I found this one and implemented it in my game: https://github.com/stackgl/glsl-specular-beckmann/blob/master/distribution.glsl
Here are results:
On the floor and walls we have standard Phong, which is ok for materials like wetstone. The metal parts of the door are shined up by sum of Phong and Beckmann specular.
What do you think? Does it looks good?
What did that view look like before? (Looks good to me but maybe it did before, too. :))
For the scroll impaired:
I think I kind of like the original better from this angle at least. Specular is sometimes very hard to judge from still photos, though.
For sure our graphics designers need to look at this. The specular map needs to be modified, as well as the parameter that determines strength of Beckmann’s component needs to be adjusted. And they can always turn it off completely 
