public LDLine toLine(LDPointList form)
{
Debug.Assert(form.length() > m_index1);
Debug.Assert(form.length() > m_index2);
return(new LDLine(form.at(m_index1), form.at(m_index2)));
}
public LDPolygon toPolygon(LDPointList points)
{
Debug.Assert((points.length() > m_index1));
Debug.Assert(points.length() > m_index2);
Debug.Assert(points.length() > m_index3);
LDPolygon v = new LDPolygon();
v.Add(new LDPoint(points.at(m_index1)));
v.Add(new LDPoint(points.at(m_index2)));
v.Add(new LDPoint(points.at(m_index3)));
return(v);
}
public LDLineList getLines(LDPointList points)
{
LDLineList result = new LDLineList();
for (int i = 0; i < size(); i++)
{
int index1 = this.at(i).getIndex1();
int index2 = this.at(i).getIndex2();
LDPoint point1 = points.at(index1);
LDPoint point2 = points.at(index2);
result.Add(new LDLine(point1, point2));
}
return(result);
}
public void setClockWise(LDPointList form, ClockWise clockWise)
{
Debug.Assert(form.length() > m_index1);
Debug.Assert(form.length() > m_index2);
Debug.Assert(form.length() > m_index3);
LDPoint v0 = form.at(m_index1);
LDPoint v1 = form.at(m_index2);
LDPoint v2 = form.at(m_index3);
//行列式で時計回りか判定
//行列式の計算。 QMatrix3x3にはないので手動で作成。
double[,] m = new double[3, 3] {
{ v0.x(), v0.y(), 1 },
{ v1.x(), v1.y(), 1 },
{ v2.x(), v2.y(), 1 }
};
double determinant = m[0, 0] * m[1, 1] * m[2, 2]
+ m[0, 1] * m[1, 2] * m[2, 0]
+ m[0, 2] * m[1, 0] * m[2, 1]
- m[0, 2] * m[1, 1] * m[2, 0]
- m[0, 0] * m[1, 2] * m[2, 1]
- m[0, 1] * m[1, 0] * m[2, 2];
ClockWise current;
if (determinant < 0) //CW
{
current = ClockWise.CW;
}
else //CCWまたは3点が一直線上など
{
current = ClockWise.CCW;
}
if (clockWise != current) //設定した順番と異なる場合 Indexを入れ替える
{
var p = m_index1;
m_index1 = m_index2;
m_index2 = p;
}
}
