I haven’t seen a glt extension before, what library is it? Anyway since it says unresolved external symbol it means it can find the .lib file (or .o if you’re using linux).
What you need to do is to tell the compiler where to find the “glt.lib” (or whatever its name).
In visual studio you go to project properties->linker->additional libraries if I remember correctly.
In gcc you probably should provide -lglt or something. Post again if you need further help.
no, its not the glut problem, because part of my gl coding is from my friend, and according to him, that is the function written by opengl superbible’s author. the author keeps the function into other separate header file, that is why i have that errors. anyhow, i still don’t have time to really figure it our actually due to the workload.