//public void SetSlope(ref List <CEdge > CEdgeLt)
//{
// CGeoFunc.SetSlope(ref CEdgeLt);
//}
/// <summary>Detect the intesection between two edges</summary>
/// <returns >the intersection point</returns>
/// <remarks>the edges have to be set slope before using this function
/// If the two edges overlap, then the IntersectCpt is the point with larger XY coordinate of the two ends of the overlap line segment
/// </remarks>
public void DetectIntersection()
{
CEdge cedge1 = _CEdge1;
CEdge cedge2 = _CEdge2;
cedge1.JudgeAndSetSlope();
cedge2.JudgeAndSetSlope();
CPoint IntersectCpt = null;
CEdge overlapcedge = null;
CEnumIntersectionType penumIntersectionType = CEnumIntersectionType.NoNo;
if (cedge1.blnHasSlope == true && cedge2.blnHasSlope == true) //this is the normal case
{
//if (CCmpMethods.Cmp(cedge1.dblSlope, cedge2.dblSlope)==0) //parallel
if (CCmpMethods.CmpDbl_ConstVerySmall(cedge1.dblSlope, cedge2.dblSlope) == 0) //parallel
{
if (CCmpMethods.CmpDbl_CoordVerySmall(cedge1.dblYIntercept, cedge2.dblYIntercept) == 0) //parallel and with the same YIntercept
{
penumIntersectionType = DetectIntersectionParralel(cedge1, cedge2, out IntersectCpt, out overlapcedge);
}
else //parallel but not with the same YIntercept
{
penumIntersectionType = CEnumIntersectionType.NoNo;
}
}
else //not parallel
{
penumIntersectionType = DetectIntersectionNormal(cedge1, cedge2, out IntersectCpt);
}
}
else if (cedge1.blnHasSlope == true && cedge2.blnHasSlope == false)
{
penumIntersectionType = DetectIntersectionOneNoSlope(cedge1, cedge2, out IntersectCpt);
}
else if (cedge1.blnHasSlope == false && cedge2.blnHasSlope == true)
{
penumIntersectionType = DetectIntersectionOneNoSlope(cedge2, cedge1, out IntersectCpt);
penumIntersectionType = ReverseIntersectionType(penumIntersectionType);
}
else if (cedge1.blnHasSlope == false && cedge2.blnHasSlope == false)
{
if (CCmpMethods.CmpDbl_CoordVerySmall(cedge1.FrCpt.X, cedge2.FrCpt.X) == 0) //parallel and with the same X Coordinate
{
penumIntersectionType = DetectIntersectionParralel(cedge1, cedge2, out IntersectCpt, out overlapcedge);
}
else //parallel but not with the same X Coordinate
{
penumIntersectionType = CEnumIntersectionType.NoNo;
}
}
_enumIntersectionType = penumIntersectionType;
_IntersectCpt = IntersectCpt;
_OverlapCEdge = overlapcedge;
}
public CIntersection(CEdge cedge1, CEdge cedge2, CPoint pIntersectCpt, CEdge pOverlapCEdge,
CEnumIntersectionType penumIntersectionType)
{
_CEdge1 = cedge1;
_CEdge2 = cedge2;
_IntersectCpt = pIntersectCpt;
_OverlapCEdge = pOverlapCEdge;
_enumIntersectionType = penumIntersectionType;
}
private CEnumIntersectionType ReverseIntersectionType(CEnumIntersectionType penumIntersectionType)
{
CEnumIntersectionType ReversedEnumIntersectionType = penumIntersectionType;
switch (penumIntersectionType)
{
case CEnumIntersectionType.NoNo:
break;
case CEnumIntersectionType.FrFr:
break;
case CEnumIntersectionType.FrIn:
ReversedEnumIntersectionType = CEnumIntersectionType.InFr;
break;
case CEnumIntersectionType.FrTo:
ReversedEnumIntersectionType = CEnumIntersectionType.ToFr;
break;
case CEnumIntersectionType.InFr:
ReversedEnumIntersectionType = CEnumIntersectionType.FrIn;
break;
case CEnumIntersectionType.InIn:
break;
case CEnumIntersectionType.InTo:
ReversedEnumIntersectionType = CEnumIntersectionType.ToIn;
break;
case CEnumIntersectionType.ToFr:
ReversedEnumIntersectionType = CEnumIntersectionType.FrTo;
break;
case CEnumIntersectionType.ToIn:
ReversedEnumIntersectionType = CEnumIntersectionType.InTo;
break;
case CEnumIntersectionType.ToTo:
break;
case CEnumIntersectionType.Overlap:
break;
default:
break;
}
return(ReversedEnumIntersectionType);
}
private CEnumIntersectionType DetectIntersectionParralelIncrease(CEdge cedge1, CEdge cedge2,
out CPoint IntersectCpt, out CEdge overlapcedge)
{
if (CCmpMethods.CmpCptXY(cedge1.ToCpt, cedge2.ToCpt) <= 0) //we compare both x and y so that we can handle two edges which have no slope
{
return(DetectIntersectionParralelIncreaseCEdge2Righter(cedge1, cedge2, out IntersectCpt, out overlapcedge));
}
else
{
CEnumIntersectionType enumIntersectionType =
DetectIntersectionParralelIncreaseCEdge2Righter(cedge2, cedge1, out IntersectCpt, out overlapcedge);
return(ReverseIntersectionType(enumIntersectionType));
}
}
private CEnumIntersectionType DetectIntersectionParralel(CEdge cedge1, CEdge cedge2,
out CPoint IntersectCpt, out CEdge overlapcedge)
{
CEdge auxCEdge1 = cedge1;
bool blnReversed1 = false;
if (CCmpMethods.CmpCptXY(cedge1.FrCpt, cedge1.ToCpt) == 1)
{
auxCEdge1 = new CEdge(cedge1.ToCpt, cedge1.FrCpt);
blnReversed1 = true;
}
CEdge auxCEdge2 = cedge2;
bool blnReversed2 = false;
if (CCmpMethods.CmpCptXY(cedge2.FrCpt, cedge2.ToCpt) == 1)
{
auxCEdge2 = new CEdge(cedge2.ToCpt, cedge2.FrCpt);
blnReversed2 = true;
}
CEnumIntersectionType penumIntersectionType =
DetectIntersectionParralelIncrease(auxCEdge1, auxCEdge2, out IntersectCpt, out overlapcedge);
if (penumIntersectionType == CEnumIntersectionType.FrTo || penumIntersectionType == CEnumIntersectionType.ToFr) //besides, penumIntersectionType coud be CEnumIntersectionType.NoNo or CEnumIntersectionType.Overlap
{
string substr1 = penumIntersectionType.ToString().Substring(0, 2);
string substr2 = penumIntersectionType.ToString().Substring(2, 2);
if (blnReversed1 == true)
{
substr1 = ReverseEnd(substr1);
}
if (blnReversed2 == true)
{
substr2 = ReverseEnd(substr2);
}
string strIntersectionType = substr1 + substr2;
return((CEnumIntersectionType)Enum.Parse(typeof(CEnumIntersectionType), strIntersectionType));
}
return(penumIntersectionType);
}
