Thats what I've read/heard as well. I'm not sure why this would be, but I'll give it a try. (It worked fine in the other NM shader, I think...)


Also, for calculating the sun. The code I'm basing mine on is matts light.
float3 Light1 = P - vecLightPos;
Out.Light1 = mul(worldToTangent, -Light1);

I replaced the light with sun, and instead of subtracting the two points, i simply input -vecSunDir (see above)...