Is there a way from a shader to sample a different level of its mip map?
Yep.
http://http.developer.nvidia.com/Cg/tex2Dlod.html
Use this with your textures, and you can specify the mip level in the call.
Is there a way from a shader to sample a different level of its mip map?
Yep.
http://http.developer.nvidia.com/Cg/tex2Dlod.html
Use this with your textures, and you can specify the mip level in the call.