/**
* Classifies the face based on the ray trace technique
*
* @param object object3d used to compute the face status
*/
public void rayTraceClassify(Object3D obj)
{
//creating a ray starting starting at the face baricenter going to the normal direction
Point3d p0 = new Point3d();
p0.x = (v1.x + v2.x + v3.x) / 3d;
p0.y = (v1.y + v2.y + v3.y) / 3d;
p0.z = (v1.z + v2.z + v3.z) / 3d;
Line ray = new Line(getNormal(), p0);
bool success;
double dotProduct, distance;
Point3d intersectionPoint;
Face closestFace = null;
double closestDistance;
do
{
success = true;
closestDistance = Double.MaxValue;
//for each face from the other solid...
for (int i = 0; i < obj.getNumFaces(); i++)
{
Face face = obj.getFace(i);
dotProduct = face.getNormal().dot(ray.getDirection());
intersectionPoint = ray.computePlaneIntersection(face.getNormal(), face.v1.getPosition());
//if ray intersects the plane...
if (intersectionPoint != null)
{
distance = ray.computePointToPointDistance(intersectionPoint);
//if ray lies in plane...
if (Math.Abs(distance) < TOL && Math.Abs(dotProduct) < TOL)
{
//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) < TOL && Math.Abs(dotProduct) > TOL)
{
//if ray intersects the face...
if (face.hasPoint(intersectionPoint))
{
//faces coincide
closestFace = face;
closestDistance = 0;
break;
}
}
//if ray intersects plane...
else if (Math.Abs(dotProduct) > TOL && distance > TOL)
{
if (distance < closestDistance)
{
//if ray intersects the face;
if (face.hasPoint(intersectionPoint))
{
//this face is the closest face untill now
closestDistance = distance;
closestFace = face;
}
}
}
}
}
} while(success == false);
//none face found: outside face
if (closestFace == null)
{
status = OUTSIDE;
}
//face found: test dot product
else
{
dotProduct = closestFace.getNormal().dot(ray.getDirection());
//distance = 0: coplanar faces
if (Math.Abs(closestDistance) < TOL)
{
if (dotProduct > TOL)
{
status = SAME;
}
else if (dotProduct < -TOL)
{
status = OPPOSITE;
}
}
//dot product > 0 (same direction): inside face
else if (dotProduct > TOL)
{
status = INSIDE;
}
//dot product < 0 (opposite direction): outside face
else if (dotProduct < -TOL)
{
status = OUTSIDE;
}
}
}
