Why is Windows 8.1 and freeglut not fitting draw calls into window (window cutoff)?

Question

I am experiencing some undesirable behavior while running these OpenGL examples (click the download to get access to the visual studio solution). Everything compiles correctly, but when running tutorial 3, the window cuts off the top and right side of the triangle. (Shown Here)

I have run this demo on Ubuntu and Mac before with no problems. I have not tried this on Windows 7 or below. In no way have I modified the code or the project. Also when I bring freeglut into fullscreen, the triangle is not cutoff at all.

Am I missing something or is this a new setback to using windows 8 and freeglut? Has any one else had this problem?

Answer 1

Most likely it is a bug. In Windows, when you specify the size of the window, the size is including system borders. Therefore the effective client area (black area in your screenshot) is less than the original size requested, and this problem propagates to glViewport. When these two do not match, you experience those cuts.

There are two opportunities for a fix. i. make adjustments to free-glut so it correctly respects requesting a window-size by their client area ii. adjust glviewport to adhere to the actual client area.