[FEATURE REQ]: gaze master app plugins

[okawo80085]

Allow plugins for gaze master to change the API it uses to comm with apps.

[okawo80085]

The first version of the gaze master plugins is done, kinda, it's a bit broken on windows at the moment, but plugins looks something like this right now:

#if defined(LINUX)
    #define PLUGIN_DLL_EXPORT extern "C" __attribute__((visibility("default")))
    #define PLUGIN_DLL_IMPORT extern "C"
#elif defined(WIN)
    #define PLUGIN_DLL_EXPORT extern "C" __declspec(dllexport)
    #define PLUGIN_DLL_IMPORT extern "C" __declspec(dllimport)
#else
    #error "Unsupported Platform."
#endif

#include "gaze_master_plugin_interface.h"

#include <fstream>

class GazeLogger: public gaze::PluginBase {
public:
    GazeLogger() = default;
    virtual ~GazeLogger() = default;

    virtual bool Activate() {
        m_file = std::move(std::ofstream("/tmp/GazeLogger_out.log", std::ios::binary));
        h = 0;
        return !m_file.bad();
    }

    virtual void ProcessData(const HoboVR_GazeState_t& data) {
        if (h % 200 == 0 && m_file.is_open()) {
            m_file << "gaze data: " << data.status << ", "
                << data.age_seconds << ", ("
                << data.pupil_position_r[0] << "," << data.pupil_position_r[1] << "), "
                << data.pupil_position_l[0] << "," << data.pupil_position_l[1] << "), "
                << data.pupil_dilation_r << ", " << data.pupil_dilation_l << ", "
                << data.eye_close_r << ", " << data.eye_close_l << ";\n";
            m_file.flush();
            h = 0;
        }
        h++;
    }

    virtual std::string GetNameAndVersion() {
        return "GazeLogger_v0.0.1";
    }

    virtual std::string GetLastError() {
        return "failed to open file";
    }

private:
    std::ofstream m_file;
    int h = 0;
};

PLUGIN_DLL_EXPORT gaze::PluginBase* gazePluginFactory() {
    return new GazeLogger;
}

I think the plugin itself needs to know GazeMaster's version though, so maybe make it the arg to Activate()? @SimLeek @Minothor what do you guys think?

[okawo80085]

Relates to #2

[okawo80085]

Yeah im adding plugin interface version as args to activate of the plugin

[Minothor]

sorry, just picked up on the mention, Id say yeah, add it as an optional arg to Activate with it assuming latest on default?

[okawo80085]

Not optional, cuz it can potentially break the plugin ABI, which would SEGFAULT our driver

[okawo80085]

This arg is meant to tell the plugin "hey this is the version we have, compare it to yours, if you can work with that, kewl, if not gtfo"

[okawo80085]

There are currently some issues with multiple plugins being loaded, almost definitely the cause is factory symbol loading, but can't test it yet.

[okawo80085]

Lets try using boost's for importing dynamic libs...