Dan Brockway (db++at++ParadigmSim.com)
Tue, 10 Mar 1998 13:31:10 -0600
Michael is right. You can populate part of the square clip map
definition. Your sub set area need not be a power of two, just a
multiple of your tile size.
You will need to create a border of tiles outside the area you plan to
use. This border will ensure that as your clip center moves to the edge
of your defined area, that there are texels to fill the clip area at
each level.
So for example, If you clip_size is 1024 then as the clip center gets to
the edge, 512 the clip area will be hanging off the populated area by
512 texels. So add a border tile to every level. The contents of the
border tiles can be a symbolic link to any other tile. This will use up
little disk space and, if all the other clip parameters are well
managed, will never be seen.
Dan
and your tile size is 512. the clip area
Michael A. Coleman wrote:
>
> perfly++at++segolene.roazhon.inra.fr wrote:
> >
> > Salut,
> >
> > is it possible to use non-square clipmaps ? (ex: 32768x8192)
> >
> > Kenavo
> > =======================================================================
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>
> One can stuff a non-square texture into a square clipmap; we had to do
> this. Decide which square power of two you want to go to and then stuff
> your image into half or fourth or eighth (or whatever your nearest
> power-of-two aspect ratio is) of the cliptexture. Your image cache
> files still have to refer to a square cliptexture. The trick is
> positioning your eyepoint so that you never look at the areas of the
> entire cliptexture that don't correspond to your actual image. We set
> up blank tiles of various sizes to cover the "undefined" area of the
> cliptexture.
>
> There may be a better way to do this, but this is what we came up with.
> We did this quite a bit of time ago, so my explanation is a little hazy.
>
> Regards,
>
> Michael A. Coleman
> mcoleman++at++txdirect.net
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