Here is the syntax I've read
tex t a b - Samples the texture in b (which should be one of the fs registers) at the coordinates in a, putting the resulting colour in t.
but In some opensource project code I found someone wrote tex like this:
tex ft0.xyzw vi0.xyzw fs0 <fLinear,mLinear,clamp,2d,rgba,b:45>//what's the bias:45?
and this
tex ft3, v3, fs0<2d, linear, miplinear,dxt1>//what is dxt1, are there any like this?
which really confusing me about what stuff I can put in <> it seems no order requirement
thanks for any hints