addTriangle method
Implementation
void addTriangle(
Coordinate p0, Coordinate p1, Coordinate p2, bool isPositiveArea) {
double sign = (isPositiveArea) ? 1.0 : -1.0;
centroid3(p0, p1, p2, triangleCent3);
double area = area2(p0, p1, p2);
cg3.x += sign * area * triangleCent3.x;
cg3.y += sign * area * triangleCent3.y;
areasum2 += sign * area;
}