I'm a beginner to shader programming, I have read some shader codes in NVIDIA FX Composer 2.0 examples. Here is part of one code: /////////////////////////////////////////////////////////////////////////////////////// // UNTWEAKABLES -- global variables that will be automatically tracked by FXComposer // // and other apps. You don't tweak these directly //////////////////////////////// /////////////////////////////////////////////////////////////////////////////////////// float4x4 WorldITXf : WorldInverseTranspose; float4x4 WVPXf : WorldViewProjection; float4x4 WorldXf : World; float4x4 ViewIXf : ViewInverse; I searched for semantics: WorldInverseTranspose,WorldViewProjection,World and ViewInverse, and found no article mentioned about these semantics even in NVIDIA's CG documents. So I wonder if someone can give me some description about these semantics and where I can found all other common used semantics? Thanks for all the reply!