[PlayerStage-Gazebo] Major changes (offscreen rendering)

[ahoward <ah...@us...>]

Hi folks:

I've committed a *major* set of changes to CVS HEAD.  Specifically:

- The Gazebo server "gazebo" no longer supports a native (compiled in)
  GUI.  All user interface functionality is handled through the
  libgazebo interface.

- I have added a new application "wxgazebo" that wraps a wxWindows GUI
  around the server; run this instead of "gazebo" (with the same
  arguments) if you want a nice pretty display.

What the hell is this all about, you may wonder.  Well, there are a few
of things going on here:

1. I want to separate out GUI functionality from core server
  functionality.  This leads to simpler code in the server (no kludged
  event handlers), rapid development of the GUI (high-level languages, not
  C/C++), and makes is possible to have more than one GUI (developers can
  easily write their own, if they see fit).

2. I want to be able to run the server in batch mode or on a remote
  machine without popping up windows or producing unnecessary X traffic.
  At the same time, I want to have the ability to attach (and detach) a
  GUI to a running server, just to check on how things are going.

3. In our earlier implementation, simulated cameras did not always produce
  correct output: if you cover the window or change to a different virtual
  desktop, the simulated camera data will not be updated.  With the new
  implementation, this is no longer a problem.

There is, of course, a penalty to all this: the server now relies entirely
on off-screen OpenGL rendering, which may not be supported (in hardware)
on cheaper graphics cards.  For these cards, the server will revert to
(slow) software rendering.  Known working hardware accelerated
combinations include Linux/nVidia and Apple/nVidia; I would appreciate
feedback from people with other brands.

	A.


Andrew Howard                           email: ah...@po...
Department of Computer Science          http:  www-robotics.usc.edu/~ahoward
University of Southern California       phone: 1 (213) 740 6416
Los Angeles, CA, U.S.A. 90089-0781      fax:   1 (213) 821 5696
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