The filter contains six modes these are, Lowpass, Highpass, Notch, Bandpass, Badboy Lowpass and Analog Lowpass. The coefficients for these filters where taken from Tobybear's filter explorer. For these, a Text box are included in the modules with the filter explorer’s output that were used for the source code.
The filter is laid out exactly the same as the state variable filter in the tool box. You could quite easily cut and paste the sub-modules for filters and place them in side SM’s state variable filter, giving you a nice selection of filters to choose from.
Here is exonerate’s original version: Bi-Quad Filters.