Re: [Plib-devel] How do I?

[Steve B. <sjb...@ai...>]

Brad Colbert wrote:

> Is there an easy way to find out what the "texture-memory-footprint"
> of my frustum is?  Meaning, how much texture am I rendering (in
> memory usage) within my current field of view.

I can't think of a way to do that short of manually transforming
each polygon and doing some pretty heavy math.

>  I want to calculate
> what my next frame texture demands may be so that I can fiddle with
> the LOD's and terrain tiles in order to keep my texture memory footprint
> within the graphics hardwares available memory.

Well, I guess if your maximum turn rate is low enough - and you
have enough spare bandwidth into the graphics card, this could
work out...but in the kinds of things I've dealt with, you'd
have to cut your polygons and fill rate down pretty low to get
enough texture into the card for a 'reasonable' turn rate.
 
> I'm leaning towards creating a class that all of my virtual objects
> inherit from and having those objects throw their names on the name
> stack.  Then I could render into the selection buffer and pull off which
> objects where rendered and then query there LOD and texture size.
> Summed up this could give me something close to what I want, but
> this doesn't allow me to plan ahead, and I blow a frame or two.

So cull to a field of view that's wider than the actual field of view
by twice the maximum turn rate in both directions.  That gives you
your two frames of decision time.
 
> Or, I guess I could add a cull and then do basically the same process as above
> (without the render to the selection buffer).

Perhaps.

> Any ideas or discussions on the above would be great.
> 
> I feel like I'm opening a can of worms here.

Yep - it seems like a pretty desperate measure.

-- 
Steve Baker                  http://web2.airmail.net/sjbaker1
sjb...@ai... (home)  http://www.woodsoup.org/~sbaker
sj...@ht...      (work)