gistfile1.c

#include "module_sine.h"
typedef enum {
    NOTE,
    VOL
} lipsynth_sine_params;

int lipsynth_module_sine_destroy(void *self){
    return 1;
}
void lipsynth_module_sine_update(void *self, lipsynth_context *ctx, lipsynth_AudioMemory *outputBuffer){
    lipsynth_module_sine* module = self;
    // fill up the output buffer with a sine wave!
    for(int i=0;i<ctx->bufferLength/2;i++){
        // must be called before any parameters are read
        if(module->_(lipsynth_Module_update_parameters)(self, ctx)){
            if(module->_(lipsynth_Module_has_parameter_value)(self, ctx, NOTE)){
                int noteVal = module->_(lipsynth_Module_get_parameter_value)(self, ctx, NOTE);
                module->freqVal = pow(2.0, (noteVal)/12.0f)*440.0f;
            }
        }
        // this number is to deal with floating point errors if the sine counter gets too big
        // what I should actually do is figure out the period of the wave in samples, and use integers to follow that
        if(module->sineCounter > 128){
            module->sineCounter -= 128.0f;
        }
        module->sineCounter += 1.0f/44100.0f*module->freqVal;
        outputBuffer->data[i*2] = outputBuffer->data[i*2+1] = sinf(module->sineCounter*M_PI_2);
    }
}
int lipsynth_module_sine_init(void *self)
{
    lipsynth_module_sine *sine = self;
    sine->_(lipsynth_Module_register_parameter)(self, sine->_(ctx), "note", NOTE);
    sine->_(lipsynth_Module_register_parameter)(self, sine->_(ctx), "volume", VOL);
    sine->sineCounter = 0;
    sine->freqVal = 440;
    return 1;
}

lipsynth_Module lipsynth_module_sine_proto = {
    .lipsynth_Module_init = lipsynth_module_sine_init,
    .lipsynth_Module_update = lipsynth_module_sine_update
};

gistfile2.c

    ctx = lipsynth_core_init(2048*2, 128);
    
    // create an output module, create a sine module, and test passing audio data out
    int outputModule = lipsynth_core_new_module(ctx, OUTPUT);
    int sineModule = lipsynth_core_new_module(ctx, SINE);
    lipsynth_core_connect_module(ctx, sineModule, outputModule);

    // set some notes on the sine module
    for(int i=0;i<16;i++){
        lipsynth_core_set_parameter(ctx, sineModule, 0, i, "note", i%2*12);
    }