For every $($s$,$t$)$ produced by the two nested for$-$loops, we need to call this:

void

ProduceVertex$($ float s$,$ float t $)$

$\{$

vec$3$ v $=?????//$ do the vertex $($s$,$t$)$ interpolation

v $=?????//$ make v$\text{'}$s cordinates be with respect to the CG

v $=$ v $*?????//$ roughly same code as morphing the cow into a sphere of radius uDiam$/2.$

v $=?????//$ put v back in the global space $($ie$,$ un$-$do the second line of code$)$

vec$4$ ECposition $=$ gl$\_$ModelViewMatrix $*$ vec$4($v$,1.)$;

vec$3$ n $=?????//$ on a sphere, the normal is a vector from the vertex $($v$)$ to the sphere center $($CG$)$

n $=?????//$ multiply the new normal by the proper matrix and normalize it

$//$ will be needed by the fragment shader to perform per$-$fragment lighting:

gN $=?????$

gL $=?????$

gE $=?????$

$//$ finally multiply the vertex by the combined matrices:

gl$\_$Position $=?????*$ vec$4(??,??)$;

EmitVertex$()$;

$\}$