/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2009 Erwin Coumans  http://bulletphysics.org

This software is provided 'as-is', without any express or implied warranty.
In no event will the authors be held liable for any damages arising from the use of this software.
Permission is granted to anyone to use this software for any purpose, 
including commercial applications, and to alter it and redistribute it freely, 
subject to the following restrictions:

1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/

#ifndef BT_CONVEX_INTERNAL_SHAPE_H
#define BT_CONVEX_INTERNAL_SHAPE_H

#include "btConvexShape.h"
#include "../../LinearMath/btAabbUtil2.h"

///The btConvexInternalShape is an internal base class, shared by most convex shape implementations.
///The btConvexInternalShape uses a default collision margin set to CONVEX_DISTANCE_MARGIN.
///This collision margin used by Gjk and some other algorithms, see also btCollisionMargin.h
///Note that when creating small shapes (derived from btConvexInternalShape),
///you need to make sure to set a smaller collision margin, using the 'setMargin' API
///There is a automatic mechanism 'setSafeMargin' used by btBoxShape and btCylinderShape
ATTRIBUTE_ALIGNED16(class)
btConvexInternalShape : public btConvexShape
{
protected:
	btVector3 m_implicitShapeDimensions;

	btScalar m_collisionMargin;

	btScalar m_padding;

	btConvexInternalShape();

public:
	BT_DECLARE_ALIGNED_ALLOCATOR();

	virtual ~btConvexInternalShape()
	{
	}

	virtual btVector3 localGetSupportingVertex(const btVector3& vec) const;

	const btVector3& getImplicitShapeDimensions() const
	{
		return m_implicitShapeDimensions;
	}

	///warning: use setImplicitShapeDimensions with care
	///changing a collision shape while the body is in the world is not recommended,
	///it is best to remove the body from the world, then make the change, and re-add it
	///alternatively flush the contact points, see documentation for 'cleanProxyFromPairs'
	void setImplicitShapeDimensions(const btVector3& dimensions)
	{
		m_implicitShapeDimensions = dimensions;
	}

	void setSafeMargin(btScalar minDimension, btScalar defaultMarginMultiplier = 0.1f)
	{
		btScalar safeMargin = defaultMarginMultiplier * minDimension;
		if (safeMargin < getMargin())
		{
			setMargin(safeMargin);
		}
	}
	void setSafeMargin(const btVector3& halfExtents, btScalar defaultMarginMultiplier = 0.1f)
	{
		//see http://code.google.com/p/bullet/issues/detail?id=349
		//this margin check could could be added to other collision shapes too,
		//or add some assert/warning somewhere
		btScalar minDimension = halfExtents[halfExtents.minAxis()];
		setSafeMargin(minDimension, defaultMarginMultiplier);
	}

	///getAabb's default implementation is brute force, expected derived classes to implement a fast dedicated version
	void getAabb(const btTransform& t, btVector3& aabbMin, btVector3& aabbMax) const
	{
		getAabbSlow(t, aabbMin, aabbMax);
	}

	void getAabbSlow(const btTransform& t, btVector3& aabbMin, btVector3& aabbMax) const;
	
	void setMargin(btScalar margin)
	{
		m_collisionMargin = margin;
	}
	btScalar getMargin() const
	{
		return m_collisionMargin;
	}

	btScalar getMarginNV() const
	{
		return m_collisionMargin;
	}

	int getNumPreferredPenetrationDirections() const
	{
		return 0;
	}

	void getPreferredPenetrationDirection(int index, btVector3& penetrationVector) const
	{
		(void)penetrationVector;
		(void)index;
		btAssert(0);
	}
};

///btConvexInternalAabbCachingShape adds local aabb caching for convex shapes, to avoid expensive bounding box calculations
class btConvexInternalAabbCachingShape : public btConvexInternalShape
{
	btVector3 m_localAabbMin;
	btVector3 m_localAabbMax;
	bool m_isLocalAabbValid;

protected:
	btConvexInternalAabbCachingShape();

	void setCachedLocalAabb(const btVector3& aabbMin, const btVector3& aabbMax)
	{
		m_isLocalAabbValid = true;
		m_localAabbMin = aabbMin;
		m_localAabbMax = aabbMax;
	}

	inline void getCachedLocalAabb(btVector3& aabbMin, btVector3& aabbMax) const
	{
		btAssert(m_isLocalAabbValid);
		aabbMin = m_localAabbMin;
		aabbMax = m_localAabbMax;
	}

	inline void getNonvirtualAabb(const btTransform& trans, btVector3& aabbMin, btVector3& aabbMax, btScalar margin) const
	{
		//lazy evaluation of local aabb
		btAssert(m_isLocalAabbValid);
		btTransformAabb(m_localAabbMin, m_localAabbMax, margin, trans, aabbMin, aabbMax);
	}

public:

	void getAabb(const btTransform& t, btVector3& aabbMin, btVector3& aabbMax) const;

	void recalcLocalAabb();
};

#endif  //BT_CONVEX_INTERNAL_SHAPE_H