source: code/branches/physics/src/bullet/BulletCollision/CollisionShapes/btHeightfieldTerrainShape.h @ 1997

/*
Bullet Continuous Collision Detection and Physics Library
Copyright (c) 2003-2006 Erwin Coumans  http://continuousphysics.com/Bullet/

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 HEIGHTFIELD_TERRAIN_SHAPE_H
#define HEIGHTFIELD_TERRAIN_SHAPE_H

#include "btConcaveShape.h"

///The btHeightfieldTerrainShape simulates a 2D heightfield terrain collision shape. You can also use the more general btBvhTriangleMeshShape instead.
///An example implementation of btHeightfieldTerrainShape is provided in Demos/VehicleDemo/VehicleDemo.cpp
class btHeightfieldTerrainShape : public btConcaveShape
{
protected:
        btVector3       m_localAabbMin;
        btVector3       m_localAabbMax;
        
        ///terrain data
        int     m_heightStickWidth;
        int m_heightStickLength;
        btScalar        m_maxHeight;
        btScalar m_width;
        btScalar m_length;
        union
        {
                unsigned char*  m_heightfieldDataUnsignedChar;
                btScalar*                       m_heightfieldDataFloat;
                void*                   m_heightfieldDataUnknown;
        };
        
        bool    m_useFloatData;
        bool    m_flipQuadEdges;
  bool  m_useDiamondSubdivision;

        int     m_upAxis;
        
        btVector3       m_localScaling;

        virtual btScalar        getHeightFieldValue(int x,int y) const;
        void            quantizeWithClamp(int* out, const btVector3& point,int isMax) const;
        void            getVertex(int x,int y,btVector3& vertex) const;

        inline bool testQuantizedAabbAgainstQuantizedAabb(int* aabbMin1, int* aabbMax1,const  int* aabbMin2,const  int* aabbMax2) const
        {
                bool overlap = true;
                overlap = (aabbMin1[0] > aabbMax2[0] || aabbMax1[0] < aabbMin2[0]) ? false : overlap;
                overlap = (aabbMin1[2] > aabbMax2[2] || aabbMax1[2] < aabbMin2[2]) ? false : overlap;
                overlap = (aabbMin1[1] > aabbMax2[1] || aabbMax1[1] < aabbMin2[1]) ? false : overlap;
                return overlap;
        }

public:
        btHeightfieldTerrainShape(int heightStickWidth,int heightStickHeight,void* heightfieldData, btScalar maxHeight,int upAxis,bool useFloatData,bool flipQuadEdges);

        virtual ~btHeightfieldTerrainShape();


        void setUseDiamondSubdivision(bool useDiamondSubdivision=true) { m_useDiamondSubdivision = useDiamondSubdivision;}


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

        virtual void    processAllTriangles(btTriangleCallback* callback,const btVector3& aabbMin,const btVector3& aabbMax) const;

        virtual void    calculateLocalInertia(btScalar mass,btVector3& inertia) const;

        virtual void    setLocalScaling(const btVector3& scaling);
        
        virtual const btVector3& getLocalScaling() const;
        
        //debugging
        virtual const char*     getName()const {return "HEIGHTFIELD";}

};

#endif //HEIGHTFIELD_TERRAIN_SHAPE_H