private static bool IsEar(List <Vector2> points, int a, int b, int c)
{
// See if the angle ABC is concave.
if (GetAngle(points[a].X, points[a].Y, points[b].X, points[b].Y, points[c].X, points[c].Y) > 0)
{
// This is a concave corner so the triangle
// cannot be an ear.
return(false);
}
// Make the triangle A, B, C.
PolygonTriangle triangle = new PolygonTriangle(points[a], points[b], points[c]);
// Check the other points to see
// if they lie in triangle A, B, C.
for (int i = 0; i < points.Count; i++)
{
if ((i != a) && (i != b) && (i != c))
{
if (triangle.Contains(points[i]))
{
// This point is in the triangle
// do this is not an ear.
return(false);
}
}
}
// This is an ear.
return(true);
}
/// <summary>
/// Gets specified copy of triangle of polygon
/// </summary>
/// <param name="index">Index of triangle</param>
/// <returns>Copy of triangle</returns>
public PolygonTriangle GetTriangle(int index)
{
PolygonTriangle orgTri = m_triangles[index];
PolygonTriangle copy = new PolygonTriangle(orgTri.A, orgTri.B, orgTri.C);
copy.m_position = m_position;
copy.m_origin = m_origin;
copy.m_rotation = m_rotation;
return(copy);
}
/// <summary>
/// Copy constructor
/// </summary>
/// <param name="polygonTriangle">Polygon triangle</param>
protected PolygonTriangle(PolygonTriangle polygonTriangle)
: base(polygonTriangle)
{
}