This diff adds rounded corners to the cycles brick texture, the brick texture is nice and useful, but it just looks too 'perfect' also i really needed an easy way to make some cobble stones.
this replaces pretty much the core of the function with a distance field ,idea taken from here but then adjusted to account for the mortar size which made the math slightly less obvious.
Tested and working: CPU / OSL / CUDA / opencl mega+split on nvidia sm_30 card, gsgl shader
Some examples on why this is useful:standard brick, with rounded corners, looks a more natural But you can go fully round if you want. or combine it with some squash and make a nice little street pattern by overdoing the radius you end up with diamond shaped patters, great for some sheet metal
A little more creative use: