getSolverArea method
Implementation
double getSolverArea(List<Position> positions) {
var area = 0.0;
for (var i = 0; i < _bodies.length; ++i) {
final next = (i == _bodies.length - 1) ? 0 : i + 1;
area += positions[_bodies[i].islandIndex].c.x *
positions[_bodies[next].islandIndex].c.y -
positions[_bodies[next].islandIndex].c.x *
positions[_bodies[i].islandIndex].c.y;
}
return area *= .5;
}