OGRE-Next  3.0.0unstable
Object-Oriented Graphics Rendering Engine
Ogre::AsyncTextureTicket Class Referenceabstract

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

#include <OgreAsyncTextureTicket.h>

+ Inheritance diagram for Ogre::AsyncTextureTicket:


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. More...
void download (TextureGpu *textureSrc, uint8 mipLevel, bool accurateTracking, TextureBox *srcBox=0, bool bImmediate=false)
 Downloads textureSrc into this ticket. More...
size_t getBytesPerImage () const
uint32 getBytesPerRow () const
uint32 getDepth () const
 For TypeCube & TypeCubeArray, this value returns 1. More...
uint32 getDepthOrSlices () const
uint32 getHeight () const
uint32 getNumSlices () const
 For TypeCube this value returns 6. More...
PixelFormatGpu getPixelFormatFamily () const
uint32 getWidth () const
TextureBox map (uint32 slice)
 Maps the buffer for CPU access. More...
void notifyTextureChanged (TextureGpu *texture, TextureGpuListener::Reason reason, void *extraData) override
 TextureGpuListener overload. More...
virtual bool queryIsTransferDone ()
void unmap ()
 Unmaps the pointer mapped with map(). More...
- 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. More...

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.

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


Constructor & Destructor Documentation

◆ AsyncTextureTicket()

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

◆ ~AsyncTextureTicket()

Ogre::AsyncTextureTicket::~AsyncTextureTicket ( )

Member Function Documentation

◆ canMapMoreThanOneSlice()

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

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.

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.
textureSrcTexture to download from. Must be resident.
mipLevelMip level to download.
accurateTrackingWhen 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.
srcBoxWhen 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!)
bImmediateWhen 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.

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

◆ notifyTextureChanged()

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

◆ queryIsTransferDone()

virtual bool Ogre::AsyncTextureTicket::queryIsTransferDone ( )

◆ unmap()

void Ogre::AsyncTextureTicket::unmap ( )

Unmaps the pointer mapped with map().

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