Python bindings (libgazebo_py)
Python bindings for libgazebo are generated automatically using SWIG. The bindings are object-oriented, using standard Python classes (for those familiar with SWIG, these are standard SWIG shadow classes). Refer to the libgazebo instructions for general information on how to use this library.General usage
Programs using the libgazebo Python bindings will generally have the following structure:
#!/usr/bin/env python # Desc: Move an object along a sinusoidal path # Author: Andrew Howard import math import time from gazebo import * if __name__ == '__main__': server = '0' #'default' id = 'object1' # Connect to server client = gz_client() if client.connect(0) != 0: raise gz_error_str() # Open the interface truth = gz_truth() if truth.open(client, id) != 0: raise gz_error_str() truth.lock(1) start_time = truth.data.time start_pos = truth.data.pos[:] truth.unlock() for i in range(1000): time.sleep(0.1) dt = truth.data.time - start_time new_pos = (start_pos[0] + 1.0 * dt, start_pos[1] + 1.0 * math.sin(dt), start_pos[2]) truth.lock(1) truth.data.cmd_new = 1 truth.data.cmd_pos = new_pos truth.data.cmd_rot = (1,0,0,0) truth.unlock()
The steps in this program mirror those described for standard C program. The key syntactical difference between the C-version and the Python version is the use of Python's object-oriented features.
This example can be demonstrated using the follow world file:
<?xml version="1.0"?> <gz:world xmlns:gz='http://playerstage.sourceforge.net/gazebo/xmlschema/#gz' xmlns:model='http://playerstage.sourceforge.net/gazebo/xmlschema/#model' xmlns:window='http://playerstage.sourceforge.net/gazebo/xmlschema/#window' xmlns:params='http://playerstage.sourceforge.net/gazebo/xmlschema/#params'> <params:GlobalParams> <gravity>0.0 0.0 -9.8</gravity> </params:GlobalParams> <model:ObserverCam> <id>userCam0</id> <xyz>-0.279 -4.715 4.388</xyz> <rpy>0 28 85</rpy> <window> <title>Gazebo1</title> <size>640 480</size> </window> </model:ObserverCam> <model:LightSource> <id>light0</id> <xyz>-10.000 -10.000 10.000</xyz> </model:LightSource> <model:GroundPlane> <id>ground1</id> </model:GroundPlane> <model:SimpleSolid> <xyz>0.000 -0.000 -0.000</xyz> <shape>box</shape> <size>0.70 0.70 1.50</size> <color>1.0 1.0 1.0</color> <model:TruthWidget> <id>object1</id> </model:TruthWidget> </model:SimpleSolid> </gz:world>
Proxy reference
Generally speaking, the Python bindings are one-to-one mappings to the libgazebo API. Thus, the C documentation can be used as a guide, so long as one makes some minor mental translations; e.g.:
pos = gz_position_alloc(...); -> pos = gz_position(...) gz_position_open(pos, ...); -> pos.open(...)
Detailed information for each C proxy can be found in the Reference section.