Problem with OpenGL and ATI HD3850

[Roland Smith]

On Thu, Apr 30, 2009 at 02:21:55PM +0200, Oliver Lehmann wrote:
> Tom Evans writes:
> > 
> > fprint(stderr, "%x %s\n", pcVer, pcVer); 
> 
> What I now did is (stolen from glxgears): 
> 
>         // Set version string
>         const GLubyte* pcVer = glGetString(GL_VERSION);
> fprintf(stderr,"100\n");
>       printf("GL_RENDERER   = %s\n", (char *) glGetString(GL_RENDERER));
>       printf("GL_VERSION    = %s\n", (char *) glGetString(GL_VERSION));
>       printf("GL_VENDOR     = %s\n", (char *) glGetString(GL_VENDOR));
>       printf("GL_EXTENSIONS = %s\n", (char *) glGetString(GL_EXTENSIONS));
>         assert(pcVer && "Problems getting GL version string using 
> glGetString");
> fprintf(stderr,"101\n");
>         String tmpStr = (const char*)pcVer; 
> 
> Just to see what glGetString returns - independently what is in pcVer.
> The output I'm getting is: 
> 
> olivleh1 at kartoffel olivleh1> freeorion
> unknown chip id 0x9515, can't guess.
> 100
> GL_RENDERER   = (null)
> GL_VERSION    = (null)
> GL_VENDOR     = (null)
> GL_EXTENSIONS = (null)
> 101
> main() caught exception(std::exception): basic_string::_S_construct NULL 
> not valid
> olivleh1 at kartoffel olivleh1> 
> 
> 
> Could it be, that there was no "GL context" created before? But than I 
> wonder about the output "unknown chip id...". And why the assert() is not 
> handling it.

According to the manual page (1), glGetString returns 0 when an error
occurs. E.g. if the name argument isn't recognized, or if it is called
between a glBegin and glEnd call. Maybe the latter is the case here?

Because otherwise it should just return a pointer to a static string.

Roland

(1) http://www.opengl.org/documentation/specs/man_pages/hardcopy/GL/html/gl/getstring.html
-- 
R.F.Smith                                   http://www.xs4all.nl/~rsmith/
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