/// <summary>
/// Computes closest distance from a vertex to a plane
/// </summary>
/// <param name="vertex">vertex used to compute the distance</param>
/// <param name="face">face representing the plane where it is contained</param>
/// <returns>the closest distance from the vertex to the plane</returns>
private double ComputeDistance(Vertex vertex, Face face)
{
Vector3 normal = face.GetNormal();
double distToV1 = face.GetPlane().distanceToPlaneFromOrigin;
double distToVertex = Vector3.Dot(normal, vertex.Position);
double distFromFacePlane = distToVertex - distToV1;
return(distFromFacePlane);
}
/// <summary>
/// Classifies the face based on the ray trace technique
/// </summary>
/// <param name="obj">object3d used to compute the face status</param>
public void RayTraceClassify(Object3D obj)
{
//creating a ray starting at the face baricenter going to the normal direction
Line ray = new Line(GetNormal(), center);
bool success;
double distance;
Vector3 intersectionPoint;
Face closestFace = null;
double closestDistance;
do
{
success = true;
closestDistance = Double.MaxValue;
//for each face from the other solid...
for (int faceIndex = 0; faceIndex < obj.GetNumFaces(); faceIndex++)
{
Face face = obj.GetFace(faceIndex);
intersectionPoint = ray.ComputePlaneIntersection(face.GetPlane());
//if ray intersects the plane...
if (intersectionPoint.x != double.PositiveInfinity)
{
double dotProduct = Vector3.Dot(face.GetNormal(), ray.Direction);
distance = ray.ComputePointToPointDistance(intersectionPoint);
//if ray lies in plane...
if (Math.Abs(distance) < EqualityTolerance && Math.Abs(dotProduct) < EqualityTolerance)
{
//disturb the ray in order to not lie into another plane
ray.PerturbDirection();
success = false;
break;
}
//if ray starts in plane...
if (Math.Abs(distance) < EqualityTolerance && Math.Abs(dotProduct) > EqualityTolerance)
{
//if ray intersects the face...
if (face.ContainsPoint(intersectionPoint))
{
//faces coincide
closestFace = face;
closestDistance = 0;
break;
}
}
//if ray intersects plane...
else if (Math.Abs(dotProduct) > EqualityTolerance && distance > EqualityTolerance)
{
if (distance < closestDistance)
{
//if ray intersects the face;
if (face.ContainsPoint(intersectionPoint))
{
//this face is the closest face until now
closestDistance = distance;
closestFace = face;
}
}
}
}
}
} while (success == false);
if (closestFace == null)
{
//none face found: outside face
status = Status.OUTSIDE;
}
else //face found: test dot product
{
double dotProduct = Vector3.Dot(closestFace.GetNormal(), ray.Direction);
//distance = 0: coplanar faces
if (Math.Abs(closestDistance) < EqualityTolerance)
{
if (dotProduct > EqualityTolerance)
{
status = Status.SAME;
}
else if (dotProduct < -EqualityTolerance)
{
status = Status.OPPOSITE;
}
}
else if (dotProduct > EqualityTolerance)
{
//dot product > 0 (same direction): inside face
status = Status.INSIDE;
}
else if (dotProduct < -EqualityTolerance)
{
//dot product < 0 (opposite direction): outside face
status = Status.OUTSIDE;
}
}
}
