1.2 External dependencies

Some parts of this package make use of other external Python packages that are not part of the standard Python installation. Whenever such functionality is used the corresponding external package must be available or an exception is raised. In general, the modules in cgkit try to delay such an exception to the point where the respective package is actually used instead of the time when it is imported. For example, you don't have to install PyOpenGL, PIL or pygame if you only write command line tools that never do a visualization.

The minimum requirement is, of course, Python itself. The target Python version is Python 2.3 and higher. However, some pure Python modules might also run on earlier versions.

As long as only the general purpose modules (see chapter 4) or the 'light' version of cgkit (see section 1.1) is used there is no external dependency. If cgkit is used to create and process a scene in memory then the following packages might get used:

PyProtocols: This is a general requirement for scene management used in various places.
numarray: This is mainly a requirement for PyOpenGL. At this time, cgkit itself does not use numarray yet.
PyOpenGL: This is only required when doing OpenGL visualizations, and even then it is only necessary for some particular geometric objects (those that are implemented in Python). As long as those objects aren't used (or are hidden) you can also do OpenGL visualizations without PyOpenGL.
PIL: This is required whenever images have to be processed (such as for textures, for example).
pygame: This is only required when the viewer tool is used.

Some individual components might have other dependencies which is documented on the respective page. However, as long as you don't use those components you don't have to install the additional packages. So far, these are:

PyODE: You need this if you want to do rigid body simulations using the ODEDynamics component.
pySerial: You need this when you want to use the FlockOfBirds component.

Windows: If you haven't already done so, it is recommended to add the Scripts directory of your Python installation to your PATH environment variable as this is the place where additional tools are installed.