HardwareBuffer::getSizeInBytes().

◆ _updateFromShadow()

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

◆ getSizeInBytes()

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

Returns the size of this buffer in bytes.

Referenced by Ogre::HardwareBuffer::copyData().

◆ getUsage()

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

Returns the Usage flags with which this buffer was created.

Referenced by Ogre::Lod0Stripifier::~Lod0Stripifier().

◆ isSystemMemory()

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

Returns whether this buffer is held in system memory.

◆ hasShadowBuffer()

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

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

Referenced by Ogre::Lod0Stripifier::~Lod0Stripifier().

◆ isLocked()

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

Returns whether or not this buffer is currently locked.

◆ suppressHardwareUpdate()

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

Pass true to suppress hardware upload of shadow buffer changes.

Friends And Related Function Documentation

◆ RenderTexture

friend class RenderTexture
friend

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