Abstract interface for lazily loading the individual time steps (frames) of a TemporalVolume. More...

#include <inviwo/core/datastructures/volume/temporalvolume.h>

Inheritance diagram for inviwo::TemporalVolumeLoader:

Public Member Functions
virtual std::shared_ptr< Volume >	load (size_t index, std::shared_ptr< Volume > reuse, std::stop_token stop) const =0

TemporalVolumeLoader &	operator= (const TemporalVolumeLoader &)=default

TemporalVolumeLoader &	operator= (TemporalVolumeLoader &&)=default

virtual VolumeConfig	prototype () const =0

virtual size_t	size () const =0
	Total number of frames.

	TemporalVolumeLoader (const TemporalVolumeLoader &)=default

	TemporalVolumeLoader (TemporalVolumeLoader &&)=default

virtual Seconds	time (size_t index) const =0

Detailed Description

Abstract interface for lazily loading the individual time steps (frames) of a TemporalVolume.

A TemporalVolumeLoader decouples the storage format from the time axis and cache management of TemporalVolume. Implementations are responsible only for loading a single frame by index and for providing the time axis and a metadata-only prototype VolumeConfig.

Note: Implementations of load() must be thread-safe since it may be called concurrently from a background thread pool. prototype() must be cheap and must not load any voxel data.

See also: TemporalVolume

Member Function Documentation

◆ load()

virtual std::shared_ptr< Volume > inviwo::TemporalVolumeLoader::load	(	size_t	index,
		std::shared_ptr< Volume >	reuse,
		std::stop_token	stop ) const

pure virtual

Load the volume at the given index. May be called from a background thread, hence implementations must be re-entrant and thread-safe.

Parameters

reuse	an optional volume whose storage may be reused to avoid reallocation. It may be null and must be ignored if its format or dimensions do not match the frame.
stop	cancellation token. Implementations should poll `stop.stop_requested()` at natural checkpoints and return nullptr as soon as a stop is requested. A partially written `reuse` volume is discarded by the caller.

Returns: the loaded volume, or nullptr if the load was cancelled.

Implemented in inviwo::ProceduralLoader, inviwo::FileSequenceLoader, and inviwo::hdf5::HDF5TemporalVolumeLoader.

◆ prototype()

virtual VolumeConfig inviwo::TemporalVolumeLoader::prototype ( ) const

pure virtual

A prototype VolumeConfig describing dimensions, format, basis, dataMap, and axes — but no voxel data. Used by downstream consumers that need metadata without triggering a load.

Implemented in inviwo::ProceduralLoader, inviwo::FileSequenceLoader, and inviwo::hdf5::HDF5TemporalVolumeLoader.