Fix rendering tests (#2086)

---------

Signed-off-by: Ian Chen <ichen@openrobotics.org>
Co-authored-by: Addisu Z. Taddese <addisu@openrobotics.org>

src/rendering/SceneManager.cc

@@ -2555,6 +2555,7 @@ void SceneManager::Clear()
   this->dataPtr->actorTrajectories.clear();
   this->dataPtr->lights.clear();
   this->dataPtr->particleEmitters.clear();
+  this->dataPtr->projectors.clear();
   this->dataPtr->sensors.clear();
   this->dataPtr->scene.reset();
   this->dataPtr->originalTransparency.clear();

src/systems/camera_video_recorder/CameraVideoRecorder.cc

@@ -425,6 +425,8 @@ void CameraVideoRecorderPrivate::OnPostRender()
       }
     }
 
+   this->scene.reset();
+   this->camera.reset();
     // reset the event connection to prevent unnecessary render callbacks
     this->postRenderConn.reset();
   }

src/systems/lens_flare/LensFlare.cc

@@ -75,15 +75,9 @@ class gz::sim::systems::LensFlarePrivate
   /// \brief Name of the camera
   public: std::string cameraName;
 
-  /// \brief Pointer to the light
-  public: rendering::LightPtr light;
-
   /// \brief Name of the Light
   public: std::string lightName;
 
-  /// \brief Pointer to the LensFlarePass
-  public: rendering::LensFlarePassPtr lensFlarePass;
-
   /// \brief Scale of the lens flare
   public: double scale = 1.0;
 
@@ -193,10 +187,7 @@ void LensFlarePrivate::OnPostRender()
   }
 
   // get light
-  if (!this->light)
-  {
-    this->light = this->scene->LightByIndex(0);
-  }
+  auto light = this->scene->LightByIndex(0);
 
   rendering::RenderEngine *engine = this->camera->Scene()->Engine();
   rendering::RenderPassSystemPtr rpSystem = engine->RenderPassSystem();
@@ -212,14 +203,14 @@ void LensFlarePrivate::OnPostRender()
       return;
     }
 
-    this->lensFlarePass =
+    auto lensFlarePass =
       std::dynamic_pointer_cast<rendering::LensFlarePass>(flarePass);
-    this->lensFlarePass->Init(this->scene);
-    this->lensFlarePass->SetEnabled(true);
-    this->lensFlarePass->SetLight(this->light);
-    this->lensFlarePass->SetScale(this->scale);
-    this->lensFlarePass->SetColor(this->color);
-    this->lensFlarePass->SetOcclusionSteps(this->occlusionSteps);
+    lensFlarePass->Init(this->scene);
+    lensFlarePass->SetEnabled(true);
+    lensFlarePass->SetLight(light);
+    lensFlarePass->SetScale(this->scale);
+    lensFlarePass->SetColor(this->color);
+    lensFlarePass->SetOcclusionSteps(this->occlusionSteps);
 
     this->camera->AddRenderPass(lensFlarePass);
     gzmsg << "LensFlare Render pass added to the camera" << std::endl;
@@ -228,6 +219,8 @@ void LensFlarePrivate::OnPostRender()
   // disconnect from render event after adding lens flare pass to prevent
   // unecessary callbacks;
   this->postRenderConn.reset();
+  this->scene.reset();
+  this->camera.reset();
 }
 
 GZ_ADD_PLUGIN(LensFlare,

src/systems/sensors/Sensors.cc

@@ -414,6 +414,7 @@ void SensorsPrivate::RenderThread()
   for (const auto id : this->sensorIds)
     this->sensorManager.Remove(id);
 
+  this->scene.reset();
   this->renderUtil.Destroy();
   gzdbg << "SensorsPrivate::RenderThread stopped" << std::endl;
 }

src/systems/shader_param/ShaderParam.cc

@@ -89,6 +89,9 @@ class gz::sim::systems::ShaderParamPrivate
   /// \brief Connection to pre-render event callback
   public: gz::common::ConnectionPtr connection{nullptr};
 
+  /// \brief Connection to render tear down event callback
+  public: gz::common::ConnectionPtr teardownConnection{nullptr};
+
   /// \brief Name of visual this plugin is attached to
   public: std::string visualName;
 
@@ -118,6 +121,9 @@ class gz::sim::systems::ShaderParamPrivate
 
   /// \brief All rendering operations must happen within this call
   public: void OnUpdate();
+
+  /// \brief Callback to rendering engine tear down
+  public: void OnRenderTeardown();
 };
 
 /////////////////////////////////////////////////
@@ -246,6 +252,10 @@ void ShaderParam::Configure(const Entity &_entity,
   this->dataPtr->connection =
       _eventMgr.Connect<gz::sim::events::SceneUpdate>(
       std::bind(&ShaderParamPrivate::OnUpdate, this->dataPtr.get()));
+
+  this->dataPtr->teardownConnection =
+      _eventMgr.Connect<gz::sim::events::RenderTeardown>(
+      std::bind(&ShaderParamPrivate::OnRenderTeardown, this->dataPtr.get()));
 }
 
 //////////////////////////////////////////////////
@@ -496,6 +506,14 @@ void ShaderParamPrivate::OnUpdate()
   }
 }
 
+//////////////////////////////////////////////////
+void ShaderParamPrivate::OnRenderTeardown()
+{
+  this->visual.reset();
+  this->scene.reset();
+  this->material.reset();
+}
+
 GZ_ADD_PLUGIN(ShaderParam,
                     gz::sim::System,
                     ShaderParam::ISystemConfigure,