/* Super Quad Geometry shader for Angel */
/* ian@dctsystems.freeserve.co.uk */


geometry superquad(
float east=1;
float north=1;
)
{
float uu,vv;
float cv,cu;
float sv,su;

uu=(u-0.5)*2*PI;
vv=(v-0.5)*PI;

cu=cos(uu);
cu=(cu<0)? -pow(-cu,east) : pow(cu,east);

cv=cos(vv);
cv=(cv<0)? -pow(-cv,north) : pow(cv,north);

su=sin(uu);
su=(su<0)? -pow(-su,east) : pow(su,east);

sv=sin(vv);
sv=(sv<0)? -pow(-sv,north) : pow(sv,north);

P=point (cu*cv,su*cv,sv);

N=calculatenormal(P);
}