Layer RGBA node's normal map operation?

[stevencaron]

I wanted to know the math/method use by the "normal map" operation in the Layer RGBA node. There are a few decent methods for mixing normal maps, outlined here...

https://blog.selfshadow.com/publications/blending-in-detail/

Is the node using any of these methods?

[stevencaron]

I might have answered my question already with porting some of the code from HLSL to OSL. Seems to match the method posted on the site...

[ramon.montoya · Accepted solution]

The result should be similar to the "reoriented detail" method