Ogre::AsyncTextureTicket Class Reference

In Ogre 2.2 reading data from GPU back to CPU is asynchronous. More...

#include <OgreAsyncTextureTicket.h>

Inheritance diagram for Ogre::AsyncTextureTicket:

Classes
struct	DelayedDownload

Public Types
enum	Status { Ready , Downloading , Mapped }
Public Types inherited from Ogre::TextureGpuListener
enum	Reason {   Unknown , FromStorageToSysRam , FromSysRamToStorage , GainedResidency ,   LostResidency , PoolTextureSlotChanged , ResidentToSysRamSync , MetadataCacheOutOfDate ,   ExceptionThrown , FsaaSettingAlteredByApi , ReadyForRendering , Deleted }

Public Member Functions
	AsyncTextureTicket (uint32 width, uint32 height, uint32 depthOrSlices, TextureTypes::TextureTypes textureType, PixelFormatGpu pixelFormatFamily)
	~AsyncTextureTicket () override
virtual bool	canMapMoreThanOneSlice () const
	See Image2::convertFromTexture for an example of how to use AyncTextureTicket.
void	download (TextureGpu *textureSrc, uint8 mipLevel, bool accurateTracking, TextureBox *srcBox=0, bool bImmediate=false)
	Downloads textureSrc into this ticket.
size_t	getBytesPerImage () const
uint32	getBytesPerRow () const
uint32	getDepth () const
	For TypeCube & TypeCubeArray, this value returns 1.
uint32	getDepthOrSlices () const
uint32	getHeight () const
uint32	getNumSlices () const
	For TypeCube this value returns 6.
PixelFormatGpu	getPixelFormatFamily () const
uint32	getWidth () const
TextureBox	map (uint32 slice)
	Maps the buffer for CPU access.
void	notifyTextureChanged (TextureGpu *texture, TextureGpuListener::Reason reason, void *extraData) override
	TextureGpuListener overload.
virtual bool	queryIsTransferDone ()
void	unmap ()
	Unmaps the pointer mapped with map().
Public Member Functions inherited from Ogre::TextureGpuListener
virtual	~TextureGpuListener ()
virtual bool	shouldStayLoaded (TextureGpu *texture)
	Return true if this TextureGpu should likely stay loaded or else graphical changes could occur.

Detailed Description

In Ogre 2.2 reading data from GPU back to CPU is asynchronous.

See TextureGpuManager::createAsyncTextureTicket to generate a ticket. While the async transfer is being performed, you should be doing something else.

Remarks

If you call map() before the transfer is done, it will produce a stall as the CPU must wait for the GPU to finish all its pending operations.

Use queryIsTransferDone to query if the transfer has finished. Beware not all APIs support querying async transfer status. In those cases there is no reliable way to determine when the transfer is done. An almost safe bet is to wait two frames before mapping.

Call TextureGpuManager::destroyAsyncTextureTicket when you're done with this ticket.

Member Enumeration Documentation

Status

enum Ogre::AsyncTextureTicket::Status

Enumerator
Ready
Downloading
Mapped

Constructor & Destructor Documentation

AsyncTextureTicket()

Ogre::AsyncTextureTicket::AsyncTextureTicket	(	uint32	width,
		uint32	height,
		uint32	depthOrSlices,
		TextureTypes::TextureTypes	textureType,
		PixelFormatGpu	pixelFormatFamily
	)

~AsyncTextureTicket()

Ogre::AsyncTextureTicket::~AsyncTextureTicket ( )

override

Member Function Documentation

canMapMoreThanOneSlice()

virtual bool Ogre::AsyncTextureTicket::canMapMoreThanOneSlice ( ) const

inlinevirtual

See Image2::convertFromTexture for an example of how to use AyncTextureTicket.

download()

void Ogre::AsyncTextureTicket::download	(	TextureGpu *	textureSrc,
		uint8	mipLevel,
		bool	accurateTracking,
		TextureBox *	srcBox = 0,
		bool	bImmediate = false
	)

Downloads textureSrc into this ticket.

The size (resolution) of this ticket must match exactly of the region to download.

Remarks

The texture must either be Resident, or being streamed (i.e. scheduled to become Resident) If the texture isn't done streaming, the ticket will automatically schedule itself to perform the actual download once the streaming is done. If the Texture has a SystemRAM copy, it won't be used. You must access that directly, not via AsyncTextureTicket.

Parameters

textureSrc	Texture to download from. Must be resident.
mipLevel	Mip level to download.
accurateTracking	When false, you will be mapping this texture much further along (i.e. after 2-3 frames) Useful when constantly streaming GPU content to the CPU with 3 frames delay. When true, we will accurately track the status of this transfer, which has higher driver overhead.
srcBox	When nullptr, we'll download the whole texture (its selected mip level) When not nullptr, we'll download the region within the texture. This region must resolution must match exactly that of this ticket (e.g. bytesPerRow may be much bigger than you expect!)
bImmediate	When bImmediate is true, we will download from the GPU if texture is currently resident and ready; even if there are pending residency changes. If it's not ready, we'll listen for when it is.

getBytesPerImage()

size_t Ogre::AsyncTextureTicket::getBytesPerImage

(

)

const

getBytesPerRow()

uint32 Ogre::AsyncTextureTicket::getBytesPerRow

(

)

const

getDepth()

uint32 Ogre::AsyncTextureTicket::getDepth

(

)

const

For TypeCube & TypeCubeArray, this value returns 1.

getDepthOrSlices()

uint32 Ogre::AsyncTextureTicket::getDepthOrSlices

(

)

const

getHeight()

uint32 Ogre::AsyncTextureTicket::getHeight

(

)

const

getNumSlices()

uint32 Ogre::AsyncTextureTicket::getNumSlices

(

)

const

For TypeCube this value returns 6.

For TypeCubeArray, value returns numSlices * 6u.

getPixelFormatFamily()

PixelFormatGpu Ogre::AsyncTextureTicket::getPixelFormatFamily

(

)

const

getWidth()

uint32 Ogre::AsyncTextureTicket::getWidth

(

)

const

map()

TextureBox Ogre::AsyncTextureTicket::map

(

uint32

slice

)

Maps the buffer for CPU access.

Will stall if transfer from GPU memory to staging area hasn't finished yet. See queryIsTransferDone.

Remarks

Attempting to write to the returned pointer is undefined behavior. Be careful of TextureBox::bytesPerRow & bytesPerImage, when downloading a subregion of a texture, these values may not always be what you expect.

NOTE: When mapping a texture bigger than 2048x2048; in D3D11 the the returned pointer will return TextureBox::numSlices = 1, In this case you will have to use that slice, unmap this ticket, and map it again with the next slice.

See Image2::convertFromTexture for an example of how to use AyncTextureTicket

Parameters

slice

First slice to map. Textures below 2048x2048 are guaranteed to be able to access [slice; getNumSlices). Textures above that will only be able to access [slice; slice+1)

Returns

The pointer with the data read from the GPU. Read only.

notifyTextureChanged()

void Ogre::AsyncTextureTicket::notifyTextureChanged ( TextureGpu *  texture, TextureGpuListener::Reason  reason, void *  extraData  )

overridevirtual

TextureGpuListener overload.

Implements Ogre::TextureGpuListener.

queryIsTransferDone()

virtual bool Ogre::AsyncTextureTicket::queryIsTransferDone ( )

virtual

Reimplemented in Ogre::D3D11AsyncTextureTicket, Ogre::GL3PlusAsyncTextureTicket, Ogre::MetalAsyncTextureTicket, Ogre::NULLAsyncTextureTicket, and Ogre::VulkanAsyncTextureTicket.

unmap()

void Ogre::AsyncTextureTicket::unmap

(

)

Unmaps the pointer mapped with map().

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

• OgreAsyncTextureTicket.h