Function VHConvexHullOrientation

src/openboardview/vectorhulls.cpp:142–148

To find orientation of ordered triplet (p, q, r). The function returns following values 0 --> p, q and r are colinear 1 --> Clockwise 2 --> Counterclockwise

// 1 --> Clockwise
// 2 --> Counterclockwise
int VHConvexHullOrientation(ImVec2 p, ImVec2 q, ImVec2 r) {

	int val = trunc(((q.y - p.y) * (r.x - q.x) - (q.x - p.x) * (r.y - q.y)));

	if (val == 0) return 0;   // colinear
	return (val > 0) ? 1 : 2; // clock or counterclock wise
}

std::vector<ImVec2> VHConvexHull(const std::vector<ImVec2> &points) {
	std::vector<ImVec2> hull;