//Orient triangles so they have the correct orientation
public static void OrientTrianglesClockwise(List <Triangle> triangles)
{
for (int i = 0; i < triangles.Count; i++)
{
Triangle tri = triangles[i];
Vector2 v1 = new Vector2(tri.v1.position.x, tri.v1.position.z);
Vector2 v2 = new Vector2(tri.v2.position.x, tri.v2.position.z);
Vector2 v3 = new Vector2(tri.v3.position.x, tri.v3.position.z);
if (!Delaunay.IsTriangleOrientedClockwise(v1, v2, v3))
{
tri.ChangeOrientation();
}
}
}
//Is a quadrilateral convex? Assume no 3 points are colinear and the shape doesnt look like an hourglass
public static bool IsQuadrilateralConvex(Vector2 a, Vector2 b, Vector2 c, Vector2 d)
{
bool isConvex = false;
bool abc = Delaunay.IsTriangleOrientedClockwise(a, b, c);
bool abd = Delaunay.IsTriangleOrientedClockwise(a, b, d);
bool bcd = Delaunay.IsTriangleOrientedClockwise(b, c, d);
bool cad = Delaunay.IsTriangleOrientedClockwise(c, a, d);
if (abc && abd && bcd & !cad)
{
isConvex = true;
}
else if (abc && abd && !bcd & cad)
{
isConvex = true;
}
else if (abc && !abd && bcd & cad)
{
isConvex = true;
}
//The opposite sign, which makes everything inverted
else if (!abc && !abd && !bcd & cad)
{
isConvex = true;
}
else if (!abc && !abd && bcd & !cad)
{
isConvex = true;
}
else if (!abc && abd && !bcd & !cad)
{
isConvex = true;
}
return(isConvex);
}
