Hi Filippo, Yup and it seems it was present in NVIDIA some years ago, but fixed now. Anyway the bug is strange because even I tried to call setlocale(LC_NUMERIC, "C"); before compiling the shader and linking, and then restore by calling setlocale(LC_NUMERIC, "");, it still does not work. I thinking the problem happens at runtime, and not when parsing shader (because no error report in the ati shader compiler log). Maybe the compiled shader is not understandable when it was parsed with locale "". If I call setlocale(LC_NUMERIC, "C"); in gstopengl.c, then the sharder works :P (Do you remember  the pb about "purple" result ? now I can see the right colors with this ATI card) Is it a problem to never restore to "" ? I am going to report the pb to the ATI Developer Support. Sincerely Julien <div class="gmail_quote">2008/11/29 Filippo Argiolas <<a href="mailto:filippo.argiolas@gmail.com">filippo.argiolas@gmail.com</a>> <blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">On Sat, Nov 29, 2008 at 4:05 PM, Julien Isorce <<a href="mailto:julien.isorce@gmail.com">julien.isorce@gmail.com</a>> wrote: > Hi, Hi Julien, <div class="Ih2E3d"> > ./test 0   give the wrong result:  red color in the window. ( setlocale > (LC_ALL, "");  is called) > ./test 1   give the right result:  yellow color in the window. ( setlocale > (LC_ALL, "C"); is called) </div>It seems that the ATI GLSL Compiler does some kind of localized string parsing on the shader source.  When you call setlocale (LC_ALL, NULL) it just sets the french locale, where the decimal separator is the "," character. In "C" locale the decimal separator is the "." character. So the decimal part of the floats in the shader source is truncated because dot is not interpreted as decimal separator. >From your testcase: gl_FragColor = vec4(1.0, 0.9, 0.1, 1.0); is yellow on a C/english locale but becomes something like vec4(1, 0, 0, 1) (red) or like vec4(1,0, 0,9, 0,1, 1,0) (red with alpha=9) on a French locale. I don't know what could cause such a behaviour but I guess it's an ATI compiler bug. You should report it to their Developer Support, quoting from  <a href="http://developer.amd.com/support/Pages/default.aspx" target="_blank">http://developer.amd.com/support/Pages/default.aspx</a> : "For all GPU-related developer inquiries, email <a href="mailto:devrel@ati.com">devrel@ati.com</a> with the subject line "GPU-Developer-Support"" Best Regards, Filippo Argiolas ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world <a href="http://moblin-contest.org/redirect.php?banner_id=100&url=/" target="_blank">http://moblin-contest.org/redirect.php?banner_id=100&url=/</a> _______________________________________________ gstreamer-devel mailing list <a href="mailto:gstreamer-devel@lists.sourceforge.net">gstreamer-devel@lists.sourceforge.net</a> <a href="https://lists.sourceforge.net/lists/listinfo/gstreamer-devel" target="_blank">https://lists.sourceforge.net/lists/listinfo/gstreamer-devel</a> </blockquote></div>