Programming with QuickTime VR

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QTVRBeginUpdateStream

You can use the QTVRBeginUpdateStream function to begin a stream of immediate updates to a QuickTime VR movie.

OSErr QTVRBeginUpdateStream (
                     QTVRInstance qtvr,
                     QTVRImagingModeimagingMode);
qtvr
An instance of a QuickTime VR movie.
imagingMode
An imaging mode. See "Imaging Modes" for a description of the available imaging modes.
function result
A result code.

DESCRIPTION

The QTVRBeginUpdateStream function configures the QuickTime VR movie specified by the qtvr parameter for a stream of immediate updates to its movie image. After calling QTVRBeginUpdateStream , you perform the updates by calling QTVRUpdate . When you are finished performing the updates, call QTVREndUpdateStream . Issuing a stream of image updates in this manner is significantly faster than simply calling QTVRUpdate repeatedly (that is, not within a begin/end update sequence).

Each call to QTVRBeginUpdateStream must be balanced by a call to QTVREndUpdateStream , but you can nest these calls.

SPECIAL CONSIDERATIONS

After you call QTVRBeginUpdateStream and before you call QTVREndUpdateStream , you must not change any of the QuickTime VR movie's imaging properties.

Calling QTVRBeginUpdateStream locks down large blocks of memory. As a result, you should minimize the amount of time before calling QTVREndUpdateStream .

QTVRBeginUpdateStream is valid only for panoramic nodes.

SEE ALSO

Use QTVREndUpdateStream (next) to end a stream of immediate updates to a QuickTime VR movie.

© 1997 Apple Computer, Inc.

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