-------------------- 1. opengl tracers
Even though I'm not experienced with it, GLinterceptor looks good and works on Windows. http://glintercept.nutty.org/
thanks! they don't list win98, but this one does actually seem to work. before, I had tried two or three other products, with limited success (best was gltrace itself, but that fails to produce a log for me, even though it manages to count the calls... strange). didn't help me much in this case, though, as tess.c crashes before producing any log entries.. -------------------- 2. tess (and most likely all gl/glu code that uses callbacks on windows, at least on windows 98 with cygwin/mingw) made some progress anyway: - tess.c from the sample link Patrick gave crashes as well, so it doesn't seem to be a HOpenGL problem (at least not directly, pls read on) - I also tried the most recent sample bundle (ftp://ftp.sgi.com/opengl), for the fourth edition, same effect - the README for the bundle mentions the need for the CALLBACK macro: "Several programs use callback functions. The method of casting those callback functions worked fine on UNIX based systems, but not on PCs. The programs quadric.c, surface.c, trim.c, tess.c, and tesswind.c have been modified. References to (GLvoid (*)) cast have been removed, and a reference to the CALLBACK type has been added to the declaration of the callback functions. Where CALLBACK is undefined (for instance, in UNIX systems), it is stubbed out by use of #ifndef." - unfortunately, the include files for cygwin/mingw are currently organized in such a way as to undefine CALLBACK on exit, so when I compile tess.c (with CC=gcc -mwindows -mno-cygwin), all the examples using CALLBACK define it as empty (check with gcc -E). This actually leads to comilation warnings about passing the callbacks at incompatible types, and then to segmentation faults at runtime. it just so happens that tess and tesswind are the two examples that use glu callbacks for non-error-recording purposes - I assume some more examples would crash if any errors occured and the error-callbacks were to be used. - replacing the CALLBACK definition in tess.c by the one that was in place in the include files before undefinition (compare the typedef for _GLUfuncptr in the gcc -E output) cures the problem and allows me to compile and run tess without errors or crashes. #ifndef CALLBACK # define CALLBACK __attribute__ ((__stdcall__)) #endif note: this may well be different for post-win98 windows systems, so the "right" way would be to bring the examples and the cygwin/ mingw include files back in sync. don't yet know where to report this.. bug reporting experience anyone? -------------------- 3. so far, so good. but since the HOpenGL version also crashes for the same two examples, I assume that someone got compilation warnings about incompatible type conversions when building the HOpenGL package for windows and didn't notice them, or that the CALLBACK types for different windows versions differ and I get these crashes because I'm compiling the examples on win98 whereas the package was most likely built on winxp..? of course, that's just a guess, and it could be something else, but it isn't a driver problem, and HOpenGL is affected by it. Could anyone please punch a hole into this, or confirm my guess? HOpenGL-FFI-mingw experience, anyone?-) Claus -- C - the portable assembly debugging target