segfault

//Singleton: OpenGL
class OpenGL
{
public:
    static OpenGL& get_instance();
    OpenGL(OpenGL const&)= delete;
    void operator=(OpenGL const&) = delete;

    void init(void);

    //methods
    enum class ProjectionMode {PROJECTION_MODE_UNSET, PROJECTION_MODE_2D};
    // GLenum get_gl_primitive(PrimitiveType type);
    // GLenum get_gl_buffer(BufferType type);
    // void draw_indexed_command(DrawCommandIndexed cmd);
    // void draw_draw_command(DrawCommand cmd);
    void set_projection_mode(ProjectionMode mode);
    //void update_projection_data(float new_window_width, float new_window_height);
    std::string load_shader_from_file(const std::string& shader_path);
    void update_projection(float new_window_width, float new_window_height);
    void update_uniform_projection();
    void set_color(float r, float g, float b);
    void set_viewport_size(float width, float height);

    //draw functions
    void draw_rectangle(float x, float y, float width, float height);
    //TODO: implement
    void draw_circle();
    OpenGL();
private:
    static OpenGL* instance;

    //OpenGL state
    struct glstate state;
    // when user doesn't provide any projection mode
    // this default one will be used
    GLsizei window_width, window_height = 0;
    ProjectionMode current_projection_mode = ProjectionMode::PROJECTION_MODE_UNSET;
    glm::mat4x4 projection_matrix;
    ~OpenGL(){};
};




OpenGL::OpenGL()
{
    //keep getting segfault here
    state.program = glCreateProgram();
    state.projection = glm::ortho(0.0f, 800.0f, 600.0f, 0.0f, -1.0f, 1.0f);
    state.r = 1.0;
    state.g = 1.0;
    state.b = 1.0;
    state.draw_calls_batched = 0;
}