11.2. Within-Source Plugins

If you’re a member of the K-3D development team creating a plugin that will become part of the "official" K-3D sources, creating an in-source plugin "foo" is the same as creating an out-of-source plugin, with just a few extra steps.

OPTION(K3D_BUILD_FOO_MODULE "Build the foo plugin module" ON)
K3D_ADD_SUBDIRECTORY(foo REQUIRES K3D_BUILD_FOO_MODULE)

And you’re done!