Don't show map if transform is missing

It's confusing when the map is shown but the transform is missing. This
leads to the map being on a wrong place.

Fixes #51

CHANGELOG.rst

@@ -4,6 +4,7 @@ Changelog for package rviz_satellite
 
 Forthcoming
 -----------
+* Don't show map if transform is missing
 * Fix demo.launch
 
 1.2.0 (2019-03-07)

launch/demo.launch

@@ -3,7 +3,7 @@
     <node pkg="rostopic" type="rostopic" name="fake_gps_fix" args="pub /gps/fix sensor_msgs/NavSatFix --latch --file=$(find rviz_satellite)/launch/demo.gps" />
 
     <!-- Start rviz with a pre-configured AerialMap instance. It will use the fake GPS fix from above. -->
-    <node pkg="rviz" type="rviz" name="rviz" args="-d $(find rviz_satellite)/launch/demo.rviz"/>
+    <node pkg="rviz" type="rviz" name="rviz" args="-d $(find rviz_satellite)/launch/demo.rviz" output="screen" />
 
     <!-- Static fake TF transform -->
     <node pkg="tf2_ros" type="static_transform_publisher" name="static_tf_fake" args="0 0 0 0 0 0 map base_link" />

src/aerialmap_display.cpp

@@ -290,8 +290,8 @@ void AerialMapDisplay::navFixCallback(sensor_msgs::NavSatFixConstPtr const& msg)
 
   // re-load imagery
   received_msg_ = true;
-  loadImagery();
   transformAerialMap();
+  loadImagery();
 }
 
 void AerialMapDisplay::loadImagery()
@@ -310,6 +310,11 @@ void AerialMapDisplay::loadImagery()
     return;
   }
 
+  if (!hasWorkingTransform_)
+  {
+    return;
+  }
+
   if (tile_url_.empty())
   {
     setStatus(StatusProperty::Error, "Message", "Tile URL is not set");
@@ -507,6 +512,8 @@ void AerialMapDisplay::transformAerialMap()
   {
     context_->getFrameManager()->setFixedFrame(lastFixedFrame_);
     setStatus(StatusProperty::Error, "Transform", QString::fromStdString(errMsg));
+    hasWorkingTransform_ = false;
+    clear();
     return;
   }
 
@@ -529,6 +536,8 @@ void AerialMapDisplay::transformAerialMap()
                 "Could not transform from [" + QString::fromStdString(frame) + "] to Fixed Frame [" + fixed_frame_ +
                     "] for an unknown reason");
     }
+    hasWorkingTransform_ = false;
+    clear();
     return;
   }
 
@@ -537,9 +546,12 @@ void AerialMapDisplay::transformAerialMap()
     // This can occur if an invalid TF is published.
     // Show an error and don't apply anything, so OGRE does not throw an assertion.
     setStatus(StatusProperty::Error, "Transform", "Received invalid transform");
+    hasWorkingTransform_ = false;
+    clear();
     return;
   }
 
+  hasWorkingTransform_ = true;
   setStatus(StatusProperty::Ok, "Transform", "Transform OK");
 
   // apply transform and add offset from origin

src/aerialmap_display.h

@@ -175,6 +175,8 @@ protected Q_SLOTS:
   boost::optional<TileId> lastTileId_;
   std::string lastFixedFrame_;
 
+  bool hasWorkingTransform_ = false;
+
   /**
    * Calculate the tile width/ height in meter
    */