public static Vector3 RandomTrianglePoint(this ThreeVector3 triangle)
{
float r1 = Mathf.Sqrt(Random.Range(0.0f, 1.0f));
float r2 = Random.Range(0.0f, 1.0f);
return((1 - r1) * triangle.x + r1 * (1 - r2) * triangle.y + r1 * r2 * triangle.z);
}
public static float CalcTriangleArea(this ThreeVector3 triangle)
{
float a = Vector3.Distance(triangle.x, triangle.y);
float b = Vector3.Distance(triangle.y, triangle.z);
float c = Vector3.Distance(triangle.z, triangle.x);
float s = (a + b + c) / 2.0f;
return(Mathf.Sqrt(s * (s - a) * (s - b) * (s - c)));
}
public static void Triangulate(Vector3[] polygon, Vector3 normal, out List <ThreeVector3> triangles)
{
if (polygon.Length < 3)
{
triangles = new List <ThreeVector3>();
return;
}
//var planeNormal = Vector3.Cross(polygon[1] - polygon[0], polygon[2] - polygon[0]);
//planeNormal.Normalize();
//if (Vector3.Angle(planeNormal, normal) > Vector3.Angle(-planeNormal, normal))
//{
// planeNormal = -planeNormal;
//}
//Quaternion rotation = Quaternion.identity;
//if (planeNormal != Vector3.forward)
//{
// rotation = Quaternion.FromToRotation(planeNormal, Vector3.forward);
//}
Quaternion rotation = Quaternion.FromToRotation(normal, Vector3.forward);
// Rotate 1 point and note where it ends up in Z
float z = (rotation * polygon[0]).z;
var poly = new Polygon(ConvertPoints(polygon, rotation));
DTSweepContext tcx = new DTSweepContext();
tcx.PrepareTriangulation(poly);
DTSweep.Triangulate(tcx);
tcx = null;
Quaternion invRot = Quaternion.Inverse(rotation);
triangles = new List <ThreeVector3>();
foreach (DelaunayTriangle t in poly.Triangles)
{
ThreeVector3 tri = new ThreeVector3();
for (int i = 0; i < 3; ++i)
{
var p = t.Points[i];
Vector3 pos = new Vector3(p.Xf, p.Yf, z);
tri[i] = invRot * pos;
}
triangles.Add(tri);
}
}
public static bool IsContainsPoint(this ThreeVector3 triangle, Vector3 point)
{
return(PointsOnSameSideLine(point, triangle.x, triangle.y, triangle.z) &&
PointsOnSameSideLine(point, triangle.y, triangle.x, triangle.z) &&
PointsOnSameSideLine(point, triangle.z, triangle.x, triangle.y));
}
