fix: default needsRaycast to true, add subscriber in RaycastResultsProcessed

- Default RaycastDataInfo::needsRaycast to true so that manually-created
  RaycastData components are processed by Physics without needing to know
  about the optimization flag. The CpuLidar system already explicitly
  manages the flag each step.
- Add a topic subscriber in the RaycastResultsProcessed test so that
  HasConnections() returns true and the CpuLidar system requests raycasts.

Generated-by: Amp <amp@ampcode.com>

Signed-off-by: Alexis Pojomovsky <apojomovsky@gmail.com>

Author: apojomovsky

include/gz/sim/components/RaycastData.hh

@@ -69,7 +69,7 @@ struct RaycastDataInfo
   std::vector<RaycastResultInfo> results;
 
   /// @brief Whether the sensor needs fresh raycast results this step.
-  bool needsRaycast = false;
+  bool needsRaycast = true;
 };
 }
 

test/integration/cpu_lidar_system.cc

@@ -57,7 +57,7 @@ static constexpr int kDiscoveryIterations = 10;
 /// \brief Iterations for raycast data validity test
 static constexpr int kRaycastDataIterations = 10;
 /// \brief Iterations for raycast results processing test
-static constexpr int kRaycastResultsIterations = 20;
+static constexpr int kRaycastResultsIterations = 200;
 /// \brief Iterations for laser scan publication test
 static constexpr int kLaserScanIterations = 200;
 /// \brief Iteration threshold for sensor topic verification
@@ -194,6 +194,13 @@ TEST_F(CpuLidarTest,
 
   bool resultsFound = false;
 
+  // Subscribe to the sensor topic so HasConnections() returns true
+  // and the system requests raycasts from Physics.
+  transport::Node node;
+  std::function<void(const msgs::LaserScan &)> cb =
+    [](const msgs::LaserScan &){};
+  node.Subscribe("/test/cpu_lidar", cb);
+
   test::Relay testSystem;
   testSystem.OnPostUpdate([&](const UpdateInfo &_info,
                               const EntityComponentManager &_ecm)