Attached Collision Object Transparency (#3093)

* Allows attached collision objects to be transparent

* Allows for config/RViz driven changing of the attached collision object transparency

---------

Co-authored-by: Sebastian Jahr <sebastian.jahr@picknik.ai>
(cherry picked from commit 1944811)

moveit_ros/visualization/planning_scene_rviz_plugin/src/planning_scene_display.cpp

@@ -347,10 +347,10 @@ void PlanningSceneDisplay::changedSceneName()
 void PlanningSceneDisplay::renderPlanningScene()
 {
   QColor color = scene_color_property_->getColor();
-  Ogre::ColourValue env_color(color.redF(), color.greenF(), color.blueF());
+  Ogre::ColourValue env_color(color.redF(), color.greenF(), color.blueF(), scene_alpha_property_->getFloat());
   if (attached_body_color_property_)
     color = attached_body_color_property_->getColor();
-  Ogre::ColourValue attached_color(color.redF(), color.greenF(), color.blueF());
+  Ogre::ColourValue attached_color(color.redF(), color.greenF(), color.blueF(), robot_alpha_property_->getFloat());
 
   try
   {

moveit_ros/visualization/rviz_plugin_render_tools/src/planning_scene_render.cpp

@@ -91,7 +91,7 @@ void PlanningSceneRender::renderPlanningScene(const planning_scene::PlanningScen
     color.r = default_attached_color.r;
     color.g = default_attached_color.g;
     color.b = default_attached_color.b;
-    color.a = 1.0f;
+    color.a = default_attached_color.a;
     planning_scene::ObjectColorMap color_map;
     scene->getKnownObjectColors(color_map);
     scene_robot_->update(moveit::core::RobotStateConstPtr(rs), color, color_map);

moveit_ros/visualization/rviz_plugin_render_tools/src/robot_state_visualization.cpp

@@ -137,7 +137,7 @@ void RobotStateVisualization::updateHelper(const moveit::core::RobotStateConstPt
       RCLCPP_ERROR_STREAM(LOGGER, "Link " << attached_body->getAttachedLinkName() << " not found in rviz::Robot");
       continue;
     }
-    Ogre::ColourValue rcolor(color.r, color.g, color.b);
+    Ogre::ColourValue rcolor(color.r, color.g, color.b, color.a);
     const EigenSTL::vector_Isometry3d& ab_t = attached_body->getShapePosesInLinkFrame();
     const std::vector<shapes::ShapeConstPtr>& ab_shapes = attached_body->getShapes();
     for (std::size_t j = 0; j < ab_shapes.size(); ++j)