[Mesa3d-users] Oddity with GL_LINE_LOOP

[Jason A. <ja...@ho...>]

Hello.

I have come across an odd behaviour with Mesa I thought I should report. I
have tried this with Mesa 3.1, 3.2, and 3.3 on my home machine (Slackware
7, XFree 3.3.5, Linux 2.2.16) and on lab machines at school (Corel
Linux, Mesa 3.1, XFree 3.3.6, Linux 2.2.16)

The source for a program demonstrating this can be found at:
http://www.pmdsystems.dhs.org/files/draw.c

You will notice that if you are drawing a line loop (off the primitive
menu) and after drawing a few points, do an 'end figure', the final
section of the loop is never drawn. However if you end the figure by
selecting a new primitive (or even another line loop from the primitives
menu) the loop is closed fine.

The End Figure is handled in MainMenu(), the primitive selection is
handled in PrimitieMenu();

The only difference between the two sections of code is one does the
glEnd();glBegin() right away, while the other does glEnd();switch(to find
new primitive);glBegin();

I have tried this with both a glFlush(); and glFinish() after the
respective glEnd()'s, with no difference.

Any explanation for this behaviour is greatly appreciated.

Thanks.

Jason

--
"If it's not fun and it's not important then why am I doing it?"
                                         -- Bill Hyde, Bell Laboratories