// calculating normal using Newell's method
private void CalcNormal(List <Vector3m> points)
{
Vector3m normal = Vector3m.Zero();
for (var i = 0; i < points.Count; i++)
{
var j = (i + 1) % (points.Count);
normal.X += (points[i].Y - points[j].Y) * (points[i].Z + points[j].Z);
normal.Y += (points[i].Z - points[j].Z) * (points[i].X + points[j].X);
normal.Z += (points[i].X - points[j].X) * (points[i].Y + points[j].Y);
}
Normal = normal;
}
public bool RaySegmentIntersection(out Vector3m intersection, out Rational distanceSquared, Vector3m linePoint1, Vector3m lineVec1, Vector3m linePoint3, Vector3m linePoint4, Vector3m direction)
{
var lineVec2 = linePoint4 - linePoint3;
Vector3m lineVec3 = linePoint3 - linePoint1;
Vector3m crossVec1and2 = lineVec1.Cross(lineVec2);
Vector3m crossVec3and2 = lineVec3.Cross(lineVec2);
var res = Misc.PointLineDistance(linePoint3, linePoint4, linePoint1);
if (res == 0) // line and ray are collinear
{
var p = linePoint1 + lineVec1;
var res2 = Misc.PointLineDistance(linePoint3, linePoint4, p);
if (res2 == 0)
{
var s = linePoint3 - linePoint1;
if (s.X == direction.X && s.Y == direction.Y && s.Z == direction.Z)
{
intersection = linePoint3;
distanceSquared = s.LengthSquared();
return(true);
}
}
}
//is coplanar, and not parallel
if (/*planarFactor == 0.0f && */ crossVec1and2.LengthSquared() > 0)
{
var s = crossVec3and2.Dot(crossVec1and2) / crossVec1and2.LengthSquared();
if (s >= 0)
{
intersection = linePoint1 + (lineVec1 * s);
distanceSquared = (lineVec1 * s).LengthSquared();
if ((intersection - linePoint3).LengthSquared() + (intersection - linePoint4).LengthSquared() <=
lineVec2.LengthSquared())
{
return(true);
}
}
}
intersection = Vector3m.Zero();
distanceSquared = 0;
return(false);
}
public void Triangulate()
{
if (Normal.Equals(Vector3m.Zero()))
{
throw new Exception("The input is not a valid polygon");
}
if (_holes != null && _holes.Count > 0)
{
ProcessHoles();
}
List <ConnectionEdge> nonConvexPoints = FindNonConvexPoints(_mainPointList);
if (nonConvexPoints.Count == _mainPointList.PointCount)
{
throw new ArgumentException("The triangle input is not valid");
}
while (_mainPointList.PointCount > 2)
{
bool guard = false;
foreach (var cur in _mainPointList.GetPolygonCirculator())
{
if (!IsConvex(cur))
{
continue;
}
if (!IsPointInTriangle(cur.Prev.Origin, cur.Origin, cur.Next.Origin, nonConvexPoints))
{
// cut off ear
guard = true;
Result.Add(cur.Prev.Origin);
Result.Add(cur.Origin);
Result.Add(cur.Next.Origin);
// Check if prev and next are still nonconvex. If not, then remove from non convex list
if (IsConvex(cur.Prev))
{
int index = nonConvexPoints.FindIndex(x => x == cur.Prev);
if (index >= 0)
{
nonConvexPoints.RemoveAt(index);
}
}
if (IsConvex(cur.Next))
{
int index = nonConvexPoints.FindIndex(x => x == cur.Next);
if (index >= 0)
{
nonConvexPoints.RemoveAt(index);
}
}
_mainPointList.Remove(cur);
break;
}
}
if (PointsOnLine(_mainPointList))
{
break;
}
if (!guard)
{
throw new Exception("No progression. The input must be wrong");
}
}
}
