} //end of subtructEar function
bool check_point_is_Ear(smart_point p, List <smart_point> points)
{
Line l1 = new Line(p.Prev, p.Current_Point);
bool point_is_Convex = false;
bool points_inside_triangle = false;
if (HelperMethods.CheckTurn(l1, p.Next) == Enums.TurnType.Left) // point is convex
{
point_is_Convex = true;
for (int j = 0; j < points.Count(); j++)
{
if (HelperMethods.PointInTriangle(points[j].Current_Point, p.Prev, p.Current_Point, p.Next) == Enums.PointInPolygon.Inside)
{
points_inside_triangle = true;
break;
}
}
}
if (point_is_Convex == true && points_inside_triangle == false) // 2 condtions are true , then this point is Ear point
{
return(true);
p.is_Ear = true;
}
else
{
p.is_Ear = false;
}
return(false);
}
public override void Run(List <Point> points, List <Line> lines, List <Polygon> polygons, ref List <Point> outPoints, ref List <Line> outLines, ref List <Polygon> outPolygons)
{
List <Point> input = new List <Point>(); // this list used only once to check the sort of points
// get minimum_X to use it in checking that the polygon points are sorted CCW OR Not
for (int i = 0; i < polygons[0].lines.Count(); i++)
{
Point p = polygons[0].lines[i].Start;
if (p.X <= mini_x.X)
{
if (p.X < mini_x.X)
{
mini_x = p;
index_of_mini_x = i;
}
else if (p.Y < mini_x.Y)
{
mini_x = p;
index_of_mini_x = i;
}
}
input.Add(p);
}
// check points are sorted CCW OR CC
bool Points_sorted_CCW = HelperMethods.IS_points_Sorted_CCW(mini_x, index_of_mini_x, input);
// if points were sorted CC then Resort them to be CCW
if (Points_sorted_CCW == false)
{
for (int i = 0; i < polygons[0].lines.Count; i++)
{
Point temp = polygons[0].lines[i].Start;
polygons[0].lines[i].Start = polygons[0].lines[i].End;
polygons[0].lines[i].End = temp;
}
polygons[0].lines.Reverse();
}
// create a list of Smart_point where each point have ( it's cordinates , Ear_or_Not , Prev_point ,Next_point )
int size = polygons[0].lines.Count();
for (int i = 0; i < size; i++)
{
// next rotational =( i + 1 ) % count ;
// pre rotational = ((i-1) + count) % count ;
Point p = polygons[0].lines[i].Start;
bool Ear_point = false;
Point Prev = polygons[0].lines[((i - 1) + size) % size].Start;
Point next = polygons[0].lines[(i + 1) % size].Start;
input_points_list.Add(new smart_point(p, Ear_point, Prev, next));
}
int current = 0;
List <smart_point> List_of_Ear_points = new List <smart_point>();
input_points_list[0].is_Ear = false;
for (int i = 0; i < input_points_list.Count(); i++)
{
// assign the Status of each vertex in the input_points_list ( Ear OR Not )
input_points_list[i].is_Ear = false;
bool check = check_point_is_Ear(input_points_list[i], input_points_list);
if (check == true) // if the point is Ear , Then add it to List_of_Ear_points
{
List_of_Ear_points.Add(input_points_list[i]);
List_of_Ear_points[current].is_Ear = true;
// the status will be updated in the 2 lists ( input_points_ lis & list_of_Ear_points )
// because List_of_Ear_points is (( Shallow copy )) of Input_points_list
current++;
}
}
while (List_of_Ear_points.Count() != 0)
{
if (input_points_list.Count() <= 3) // polygon now is Traingle
{
break;
}
/*While (E is not Empty)
* {
* ear = any point from E;
* l = subtractEar(ear, E);
* outlines.Add(l);
* }*/
smart_point p = List_of_Ear_points[0];
Line l1 = subtractEar(p, ref List_of_Ear_points);
outLines.Add(l1);
} //End of While loop
} // end of Run Function
} // end of Run Function
public Line subtractEar(smart_point Ear, ref List <smart_point> E)
{
/*SubtractEar(p, E)
* {
*
* 1 - Remove earPoint from E.
* 2- Update neighbours.
* - If p.prev isEar and wasn’t already in E, add it to E.
* - If p.next isEar and wasn’t already in E, add it to E.
* 3- return segment from p.prev to p.next.
*
* }*/
Line interor_line = new Line(Ear.Prev, Ear.Next);
E.Remove(Ear);
// update also original polygon after Remove the ear point form ears_list and Then remove the point also from the polygon
// This update wiil affect in both the input_points_list & List_of_Ear_points (( because it's Shallow copy ))
bool Status_of_prev_Before = false, Status_of_Next_Before = false;
int ind_OF_Ear_in_polygon = 0; // any intial value
for (int i = 0; i < input_points_list.Count; i++)
{
if (input_points_list[i].Current_Point == Ear.Prev)
{
input_points_list[i].Next = Ear.Next;
Status_of_prev_Before = input_points_list[i].is_Ear;
input_points_list[i].is_Ear = check_point_is_Ear(input_points_list[i], input_points_list);
if (Status_of_prev_Before == false && input_points_list[i].is_Ear == true) // Kant Not_Ear WE b2t Ear , fa lazm a3mlha add fe List_of_EAr_points
{
E.Add(input_points_list[i]);
}
ind_OF_Ear_in_polygon = (i + 1) % input_points_list.Count; // get index of Ear in the polygon to remove it from the polygon
input_points_list.RemoveAt(ind_OF_Ear_in_polygon);
}
else if (input_points_list[i].Current_Point == Ear.Next)
{
input_points_list[i].Prev = Ear.Prev;
Status_of_Next_Before = input_points_list[i].is_Ear;
input_points_list[i].is_Ear = check_point_is_Ear(input_points_list[i], input_points_list);
if (Status_of_Next_Before == false && input_points_list[i].is_Ear == true) // Kant Not_Ear WE b2t Ear , fa lazm a3mlha add fe List_of_EAr_points
{
E.Add(input_points_list[i]);
}
}
}
// دلوقتى هلف على ال
// list_of_Ear_points
// وهشوف كل بوينت فيها لو لاقيت انها بعد ال
//update
// بقت
// Not Ear
// واشيلها من ال
// list_of_ear_points
for (int i = 0; i < E.Count(); i++)
{
if (E[i].is_Ear == false)
{
E.RemoveAt(i);
}
}
return(interor_line);
} //end of subtructEar function