Re: Calling pfDraw twice....
John Rohlf (jrohlf++at++tubes)
Tue, 22 Mar 94 17:22:29 PST
>
>
> How can one render objects in the pfScene to the same frame number when the
> objects are located in different parts of the view frustrum, separated by a
> delta view voulme in which objects should not be rendered?
>
>
> | NearPlane=1.0 FarPlane=100.0 NearPlane=500.0 FarPlane=10000.0
> | | | | |
> | | | | |
> ----> |--------------------------------------------------------------------
> | | | | |
> | | | | |
> | Draw objects No drawing Draw objects
> View direction
> and viewplane
>
> Basically I want to do the following:
>
> 0. Clear channel.
> 1. Cull scene against the view volume defined by near=1.0, far=100.0.
> 2. Draw the objects which were not culled, i.e. the display list.
> 3. Cull scene against the view volume defined by near=500.0, far=10000.0
> 4. Draw the new objects which were not culled, i.e a new display list.
> 5. Swap buffers, and start over at 0.
>
> How can this be done?
>
Use 2 pfChannels. Give each channel a different frustum as
you've illustrated above and combine them into a channel group
with pfAttachChan so they can share attributes like view point and
view direction, viewport, etc. Just make sure that the second channel
doesn't clear the frame buffer and wipe out the results of the
first. This should be easy to do in the draw callback.
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on Mon Aug 10 1998 - 17:50:13 PDT