Angus Dorbie (dorbie++at++bitch.reading.sgi.com)
Mon, 10 Jul 1995 11:16:34 -0600
This would work, but you could also create three or more versions of the
model and add them below a pfSequence. If you model your river with s
coordinates across the river and t coordinates downstream then all you have
to do is scroll your texture vertically either using coordinates or different
textures (perhaps applied via a pfSequence).
>
> b) Develop a simulation program with objects (eg many vehicles) moving
> about in pre-defined paths. What kind of function calls do I need to
> use?
You'd add each object below a pfDCS and then update the 4x4 matrix information
held in the DCS, you do this in the application so no matter how you are
forking this appears single threaded from a programming point of view. Try man
pfMatrix to see lots of helpfull functions.
>
> c) Develop a program to interactively change colours and textures of
> polygons (eg change wall paper designs and colours for different
> walls in a house). Again what would be the most appropriate approach
> and calls?
You can change and override this kind of thing using draw callbacks for a
specific object, or modify the scene graph to accomplish the desired effect.
>
> d) This is the ambitious one. What should I be considering if I am to
> write code to interface Performer applications to a remote relational
> database (eg INFORMIX), such that when I bump into an object during
> flythrough, the system would respond by, for example, identifying
> the object that was bumped into. The sort of messages returned by the
> application should include responses to queries to a database. Some
> responses could include text or image data popping up in sub-windows.
> I was thinking along the lines of using something related to the
> intersection traversal.
Each performer node has a user data field which could be used to hold
some database information, you'd probably then want to pass this information
via shared memory or pipe to another process which would use this as a handle
on the database information. As for the collision detection using intersection,
this has been done before and there are examples with Performer.
>
> Cheers
Hope this helps.
-- Angus Dorbie, The Reality Centre, Silicon Graphics Ltd, UK dorbie++at++reading.sgi.com
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