Examples and tutorial on using rendering API from plugins (#596)

Signed-off-by: Louise Poubel <[email protected]>

Edifice to Citadel (#945)

Signed-off-by: Louise Poubel <[email protected]>

examples/plugin/custom_component/README.md

@@ -9,7 +9,7 @@ See `CustomComponentPlugin.hh` for more information.
 From the root of the `ign-gazebo` repository, do the following to build the example:
 
 ~~~
-cd ign-gazebo/examples/plugins/custom_component
+cd examples/plugin/custom_component
 mkdir build
 cd build
 cmake ..
@@ -23,7 +23,7 @@ This will generate the `CustomComponent` library under `build`.
 Add the library to the path:
 
 ~~~
-cd ign-gazebo/examples/plugins/custom_component
+cd examples/plugin/custom_component
 export IGN_GAZEBO_SYSTEM_PLUGIN_PATH=`pwd`/build
 ~~~
 

examples/plugin/gui_system_plugin/README.md

@@ -14,7 +14,7 @@ See `GuiSystemPluginPlugin.hh` for more information.
 From the root of the `ign-gazebo` repository, do the following to build the example:
 
 ~~~
-cd ign-gazebo/examples/plugins/gui_system_plugin
+cd examples/plugin/gui_system_plugin
 mkdir build
 cd build
 cmake ..
@@ -28,7 +28,7 @@ This will generate the `GuiSystemPlugin` library under `build`.
 Add the library to the path:
 
 ~~~
-cd ign-gazebo/examples/plugins/gui_system_plugin
+cd examples/plugin/gui_system_plugin
 export IGN_GUI_PLUGIN_PATH=`pwd`/build
 ~~~
 

examples/plugin/rendering_plugins/CMakeLists.txt

@@ -0,0 +1,44 @@
+cmake_minimum_required(VERSION 3.10.2 FATAL_ERROR)
+
+if(POLICY CMP0100)
+  cmake_policy(SET CMP0100 NEW)
+endif()
+
+project(RenderingPlugins)
+
+# Common to both plugins
+find_package(ignition-rendering3 REQUIRED)
+
+# GUI plugin
+set(GUI_PLUGIN RenderingGuiPlugin)
+
+set(CMAKE_AUTOMOC ON)
+
+find_package(ignition-gui3 REQUIRED)
+
+QT5_ADD_RESOURCES(resources_RCC ${GUI_PLUGIN}.qrc)
+
+add_library(${GUI_PLUGIN} SHARED
+  ${GUI_PLUGIN}.cc
+  ${resources_RCC}
+)
+target_link_libraries(${GUI_PLUGIN}
+  PRIVATE
+    ignition-gui3::ignition-gui3
+    ignition-rendering3::ignition-rendering3
+)
+
+# Server plugin
+set(SERVER_PLUGIN RenderingServerPlugin)
+
+find_package(ignition-plugin1 REQUIRED COMPONENTS register)
+find_package(ignition-gazebo3 REQUIRED)
+
+add_library(${SERVER_PLUGIN} SHARED ${SERVER_PLUGIN}.cc)
+set_property(TARGET ${SERVER_PLUGIN} PROPERTY CXX_STANDARD 17)
+target_link_libraries(${SERVER_PLUGIN}
+  PRIVATE
+    ignition-plugin1::ignition-plugin1
+    ignition-gazebo3::ignition-gazebo3
+    ignition-rendering3::ignition-rendering3
+)

examples/plugin/rendering_plugins/README.md

@@ -0,0 +1,38 @@
+# Rendering plugins
+
+Demo of 2 plugins that use Ignition Rendering, one for the server and one for the client.
+
+## Build
+
+From the root of the `ign-gazebo` repository, do the following to build the example:
+
+~~~
+cd examples/plugin/rendering_plugins
+mkdir build
+cd build
+cmake ..
+make
+~~~
+
+This will generate the `RenderingGuiPlugin` and `RenderingServerPlugin` libraries under `build`.
+
+## Run
+
+Add the libraries to the correct paths:
+
+~~~
+cd examples/plugin/rendering_plugins
+export IGN_GUI_PLUGIN_PATH=`pwd`/build
+export IGN_GAZEBO_SYSTEM_PLUGIN_PATH=`pwd`/build
+~~~
+
+Run the example world
+
+~~~
+cd examples/plugin/rendering_plugins
+ign gazebo -v 4 -r rendering_plugins.sdf
+~~~
+
+The ambient light on the server scene, visible from the camera sensor, will change every 2 seconds.
+
+The ambient light on the client scene, visible from the GUI, will change every time the button is pressed.

examples/plugin/rendering_plugins/RenderingGuiPlugin.cc

@@ -0,0 +1,145 @@
+/*
+ * 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.
+ *
+*/
+
+#include <ignition/gui/Application.hh>
+//! [includeGuiEvents]
+#include <ignition/gui/GuiEvents.hh>
+//! [includeGuiEvents]
+#include <ignition/gui/MainWindow.hh>
+#include <ignition/math/Rand.hh>
+#include <ignition/plugin/Register.hh>
+#include <ignition/rendering/RenderEngine.hh>
+#include <ignition/rendering/RenderingIface.hh>
+#include <ignition/rendering/Scene.hh>
+
+#include "RenderingGuiPlugin.hh"
+
+/////////////////////////////////////////////////
+void RenderingGuiPlugin::LoadConfig(const tinyxml2::XMLElement * /*_pluginElem*/)
+{
+  // This is necessary to receive the Render event on eventFilter
+//! [connectToGuiEvent]
+  ignition::gui::App()->findChild<
+      ignition::gui::MainWindow *>()->installEventFilter(this);
+//! [connectToGuiEvent]
+}
+
+/////////////////////////////////////////////////
+void RenderingGuiPlugin::RandomColor()
+{
+  this->dirty = true;
+}
+
+/////////////////////////////////////////////////
+//! [eventFilter]
+bool RenderingGuiPlugin::eventFilter(QObject *_obj, QEvent *_event)
+{
+  if (_event->type() == ignition::gui::events::Render::kType)
+  {
+    // This event is called in the render thread, so it's safe to make
+    // rendering calls here
+    this->PerformRenderingOperations();
+  }
+
+  // Standard event processing
+  return QObject::eventFilter(_obj, _event);
+}
+//! [eventFilter]
+
+/////////////////////////////////////////////////
+//! [performRenderingOperations]
+void RenderingGuiPlugin::PerformRenderingOperations()
+{
+  if (!this->dirty)
+  {
+    return;
+  }
+
+  if (nullptr == this->scene)
+  {
+    this->FindScene();
+  }
+
+  if (nullptr == this->scene)
+    return;
+
+  this->scene->SetAmbientLight({
+      static_cast<float>(ignition::math::Rand::DblUniform(0.0, 1.0)),
+      static_cast<float>(ignition::math::Rand::DblUniform(0.0, 1.0)),
+      static_cast<float>(ignition::math::Rand::DblUniform(0.0, 1.0)),
+      1.0});
+
+  this->dirty = false;
+}
+//! [performRenderingOperations]
+
+/////////////////////////////////////////////////
+void RenderingGuiPlugin::FindScene()
+{
+  auto loadedEngNames = ignition::rendering::loadedEngines();
+  if (loadedEngNames.empty())
+  {
+    igndbg << "No rendering engine is loaded yet" << std::endl;
+    return;
+  }
+
+  // assume there is only one engine loaded
+  auto engineName = loadedEngNames[0];
+  if (loadedEngNames.size() > 1)
+  {
+    igndbg << "More than one engine is available. "
+      << "Using engine [" << engineName << "]" << std::endl;
+  }
+  auto engine = ignition::rendering::engine(engineName);
+  if (!engine)
+  {
+    ignerr << "Internal error: failed to load engine [" << engineName
+      << "]. Grid plugin won't work." << std::endl;
+    return;
+  }
+
+  if (engine->SceneCount() == 0)
+  {
+    igndbg << "No scene has been created yet" << std::endl;
+    return;
+  }
+
+  // Get first scene
+  auto scenePtr = engine->SceneByIndex(0);
+  if (nullptr == scenePtr)
+  {
+    ignerr << "Internal error: scene is null." << std::endl;
+    return;
+  }
+
+  if (engine->SceneCount() > 1)
+  {
+    igndbg << "More than one scene is available. "
+      << "Using scene [" << scene->Name() << "]" << std::endl;
+  }
+
+  if (!scenePtr->IsInitialized() || nullptr == scenePtr->RootVisual())
+  {
+    return;
+  }
+
+  this->scene = scenePtr;
+}
+
+// Register this plugin
+IGNITION_ADD_PLUGIN(RenderingGuiPlugin,
+                    ignition::gui::Plugin)

examples/plugin/rendering_plugins/RenderingGuiPlugin.hh

@@ -0,0 +1,57 @@
+/*
+ * 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 RENDERING_GUI_PLUGIN_HH_
+#define RENDERING_GUI_PLUGIN_HH_
+
+#include <ignition/gui/qt.h>
+#include <ignition/gui/Plugin.hh>
+#include <ignition/rendering/Scene.hh>
+
+/// \brief Example of a GUI plugin that uses Ignition Rendering.
+/// This plugin works with either Ignition GUI's Scene3D or Ignition Gazebo's
+/// Scene3D.
+class RenderingGuiPlugin : public ignition::gui::Plugin
+{
+  Q_OBJECT
+
+  ///\brief Called once at startup.
+  public: void LoadConfig(const tinyxml2::XMLElement *) override;
+
+  /// \brief Callback when user clicks button.
+  public slots: void RandomColor();
+
+  /// \brief Callback for all installed event filters.
+  /// \param[in] _obj Object that received the event
+  /// \param[in] _event Event
+  private: bool eventFilter(QObject *_obj, QEvent *_event) override;
+
+  /// \brief All rendering operations must happen within this call
+  private: void PerformRenderingOperations();
+
+  /// \brief Encapsulates the logic to find the rendering scene through the
+  /// render engine singleton.
+  private: void FindScene();
+
+  /// \brief Marks when a new change has been requested.
+  private: bool dirty{false};
+
+  /// \brief Pointer to the rendering scene.
+  private: ignition::rendering::ScenePtr scene{nullptr};
+};
+
+#endif

examples/plugin/rendering_plugins/RenderingGuiPlugin.qml

@@ -0,0 +1,34 @@
+/*
+ * 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.
+ *
+*/
+import QtQuick 2.9
+import QtQuick.Controls 2.2
+import QtQuick.Layouts 1.3
+
+Rectangle {
+  color: "transparent"
+  anchors.fill: parent
+  Layout.minimumWidth: 250
+  Layout.minimumHeight: 100
+  Button {
+    text: qsTr("Random GUI color!")
+    onClicked: {
+      RenderingGuiPlugin.RandomColor();
+    }
+    anchors.horizontalCenter: parent.horizontalCenter
+    anchors.verticalCenter: parent.verticalCenter
+  }
+}

examples/plugin/rendering_plugins/RenderingGuiPlugin.qrc

@@ -0,0 +1,5 @@
+<!DOCTYPE RCC><RCC version="1.0">
+<qresource prefix="RenderingGuiPlugin/">
+  <file>RenderingGuiPlugin.qml</file>
+</qresource>
+</RCC>