public override double3 GetNormal(IntersectData data)
{
CsgIntersectData csgIsecData = data as CsgIntersectData;
double3 n = csgIsecData.RealObject.GetNormal(csgIsecData.RealData);
return(csgIsecData.IsFrontSurface ? n : -n);
}
public override List <IntersectData> Intersect(Ray r)
{
List <IntersectData> frontIsecs = new List <IntersectData> ();
foreach (Traceable operand in Operands)
{
frontIsecs.AddRange(operand.Intersect(r));
}
// Note: the following calculations assume that
// nDotRay == 0 ignored cos it produces both
// enter and exit at the same time.
// Also operands should be non-self-intersecting figures.
if (frontIsecs.Count > 0)
{
List <IntersectData> backIsecs = new List <IntersectData> ();
Ray nR = -r;
foreach (Traceable operand in Operands)
{
backIsecs.AddRange(operand.Intersect(nR));
}
var sortedIsecs = backIsecs.OrderByDescending(isecData => (isecData.P - r.p).LengthSq)
.Concat(frontIsecs.OrderBy(isecData => (isecData.P - r.p).LengthSq))
.Distinct();
List <IntersectData> resultIsecs = new List <IntersectData> ();
if (Operation == CsgOp.Subtract)
{
int numSubtrahendEnters = 0;
int numOpAEnters = 0;
foreach (IntersectData isecData in sortedIsecs)
{
bool isFrontSurface = true;
bool InsideAAndExitedSubtrahends = false;
bool InsideAAndEnteredSubtrahend = false;
bool ExitedAAndOutsideSubtrahends = false;
bool EnteredAAndOutsideSubtrahends = false;
double3 n = isecData.Object.GetNormal(isecData);
double nDotRay = n & r.l;
if (isecData.Object != Operands [0])
{
if (nDotRay < 0)
{
numSubtrahendEnters++;
if (numSubtrahendEnters == 1 && numOpAEnters == 1)
{
InsideAAndEnteredSubtrahend = true;
isFrontSurface = false;
}
}
else if (nDotRay > 0)
{
numSubtrahendEnters--;
if (numSubtrahendEnters == 0 && numOpAEnters == 1)
{
InsideAAndExitedSubtrahends = true;
isFrontSurface = false;
}
}
}
else
{
if (nDotRay < 0)
{
numOpAEnters++;
if (numSubtrahendEnters == 0 && numOpAEnters == 1)
{
EnteredAAndOutsideSubtrahends = true;
}
}
else if (nDotRay > 0)
{
numOpAEnters--;
if (numSubtrahendEnters == 0 && numOpAEnters == 0)
{
ExitedAAndOutsideSubtrahends = true;
}
}
}
if (InsideAAndExitedSubtrahends || InsideAAndEnteredSubtrahend ||
ExitedAAndOutsideSubtrahends || EnteredAAndOutsideSubtrahends)
{
CsgIntersectData csgIsecData = new CsgIntersectData(isecData.P, this, isecData.Object, isFrontSurface, isecData);
resultIsecs.Add(csgIsecData);
}
}
}
else if (Operation == CsgOp.Intersect)
{
List <Traceable> insideList = new List <Traceable> ();
bool isInside = false;
foreach (IntersectData isecData in sortedIsecs)
{
double3 n = isecData.Object.GetNormal(isecData);
double nDotRay = n & r.l;
if (nDotRay < 0)
{
insideList.Add(isecData.Object);
if (insideList.Count == Operands.Count)
{
CsgIntersectData csgIsecData = new CsgIntersectData(isecData.P, this, isecData.Object, true, isecData);
resultIsecs.Add(csgIsecData);
isInside = true;
}
}
else if (nDotRay > 0)
{
insideList.Remove(isecData.Object);
if (insideList.Count == Operands.Count - 1 && isInside)
{
CsgIntersectData csgIsecData = new CsgIntersectData(isecData.P, this, isecData.Object, true, isecData);
resultIsecs.Add(csgIsecData);
isInside = false;
}
}
}
}
else if (Operation == CsgOp.Union)
{
List <Traceable> insideList = new List <Traceable> ();
foreach (IntersectData isecData in sortedIsecs)
{
double3 n = isecData.Object.GetNormal(isecData);
double nDotRay = n & r.l;
if (nDotRay < 0)
{
insideList.Add(isecData.Object);
if (insideList.Count == 1)
{
CsgIntersectData csgIsecData = new CsgIntersectData(isecData.P, this, isecData.Object, true, isecData);
resultIsecs.Add(csgIsecData);
}
}
else if (nDotRay > 0)
{
insideList.Remove(isecData.Object);
if (insideList.Count == 0)
{
CsgIntersectData csgIsecData = new CsgIntersectData(isecData.P, this, isecData.Object, true, isecData);
resultIsecs.Add(csgIsecData);
}
}
}
}
resultIsecs = resultIsecs.Where(isecData => !backIsecs.Contains((isecData as CsgIntersectData).RealData)).ToList();
return(resultIsecs);
}
else
{
return(frontIsecs);
}
}