Add a flexible mechanism to combine user and default plugins

examples/worlds/camera_sensor.sdf

@@ -8,127 +8,34 @@
       <max_step_size>0.001</max_step_size>
       <real_time_factor>1.0</real_time_factor>
     </physics>
-    <plugin
-      filename="gz-sim-physics-system"
-      name="gz::sim::systems::Physics">
-    </plugin>
     <plugin
       filename="gz-sim-sensors-system"
       name="gz::sim::systems::Sensors">
       <render_engine>ogre2</render_engine>
     </plugin>
-    <plugin
-      filename="gz-sim-user-commands-system"
-      name="gz::sim::systems::UserCommands">
-    </plugin>
-    <plugin
-      filename="gz-sim-scene-broadcaster-system"
-      name="gz::sim::systems::SceneBroadcaster">
-    </plugin>
 
     <scene>
       <ambient>1.0 1.0 1.0</ambient>
       <background>0.8 0.8 0.8</background>
       <grid>true</grid>
     </scene>
 
+    <gz:policies>
+      <include_default_gui_plugins>true</include_default_gui_plugins>
+    </gz:policies>
     <gui fullscreen="0">
 
-      <!-- 3D scene -->
       <plugin filename="MinimalScene" name="3D View">
         <gz-gui>
           <title>3D View</title>
           <property type="bool" key="showTitleBar">false</property>
           <property type="string" key="state">docked</property>
         </gz-gui>
-
         <engine>ogre2</engine>
         <scene>scene</scene>
         <ambient_light>0.4 0.4 0.4</ambient_light>
         <background_color>0.8 0.8 0.8</background_color>
-        <camera_pose>-6 0 6 0 0.5 0</camera_pose>
-      </plugin>
-
-      <!-- Plugins that add functionality to the scene -->
-      <plugin filename="EntityContextMenuPlugin" name="Entity context menu">
-        <gz-gui>
-          <property key="state" type="string">floating</property>
-          <property key="width" type="double">5</property>
-          <property key="height" type="double">5</property>
-          <property key="showTitleBar" type="bool">false</property>
-        </gz-gui>
-      </plugin>
-      <plugin filename="GzSceneManager" name="Scene Manager">
-        <gz-gui>
-          <property key="resizable" type="bool">false</property>
-          <property key="width" type="double">5</property>
-          <property key="height" type="double">5</property>
-          <property key="state" type="string">floating</property>
-          <property key="showTitleBar" type="bool">false</property>
-        </gz-gui>
-      </plugin>
-      <plugin filename="InteractiveViewControl" name="Interactive view control">
-        <gz-gui>
-          <property key="resizable" type="bool">false</property>
-          <property key="width" type="double">5</property>
-          <property key="height" type="double">5</property>
-          <property key="state" type="string">floating</property>
-          <property key="showTitleBar" type="bool">false</property>
-        </gz-gui>
-      </plugin>
-      <plugin filename="CameraTracking" name="Camera Tracking">
-        <gz-gui>
-          <property key="resizable" type="bool">false</property>
-          <property key="width" type="double">5</property>
-          <property key="height" type="double">5</property>
-          <property key="state" type="string">floating</property>
-          <property key="showTitleBar" type="bool">false</property>
-        </gz-gui>
-      </plugin>
-      <!-- World control -->
-      <plugin filename="WorldControl" name="World control">
-        <gz-gui>
-          <title>World control</title>
-          <property type="bool" key="showTitleBar">false</property>
-          <property type="bool" key="resizable">false</property>
-          <property type="double" key="height">72</property>
-          <property type="double" key="z">1</property>
-
-          <property type="string" key="state">floating</property>
-          <anchors target="3D View">
-            <line own="left" target="left"/>
-            <line own="bottom" target="bottom"/>
-          </anchors>
-        </gz-gui>
-
-        <play_pause>true</play_pause>
-        <step>true</step>
-        <start_paused>true</start_paused>
-        <use_event>true</use_event>
-
-      </plugin>
-
-      <!-- World statistics -->
-      <plugin filename="WorldStats" name="World stats">
-        <gz-gui>
-          <title>World stats</title>
-          <property type="bool" key="showTitleBar">false</property>
-          <property type="bool" key="resizable">false</property>
-          <property type="double" key="height">110</property>
-          <property type="double" key="width">290</property>
-          <property type="double" key="z">1</property>
-
-          <property type="string" key="state">floating</property>
-          <anchors target="3D View">
-            <line own="right" target="right"/>
-            <line own="bottom" target="bottom"/>
-          </anchors>
-        </gz-gui>
-
-        <sim_time>true</sim_time>
-        <real_time>true</real_time>
-        <real_time_factor>true</real_time_factor>
-        <iterations>true</iterations>
+        <camera_pose>-3 0 3 0 0.5 0</camera_pose>
       </plugin>
 
       <plugin filename="ImageDisplay" name="Image Display">
@@ -137,20 +44,6 @@
         </gz-gui>
         <topic>camera</topic>
       </plugin>
-
-      <!-- Inspector -->
-      <plugin filename="ComponentInspector" name="Component inspector">
-        <gz-gui>
-          <property type="string" key="state">docked</property>
-        </gz-gui>
-      </plugin>
-
-      <!-- Entity tree -->
-      <plugin filename="EntityTree" name="Entity tree">
-        <gz-gui>
-          <property type="string" key="state">docked</property>
-        </gz-gui>
-      </plugin>
     </gui>
 
     <light type="directional" name="sun">

examples/worlds/contact_sensor.sdf

@@ -9,22 +9,7 @@ Run the following to print out contacts,
 -->
 
   <world name="contact_sensor">
-    <plugin
-      filename="gz-sim-physics-system"
-      name="gz::sim::systems::Physics">
-    </plugin>
-    <plugin
-      filename="gz-sim-contact-system"
-      name="gz::sim::systems::Contact">
-    </plugin>
-    <plugin
-      filename="gz-sim-user-commands-system"
-      name="gz::sim::systems::UserCommands">
-    </plugin>
-    <plugin
-      filename="gz-sim-scene-broadcaster-system"
-      name="gz::sim::systems::SceneBroadcaster">
-    </plugin>
+    <plugin filename="gz-sim-contact-system" name="gz::sim::systems::Contact"/>
 
     <scene>
       <grid>false</grid>

examples/worlds/mimic_fast_slow_pendulums_world.sdf

@@ -16,6 +16,10 @@
       <real_time_factor>1</real_time_factor>
     </physics>
 
+    <plugin filename="gz-sim-physics-system" name="gz::sim::systems::Physics">
+      <engine><filename>gz-physics-bullet-featherstone-plugin</filename></engine>
+    </plugin>
+
     <light type="directional" name="sun">
       <cast_shadows>true</cast_shadows>
       <pose>0 0 10 0 0 0</pose>

examples/worlds/quadcopter.sdf

@@ -17,18 +17,6 @@
       <max_step_size>0.001</max_step_size>
       <real_time_factor>1.0</real_time_factor>
     </physics>
-    <plugin
-      filename="gz-sim-physics-system"
-      name="gz::sim::systems::Physics">
-    </plugin>
-    <plugin
-      filename="gz-sim-scene-broadcaster-system"
-      name="gz::sim::systems::SceneBroadcaster">
-    </plugin>
-    <plugin
-      filename="gz-sim-user-commands-system"
-      name="gz::sim::systems::UserCommands">
-    </plugin>
     <plugin
       filename="gz-sim-sensors-system"
       name="gz::sim::systems::Sensors">

include/gz/sim/Constants.hh

@@ -0,0 +1,33 @@
+/*
+ * 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.
+ *
+ */
+
+#ifndef GZ_SIM_CONSTANTS_HH_
+#define GZ_SIM_CONSTANTS_HH_
+
+#include "gz/sim/config.hh"
+#include <string_view>
+
+namespace gz::sim
+{
+// Inline bracket to help doxygen filtering.
+inline namespace GZ_SIM_VERSION_NAMESPACE
+{
+  constexpr std::string_view kPoliciesTag{"gz:policies"};
+}
+}  // namespace gz::sim
+
+#endif

src/SimulationRunner.cc

@@ -18,6 +18,7 @@
 #include "SimulationRunner.hh"
 
 #include <algorithm>
+#include <unordered_set>
 #ifdef HAVE_PYBIND11
 #include <pybind11/pybind11.h>
 #endif
@@ -36,6 +37,7 @@
 #include <vector>
 
 #include "gz/common/Profiler.hh"
+#include "gz/sim/Constants.hh"
 #include "gz/sim/components/Model.hh"
 #include "gz/sim/components/Name.hh"
 #include "gz/sim/components/Sensor.hh"
@@ -50,6 +52,7 @@
 #include "gz/sim/components/RenderEngineServerHeadless.hh"
 #include "gz/sim/components/RenderEngineServerPlugin.hh"
 #include "gz/sim/Events.hh"
+#include "gz/sim/ServerConfig.hh"
 #include "gz/sim/SdfEntityCreator.hh"
 #include "gz/sim/Util.hh"
 #include "gz/transport/TopicUtils.hh"
@@ -263,6 +266,18 @@ SimulationRunner::SimulationRunner(const sdf::World &_world,
   if (_world.Gui())
   {
     this->guiMsg = convert<msgs::GUI>(*_world.Gui());
+
+    auto worldElem = this->sdfWorld.Element();
+    if (worldElem)
+    {
+      auto policies = worldElem->FindElement("gz:policies");
+      if (policies)
+      {
+        auto headerData = this->guiMsg.mutable_header()->add_data();
+        headerData->set_key("gz:policies");
+        headerData->add_value(policies->ToString(""));
+      }
+    }
   }
 
   std::string infoService{"gui/info"};
@@ -1586,21 +1601,60 @@ void SimulationRunner::CreateEntities(const sdf::World &_world)
   // Load any additional plugins from the Server Configuration
   this->LoadServerPlugins(this->serverConfig.Plugins());
 
+  auto loadedWorldPlugins = this->systemMgr->TotalByEntity(worldEntity);
   // If we have reached this point and no world systems have been loaded, then
   // load a default set of systems.
-  if (this->systemMgr->TotalByEntity(worldEntity).empty())
+
+  auto worldElem = this->sdfWorld.Element();
+  bool includeServerConfigPlugins = true;
+  if (worldElem)
   {
-    gzmsg << "No systems loaded from SDF, loading defaults" << std::endl;
-    bool isPlayback = !this->serverConfig.LogPlaybackPath().empty();
-    auto plugins = gz::sim::loadPluginInfo(isPlayback);
-    this->LoadServerPlugins(plugins);
+    auto policies = worldElem->FindElement(std::string(kPoliciesTag));
+    if (policies)
+    {
+      includeServerConfigPlugins =
+        policies
+        ->Get<bool>("include_server_config_plugins", includeServerConfigPlugins)
+        .first;
+    }
   }
 
+  if (includeServerConfigPlugins || loadedWorldPlugins.empty())
+  {
+    bool isPlayback = !this->serverConfig.LogPlaybackPath().empty();
+    auto defaultPlugins = gz::sim::loadPluginInfo(isPlayback);
+    if (loadedWorldPlugins.empty())
+    {
+      gzmsg << "No systems loaded from SDF, loading defaults" << std::endl;
+    }
+    else
+    {
+      std::unordered_set<std::string> loadedWorldPluginFileNames;
+      for (const auto &pl : loadedWorldPlugins)
+      {
+        loadedWorldPluginFileNames.insert(pl.fname);
+      }
+      auto isPluginLoaded =
+          [&loadedWorldPluginFileNames](const ServerConfig::PluginInfo &_pl)
+      {
+          return loadedWorldPluginFileNames.count(_pl.Plugin().Filename()) != 0;
+      };
+
+      // Remove plugin if it's already loaded so as to not duplicate world
+      // plugins.
+      defaultPlugins.remove_if(isPluginLoaded);
+
+      gzdbg << "Also loading the following default jplugins:\n";
+      for (const auto &plugin : defaultPlugins)
+      {
+        gzdbg << plugin.Plugin().Name() << " " << plugin.Plugin().Filename()
+              << "\n";
+      }
+    }
+
+    this->LoadServerPlugins(defaultPlugins);
+  };
+
   // Store the initial state of the ECM;
   this->initialEntityCompMgr.CopyFrom(this->entityCompMgr);
-
-  // Publish empty GUI messages for worlds that have no GUI in the beginning.
-  // In the future, support modifying GUI from the server at runtime.
-  if (_world.Gui())
-    this->guiMsg = convert<msgs::GUI>(*_world.Gui());
 }