Re: Re: Terragear-devel Digest, Vol 9, Issue 1

On Tue, 6 Jan 2004, mat churchill wrote:

> Using Gimp i created an all black scenery tile with a white single pixel
> width border along the top and left hand edge only . I copied it to
> drycrop.rgb in the data/Textures/Terrain folder - drycrop being the
> predominant terrain in Cornwall.

*snip snip*

> Although it took a while to get to the point where I had the overlaid
> semi-transparent grid in Gimp, once I had it set up it was quick to do
> the same operation for a different tile in the grid or to slighty move
> the grid over the photo scenery to get it to line up correctly.

Ouch - I see what you mean about the time it takes!

> I'm going to try to follow what David Luffs mentioned just before
> christmas and here:
>
> http://www.mail-archive.com/[email protected]/msg18457.html
>
> My current questions are very basic apologies in advance.
>
>
> "As you say, defining a polygon with a custom name, and then defining
> the texture for that name to be the photo, works just fine."  How does
> this work?

Well, I fed this to tguserdef:

<?xml version="1.0"?>
<PropertyList>

 <polygon>
  <name>Wakefield Aerial</name>
  <material>Freeway</material>
  <contour>
   <hole>false</hole>
   <v>
    -1.54734 53.67561
    -1.39597 53.67494
    -1.39468 53.76482
    -1.54637 53.76549
   </v>
  </contour>
 </polygon>

</PropertyList>

I discovered that you can't use any old material (Ideally you'd want to
specify something unique in there, and add an entry to the materials.xml
file to match) so I just used Freeway as a placeholder.

> "If you give your polygons the extension .osgb36" - which polygons are
> these ?

I *think* this is the polygon files in the tree beneath the work
directory.

So in $work/User/w010n50/w002n53/ tguserdef created:

2925545.74106  2925546.74106  2925553.74106  2925554.74106

the filenames are tile.poly_id

I'm guessing that if the coordinates in there were specified in OSGB
coordinates then they would be tile.poly_id.osgb36

The problem is that when something spans multiple tiles it's not exactly
trivial to work out all the intersection points - tguserdef will do this
for you.

> "--useUKgrid at the construct stage". What stage of construction is this
> ?

normally you'd use a combination of fgfs-tools-client and
fgfs-tools-server to produce the scenery. fgfs-tools-client just makes
repeated calls to fgfs-construct, which does have the option of working
with OSGB aligned tiles.

> "I then chopped the images up along osgb36 grid lines". How? was this
> done using Image::Imlib2 perl library.

The getmapping data appears to be already OSGB aligned - which is why you
need to work to an OSGB grid internally - it avoids discontinuity in the
processed scenery.

> If anyone answers these questions could they include some example
> commands, this helps me a lot.  I'm happily building UK landmass by
> combining Gshhs coastline with srt-3 height data, so am not a 100%
> beginner.  but my learning curve has been rapidly accelerated by seeing
> the commands others have used. Been having a lot of fun in the process
> by the way !

I'm still busy with the RAF airfields - currently doing St Mawgan, so not
*too* far from finishing them. Once they're done I'll ship them all off to
Robin Peel for inclusion in the database.

-- 
Jon Stockill
[email protected]