/// <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; } } }