// header

#ifndef _RENDERER_H_
#define _RENDERER_H_

#include "Grid.h"

namespace tmplq
{

    class Renderer
    {

    public:

        static Renderer& Get();

        // we create the instance inside the dll
        // and set the program's instance to the
        // same pointer
        static void Set(Renderer* a_Instance);

        // test function
        Grid* CreateGrid();

    private:

        // constructors are private to avoid
        // having a singleton with two instances,
        // one for the dll and one for the program
        Renderer();
        ~Renderer();

        static Renderer* s_Instance;

    }; // class Renderer

    // DLL_FUNC is __declspec(dllexport) when
    // compiling DLL and __declspec(dllimport) when
    // compiling program

    extern "C" DLL_FUNC Renderer* CreateRenderer();

}; // namespace tmplq

#endif

// source

#include "Defines.h"

#include "Renderer.h"

namespace tmplq
{

    Renderer* Renderer::s_Instance = NULL;

    void Renderer::Set(Renderer* a_Instance)
    {
        s_Instance = a_Instance;
    }

    Renderer::Renderer()
    {

    }

    Renderer::~Renderer()
    {

    }

    Renderer& Renderer::Get()
    {
        if (!s_Instance) { s_Instance = new Renderer; }
        return *s_Instance;
    }

    // this is to avoid "inconsistent linkage" warnings
#ifdef COMPILE_DLL

    Renderer* CreateRenderer()
    {
        return &Renderer::Get();
    }

#endif

}

// usage

HINSTANCE dll = LoadLibrary("Render.dll");
typedef Renderer* (*RendererFunc)();
RendererFunc func = (RendererFunc)GetProcAddress(dll, "CreateRenderer");
Renderer::Set(func());

Grid* createsuccess = Renderer::Get().CreateGrid();