struct CVertex
{
	CPoint Point;
	CPoint Delta;
	bool Moving;
};

struct CVertexLine
{
	list<CVertex>::iterator Vertex1, Vertex2;
};


void CDragnDropView::CheckConvexity()
{
	VertexLines.clear();
	list<CVertex> NewVertices;
	for (list<CVertex>::iterator iter1 = GetDocument()->Vertices.begin();
		iter1 != GetDocument()->Vertices.end(); iter1++)
	{
		for (list<CVertex>::iterator iter2 = GetDocument()->Vertices.begin();
			iter2 != GetDocument()->Vertices.end(); iter2++)
		{
			if (iter1 == iter2) continue;
			bool FirstPoint = true, IsValidSegment = true;
			bool FirstSign;
			for (list<CVertex>::iterator iter3 = GetDocument()->Vertices.begin();
				iter3 != GetDocument()->Vertices.end(); iter3++)
			{
				if (iter3 == iter1 || iter3 == iter2) continue;
				float Val;
				if (iter2->Point.x == iter1->Point.x)
					Val = (float)(iter3->Point.y-iter1->Point.y)/(float)(iter2->Point.y-iter1->Point.y); 
				else if (iter2->Point.y == iter1->Point.y)
					Val = (float)(iter3->Point.x-iter1->Point.x)/(float)(iter2->Point.x-iter1->Point.x);
				else
					Val = (float)(iter3->Point.x-iter1->Point.x)/(float)(iter2->Point.x-iter1->Point.x)
					- (float)(iter3->Point.y-iter1->Point.y)/(float)(iter2->Point.y-iter1->Point.y);
				if (Val == 0)
					continue;
				if (FirstPoint)
				{
					FirstPoint = false;
					FirstSign = Val > 0;
				}
				else
				{
					if ((Val > 0) != FirstSign)
					{
						IsValidSegment = false;
						break;
					}
				}
			}
			if (IsValidSegment)
			{
				bool Contains = false;
				for (list<CVertex>::iterator iter4 = NewVertices.begin();
					iter4 != NewVertices.end(); iter4++)
					if (iter4->Point == iter1->Point)
					{
						Contains = true;
						break;
					}
				if (!Contains)
					NewVertices.push_back(*iter1);
				Contains = false;
				for (list<CVertex>::iterator iter5 = NewVertices.begin();
					iter5 != NewVertices.end(); iter5++)
				if (iter5->Point == iter2->Point)
				{
					Contains = true;
					break;
				}
				if (!Contains)
					NewVertices.push_back(*iter2);
				Contains = false;
				for (list<CVertexLine>::iterator iter6 = VertexLines.begin();
					iter6 != VertexLines.end(); iter6++)
				{
					if ((iter6->Vertex1->Point == iter1->Point &&
						iter6->Vertex2->Point == iter2->Point) ||
						(iter6->Vertex1->Point == iter2->Point &&
						iter6->Vertex2->Point == iter1->Point))
					{
						Contains = true;
						break;
					}
				}
				/*if (!Contains)
				{
					CVertexLine vl;
					vl.Vertex1 = iter1;
					vl.Vertex2 = iter2;
					VertexLines.push_back(vl);
				}*/
			}
		}
	}
	GetDocument()->Vertices.clear();
	GetDocument()->Vertices = NewVertices;
}