realistic refelection like unity 3ngine

[Veleno]

Cube maps work best on surfaces that are curvy or have distorted normals. Their main weakness, like what you're seeing here, is smooth flat surfaces. The parallax technique seen in your original example does improve things quite a bit under certain conditions, but we don't have an artist-friendly workflow for that right now. Even in the unity example they make sure to rough up the surface to mask the shortcomings of the technique.

For mirror-like reflections, the most performance friendly approach is often to use the old-school method of making a mirrored duplicate of your scene on the others side of a transparent texture. Some games and movies still use this technique today because it's so low-tech.

It's also possible to do a camera-rendered one through code, I'd need a programer to talk about this approach as well.