Portuguese Ledge world

README.md

@@ -490,6 +490,45 @@ for example:
 1. `~/lrauv_ws/src/lrauv-application-2/bin/LRAUV`
 1. Start more `bin/LRAUV` as needed
 
+## Levels
+
+Some worlds support [levels](https://ignitionrobotics.org/api/gazebo/6.7/levels.html).
+Levels are turned off by default, which means that all heightmap tiles will
+be loaded at all times. When levels are enabled, only the tiles containing
+vehicles (performers) spawned with `WorldCommPlugin` with an
+[lrauv_init](https://github.com/osrf/lrauv/blob/main/lrauv_ignition_plugins/proto/lrauv_init.proto)
+message will be loaded.
+
+For example, loading without levels:
+
+`ign gazebo -v 4 portuguese_ledge.sdf`
+
+![portuguese_ledge_no_levels](https://user-images.githubusercontent.com/5751272/159629754-9206a9fe-eeed-4afc-a516-5c25a9fbdaf6.png)
+
+And with levels:
+
+`ign gazebo -v 4 portuguese_ledge.sdf --levels`
+
+![portuguese_ledge_no_levels](https://user-images.githubusercontent.com/5751272/159813230-809d1cad-b3f5-457a-af19-3752bec0710f.gif)
+
+#### Generating Portuguese Ledge world
+
+The generated file is committed to the repository. Whenever it is changed, a
+manual step is needed to regenerate it.
+
+Pre-requisites:
+
+```
+sudo apt install python3-empy
+```
+
+Generate:
+
+```
+cd lrauv_ignition_plugins/worlds
+python3 portuguese_ledge.py
+```
+
 ### Troubleshoot
 
 After issuing control commands, for example, rudder and thrust, if you then

lrauv_ignition_plugins/src/WorldCommPlugin.cc

@@ -103,6 +103,7 @@ void WorldCommPlugin::Configure(
 
   // Services
   this->createService = "/world/" + topicWorldName + "/create";
+  this->performerService = "/world/" + topicWorldName + "/level/set_performer";
   this->setSphericalCoordsService = "/world/" + topicWorldName
     + "/set_spherical_coordinates";
 
@@ -213,6 +214,18 @@ void WorldCommPlugin::SpawnCallback(
     ignerr << "Failed to request service [" << this->createService
            << "]" << std::endl;
   }
+  else
+  {
+    // Make spawned model a performer
+    ignition::msgs::StringMsg performerReq;
+    performerReq.set_data(_msg.id_().data());
+    if (!this->node.Request(this->performerService, performerReq,
+        &WorldCommPlugin::ServiceResponse, this))
+    {
+      ignerr << "Failed to request service [" << this->performerService
+             << "]" << std::endl;
+    }
+  }
 }
 
 /////////////////////////////////////////////////

lrauv_ignition_plugins/src/WorldCommPlugin.hh

@@ -80,6 +80,9 @@ namespace tethys
     /// Service to create entities
     private: std::string createService;
 
+    /// Service to make spawned entities performers (for levels)
+    private: std::string performerService;
+
     /// Whether the world origin's latitude and longitude have already been set.
     private: bool hasWorldLatLon{false};
   };

lrauv_ignition_plugins/worlds/portuguese_ledge.py

@@ -0,0 +1,17 @@
+# Takes in a template and generates an SDF file.
+
+import em
+import os
+import sys
+
+def main():
+    in_file = 'portuguese_ledge.sdf.em'
+    out_file = 'portuguese_ledge.sdf'
+    template = open(in_file).read()
+    arguments = {}
+    result = em.expand(template, arguments)
+    with open(os.path.join(out_file), 'w') as outfile:
+        outfile.write(result)
+
+if __name__ == '__main__':
+    sys.exit(main())