public PortalIntersectResult intersects( PCZSceneNode pczsn )
{
// Only check if portal is open
if ( mOpen )
{
if ( pczsn == mNode )
{
// ignore the scene node if it is the node the portal is associated with
return PortalIntersectResult.NO_INTERSECT;
}
// most complicated case - if the portal is a quad:
if ( mType == PORTAL_TYPE.PORTAL_TYPE_QUAD )
{
// the node is modeled as a line segment (prevPostion to currentPosition)
// intersection test is then between the capsule and the line segment.
Segment nodeSegment = new Segment();
nodeSegment.Set( pczsn.PreviousPosition, pczsn.DerivedPosition );
// we model the portal as a line swept sphere (mPrevDerivedCP to mDerivedCP).
Capsule portalCapsule = new Capsule();
portalCapsule.Set( mPrevDerivedCP, mDerivedCP, mRadius );
if ( portalCapsule.Intersects( nodeSegment ) )
{
// the portal intersected the node at some time from last frame to this frame.
// Now check if node "crossed" the portal
// a crossing occurs if the "side" of the final position of the node compared
// to the final position of the portal is negative AND the initial position
// of the node compared to the initial position of the portal is non-negative
if ( mDerivedPlane.GetSide( pczsn.DerivedPosition ) == PlaneSide.Negative &&
mPrevDerivedPlane.GetSide( pczsn.DerivedPosition ) != PlaneSide.Negative )
{
// safety check - make sure the node has at least one dimension which is
// small enough to fit through the portal! (avoid the "elephant fitting
// through a mouse hole" case)
Vector3 nodeHalfVector = pczsn.WorldAABB.HalfSize;
Vector3 portalBox = new Vector3( mRadius, mRadius, mRadius );
portalBox.Floor( nodeHalfVector );
if ( portalBox.x < mRadius )
{
// crossing occurred!
return PortalIntersectResult.INTERSECT_CROSS;
}
}
}
// there was no crossing of the portal by the node, but it might be touching
// the portal. We check for this by checking the bounding box of the node vs.
// the sphere of the portal
if ( mDerivedSphere.Intersects( pczsn.WorldAABB ) &&
mDerivedPlane.GetSide( pczsn.WorldAABB ) == PlaneSide.Both )
{
// intersection but no crossing
// note this means that the node is CURRENTLY touching the portal.
if ( mDerivedPlane.GetSide( pczsn.DerivedPosition ) != PlaneSide.Negative )
{
// the node is on the positive (front) or exactly on the CP of the portal
return PortalIntersectResult.INTERSECT_NO_CROSS;
}
else
{
// the node is on the negative (back) side of the portal - it might be in the wrong zone!
return PortalIntersectResult.INTERSECT_BACK_NO_CROSS;
}
}
// no intersection CURRENTLY. (there might have been an intersection
// during the time between last frame and this frame, but it wasn't a portal
// crossing, and it isn't touching anymore, so it doesn't matter.
return PortalIntersectResult.NO_INTERSECT;
}
else if ( mType == PORTAL_TYPE.PORTAL_TYPE_AABB )
{
// for aabb's we check if the center point went from being inside to being outside
// the aabb (or vice versa) for crossing.
AxisAlignedBox aabb = new AxisAlignedBox( mDerivedCorners[ 0 ], mDerivedCorners[ 1 ] );
//bool previousInside = aabb.contains(pczsn->getPrevPosition());
bool currentInside = aabb.Contains( pczsn.DerivedPosition );
if ( mDirection == Vector3.UnitZ )
{
// portal norm is "outward" pointing, look for going from outside to inside
//if (previousInside == false &&
if ( currentInside == true )
{
return PortalIntersectResult.INTERSECT_CROSS;
}
}
else
{
// portal norm is "inward" pointing, look for going from inside to outside
//if (previousInside == true &&
if ( currentInside == false )
{
return PortalIntersectResult.INTERSECT_CROSS;
}
}
// doesn't cross, but might be touching. This is a little tricky because we only
// care if the node aab is NOT fully contained in the portal aabb because we consider
// the surface of the portal aabb the actual 'portal'. First, check to see if the
// aab of the node intersects the aabb portal
if ( aabb.Intersects( pczsn.WorldAABB ) )
{
// now check if the intersection between the two is not the same as the
// full node aabb, if so, then this means that the node is not fully "contained"
// which is what we are looking for.
AxisAlignedBox overlap = aabb.Intersection( pczsn.WorldAABB );
if ( overlap != pczsn.WorldAABB )
{
return PortalIntersectResult.INTERSECT_NO_CROSS;
}
}
return PortalIntersectResult.NO_INTERSECT;
}
else
{
// for spheres we check if the center point went from being inside to being outside
// the sphere surface (or vice versa) for crossing.
//Real previousDistance2 = mPrevDerivedCP.squaredDistance(pczsn->getPrevPosition());
Real currentDistance2 = mDerivedCP.DistanceSquared( pczsn.DerivedPosition );
Real mRadius2 = mRadius * mRadius;
if ( mDirection == Vector3.UnitZ )
{
// portal norm is "outward" pointing, look for going from outside to inside
//if (previousDistance2 >= mRadius2 &&
if ( currentDistance2 < mRadius2 )
{
return PortalIntersectResult.INTERSECT_CROSS;
}
}
else
{
// portal norm is "inward" pointing, look for going from inside to outside
//if (previousDistance2 < mRadius2 &&
if ( currentDistance2 >= mRadius2 )
{
return PortalIntersectResult.INTERSECT_CROSS;
}
}
// no crossing, but might be touching - check distance
if ( System.Math.Sqrt( System.Math.Abs( mRadius2 - currentDistance2 ) ) <= mRadius )
{
return PortalIntersectResult.INTERSECT_NO_CROSS;
}
return PortalIntersectResult.NO_INTERSECT;
}
}
return PortalIntersectResult.NO_INTERSECT;
}
