   Converting to GLSL
  DP2AX shadow.w, shadow, oneover8, shadow.w;I would like to convert the above line to GLSL. It is a NV_fragment_program2 instruction.It comes out toshadow.w = dot(shadow.xy, oneover8) + shadow.w;and I have declared shadow as half4 and oneover8 as half.But the X in DP2AX means to do the operation in 12 bit fixed precision. How to indicate that to the driver with GLSL?Is it even possible to convert low level nv shader crap to GLSL? Is there a document that can help?   
  In short; no.GLSL has no concept of precision directly, it has a float type but no fixed precision type nor does it offically have a "half" type, be it half4 or half in general, those are going to be NV extensions and will break on AMD/ATI hardware.   ;Quote:will break on AMD/ATI hardwareThat's fine because I intend to code for NV only.I would like to know how to convert it to GLSL. I'm sure there is #extension I need to put. I just haven't seen any examples on how to use those NV specific features through GLSL so I need some help.   