/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2013 Torus Knot Software Ltd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
-----------------------------------------------------------------------------
PortalBase.cpp  -  

*/

#include "OgrePortalBase.h"
//#include "OgreSegment.h"
//#include "OgreRay.h"
#include "OgrePCZone.h"   // need access to real zone class 

using namespace Ogre;

PortalBase::PortalBase(const String& name, const PORTAL_TYPE type)
	: MovableObject(name),
	mType(type),
	mCurrentHomeZone(0),
	mNewHomeZone(0),
    mDirection(Vector3::UNIT_Z),
	mRadius(0.0),
	mLocalsUpToDate(false),
	mDerivedUpToDate(false),
	// set prevWorldTransform to a zero'd out matrix
	mPrevWorldTransform(Matrix4::ZERO),
	// default to enabled
	mEnabled(true),
	mWasMoved(true)
{
	switch (mType)
	{
	default:
	case PORTAL_TYPE_QUAD:
		mCorners = OGRE_ALLOC_T(Vector3, 4, MEMCATEGORY_SCENE_CONTROL);
		mDerivedCorners = OGRE_ALLOC_T(Vector3, 4, MEMCATEGORY_SCENE_CONTROL);
		break;
	case PORTAL_TYPE_AABB:
		mCorners = OGRE_ALLOC_T(Vector3, 2, MEMCATEGORY_SCENE_CONTROL);
		mDerivedCorners = OGRE_ALLOC_T(Vector3, 2, MEMCATEGORY_SCENE_CONTROL);
		break;
	case PORTAL_TYPE_SPHERE:
		mCorners = OGRE_ALLOC_T(Vector3, 2, MEMCATEGORY_SCENE_CONTROL);
		mDerivedCorners = OGRE_ALLOC_T(Vector3, 2, MEMCATEGORY_SCENE_CONTROL);
		break;
	}
}

PortalBase::~PortalBase()
{
	if (mCorners)
		OGRE_FREE(mCorners, MEMCATEGORY_SCENE_CONTROL);
	mCorners = 0;
	if (mDerivedCorners)
		OGRE_FREE(mDerivedCorners, MEMCATEGORY_SCENE_CONTROL);
	mDerivedCorners = 0;
}

const AxisAlignedBox& PortalBase::getWorldBoundingBox(bool derive) const
{
//	if (derive)
//	{
//		updateDerivedValues();
//	}

	return mPortalAAB;
}

const Sphere& PortalBase::getWorldBoundingSphere(bool derive) const
{
//	if (derive)
//	{
//		updateDerivedValues();
//	}

	return mDerivedSphere;
}

// Set the SceneNode the Portal is associated with
void PortalBase::setNode(SceneNode* sn)
{
	if (mParentNode) ((SceneNode*)mParentNode)->detachObject(this);
	if (sn) sn->attachObject(this);
}
// Set the zone this portal is in.
void PortalBase::setCurrentHomeZone(PCZone* zone)
{
	// do this here since more than one function calls setCurrentHomeZone
	// also _addPortal is abstract, so easier to do it here.
	if(zone)
	{
		// inform old zone of portal change.
		if(mCurrentHomeZone)  
		{
			mCurrentHomeZone->setPortalsUpdated(true);
		}
		zone->setPortalsUpdated(true);   // inform new zone of portal change
	}
	mCurrentHomeZone = zone;
}

// Set the zone this portal should be moved to
void PortalBase::setNewHomeZone(PCZone* zone)
{
	mNewHomeZone = zone;
}

// Set the local coordinates of one of the portal corners    
void PortalBase::setCorner(int index, const Vector3& point)
{
	mCorners[index] = point;
	mLocalsUpToDate = false;
	mDerivedUpToDate = false;
}
/** Set the local coordinates of all of the portal corners
*/
// NOTE: there are 4 corners if the portal is a quad type
//       there are 2 corners if the portal is an AABB type (min corner & max corner)
//       there are 2 corners if the portal is a sphere type (center and point on sphere)
void PortalBase::setCorners(const Vector3* corners)
{
	switch (mType)
	{
	default:
	case PORTAL_TYPE_QUAD:
		mCorners[0] = corners[0];
		mCorners[1] = corners[1];
		mCorners[2] = corners[2];
		mCorners[3] = corners[3];
		break;
	case PORTAL_TYPE_AABB:
		mCorners[0] = corners[0]; // minimum corner
		mCorners[1] = corners[1]; // maximum corner (opposite from min corner)
		break;
	case PORTAL_TYPE_SPHERE:
		mCorners[0] = corners[0]; // center point
		mCorners[1] = corners[1]; // point on sphere surface
		break;
	}
	mLocalsUpToDate = false;
	mDerivedUpToDate = false;
}

// calculate the local direction of the portal from the corners
void PortalBase::calcDirectionAndRadius(void) const
{
	Vector3 radiusVector;
	Vector3 side1, side2;

	// for AAB building.
	Vector3 min(Math::POS_INFINITY, Math::POS_INFINITY, Math::POS_INFINITY);
	Vector3 max(Math::NEG_INFINITY, Math::NEG_INFINITY, Math::NEG_INFINITY);

	switch (mType)
	{
	default:
	case PORTAL_TYPE_QUAD:
		// first calculate local direction
		side1 = mCorners[1] - mCorners[0];
		side2 = mCorners[2] - mCorners[0];
		mDirection = side1.crossProduct(side2);
		mDirection.normalise();
		// calculate local cp
		mLocalCP = Vector3::ZERO;
		for (int i=0;i<4;i++)
		{
			mLocalCP += mCorners[i];

			min.makeFloor(mCorners[i]);
			max.makeCeil(mCorners[i]);
		}
		mLocalCP *= 0.25f;
		// then calculate radius
		radiusVector = mCorners[0] - mLocalCP;
		mRadius = radiusVector.length();
		break;
	case PORTAL_TYPE_AABB:
		// "direction" is is either pointed inward or outward and is set by user, not calculated.
		// calculate local cp
		mLocalCP = Vector3::ZERO;
		for (int i=0;i<2;i++)
		{
			mLocalCP += mCorners[i];
		}
		mLocalCP *= 0.5f;
		// for radius, use distance from corner to center point
		// this gives the radius of a sphere that encapsulates the aabb
		radiusVector = mCorners[0] - mLocalCP;
		mRadius = radiusVector.length();

		min = mCorners[0];
		max = mCorners[1];
		break;
	case PORTAL_TYPE_SPHERE:
		// "direction" is is either pointed inward or outward and is set by user, not calculated.
		// local CP is same as corner point 0
		mLocalCP = mCorners[0];
		// since corner1 is point on sphere, radius is simply corner1 - center point
		radiusVector = mCorners[1] - mLocalCP;
		mRadius = radiusVector.length();

		min = mDerivedCP - mRadius;
		max = mDerivedCP + mRadius;
		break;
	}
	mDerivedSphere.setRadius(mRadius);
	mLocalPortalAAB.setExtents(min, max);
	// locals are now up to date
	mLocalsUpToDate = true;
}

// Calculate the local bounding sphere of the portal from the corner points
Real PortalBase::getRadius( void ) const
{
	if (!mLocalsUpToDate)
	{
		calcDirectionAndRadius();
	}
	return mRadius;
}
// Update (Calculate) the world spatial values
void PortalBase::updateDerivedValues(void) const
{
	// make sure local values are up to date
	if (!mLocalsUpToDate)
	{
		calcDirectionAndRadius();
	}
	int numCorners = 4;
	if (mType == PORTAL_TYPE_AABB)
		numCorners = 2;
	else if (mType == PORTAL_TYPE_SPHERE)
		numCorners = 2;

	// calculate derived values
	if (mParentNode)
	{
		if(mCurrentHomeZone)
		{
			// inform home zone that a portal has been updated 
			mCurrentHomeZone->setPortalsUpdated(true);
		}
		// save world transform
		Matrix4 transform = mParentNode->_getFullTransform();
		Matrix3 rotation;
		// save off the current DerivedCP
		mPrevDerivedCP = mDerivedCP;
		mDerivedCP = transform * mLocalCP;
		mDerivedSphere.setCenter(mDerivedCP);
		switch(mType)
		{
		case PORTAL_TYPE_QUAD:
			for (int i=0;i<numCorners;i++)
			{
				mDerivedCorners[i] =  transform * mCorners[i];
			}
			transform.extract3x3Matrix(rotation);
			mDerivedDirection = rotation * mDirection;
			break;
		case PORTAL_TYPE_AABB:
			{
				AxisAlignedBox aabb;
				aabb.setExtents(mCorners[0], mCorners[1]);
				aabb = ((SceneNode*)mParentNode)->_getWorldAABB();
				//aabb.transform(mParentNode->_getFullTransform());
				mDerivedCorners[0] = aabb.getMinimum();
				mDerivedCorners[1] = aabb.getMaximum();
				mDerivedDirection = mDirection;
			}
			break;
		case PORTAL_TYPE_SPHERE:
			{
				mDerivedCorners[0] = mDerivedCP;
				mDerivedCorners[1] = transform * mCorners[1];
				mDerivedDirection = mDirection;
			}
			break;
		}
		if (mPrevWorldTransform != Matrix4::ZERO)
		{
			// save previous calc'd plane
			mPrevDerivedPlane = mDerivedPlane;
			// calc new plane
			mDerivedPlane = Ogre::Plane(mDerivedDirection, mDerivedCP);
			// only update prevWorldTransform if did not move
			// we need to add this conditional to ensure that
			// the portal fully updates when it changes position.
			if (mPrevDerivedPlane == mDerivedPlane &&
				mPrevDerivedCP == mDerivedCP)
			{
				mPrevWorldTransform = transform;
			}
			mPrevDerivedCP = mDerivedCP;
		}
		else
		{
			// calc new plane
			mDerivedPlane = Ogre::Plane(mDerivedDirection, mDerivedCP);
			// this is first time, so there is no previous, so prev = current.
			mPrevDerivedPlane = mDerivedPlane;
			mPrevDerivedCP = mDerivedCP;
			mPrevWorldTransform = Matrix4::IDENTITY;
			mPrevWorldTransform = transform;
		}
	}
	else // no associated node, so just use the local values as derived values
	{
		if (mPrevWorldTransform != Matrix4::ZERO)
		{
			// save off the current DerivedCP
			mPrevDerivedCP = mDerivedCP;
			mDerivedCP = mLocalCP;
			mDerivedSphere.setCenter(mDerivedCP);
			for (int i=0;i<numCorners;i++)
			{
				mDerivedCorners[i] = mCorners[i];
			}
			mDerivedDirection = mDirection;
			// save previous calc'd plane
			mPrevDerivedPlane = mDerivedPlane;
			// calc new plane
			mDerivedPlane = Ogre::Plane(mDerivedDirection, mDerivedCP);
		}
		else
		{
			if(mCurrentHomeZone)
			{
				// this case should only happen once 
				mCurrentHomeZone->setPortalsUpdated(true);
			}
			// this is the first time the derived CP has been calculated, so there
			// is no "previous" value, so set previous = current.
			mDerivedCP = mLocalCP;
			mPrevDerivedCP = mDerivedCP;
			mDerivedSphere.setCenter(mDerivedCP);
			for (int i=0;i<numCorners;i++)
			{
				mDerivedCorners[i] = mCorners[i];
			}
			mDerivedDirection = mDirection;
			// calc new plane
			mDerivedPlane = Ogre::Plane(mDerivedDirection, mDerivedCP);
			// this is first time, so there is no previous, so prev = current.
			mPrevDerivedPlane = mDerivedPlane;
			// flag as initialized
			mPrevWorldTransform = Matrix4::IDENTITY;
		}
	}

	// rebuild AAB.
	mPortalAAB = mWorldAABB;
	mPortalAAB.merge(mPrevPortalAAB);
	mPrevPortalAAB = mWorldAABB;

	mPortalCapsule.set(mPrevDerivedCP, mDerivedCP, mRadius);
	mDerivedUpToDate = true;
}

// Adjust the portal so that it is centered and oriented on the given node
// NOTE: This function will move/rotate the node as well!
// NOTE: The node will become the portal's "associated" node (mParentNode).
void PortalBase::adjustNodeToMatch(SceneNode *node)
{
	int i;

	// make sure local values are up to date
	if (!mLocalsUpToDate)
	{
		calcDirectionAndRadius();
	}
	// move the parent node to the center point
	node->setPosition(mLocalCP);

	// move the corner points to be relative to the node
	int numCorners = 4;
	if (mType == PORTAL_TYPE_AABB)
		numCorners = 2;
	else if (mType == PORTAL_TYPE_SPHERE)
		numCorners = 2;

	for (i=0;i<numCorners;i++)
	{
		mCorners[i] -= mLocalCP;
	}
	if (mType != PORTAL_TYPE_AABB &&
		mType != PORTAL_TYPE_SPHERE)
	{
		// NOTE: UNIT_Z is the basis for our local direction
		// orient the node to match the direction
		Quaternion q;
		q = Vector3::UNIT_Z.getRotationTo(mDirection);
		node->setOrientation(q);
	}

	// set the node as the portal's associated node
	setNode(node);

	return;
}

// Check if a portal intersects an AABB
// NOTE: This check is not exact.
bool PortalBase::intersects(const AxisAlignedBox& aab)
{
	// Only check if portal is enabled
	if (mEnabled)
	{
		switch(mType)
		{
		case PORTAL_TYPE_QUAD:
			// since ogre doesn't have built in support for a quad, just check
			// if the box intersects both the sphere of the portal and the plane
			// this can result in false positives, but they will be minimal
			if (!aab.intersects(mDerivedSphere))
			{
				return false;
			}
			if (aab.intersects(mDerivedPlane))
			{
				return true;
			}
			break;
		case PORTAL_TYPE_AABB:
			{
				// aab to aab check
				AxisAlignedBox aabb;
				aabb.setExtents(mDerivedCorners[0], mDerivedCorners[1]);
				return (aab.intersects(aabb));
			}
		case PORTAL_TYPE_SPHERE:
			// aab to sphere check
			return (aab.intersects(mDerivedSphere));
		}
	}
	return false; 
}

// Check if a portal intersects a sphere
// NOTE: This check is not exact.
bool PortalBase::intersects(const Sphere& sphere)
{
	// Only check if portal is enabled
	if (mEnabled)
	{
		switch(mType)
		{
		case PORTAL_TYPE_QUAD:
			// since ogre doesn't have built in support for a quad, just check
			// if the sphere intersects both the sphere of the portal and the plane
			// this can result in false positives, but they will be minimal
			if (!sphere.intersects(mDerivedSphere))
			{
				return false;
			}
			if (sphere.intersects(mDerivedPlane))
			{
				return true;
			}
			break;
		case PORTAL_TYPE_AABB:
			{
				// aab to aab check
				AxisAlignedBox aabb;
				aabb.setExtents(mDerivedCorners[0], mDerivedCorners[1]);
				return (aabb.intersects(sphere));
			}
		case PORTAL_TYPE_SPHERE:
			return (mDerivedSphere.intersects(sphere));
		}
	}
	return false;
}

// Check if a portal intersects a plane bounded volume
// NOTE: This check is not exact.
// NOTE: UNTESTED as of 5/30/07 (EC)
bool PortalBase::intersects(const PlaneBoundedVolume& pbv)
{
	// Only check if portal is enabled
	if (mEnabled)
	{
		switch(mType)
		{
		case PORTAL_TYPE_QUAD:
			{
				// first check sphere of the portal
				if (!pbv.intersects(mDerivedSphere))
				{
					return false;
				}
				// if the portal corners are all outside one of the planes of the pbv, 
				// then the portal does not intersect the pbv. (this can result in 
				// some false positives, but it's the best I can do for now)
				PlaneList::const_iterator it = pbv.planes.begin();
				while (it != pbv.planes.end())
				{
					const Plane& plane = *it;
					// check if all 4 corners of the portal are on negative side of the pbv
					bool allOutside = true;
					for (int i=0;i<4;i++)
					{
						if (plane.getSide(mDerivedCorners[i]) != pbv.outside)
						{
							allOutside = false;
						}
					}
					if (allOutside)
					{
						return false;
					}
					it++;
				};
			}
			break;
		case PORTAL_TYPE_AABB:
			{
				AxisAlignedBox aabb;
				aabb.setExtents(mDerivedCorners[0], mDerivedCorners[1]);
				if (!pbv.intersects(aabb))
				{
					return false;
				}
			}
			break;
		case PORTAL_TYPE_SPHERE:
			if (!pbv.intersects(mDerivedSphere))
			{
				return false;
			}
			break;
		}
	}
	return false;
}

// Check if a portal intersects a ray
// NOTE: Kinda using my own invented routine here for quad portals... Better do a lot of testing!
bool PortalBase::intersects(const Ray& ray )
{
	// Only check if portal is enabled
	if (mEnabled)
	{
		if (mType == PORTAL_TYPE_QUAD)
		{
			// since ogre doesn't have built in support for a quad, I'm going to first
			// find the intersection point (if any) of the ray and the portal plane.  Then
			// using the intersection point, I take the cross product of each side of the portal
			// (0,1,intersect), (1,2, intersect), (2,3, intersect), and (3,0,intersect).  If
			// all 4 cross products have vectors pointing in the same direction, then the
			// intersection point is within the portal, otherwise it is outside.

			std::pair<bool, Real> result = ray.intersects(mDerivedPlane);

			if (result.first == true)
			{
				// the ray intersects the plane, now walk around the edges 
				Vector3 isect = ray.getPoint(result.second);
				Vector3 cross, vect1, vect2;
				Vector3 cross2, vect3, vect4;
				vect1 = mDerivedCorners[1] - mDerivedCorners[0];
				vect2 = isect - mDerivedCorners[0];
				cross = vect1.crossProduct(vect2);
				vect3 = mDerivedCorners[2] - mDerivedCorners[1];
				vect4 = isect - mDerivedCorners[1];
				cross2 = vect3.crossProduct(vect4);
				if (cross.dotProduct(cross2) < 0)
				{
					return false;
				}
				vect1 = mDerivedCorners[3] - mDerivedCorners[2];
				vect2 = isect - mDerivedCorners[2];
				cross = vect1.crossProduct(vect2);
				if (cross.dotProduct(cross2) < 0)
				{
					return false;
				}
				vect1 = mDerivedCorners[0] - mDerivedCorners[3];
				vect2 = isect - mDerivedCorners[3];
				cross = vect1.crossProduct(vect2);
				if (cross.dotProduct(cross2) < 0)
				{
					return false;
				}
				// all cross products pointing same way, so intersect
				// must be on the inside of the portal!
				return true;
			}

			return false;
		}
		else if (mType == PORTAL_TYPE_AABB)
		{
			AxisAlignedBox aabb;
			aabb.setExtents(mDerivedCorners[0], mDerivedCorners[1]);
			std::pair<bool, Real> result = ray.intersects(aabb);
			return result.first;
		}
		else // sphere
		{
			std::pair<bool, Real> result = ray.intersects(mDerivedSphere);
			return result.first;
		}
	}
	return false;
}



/* Test if a scene node intersected a portal during the last time delta 
	* (from last frame time to current frame time).  This function checks
	* if the node "crossed over" the portal also.
*/
PortalBase::PortalIntersectResult PortalBase::intersects(PCZSceneNode* pczsn)
{
	// Only check if portal is enabled
	if (mEnabled)
	{
		if (pczsn == mParentNode)
		{
			// ignore the scene node if it is the node the portal is associated with
			return PortalBase::NO_INTERSECT;
		}
		// most complicated case - if the portal is a quad:
		if (mType == PORTAL_TYPE_QUAD)
		{
			// the node is modelled as a line segment (prevPostion to currentPosition)
			// intersection test is then between the capsule and the line segment.
			Segment nodeSegment;
			nodeSegment.set(pczsn->getPrevPosition(), pczsn->_getDerivedPosition());

			// we model the portal as a line swept sphere (mPrevDerivedCP to mDerivedCP).
			if (getCapsule().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->_getDerivedPosition()) == Plane::NEGATIVE_SIDE &&
					mPrevDerivedPlane.getSide(pczsn->getPrevPosition()) != Plane::NEGATIVE_SIDE)
				{
					// 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->_getWorldAABB().getHalfSize();
					Vector3 portalBox = Vector3(mRadius, mRadius, mRadius);
					portalBox.makeFloor(nodeHalfVector);
					if (portalBox.x < mRadius)
					{
						// crossing occurred!
						return PortalBase::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->_getWorldAABB()) &&
				mDerivedPlane.getSide(pczsn->_getWorldAABB()) == Plane::BOTH_SIDE )
			{
				// intersection but no crossing
				// note this means that the node is CURRENTLY touching the portal.
				if (mDerivedPlane.getSide(pczsn->_getDerivedPosition()) != Plane::NEGATIVE_SIDE)
				{
					// the node is on the positive (front) or exactly on the CP of the portal
					return PortalBase::INTERSECT_NO_CROSS;
				}
				else
				{
					// the node is on the negative (back) side of the portal - it might be in the wrong zone!
					return PortalBase::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 PortalBase::NO_INTERSECT;
		}
		else if (mType == 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;
			aabb.setExtents(mDerivedCorners[0], mDerivedCorners[1]);
			//bool previousInside = aabb.contains(pczsn->getPrevPosition());
			bool currentInside = aabb.contains(pczsn->_getDerivedPosition());
			if (mDirection == Vector3::UNIT_Z)
			{
				// portal norm is "outward" pointing, look for going from outside to inside
				//if (previousInside == false &&
				if (currentInside == true)
				{
					return PortalBase::INTERSECT_CROSS;
				}
			}
			else
			{
				// portal norm is "inward" pointing, look for going from inside to outside
				//if (previousInside == true &&
				if (currentInside == false)
				{
					return PortalBase::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->_getWorldAABB()))
			{
				// 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->_getWorldAABB());
				if (overlap != pczsn->_getWorldAABB())
				{
					return PortalBase::INTERSECT_NO_CROSS;
				}
			}
			return PortalBase::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.squaredDistance(pczsn->_getDerivedPosition());
			Real mRadius2 = mRadius * mRadius;
			if (mDirection == Vector3::UNIT_Z)
			{
				// portal norm is "outward" pointing, look for going from outside to inside 
				//if (previousDistance2 >= mRadius2 &&
				if (currentDistance2 < mRadius2)
				{
					return PortalBase::INTERSECT_CROSS;
				}
			}
			else
			{
				// portal norm is "inward" pointing, look for going from inside to outside
				//if (previousDistance2 < mRadius2 &&
				if (currentDistance2 >= mRadius2)
				{
					return PortalBase::INTERSECT_CROSS;
				}
			}
			// no crossing, but might be touching - check distance 
			if (Math::Sqrt(Math::Abs(mRadius2 - currentDistance2)) <= mRadius)
			{
				return PortalBase::INTERSECT_NO_CROSS;
			}
			return PortalBase::NO_INTERSECT;
		}
	}
	return PortalBase::NO_INTERSECT; 
}

/** check if portal crossed over portal */
bool PortalBase::crossedPortal(const PortalBase* otherPortal)
{
	// Only check if portal is open and is not an antiportal
	if (otherPortal->getEnabled())
	{
		// we model both portals as line swept spheres (mPrevDerivedCP to mDerivedCP).
		// intersection test is then between the capsules.
		// BUGBUG! This routine needs to check for case where one or both objects
		//         don't move - resulting in simple sphere tests
		// BUGBUG! If one (or both) portals are aabb's this is REALLY not accurate.
		const Capsule& otherPortalCapsule(otherPortal->getCapsule());
		if (getCapsule().intersects(otherPortalCapsule))
		{
			// the portal intersected the other portal at some time from last frame to this frame. 
			// Now check if this portal "crossed" the other portal
			switch (otherPortal->getType())
			{
			case PORTAL_TYPE_QUAD:
				// a crossing occurs if the "side" of the final position of this portal compared
				// to the final position of the other portal is negative AND the initial position
				// of this portal compared to the initial position of the other portal is non-negative
				// NOTE: This function assumes that this portal is the smaller portal potentially crossing
				//       over the otherPortal which is larger.
				if (otherPortal->getDerivedPlane().getSide(mDerivedCP) == Plane::NEGATIVE_SIDE &&
					otherPortal->getPrevDerivedPlane().getSide(mPrevDerivedCP) != Plane::NEGATIVE_SIDE)
				{
					// crossing occurred!
					return true;
				}
				break;
			case 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;
					aabb.setExtents(otherPortal->getDerivedCorner(0), otherPortal->getDerivedCorner(1));
					//bool previousInside = aabb.contains(mPrevDerivedCP);
					bool currentInside = aabb.contains(mDerivedCP);
					if (otherPortal->getDerivedDirection() == Vector3::UNIT_Z)
					{
						// portal norm is "outward" pointing, look for going from outside to inside
						//if (previousInside == false &&
						if (currentInside == true)
						{
							return true;
						}
					}
					else
					{
						// portal norm is "inward" pointing, look for going from inside to outside
						//if (previousInside == true &&
						if (currentInside == false)
						{
							return true;
						}
					}
				}
				break;
			case PORTAL_TYPE_SPHERE:
				{
					// 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(otherPortal->getPrevDerivedCP());
					Real currentDistance2 = mDerivedCP.squaredDistance(otherPortal->getDerivedCP());
					Real mRadius2 = Math::Sqr(otherPortal->getRadius());
					if (otherPortal->getDerivedDirection() == Vector3::UNIT_Z)
					{
						// portal norm is "outward" pointing, look for going from outside to inside 
						//if (previousDistance2 >= mRadius2 &&
						if (currentDistance2 < mRadius2)
						{
							return true;
						}
					}
					else
					{
						// portal norm is "inward" pointing, look for going from inside to outside
						//if (previousDistance2 < mRadius2 &&
						if (currentDistance2 >= mRadius2)
						{
							return true;
						}
					}
				}
				break;
			}
		}
	}
	// there was no crossing of the portal by this portal. It might be touching
	// the other portal (but we don't care currently) or the other
	// portal might be an antiportal (crossing not possible) or the
	// other portal might be closed.
	return false;
}

/** check if portal touches another portal */
bool PortalBase::closeTo(const PortalBase* otherPortal)
{
	// only portals of the same type can be "close to" each other.
	if (mType != otherPortal->getType())
	{
		return false;
	}
	bool close = false;
	switch(mType)
	{
	default:
	case PORTAL_TYPE_QUAD:
		{
			// quad portals must be within 1/4 sphere of each other
			Sphere quarterSphere1 = mDerivedSphere;
			quarterSphere1.setRadius(quarterSphere1.getRadius()*0.25f);
			Sphere quarterSphere2 = otherPortal->getDerivedSphere();
			quarterSphere2.setRadius(quarterSphere2.getRadius()*0.25f);
			close = quarterSphere1.intersects(quarterSphere2);
		}
		break;
	case PORTAL_TYPE_AABB:
		// NOTE: AABB's must match perfectly
		if (mDerivedCP == otherPortal->getDerivedCP() &&
			mCorners[0] == otherPortal->getCorner(0) &&
			mCorners[1] == otherPortal->getCorner(1))
		{
			close = true;
		}
		break;
	case PORTAL_TYPE_SPHERE:
		// NOTE: Spheres must match perfectly
		if (mDerivedCP == otherPortal->getDerivedCP() &&
			mRadius == otherPortal->getRadius())
		{
			close = true;
		}
		break;
	}
	return close;
}


/** @copydoc MovableObject::getBoundingBox. */
const AxisAlignedBox& PortalBase::getBoundingBox() const
{
	if (!mLocalsUpToDate)
	{
		calcDirectionAndRadius();
	}
	return mLocalPortalAAB;
}

bool PortalBase::needUpdate()
{
	PCZSceneNode* pczNode = (PCZSceneNode*)mParentNode;
	return (!mLocalsUpToDate || (pczNode && pczNode->isMoved()));
}

/** Returns an updated capsule of the portal for intersection test. */
const Capsule& PortalBase::getCapsule() const
{
	PCZSceneNode* pczNode = (PCZSceneNode*)mParentNode;
	bool justStoppedMoving = mWasMoved && (pczNode && !pczNode->isMoved());
	if (!mDerivedUpToDate || justStoppedMoving)
	{
		updateDerivedValues();
		mWasMoved = false;
	}
	return mPortalCapsule;
}

/** Returns an updated AAB of the portal for intersection test. */
const AxisAlignedBox& PortalBase::getAAB()
{
	PCZSceneNode* pczNode = (PCZSceneNode*)mParentNode;
	bool justStoppedMoving = mWasMoved && (pczNode && !pczNode->isMoved());
	if (!mDerivedUpToDate || justStoppedMoving)
	{
		updateDerivedValues();
		mWasMoved = false;
	}

	return mPortalAAB;
}

/** get the portal type from name value pair. */
PortalBase::PORTAL_TYPE PortalBaseFactory::getPortalType(const NameValuePairList* params)
{
	if (params)
	{
		NameValuePairList::const_iterator ni = params->find("type");
		if (ni != params->end())
		{
			if (ni->second == "Quad") return PortalBase::PORTAL_TYPE_QUAD;
			else if (ni->second == "AABB") return PortalBase::PORTAL_TYPE_AABB;
			else if (ni->second == "Sphere") return PortalBase::PORTAL_TYPE_SPHERE;
		}
	}

	return PortalBase::PORTAL_TYPE_QUAD;
}
