Thought I'd post this reply to an email from Stacie re photo scenery so
it will show up for anyone searching on the subject.
Hi Stacie,
The following is an outline of how I created the photo scenery. All the
working out of things such as the size of the squares on the "mystery
grid" was done purely by tedious trial and error. I can't write in any
computer language such as perl, so I processed the figures for the
larger grid of squares using a spreadsheet ! As such it is terrible
route to getting photo imagery into Flightgear. Having said that it does
work.
It could be improved dramatically if a few things were in place. Two
things would make the entire operation vastly simpler.
1. If someone was able to extract the lat/long information of the
"mystery grid" from Flightgear and use this directly to create the
grid of squares for the scenery build.
2. If tguserdef was able to attribute textures with any name then the
manual re attribution of texture type to each triangle could be
avoided.
If I was doing this again I would try to get these two things resolved before I
went ahead.
Someone could then write a perl script to automate much of the following.
Unfortunately I lost a hard drive not long after doing the photo
scenery, so I don't have the spreadsheets or xml files I used. Also if
the area you are building has coastline I also worked out a solution for
getting that to look OK.
Mat Churchill
*Flightgear places textures inside a mystery grid* (that I don't fully
understand). I have asked a couple of times on the forum and haven't got
an answer as to what it is. Textures are assigned a size (amongst other
things) in the materials.xml file. I think the ones with a size around
1000 seem to fit exactly into this grid, smaller ones are fitted into
the grid multiple times. To show the grid I created a texture that was
all black with a single pixel white border and loaded it into the scenery.
The resulting scenery looks like this:
http://www.projects.34sp.com/Flightgear/tn/a-Black-grid.jpg.html
*The boundaries of “texture areas” are built into the mesh itself*
If you look at this image above KSFO
http://www.projects.34sp.com/Flightgear/tn/textures-ksfo.jpg.html
And then look at the mesh of the same scenery you can see that when
terragear builds the scenery mesh the triangles not only create the
height data, but they also define the texture areas.
http://www.projects.34sp.com/Flightgear/tn/mesh-ksfo.jpg.html
As well as using the vmap0 data as described in 3.3 of
fg-scenery-tutorial
(http://www.terragear.org/docs/scenery-tutorial/fg-scenery-tutorial.html)
you can also create and define your own texture areas using the
tguserdef command in conjunction with your own .xml file containing the
required lat/long points.
**I created a grid of squares using tgusedef that exactly mimicked the
mystery grid.** I gave each square the property of LandMass.
Unfortunately tguserdef won't let you assign custom textures that you
have added in materials.xml, it fails unless you use one of the default
texture definitions (this may have been fixed by now) This is a big
drawback as it means you then have to find another way of subsequently
changing the assigned texture for each individual triangle in the mesh.
*
*Because the photo scenery provides all the land use data, you then only
need to run a very simple version of the build e.g.**
fgfs-tools-client --rude --min-angle=0 --output-dir=. --work-dir=. --port=33933
DEM-30 LandMass
**Then when I viewed the mesh I had built I could see the squares built
into the mesh*.*
I then cut up my photo image using chop.pl (/TerraGear/src/Prep/Photo)
into pieces that corresponded with the grid I made. I added each photo
square with the correct size to materials.xml
Then using Flightgear Scenery Designer I manually re-assigned each
triangle in the grid to correspond with the photo square I wanted to be
in that position.
Fire up FGFS and you have your photo scenery :-)
http://www.projects.34sp.com/Flightgear/
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