kOfxImageEffectInstancePropSequentialRender
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Name

kOfxImageEffectInstancePropSequentialRender — Indicates whether a plugin needs sequential rendering, and a host support it

Synopsis

#include "/ofxImageEffect.h"
#define kOfxImageEffectInstancePropSequentialRender "OfxImageEffectInstancePropSequentialRender"

Type

kOfxImageEffectInstancePropSequentialRender is of type int, and has only a single dimension.

Property Set

This is a property that belongs to the plugin descriptor (read/write) or plugin instance (read/write), and host descriptor (read only).

Default

The default value is 0.

Valid Values

  • 0 - for a plugin, indicates that a plugin does not need to be sequentially rendered to be correct, for a host, indicates that it cannot ever guarantee sequential rendering,
  • 1 - for a plugin, indicates that it needs to be sequentially rendered to be correct, for a host, indicates that it can always support sequential rendering of plugins that are sequentially rendered,
  • 2 - for a plugin, indicates that it is best to render sequentially, but will still produce correct results if not, for a host, indicates that it can sometimes render sequentially, and will have set kOfxImageEffectPropSequentialRenderStatus on the relevant actions

Description

Indicates whether a plugin needs sequential rendering, and a host support it

Some effects have temporal dependancies, some information from from the rendering of frame N-1 is needed to render frame N correctly. This property is set by an effect to indicate such a situation. Also, some effects are more efficient if they run sequentially, but can still render correct images even if they do not, eg: a complex particle system.

During an interactive session a host may attempt to render a frame out of sequence (for example when the user scrubs the current time), and the effect needs to deal with such a situation as best it can to provide feedback to the user.

However if a host caches output, any frame frame generated in random temporal order needs to be considered invalid and needs to be re-rendered when the host finally performs a first to last render of the output sequence.

In all cases, a host will set the kOfxImageEffectPropSequentialRenderStatus flag to indicate its sequential render status.

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