public Polygon.Error add(double[] x, double[] y, double[] z, int len){
bool DIRECTION = false;
bool FIRST_DIRECTION = false;
// The constraint we have for each side is a 0-constraint (great circle)
// passing through the 2 corners. Since we are in counterclockwise order,
// the vector product of the two successive corners just gives the correct
// constraint.
//
// Polygons should be counterclockwise
// Polygons are assumed to be convex, otherwise windingerror is
// computed wrong.
int ix;
Cartesian v = new Cartesian();
Convex cvx =
new Convex(Convex.Mode.Normal);
int i;
/* PASS 1: check for winding error */
for(i = 0; i < len; i++) {
// Keep track of winding direction. Should be positive
// that is, CCW.
ix = (i==len-1 ? 0 : i+1);
if (i>0){
// test third corner against the constraint just formed
// v is computed in the previous iteration
// Look at a corner dot v
if (v.dot(x[ix], y[ix], z[ix]) < Cartesian.Epsilon) {
DIRECTION = true;
if (i == 1) {
FIRST_DIRECTION = true;
}
// break; // Move to pass 2
} else {
DIRECTION = false;
if (i == 1) {
FIRST_DIRECTION = false;
}
}
if (i > 1) {
if (DIRECTION != FIRST_DIRECTION) {
// C++: must clea up new Cartesian and convex
// or better yet, do no allocate on top until you know
// you need it
return Polygon.Error.errBowtieOrConcave; // BOWTie error
}
}
}
// v = corners[i] ^ corners[ i == len-1 ? 0 : i + 1];
v.assign(x[i], y[i], z[i]);
v.crossMe(x[ix], y[ix], z[ix]);
if (v.isLength(0.0, Cartesian.Epsilon)) {
return Polygon.Error.errZeroLength;
}
// WARNING! if v = zerovector, then edge error!!!
}
/* PASS 2: build convex in either original or reverse
order */
/* forward:
Go from 0 to len-1 by +1, cross i and i+1 (or 0)
reverse:
Go from len-1 to 0 by -1, cross i and i-1 (or len-1)
*/
if (DIRECTION) {
for(i=len-1; i>=0; i--){
// v = corners[i] ^ corners[ i == 0 ? len-1 : i-1];
// v.normalize();
ix = (i==0? len-1 : i-1);
v.assign(x[i], y[i], z[i]);
v.crossMe(x[ix], y[ix], z[ix]);
// WARNING! if v = zerovector, then edge error!!!
v.normalizeMe();
Halfspace c = new Halfspace(v, 0.0);
// SpatialConstraint c(v,0);
cvx.add(c);
}
} else {
for(i=0; i<len; i++){
//v = corners[i] ^ corners[ i == len-1 ? 0 : i+1];
// v.normalize();
ix = (i==len-1 ? 0 : i+1);
v.assign(x[i], y[i], z[i]);
v.crossMe(x[ix], y[ix], z[ix]);
// WARNING! if v = zerovector, then edge error!!!
v.normalizeMe();
Halfspace c = new Halfspace(v, 0.0);
cvx.add(c);
}
}
_reg.add(cvx);
return Polygon.Error.Ok;
}
