StateCapturer.h

// simplest version

struct StateCapturer {
    StateCapturer() {
        glPushAttrib(...);
        glPushMatrix(...);
        glPushTheWholeDamnWorld();
    }
    ~StateCapturer() {
        glPopEverything();
    }
};

// probably the most practical version

struct StateCapturer {
    StateCapturer(Renderer *r): m_renderer(r) {
        assert(r);
        m_renderer->PushState();
    }
    ~StateCapturer() {
        m_renderer->PopState();
    }
private:
    Renderer *m_renderer;
};

// alternative

struct Renderer {
   ...
   StateCapturer *CaptureState() { return new ConcreteStateCapturer; }
};

void SomeCodeUsingA(Renderer *renderer) {
    ScopedPtr<StateCapturer> saveState(renderer->CaptureState());
    // ...
}