glGetAttachedShaders_func = (PFNGLGETATTACHEDSHADERSPROC) glutGetProcAddress("glGetAttachedShaders");
glGetAttribLocation_func = (PFNGLGETATTRIBLOCATIONPROC) glutGetProcAddress("glGetAttribLocation");
glGetProgramInfoLog_func = (PFNGLGETPROGRAMINFOLOGPROC) glutGetProcAddress("glGetProgramInfoLog");
glGetAttachedShaders_func = (PFNGLGETATTACHEDSHADERSPROC) glutGetProcAddress("glGetAttachedShaders");
glGetAttribLocation_func = (PFNGLGETATTRIBLOCATIONPROC) glutGetProcAddress("glGetAttribLocation");
glGetProgramInfoLog_func = (PFNGLGETPROGRAMINFOLOGPROC) glutGetProcAddress("glGetProgramInfoLog");