public static Circle2D GetCircumscribedCircle(Triangle2D triangle)
{
var x1 = triangle.a.Coordinate.x;
var y1 = triangle.a.Coordinate.y;
var x2 = triangle.b.Coordinate.x;
var y2 = triangle.b.Coordinate.y;
var x3 = triangle.c.Coordinate.x;
var y3 = triangle.c.Coordinate.y;
float x1_2 = x1 * x1;
float x2_2 = x2 * x2;
float x3_2 = x3 * x3;
float y1_2 = y1 * y1;
float y2_2 = y2 * y2;
float y3_2 = y3 * y3;
// 外接円の中心座標を計算
float c = 2f * ((x2 - x1) * (y3 - y1) - (y2 - y1) * (x3 - x1));
float x = ((y3 - y1) * (x2_2 - x1_2 + y2_2 - y1_2) + (y1 - y2) * (x3_2 - x1_2 + y3_2 - y1_2)) / c;
float y = ((x1 - x3) * (x2_2 - x1_2 + y2_2 - y1_2) + (x2 - x1) * (x3_2 - x1_2 + y3_2 - y1_2)) / c;
float _x = (x1 - x);
float _y = (y1 - y);
float r = Mathf.Sqrt((_x * _x) + (_y * _y));
return(new Circle2D(new Vector2(x, y), r));
}
bool ExternalPSLG(Triangle2D t)
{
// return ExternalPSLG(t.s0) && ExternalPSLG(t.s1) && ExternalPSLG(t.s2);
return
(ExternalPSLG(t.a.Coordinate) ||
ExternalPSLG(t.b.Coordinate) ||
ExternalPSLG(t.c.Coordinate)
);
}
public Triangle2D AddTriangle(Vertex2D a, Vertex2D b, Vertex2D c)
{
var s0 = CheckAndAddSegment(a, b);
var s1 = CheckAndAddSegment(b, c);
var s2 = CheckAndAddSegment(c, a);
var t = new Triangle2D(s0, s1, s2);
T.Add(t);
return(t);
}
void RemoveCommonTriangles(Triangle2D target)
{
for (int i = 0, n = T.Count; i < n; i++)
{
var t = T[i];
if (t.HasCommonPoint(target))
{
RemoveTriangle(t);
i--;
n--;
}
}
}
bool HasOuterSegments(Triangle2D t)
{
if (!ContainsSegments(t.s0, S))
{
return(ExternalPSLG(t.s0));
}
if (!ContainsSegments(t.s1, S))
{
return(ExternalPSLG(t.s1));
}
if (!ContainsSegments(t.s2, S))
{
return(ExternalPSLG(t.s2));
}
return(false);
}
void RemoveTriangle(Triangle2D t)
{
T.Remove(t);
if (t.s0.Decrement() <= 0)
{
RemoveSegment(t.s0);
}
if (t.s1.Decrement() <= 0)
{
RemoveSegment(t.s1);
}
if (t.s2.Decrement() <= 0)
{
RemoveSegment(t.s2);
}
}
public static bool CheckEqual(Triangle2D t0, Triangle2D t1)
{
// 0,1,2 == 0,1,2
// 0,1,2 == 0,2,1
// 0,1,2 == 1,0,2
// 0,1,2 == 1,2,0
// 0,1,2 == 2,0,1
// 0,1,2 == 2,1,0
return
((CheckEqual(t0.s0, t1.s0) && CheckEqual(t0.s1, t1.s1) && CheckEqual(t0.s2, t1.s2)) ||
(CheckEqual(t0.s0, t1.s0) && CheckEqual(t0.s1, t1.s2) && CheckEqual(t0.s2, t1.s1)) ||
(CheckEqual(t0.s0, t1.s1) && CheckEqual(t0.s1, t1.s0) && CheckEqual(t0.s2, t1.s2)) ||
(CheckEqual(t0.s0, t1.s1) && CheckEqual(t0.s1, t1.s2) && CheckEqual(t0.s2, t1.s0)) ||
(CheckEqual(t0.s0, t1.s2) && CheckEqual(t0.s1, t1.s0) && CheckEqual(t0.s2, t1.s1)) ||
(CheckEqual(t0.s0, t1.s2) && CheckEqual(t0.s1, t1.s1) && CheckEqual(t0.s2, t1.s0)));
}
public void RemoveTriangle(Triangle2D t)
{
var idx = T.IndexOf(t);
if (idx < 0)
{
return;
}
T.RemoveAt(idx);
if (t.s0.Decrement() <= 0)
{
RemoveSegment(t.s0);
}
if (t.s1.Decrement() <= 0)
{
RemoveSegment(t.s1);
}
if (t.s2.Decrement() <= 0)
{
RemoveSegment(t.s2);
}
}
public bool HasCommonPoint(Triangle2D t)
{
return(HasPoint(t.a) || HasPoint(t.b) || HasPoint(t.c));
}
public bool Equals(Triangle2D t)
{
return(HasPoint(t.a) && HasPoint(t.b) && HasPoint(t.c));
}
void SplitTriangle(Triangle2D t)
{
var c = t.Circumcenter();
UpdateTriangulation(c);
}