[Dev-C++] "win32 api + opengl" uses too much CPU resourses (performance problem)

[Jessica C. <jes...@gm...>]

When I run the .exe file whose function is to display OpenGL in win32
api controls, I found the CPU resource is used by 50% (showed in
Windows Task Manager).  My computer is Pentium CPU 3.40GHz.

I attached a sample code here to see if anyone can help me to solve
the "performance" problem.  I would like to say thanks in advance.
:-)