Making a New C/C++ Basilisk Module#

Note

This page provides guidelines on how to get started writing a new Basilisk module in C or C++. The intent is to

offer general tips and best practices. It’s recommended to also study existing modules that are similar to the one you’re creating.

Getting Started#

If this is your first time writing a Basilisk module, a good starting point is the cModuleTemplate located at fswAlgorithms/_cModuleTemplateFolder. This folder provides a generic ANSI-C Basilisk module, but the general steps are also applicable to C++ modules.

The template includes detailed instructions on:

  • Copying an existing Basilisk module folder.

  • Renaming module methods in *.c/cpp, *.h, *.i, and *.rst files.

  • Properly documenting module functionality and usage.

  • Writing and documenting unit tests for the module.

Templates and Examples#

  • For C++ modules, refer to the sample C++ module at cppModuleTemplate, located in

src/simulation/cppModuleTemplate.

In addition to using these templates, you can base your new module on an existing one with similar functionality, such as dynamics, sensors, environment models, attitude control, or navigation.

Note: The dynamicEffector and stateEffector classes are special cases. These use a state engine to manage the numerical integration of differential equations and are handled differently from standard modules.

Base Classes and Custom Methods#

Some modules—like magneticFieldCenteredDipole, exponentialAtmosphere, or simpleBattery—inherit from base classes. Ensure you understand the expected behaviors defined by these base classes. Override and implement the relevant customXXXX() methods to define your module’s specific behavior.

Linear Algebra and Kinematics Support#

If your module includes vector or tensor math:

  • Refer to the codingGuidelines for naming conventions related to matrix representations.

  • For C++ modules, Basilisk supports the Eigen library. Keep in mind that Eigen’s

.toRotationMatrix() method returns the direction cosine matrix (DCM) \([NB]\), not \([BN]\). Basilisk’s Eigen MRP implementation follows this same convention. - Modules can use the provided linearAlgebra.c/h for common operations, and rigidBodyKinematics.cpp/hpp` or rigidBodyKinematics.c/h` for rigid body kinematics.

Finalizing and Contributing#

Once your module is complete and you’re ready to contribute it to the Basilisk repository, make sure to go through the Basilisk Module Checkout List to complete all required review and integration steps.