test.cpp

class RenderContext final {
public:
    RenderContext(Window *window)
    {
        glfwMakeContextCurrent(window.window());
    }
    
    void setViewport(const BaseViewport &viewport)
    {
        s_viewport = viewport;
    }
    
    void setClearColor(int r, int g, int b, int a = 255)
    {
        glClearColor(r / 255.0f, g / 255.0f, b / 255.0f, a / 255.0f);
    }
    
    void clear(bool color = true, bool depth = false, bool stencil = false)
    {
        GLbitfield flags = 0;
        if(color)
            flags |= GL_COLOR_BUFFER_BIT;
        if(depth)
            flags |= GL_DEPTH_BUFFER_BIT;
        if(stencil)
            flags |= GL_STENCIL_BUFFER_BIT;
        if(flags != 0)
            glClear(flags);
    }
    
private:
    static BaseViewport s_viewport;
    static ProjMode s_proj_mode;
};

//
// ...
//

RenderContext r(window);
r.setClearColor(0, 0, 128);
r.clear(true, true);
r.xxx(...);