Rejean Chartrand (rejeanc++at++cae.ca)
Mon, 13 Mar 95 19:31:27 EST
pfNodeTravFuncs specify the user supplied functions which are to be
invoked during the traversal indicated by which. For each traversal,
there is a pre and post traversal callback. pre is invoked before node
and its children are processed while post is invoked after. The pre- and
post- methodology supports save and restore or push and pop programming
constructs. Node callbacks are passed pointers to the user supplied
traversal data pointer for that node and a pfTraverser which defines the
current traversal state. pfGetNodeTravFuncs copies node's pre and post
callbacks of traversal type which into pre and post respectively.
The data argument to pfNodeTravData is the pointer which is passed to the
traversal callbacks indicated by which. Both pre- and post-callbacks
will be passed data in addition to a pfTraverser*. When multiprocessing,
data should point to memory in a shared arena. pfGetNodeTravData returns
the current data pointer for the specified traversal.
The pre- or post-callbacks for the cull and intersection traversals may
return PFTRAV_CONT, PFTRAV_PRUNE, PFTRAV_TERM to indicate that traversal
should continue normally, skip this node or terminate the traversal,
respectively. PFTRAV_PRUNE is equivalent to PFTRAV_CONT for the post-
callback.
Currently the return value from the draw callbacks is ignored.
[end of the abstract]
So, given that the return value from the draw callbacks are ignored, how
can I tell Performer that in the pre-callback I will be drawing myself
(for example) pfLightPoint since I cannot prevent Performer from drawing
the node using PFTRAV_PRUNE ? For sure I can draw in my own way a
pfLightPoint node but at the same time I cannot tell Performer not to
draw it since it is not looking at the return value PFTRAV_PRUNE from
the pre-callback !
Thanks in advance !
Rejean.
Rejean Chartrand.
CAE Electronics Ltd., Montreal CANADA
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