[vtkusers] Animation (was Re: VRMLServer examples)

[Sebastien BARRE]

At 04/12/2000 14:25, Christian Poecher wrote:
>Info on video creation is on:
>http://www.rug.nl/hpc/VTK/vtk/output/man.html

If someone wants to implement basic animation stuff, I'd also advise to 
look at KeyBottle and stuff. Then implement something running asynchronously.

For example, I made two classes : KeyFramers are used to record or set the 
parameters of whatever VTK object. They maintain a list of valued keys and 
interpolate between them using splines. Usual stuff.

They are registred to a KeyScheduler that is used to drive the animation : 
on recording, it asks each KeyFramer to record a new value key 
asynchronously (say for example, 5 times by second). On playing, it asks 
them to interpolate the parameters  (say, 30 times by second). It's a bit 
more tricky : you do not ask the exact number of frame per sec. on playing, 
but the duration of the recorded animation to playback : then, it will use 
the fastest possible framerate and adjust it during the animation so that 
it wil never be late. That's the big picture. Not a big deal anyway. It 
someone is interested, I might clean it up and give it away next year.

It looks like this :

set viewport [lindex [$widget get_viewports] 0]
set camera [$viewport GetActiveCamera]

::sb::vtkoo::KeyFramer keyfpos \
         -runmethod "$camera SetPosition" \
         -recordmethod "$camera GetPosition" \

::sb::vtkoo::KeyFramer keyffp \
         -runmethod "$camera SetFocalPoint" \
         -recordmethod "$camera GetFocalPoint" \

::sb::vtkoo::KeyScheduler keys \
         -runfps 25 \
         -recordaps 5 \
         -messagecommand {set ::messagevar %s} \
         -runprogressvar ::messagevar \
         -runcallback "$widget camera_has_changed $viewport ;   $widget 
render $viewport"

keys insert_child end keyfpos keyffp

bind $d <Key-F1> {keys run}
bind $d <Key-F2> {keys stop}

bind $d <Key-F6> {keys record -duration 60000}