Add cave world generator

[iche033]

Update: Updated code to work with both Cave Type A and Type B tiles. Added an extra -t <type> arg that lets user specify the type of cave to create: anastomotic - creates world using Type A tiles, rectilinear - creates world using Type B tiles, and curvilinear - creates world using Type A and Type B tiles. Also updated PR description.

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Added world_generator_cave that generates a world from type A and type B tiles. The tool constructs a world from a collection of prefab world sections and certain individual tiles. Note that the code is currently specific to Cave Type A and Type B Tiles.

Some options are available:

Usage: world_generator_cave [options]
Options:
    -h		 Print this help message
    -o <file>	 Output sdf filename
    -s <seed>	 Seed
    -c <count>	 Min tile count
    -n <name>	 World name
    -t <type>	 Cave Type:
             	    'anastomotic' or 'a',
             	    'curvilinear' or 'c',
             	    'rectilinear' or 'r'
    -g		 Generate sdf with GUI plugin

You can generate a different world by setting a different seed value and minimum tile count.

Note the optional g arg that lets users generate a world sdf with GUI plugin, which is useful for viewing the world without launching the whole subt stack. Leave out the g arg when generating the final world.

Example usage:

./install/share/subt_ign/world_generator_cave -g -t a -c 60 -n cave_test -s 25 -o cave_test.sdf

If you do not have the Cave Type A and Type B tiles in your fuel cache, the tool will go and download them as it needs to compute bounding box info for these tiles in order to do intersection checks.

View the world using ign-gazebo

ign gazebo -v 4 cave_test.sdf

Signed-off-by: Ian Chen ichen@osrfoundation.org

[caguero]

It worked for me! I just left one minor comment about Ignition-fuel-tools4.

[caguero]

So far master uses Ignition Blueprint and that contains ignition-fuel-tools3. Just checking if this is expected...

[iche033]

good catch, fixed in 3972783

[angelacmaio]

Should all tiles be static?

[iche033]

yes they should be static. The models are actually already marked as static in the model.sdf file so this is probably redundant. I added this to be consistent with the existing world files.

[angelacmaio]

Should all caps be static?

[iche033]

yes same as the tiles