What are mat and nmat matrix in mesh.vert shader?

[isidisi]

Hello:

 

I'm starting doing my own shaders, and after reading some book, I see something different in Leadwerks shaders.

 

Usually (in book)

gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;

 

but in Leadwerks mesh.vert shader:

gl_Position = gl_ModelViewProjectionMatrix * mat * gl_Vertex;

 

Also normals are transformed with nmat matrix...

 

Why is necesary multiply positions by mat and normals by nmat?

 

Thanks

[isidisi]

No help??? :-( anybody from leadwerks?