example vst processor.

#include "audioeffectx.h"
#include <stdlib.h>
#include <string.h>

class Processor : public AudioEffectX
{

public:

    enum Params
    {
        kResonance,
        kCutoff,
    };

    Processor(audioMasterCallback cb)
        : AudioEffectX(cb, 2, 2), stateData()
    {
        // move this into a .cpp file to avoid cyclical dependency, obviously.
        setEditor(new GUI(this));
        // experiment with this:
        //programsAreChunks(true);
    }

    struct Data
    {
        // program data:
        float params[2];
        // state data - not public to the host:
        float curve;
        int someOtherData;
    } stateData;

    void setCurve(float curve)
    {
        stateData.curve = curve;
    }


    VstInt32 getChunk(void ** data, bool preset) override
    {
        // save all data, even including the non-parameters.
        *data = malloc(sizeof(Data)); // can't remember where to free() this.
        memcpy(*data, &stateData, sizeof(Data));
        return sizeof(Data);
    }

    VstInt32 setChunk(void * data, VstInt32 dataSize, bool preset) override
    {
        // some error checking  goes here.
        memcpy(&stateData, data, sizeof(Data));
    }

    void setParameter(VstInt32 index, float value) override
    {
        stateData.params[index] = value;
    }

    float getParameter(VstInt32 index) override
    {
        return stateData.params[index];
    }

    // rest of code, processing, etc.
};