Attempted Custom Rendering Sensor Example

examples/plugin/custom_rendering_sensor/MirroredCamera.cpp

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+/*
+ * Copyright (C) 2024 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+//needed in order to register plugins
+#include <gz/plugin/Register.hh>
+
+//header file
+#include "MirroredCamera.hh"
+
+//headers for other code used
+#include </gz/sensors/CameraSensor.hh>
+#include </gz/common/Image.hh>
+#include <FreeImage.h>
+#include </gz/sensors/RenderingSensor.hh>
+
+using namespace custom;
+
+//////////////////////////////////////////////////
+void MirroredCamera::PostUpdate(const gz::sim::UpdateInfo &_info,
+                            const gz::sim::EntityComponentManager &_ecm)
+{
+    //create a camera
+    gz:sensors:CameraSensor camera;
+    camera->CreateCamera();
+
+    //flip image horizontally by accessing the bitmap pointer?
+    FreeImage_FlipHorizontal(camera->image->*bitmap);
+}
+
+GZ_ADD_PLUGIN(custom_rendering_sensor::MirroredCamera, gz::sim::System,
+        custom_rendering_sensor::MirroredCamera::ISystemPostUpdate)

examples/plugin/custom_rendering_sensor/MirroredCamera.hh

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+/*
+ * Copyright (C) 2021 Open Source Robotics Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+*/
+
+#ifndef GAZEBO_MIRROREDCAMERA_HH
+#define GAZEBO_MIRROREDCAMERA_HH
+
+#include <gz/sim/System.hh>
+
+#include </gz/sensors/CameraSensor.hh>
+#include </gz/common/Image.hh>
+#include <FreeImage.h>
+#include </gz/sensors/RenderingSensor.hh>
+
+namespace custom
+{
+    /// \brief Attempt at creating a custom rendering sensor (in this case,
+    /// a camera sensor with its image flipped horizontally) as an example
+    /// for future developers)
+    class MirroredCamera:
+            public gz::sim::System,
+            public gz::sim::ISystemPostUpdate
+
+    /// \brief Creates a camera sensor, then calls the FlipHorizontal method
+    /// from the FreeImage library on the the pointer to the bitmap data
+    /// from the camera sensor's image field
+    {
+        void PostUpdate(const gz::sim::UpdateInfo &_info,
+                        const gz::sim::EntityComponentManager &_ecm)
+    };
+}
+
+#endif //GAZEBO_MIRROREDCAMERA_HH

examples/plugin/custom_rendering_sensor/README.md

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+# Custom Rendering Sensor
+
+This is a very basic, incomplete class that's meant to demonstrate custom rendering sensors in Gazebo.
+
+It attempts to implement the suggestions offered on Issue #1673:
+[https://github.com/gazebosim/gz-sim/issues/1673]
+
+All the code is untested due to my inability to provide a proper testing environment at this time.
+No CMakeLists.txt file is included with this directory due to my lack of knowledge of CMake.
+Apologies in advance for the likely non-functional code.
+I am not very experienced with the tools used in this development stack.
+
+## Build
+
+Not currently functional.
+
+## Run
+
+Not currently functional.
+