how glx extension uses the software render

[Wang Baisheng]

Dear all,

Now I am studying the DRI. But I have some questions and I can not get more 
information from internet. So would you please give me some information for 
my following questions:

How glx extension requests are dispatched to mesa for software render? And how 
glx extension requests are dispatched to DRI driver ? And I also find in x 
server 1.3, there is a glcore, but in x server 1.5, the glcore is disappear.

Thanks!
Regards,
Baisheng