On 15.03.2011 19:40, Greg Ercolano wrote:
> Greg Ercolano wrote:
...
>      I updated the cheat page to show this newer technique
>      for the 'Sphere' example that compiles and runs on both 1.1 and 1.3:
>      http://seriss.com/people/erco/fltk/#OpenGLSphereWithLight
>
>      Had to make some changes to the #include's at the top to ensure
>      it builds and runs correctly on both.
>
>      I couldn't find a combo of #include's that worked for both versions.
>      Ran out of time, and had to make conditional #if's based on FL_MINOR_VERSION
>      to get it to build and run on 1.1 and 1.3.
>
>      This perhaps reveals some (undesirable) incompatibilities.
>
>      If someone can tell me what the correct #includes should be
>      which works for both 1.1 and 1.3 in that example, I'd appreciate it.
>      As it is, the example is now a bit ugly with all those #if conditionals,
>      which seems to show an undesirable FLTK incompatibility between 1.1 and 1.3.

I removed *all* #includes (including math.h) except this one (note also
the upper case 'H'):

#include <FL/glut.H>

and it works with FLTK 1.1 and FLTK 1.3 on Windows and Linux. I didn't
try Mac OS though. Compiled with:

$ ./fltk-config --use-gl --use-glut --compile opengl_sphere.cxx

The docs <http://www.fltk.org/doc-1.1/opengl.html> say:

"You must include FLTK's <FL/gl.h> header file. It will include the
  file <GL/gl.h>, define some extra drawing functions provided by FLTK,
  and include the <windows.h> header file needed by WIN32 applications."

I assume that this also applies to glut, and thus I used FL/glut.H.
This also includes FL/gl.h (lower case 'h').
That's all you need :-)

The "incompatibilities" are probably because you didn't include the
correct header(s) in the old code, and it worked nevertheless.

BTW.: perhaps you could add linker commands (like mine above) to
your cheat page. At least I didn't find one for this example.

Albrecht