Function robust_geo::orient_2d

pub fn orient_2d(a: Vector2<f64>, b: Vector2<f64>, c: Vector2<f64>) -> f64

Calculates the orientation of points a, b, c in a plane. Returns twice the area of the triangle formed by a, b, and c, which is a positive number if they define a left turn, a negative number if they define a right turn, and 0 if they are collinear.