void TrianglePlaneRelations(ref Triangle3d triangle, ref Plane3d plane,
out Vector3d distance, out Index3i sign, out int positive, out int negative, out int zero)
{
// Compute the signed distances of triangle vertices to the plane. Use
// an epsilon-thick plane test.
positive = 0;
negative = 0;
zero = 0;
distance = Vector3d.Zero;
sign = Index3i.Zero;
for (int i = 0; i < 3; ++i)
{
distance[i] = plane.DistanceTo(triangle[i]);
if (distance[i] > MathUtil.ZeroTolerance)
{
sign[i] = 1;
positive++;
}
else if (distance[i] < -MathUtil.ZeroTolerance)
{
sign[i] = -1;
negative++;
}
else
{
distance[i] = (double)0;
sign[i] = 0;
zero++;
}
}
}
public bool Find()
{
if (Result != IntersectionResult.NotComputed)
{
return(Result != IntersectionResult.NoIntersection);
}
double DdN = line.Direction.Dot(plane.Normal);
double signedDistance = plane.DistanceTo(line.Origin);
if (Math.Abs(DdN) > MathUtil.ZeroTolerance)
{
// The line is not parallel to the plane, so they must intersect.
Quantity = 1;
LineParameter = -signedDistance / DdN;
Point = Line.PointAt(LineParameter);
Type = IntersectionType.Point;
Result = IntersectionResult.Intersects;
return(true);
}
// The line and plane are parallel. Determine if they are numerically
// close enough to be coincident.
if (Math.Abs(signedDistance) <= MathUtil.ZeroTolerance)
{
// The line is coincident with the plane, so choose t = 0 for the
// parameter.
Quantity = 1;
Point = Line.PointAt(0);
CoincidentLine = new Line3d(line.Origin, line.Direction);
Result = IntersectionResult.Intersects;
Type = IntersectionType.Line;
return(true);
}
Result = IntersectionResult.NoIntersection;
Type = IntersectionType.Empty;
return(false);
}