Release Notes

Stage RELEASE.txt

These are the Stage release notes.

For introduction and license see README.txt For installation notes see INSTALL.txt

Version 4.1.0

  • many bugfixes
  • support for basic dynamics: position models simulate acceleration and have a new acceleration control mode.
  • visualization options can be loaded from and saved to worldfiles
  • API change: new World::Run() methed provides the same interface to GUI and non-GUI worlds (by chmp)
  • saved screenshots are numbered with leading zeros for convenience when using movie-making tools (by mani-monaj)
  • major performance enhancement: position updates now run in parallel with sensor updates, using a double-buffer-style alternating pair of occupancy grids
  • several minor performance enhancements
  • much faster debug visualization (occupancy grid and voxel views)
  • build scripts are more portable

Richard Vaughan (rtv) - 2011.12.28

Version 4.0.1

  • Bugfixes
  • more sparing use of memory to support very large worlds (square kms!)

Richard Vaughan (rtv) - 2010.12.2

Version 4.0.0

Major new release since worldfile syntax and API have both changed due to a new unified ranger model. Laser model is now deprecated in favour of the ranger. This follows a similar change in Player 3, where laser interface support was deprecated but still in place due to lack of Stage support. This release fixes that.

Also includes many bugfixes, a much improved build system and some performance enhancements and documentation improvements.

Richard Vaughan (rtv) - 2010.11.25

Version 3.2.2

Bugfix, performance and cleanup release. This is the fastest Stage ever for most use cases.

Externally visible changes

  • removed property database from models. This will break user code that depends on it. The rationale for removing it is that it is not useful to libstage users, and only to libstageplugin users who used it for Player-based IPC. It should be provided by a Player driver. Removing this little-used code is a useful clean up.

Richard Vaughan (rtv) - 2009.10.28

Version 3.2.1

Bugfix release, contains mainly bugfixes but some performance tweaks.

Richard Vaughan (rtv) - 2009.10.13

Version 3.2.0

This minor release fixes many bugs, has some performance improvements and some significant internal and API changes, including:

  • introduced an internal event queue, so that there is no longer any atomic world update interval. Each model can have its update interval specified individually
  • worldfile syntax checking improved: poses and sizes are checked for correct vector length
  • pkg-config file for libstage now contains correct dependencies, making it much easier to build things using libstage
  • controllers can now take an argument string from the worldfile and command line
  • better powerpack model
  • cleaned up namespace quite a bit - controllers and simulators using libstage may need some simple tweaks, but the design is cleaner and more consistent.

Richard Vaughan (rtv) - 2009.9.12

Version 3.1.0

This minor release includes some major improvements, including:

  • Added or reinstated models
    • grippers
    • linear actuator
  • Powerpacks models power consumption, charging and transferring
  • Models can provide occuapancy grids with Stg::Model::Rasterize()
  • WebStage is Stage with WebSim support
  • Many bugfixes
  • Many performance improvements, including faster raytracing
  • Better support for very large worlds
  • More example controllers in <stage>/examples/ctrl
  • Faster raytracing
  • Replaced GLib-2.0 with STL, pthreads, etc.
  • Better docs (but still lots to do here)

Richard Vaughan (rtv) - 2009.7.22

Version 3.0.1

This version incorporates a number of fixes made since the previous major release:

  • Player plugin
    • added unit test suite to verify functionality (build instructions in libstageplugin/test directory)
    • many bug fixes
    • blobfinder, fiducial, laser, position2d, simulation, sonar, and speech interfaces are now working correctly
  • CMake script fixes
    • OpenGL headers located properly
    • FLTK sourced correctly
    • dependency failures should show up before compiling
  • fixed bug where fiducial sensor would return duplicate results
  • fixed some rendering glitches
  • blobfinder now returns blobs in the correct horizontal order
  • blobfinder sensor visualization displays in the plane of the screen

Version 3.0.0

Stage 3.0.0 consists of these components:

  • libstage - a robot simulation C++ library.
  • libstageplugin - a simulation plugin for Player
  • stage - a stand-alone robot simulator

This is a a major new release of Stage. The main new features are:

  • 2.5D models
  • 3D user interface
  • very much faster raytracing than 2.X series
  • plugin code modules attach at run time to any model. Useful for data filtering or complete robot controllers without Player (examples included)
  • 3D camera model, with color and depth for each pixel
  • first "official" release of the libstage API
  • save/save-as/reload file dialog box
  • improved data visualization options
  • select and drag/rotate multuple robots by shift-clicking

libstageplugin still needs some work - currently it only supports position2d, laser and sonar interfaces It also uses too much CPU. Player/Stage users may choose to wait for libstageplugin to improve before trying Stage-3.0.

Note that your Stage-2.0 world files will probably need to be updated to work with Stage-3.0. The main difference world file syntax is that poses and velocities are now specied as [x y z theta] instead of the old [x y theta]. Sizes are now specifed as [x y z] instead of [x y].

Some useful parts of Stage 2.x have not yet been ported to 3.0, including

  • gripper & puck
  • wireless comms
  • audio comms
  • blinkenights

This is the first release of a lot of new code. It has been used in my lab for a while now, but there are bound to be bugs and quirks. Please use the bug tracker and feature request system on Sourceforge to help us fix and improve Stage. As always, your patches are very welcome.

Richard Vaughan (rtv) - 2008.7.12

Version 2.0.1

This is mainly a bugfix and performance-enhancement release. This release requires Player-2.0.1, released simultaneously.

The only major new feature is the addition of support for Player's speech interface: speech bubbles show the text being "spoken" by each robot. The text is rendered using Pango, so non-Roman alphabets are supported.

Richard Vaughan (rtv) 2006.3.24

Version 2.0.0

This is a major new release of Stage, and is intended to replace all previous versions. It requires Player-2.0.0 or later.

Please report bugs to the tracker and let us know what you do with Stage.

Richard Vaughan (rtv) 2006.2.26

New Features

Significant user-level changes include:

  • Stage is now implemented as the C library libstage. Using libstage, your programs can include a sophisticated robot simulator with a few lines of code. The Player plugin libstageplugin is a wrapper for libstage that provides simulation services to Player. Player with libstageplugin is the Player/Stage system.

  • Player clients can draw directly in the Stage window using the graphics2d interface. libstage programs can use the internal user graphics API.

  • Configurable odometry error in position model

  • Gripper model that can pick up anything. Any object can be made grippable/pushable by setting the the gripper_return property.

  • Pan-tilt-zoom (PTZ) model.

  • More and improved visualizations, including models leaving trails over time

  • Any object can now have its shape specified by a bitmap file (JPG, PNG, etc.).

  • Worldfile syntax has changed slightly, so you may need to edit your existing worlds to get them to work. Look at the example worlds in (stage src)/worlds to get the idea.

  • Worlds can be very large (thousands of meters square).

Version 1.6.1

This is a bug-fix release that replaces 1.6.0.

  • Fixes several GUI bugs, including the [View/Fill Polygons] menu item.

  • Some code clean-up and thread-safety fixes

Version 1.6.0

This release of Stage is the first after a major rewrite. There are bound to be bugs and teething troubles, but the Autonomy Lab ( has been using this code for serious work for a few months now and we think it's useful and usable.

Significant changes visible to the user

  1. Stage is now a Player plugin, instead of an executable. The key benefit of this is that all Player drivers are now available for use directly with Stage, including sophisticated drivers like AMCL, without needing passthrough drivers.

  2. Stage depends on Player 1.6 or newer.

  3. Worldfile syntax has a changed, so you need to edit your existing worlds to get them to work. Look at the example worlds in <stage src>="">/worlds to get the idea.

  4. Any object can now have its shape specified by a bitmap file

  5. Several bitmap file formats are supported, using a third-party library. Load maps and robot bodies from JPG, PNG, etc. No more PNM troubles.

  6. Worlds can now be very large (thousands of meters square).

  7. Several models are missing from this release - notably the gripper and puck. These will be available soon. Meanwhile, enjoy the full power of Player with the basic laser, sonar, position, fiducial and blobfinder models.

  8. Stage no longer depends on libRTK.

  9. Some models from previous versions may not yet be available in this release (e.g. gripper & puck), but we're working on them. Let us know which ones you need.

Significant changes under the hood

  1. The Stage simulation engine is now a library rather than an application. The library can be used to write custom robot simulations. This is very useful if you need to do synchronous control of robots (e.g for perfectly repeatable experiments), or dynamically create and destroy robots or other objects. You can't (yet) do this though Player. Refer to the libstage reference manual ( for the API and developer docs.

  2. Stage is now mostly written in C. A simple object-oriented system allows one level of inheritance for writing polymorphic model code.

  3. The underlying occupancy grid model has changed from a simple fixed-size array to a sparse array of (almost) unlimited size (implemented with a hash table). To compensate for the performance hit of raytracing in the hash table, a three-level multiple-resolution approach is used. Raytracing is now usually much faster than in Stage-1.3. To get an idea how this works, select the View/Debug/Raytrace menu item while a laser or ranger is producing data.

  4. Most home-rolled data structures have been replaced by glib versions.