Hello DELTA_12,
There are a number of ways to achieve this effect. However, you have stated that everything that you have found either does not work or you are not satisfied with the result. If you would please post a screenshot of your glass that you are most satisfied with as well as a link to the documentation that you are using to achieve this effect I can start to eliminate some of these methods. This way I can see exactly what you have so far and attempt to get you closer to what you to what you want to see in your project.
Thanks,