Just spent a few hours debugging this silly bug and thought I’d share what I found.
Brought over some working shaders from Max2008 to Max2010 and there were some new clamping issues with textures. In Max 2010, it appears that the AddressU and AddressV addressmodes are uninitialized. For me this has yielded erratic addressmode results, where textures wrap properly SOMETIMES, but on recompile they will often will be clamped
Make sure that you manually specify addressmodes for FX shaders in 2010:
sampler2D DiffuseTextureSampler = sampler_state
{
Texture = <diffuseTexture>;
MinFilter = Linear;
MagFilter = Linear;
MipFilter = None;
AddressU = Wrap;
AddressV = Wrap;
};
cheers~