path: root/libs/ode-0.16.1/ode/src/collision_cylinder_box.cpp

/*************************************************************************
 *                                                                       *
 * Open Dynamics Engine, Copyright (C) 2001-2003 Russell L. Smith.       *
 * All rights reserved.  Email: russ@q12.org   Web: www.q12.org          *
 *                                                                       *
 * This library is free software; you can redistribute it and/or         *
 * modify it under the terms of EITHER:                                  *
 *   (1) The GNU Lesser General Public License as published by the Free  *
 *       Software Foundation; either version 2.1 of the License, or (at  *
 *       your option) any later version. The text of the GNU Lesser      *
 *       General Public License is included with this library in the     *
 *       file LICENSE.TXT.                                               *
 *   (2) The BSD-style license that is included with this library in     *
 *       the file LICENSE-BSD.TXT.                                       *
 *                                                                       *
 * This library is distributed in the hope that it will be useful,       *
 * but WITHOUT ANY WARRANTY; without even the implied warranty of        *
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files    *
 * LICENSE.TXT and LICENSE-BSD.TXT for more details.                     *
 *                                                                       *
 *************************************************************************/

/*
 *	Cylinder-box collider by Alen Ladavac
 *  Ported to ODE by Nguyen Binh
 */

#include <ode/collision.h>
#include <ode/rotation.h>
#include "config.h"
#include "matrix.h"
#include "odemath.h"
#include "collision_util.h"

static const int MAX_CYLBOX_CLIP_POINTS  = 16;
static const int nCYLINDER_AXIS			 = 2;
// Number of segment of cylinder base circle.
// Must be divisible by 4.
static const int nCYLINDER_SEGMENT		 = 8;

#define MAX_FLOAT	dInfinity

// Data that passed through the collider's functions
struct sCylinderBoxData
{
    sCylinderBoxData(dxGeom *Cylinder, dxGeom *Box, int flags, dContactGeom *contact, int skip):
        m_gBox(Box), m_gCylinder(Cylinder), m_gContact(contact), m_iFlags(flags), m_iSkip(skip), m_nContacts(0)
    {
    }

    void _cldInitCylinderBox();
    int _cldTestAxis( dVector3& vInputNormal, int iAxis );
    int _cldTestEdgeCircleAxis( const dVector3 &vCenterPoint, 
        const dVector3 &vVx0, const dVector3 &vVx1, int iAxis );
    int _cldTestSeparatingAxes();
    int _cldClipCylinderToBox();
    void _cldClipBoxToCylinder();
    int PerformCollisionChecking();

    // cylinder parameters
    dMatrix3			m_mCylinderRot;
    dVector3			m_vCylinderPos;
    dVector3			m_vCylinderAxis;
    dReal				m_fCylinderRadius;
    dReal				m_fCylinderSize;
    dVector3			m_avCylinderNormals[nCYLINDER_SEGMENT];

    // box parameters

    dMatrix3			m_mBoxRot;
    dVector3			m_vBoxPos;
    dVector3			m_vBoxHalfSize;
    // box vertices array : 8 vertices
    dVector3			m_avBoxVertices[8];

    // global collider data
    dVector3			m_vDiff;			
    dVector3			m_vNormal;
    dReal				m_fBestDepth;
    dReal				m_fBestrb;
    dReal				m_fBestrc;
    int					m_iBestAxis;

    // contact data
    dVector3			m_vEp0, m_vEp1;
    dReal				m_fDepth0, m_fDepth1;

    // ODE stuff
    dGeomID				m_gBox;
    dGeomID				m_gCylinder;
    dContactGeom*		m_gContact;
    int					m_iFlags;
    int					m_iSkip;
    int					m_nContacts;

};


// initialize collision data
void sCylinderBoxData::_cldInitCylinderBox() 
{
    // get cylinder position, orientation
    const dReal* pRotCyc = dGeomGetRotation(m_gCylinder); 
    dMatrix3Copy(pRotCyc,m_mCylinderRot);

    const dVector3* pPosCyc = (const dVector3*)dGeomGetPosition(m_gCylinder);
    dVector3Copy(*pPosCyc,m_vCylinderPos);

    dMat3GetCol(m_mCylinderRot,nCYLINDER_AXIS,m_vCylinderAxis);

    // get cylinder radius and size
    dGeomCylinderGetParams(m_gCylinder,&m_fCylinderRadius,&m_fCylinderSize);

    // get box position, orientation, size
    const dReal* pRotBox = dGeomGetRotation(m_gBox);
    dMatrix3Copy(pRotBox,m_mBoxRot);
    const dVector3* pPosBox  = (const dVector3*)dGeomGetPosition(m_gBox);
    dVector3Copy(*pPosBox,m_vBoxPos);

    dGeomBoxGetLengths(m_gBox, m_vBoxHalfSize);
    m_vBoxHalfSize[0] *= REAL(0.5);
    m_vBoxHalfSize[1] *= REAL(0.5);
    m_vBoxHalfSize[2] *= REAL(0.5);

    // vertex 0
    m_avBoxVertices[0][0] = -m_vBoxHalfSize[0];
    m_avBoxVertices[0][1] =  m_vBoxHalfSize[1];
    m_avBoxVertices[0][2] = -m_vBoxHalfSize[2];

    // vertex 1
    m_avBoxVertices[1][0] =  m_vBoxHalfSize[0];
    m_avBoxVertices[1][1] =  m_vBoxHalfSize[1];
    m_avBoxVertices[1][2] = -m_vBoxHalfSize[2];

    // vertex 2
    m_avBoxVertices[2][0] = -m_vBoxHalfSize[0];
    m_avBoxVertices[2][1] = -m_vBoxHalfSize[1];
    m_avBoxVertices[2][2] = -m_vBoxHalfSize[2];

    // vertex 3
    m_avBoxVertices[3][0] =  m_vBoxHalfSize[0];
    m_avBoxVertices[3][1] = -m_vBoxHalfSize[1];
    m_avBoxVertices[3][2] = -m_vBoxHalfSize[2];

    // vertex 4
    m_avBoxVertices[4][0] =  m_vBoxHalfSize[0];
    m_avBoxVertices[4][1] =  m_vBoxHalfSize[1];
    m_avBoxVertices[4][2] =  m_vBoxHalfSize[2];

    // vertex 5
    m_avBoxVertices[5][0] =  m_vBoxHalfSize[0];
    m_avBoxVertices[5][1] = -m_vBoxHalfSize[1];
    m_avBoxVertices[5][2] =  m_vBoxHalfSize[2];

    // vertex 6
    m_avBoxVertices[6][0] = -m_vBoxHalfSize[0];
    m_avBoxVertices[6][1] = -m_vBoxHalfSize[1];
    m_avBoxVertices[6][2] =  m_vBoxHalfSize[2];

    // vertex 7
    m_avBoxVertices[7][0] = -m_vBoxHalfSize[0];
    m_avBoxVertices[7][1] =  m_vBoxHalfSize[1];
    m_avBoxVertices[7][2] =  m_vBoxHalfSize[2];

    // temp index
    int i = 0;
    dVector3	vTempBoxVertices[8];
    // transform vertices in absolute space
    for(i=0; i < 8; i++) 
    {
        dMultiplyMat3Vec3(m_mBoxRot,m_avBoxVertices[i], vTempBoxVertices[i]);
        dVector3Add(vTempBoxVertices[i], m_vBoxPos, m_avBoxVertices[i]);
    }

    // find relative position
    dVector3Subtract(m_vCylinderPos,m_vBoxPos,m_vDiff);
    m_fBestDepth = MAX_FLOAT;
    m_vNormal[0] = REAL(0.0);
    m_vNormal[1] = REAL(0.0);
    m_vNormal[2] = REAL(0.0);

    // calculate basic angle for nCYLINDER_SEGMENT-gon
    dReal fAngle = (dReal) (M_PI/nCYLINDER_SEGMENT);

    // calculate angle increment
    dReal fAngleIncrement = fAngle * REAL(2.0); 

    // calculate nCYLINDER_SEGMENT-gon points
    for(i = 0; i < nCYLINDER_SEGMENT; i++) 
    {
        m_avCylinderNormals[i][0] = -dCos(fAngle);
        m_avCylinderNormals[i][1] = -dSin(fAngle);
        m_avCylinderNormals[i][2] = 0;

        fAngle += fAngleIncrement;
    }

    m_fBestrb		= 0;
    m_fBestrc		= 0;
    m_iBestAxis		= 0;
    m_nContacts		= 0;

}

// test for given separating axis
int sCylinderBoxData::_cldTestAxis( dVector3& vInputNormal, int iAxis ) 
{
    // check length of input normal
    dReal fL = dVector3Length(vInputNormal);
    // if not long enough
    if ( fL < REAL(1e-5) ) 
    {
        // do nothing
        return 1;
    }

    // otherwise make it unit for sure
    dNormalize3(vInputNormal);

    // project box and Cylinder on mAxis
    dReal fdot1 = dVector3Dot(m_vCylinderAxis, vInputNormal);

    dReal frc;

    if (fdot1 > REAL(1.0)) 
    {
        // assume fdot1 = 1
        frc = m_fCylinderSize*REAL(0.5);
    }
    else if (fdot1 < REAL(-1.0))
    {
        // assume fdot1 = -1
        frc = m_fCylinderSize*REAL(0.5);
    }
    else
    {
        // project box and capsule on iAxis
        frc = dFabs( fdot1 * (m_fCylinderSize*REAL(0.5))) + m_fCylinderRadius * dSqrt(REAL(1.0)-(fdot1*fdot1));
    }

    dVector3	vTemp1;

    dMat3GetCol(m_mBoxRot,0,vTemp1);
    dReal frb = dFabs(dVector3Dot(vTemp1,vInputNormal))*m_vBoxHalfSize[0];

    dMat3GetCol(m_mBoxRot,1,vTemp1);
    frb += dFabs(dVector3Dot(vTemp1,vInputNormal))*m_vBoxHalfSize[1];

    dMat3GetCol(m_mBoxRot,2,vTemp1);
    frb += dFabs(dVector3Dot(vTemp1,vInputNormal))*m_vBoxHalfSize[2];

    // project their distance on separating axis
    dReal fd  = dVector3Dot(m_vDiff,vInputNormal);

    // get depth 

    dReal fDepth = frc + frb;  // Calculate partial depth

    // if they do not overlap exit, we have no intersection
    if ( dFabs(fd) > fDepth )
    { 
        return 0; 
    } 

    // Finalyze the depth calculation
    fDepth -= dFabs(fd);

    // get maximum depth
    if ( fDepth < m_fBestDepth ) 
    {
        m_fBestDepth = fDepth;
        dVector3Copy(vInputNormal,m_vNormal);
        m_iBestAxis  = iAxis;
        m_fBestrb    = frb;
        m_fBestrc    = frc;

        // flip normal if interval is wrong faced
        if (fd > 0) 
        { 
            dVector3Inv(m_vNormal);
        }
    }

    return 1;
}


// check for separation between box edge and cylinder circle edge
int sCylinderBoxData::_cldTestEdgeCircleAxis( 
    const dVector3 &vCenterPoint, 
    const dVector3 &vVx0, const dVector3 &vVx1, 
    int iAxis ) 
{
    // calculate direction of edge
    dVector3 vDirEdge;
    dVector3Subtract(vVx1,vVx0,vDirEdge);
    dNormalize3(vDirEdge);
    // starting point of edge 
    dVector3 vEStart;
    dVector3Copy(vVx0,vEStart);;

    // calculate angle cosine between cylinder axis and edge
    dReal fdot2 = dVector3Dot (vDirEdge,m_vCylinderAxis);

    // if edge is perpendicular to cylinder axis
    if(dFabs(fdot2) < REAL(1e-5)) 
    {
        // this can't be separating axis, because edge is parallel to circle plane
        return 1;
    }

    // find point of intersection between edge line and circle plane
    dVector3 vTemp1;
    dVector3Subtract(vCenterPoint,vEStart,vTemp1);
    dReal fdot1 = dVector3Dot(vTemp1,m_vCylinderAxis);
    dVector3 vpnt;
    vpnt[0]= vEStart[0] + vDirEdge[0] * (fdot1/fdot2);
    vpnt[1]= vEStart[1] + vDirEdge[1] * (fdot1/fdot2);
    vpnt[2]= vEStart[2] + vDirEdge[2] * (fdot1/fdot2);

    // find tangent vector on circle with same center (vCenterPoint) that
    // touches point of intersection (vpnt)
    dVector3 vTangent;
    dVector3Subtract(vCenterPoint,vpnt,vTemp1);
    dVector3Cross(vTemp1,m_vCylinderAxis,vTangent);

    // find vector orthogonal both to tangent and edge direction
    dVector3 vAxis;
    dVector3Cross(vTangent,vDirEdge,vAxis);

    // use that vector as separating axis
    return _cldTestAxis( vAxis, iAxis );
}

// Test separating axis for collision
int sCylinderBoxData::_cldTestSeparatingAxes() 
{
    // reset best axis
    m_fBestDepth = MAX_FLOAT;
    m_iBestAxis = 0;
    m_fBestrb = 0;
    m_fBestrc = 0;
    m_nContacts = 0;

    dVector3  vAxis = {REAL(0.0),REAL(0.0),REAL(0.0),REAL(0.0)};

    // Epsilon value for checking axis vector length 
    const dReal fEpsilon = REAL(1e-6);

    // axis A0
    dMat3GetCol(m_mBoxRot, 0 , vAxis);
    if (!_cldTestAxis( vAxis, 1 )) 
    {
        return 0;
    }

    // axis A1
    dMat3GetCol(m_mBoxRot, 1 , vAxis);
    if (!_cldTestAxis( vAxis, 2 )) 
    {
        return 0;
    }

    // axis A2
    dMat3GetCol(m_mBoxRot, 2 , vAxis);
    if (!_cldTestAxis( vAxis, 3 )) 
    {
        return 0;
    }

    // axis C - Cylinder Axis
    //vAxis = vCylinderAxis;
    dVector3Copy(m_vCylinderAxis , vAxis);
    if (!_cldTestAxis( vAxis, 4 )) 
    {
        return 0;
    }

    // axis CxA0
    //vAxis = ( vCylinderAxis cross mthGetColM33f( mBoxRot, 0 ));
    dVector3CrossMat3Col(m_mBoxRot, 0 ,m_vCylinderAxis, vAxis);
    if(dVector3LengthSquare( vAxis ) > fEpsilon ) 
    {
        if (!_cldTestAxis( vAxis, 5 ))
        {
            return 0;
        }
    }

    // axis CxA1
    //vAxis = ( vCylinderAxis cross mthGetColM33f( mBoxRot, 1 ));
    dVector3CrossMat3Col(m_mBoxRot, 1 ,m_vCylinderAxis, vAxis);
    if(dVector3LengthSquare( vAxis ) > fEpsilon ) 
    {
        if (!_cldTestAxis( vAxis, 6 )) 
        {
            return 0;
        }
    }

    // axis CxA2
    //vAxis = ( vCylinderAxis cross mthGetColM33f( mBoxRot, 2 ));
    dVector3CrossMat3Col(m_mBoxRot, 2 ,m_vCylinderAxis, vAxis);
    if(dVector3LengthSquare( vAxis ) > fEpsilon ) 
    {
        if (!_cldTestAxis( vAxis, 7 ))
        {
            return 0;
        }
    }

    int i = 0;
    dVector3	vTemp1;
    dVector3	vTemp2;
    // here we check box's vertices axis
    for(i=0; i< 8; i++) 
    {
        //vAxis = ( vCylinderAxis cross (m_avBoxVertices[i] - vCylinderPos));
        dVector3Subtract(m_avBoxVertices[i],m_vCylinderPos,vTemp1);
        dVector3Cross(m_vCylinderAxis,vTemp1,vTemp2);
        //vAxis = ( vCylinderAxis cross vAxis );
        dVector3Cross(m_vCylinderAxis,vTemp2,vAxis);
        if(dVector3LengthSquare( vAxis ) > fEpsilon ) 
        {
            if (!_cldTestAxis( vAxis, 8 + i ))
            {
                return 0;
            }
        }
    }

    // ************************************
    // this is defined for first 12 axes
    // normal of plane that contains top circle of cylinder
    // center of top circle of cylinder
    dVector3 vcc;
    vcc[0] = (m_vCylinderPos)[0] + m_vCylinderAxis[0]*(m_fCylinderSize*REAL(0.5));
    vcc[1] = (m_vCylinderPos)[1] + m_vCylinderAxis[1]*(m_fCylinderSize*REAL(0.5));
    vcc[2] = (m_vCylinderPos)[2] + m_vCylinderAxis[2]*(m_fCylinderSize*REAL(0.5));
    // ************************************

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[1], m_avBoxVertices[0], 16)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[1], m_avBoxVertices[3], 17)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[2], m_avBoxVertices[3], 18))
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[2], m_avBoxVertices[0], 19)) 
    {
        return 0;
    }


    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[4], m_avBoxVertices[1], 20))
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[4], m_avBoxVertices[7], 21))
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[0], m_avBoxVertices[7], 22)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[5], m_avBoxVertices[3], 23)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[5], m_avBoxVertices[6], 24)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[2], m_avBoxVertices[6], 25)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[4], m_avBoxVertices[5], 26)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[6], m_avBoxVertices[7], 27)) 
    {
        return 0;
    }

    // ************************************
    // this is defined for second 12 axes
    // normal of plane that contains bottom circle of cylinder
    // center of bottom circle of cylinder
    //	vcc = vCylinderPos - vCylinderAxis*(fCylinderSize*REAL(0.5));
    vcc[0] = (m_vCylinderPos)[0] - m_vCylinderAxis[0]*(m_fCylinderSize*REAL(0.5));
    vcc[1] = (m_vCylinderPos)[1] - m_vCylinderAxis[1]*(m_fCylinderSize*REAL(0.5));
    vcc[2] = (m_vCylinderPos)[2] - m_vCylinderAxis[2]*(m_fCylinderSize*REAL(0.5));
    // ************************************

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[1], m_avBoxVertices[0], 28)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[1], m_avBoxVertices[3], 29)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[2], m_avBoxVertices[3], 30)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[2], m_avBoxVertices[0], 31)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[4], m_avBoxVertices[1], 32)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[4], m_avBoxVertices[7], 33)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[0], m_avBoxVertices[7], 34)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[5], m_avBoxVertices[3], 35)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[5], m_avBoxVertices[6], 36)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[2], m_avBoxVertices[6], 37)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[4], m_avBoxVertices[5], 38)) 
    {
        return 0;
    }

    if (!_cldTestEdgeCircleAxis( vcc, m_avBoxVertices[6], m_avBoxVertices[7], 39)) 
    {
        return 0;
    }

    return 1;
}

int sCylinderBoxData::_cldClipCylinderToBox()
{
    dIASSERT(m_nContacts != (m_iFlags & NUMC_MASK));

    // calculate that vector perpendicular to cylinder axis which closes lowest angle with collision normal
    dVector3 vN;
    dReal fTemp1 = dVector3Dot(m_vCylinderAxis,m_vNormal);
    vN[0]	=	m_vNormal[0] - m_vCylinderAxis[0]*fTemp1;
    vN[1]	=	m_vNormal[1] - m_vCylinderAxis[1]*fTemp1;
    vN[2]	=	m_vNormal[2] - m_vCylinderAxis[2]*fTemp1;

    // normalize that vector
    dNormalize3(vN);

    // translate cylinder end points by the vector
    dVector3 vCposTrans;
    vCposTrans[0] = m_vCylinderPos[0] + vN[0] * m_fCylinderRadius;
    vCposTrans[1] = m_vCylinderPos[1] + vN[1] * m_fCylinderRadius;
    vCposTrans[2] = m_vCylinderPos[2] + vN[2] * m_fCylinderRadius;

    m_vEp0[0]  = vCposTrans[0] + m_vCylinderAxis[0]*(m_fCylinderSize*REAL(0.5));
    m_vEp0[1]  = vCposTrans[1] + m_vCylinderAxis[1]*(m_fCylinderSize*REAL(0.5));
    m_vEp0[2]  = vCposTrans[2] + m_vCylinderAxis[2]*(m_fCylinderSize*REAL(0.5));

    m_vEp1[0]  = vCposTrans[0] - m_vCylinderAxis[0]*(m_fCylinderSize*REAL(0.5));
    m_vEp1[1]  = vCposTrans[1] - m_vCylinderAxis[1]*(m_fCylinderSize*REAL(0.5));
    m_vEp1[2]  = vCposTrans[2] - m_vCylinderAxis[2]*(m_fCylinderSize*REAL(0.5));

    // transform edge points in box space
    m_vEp0[0] -= m_vBoxPos[0];
    m_vEp0[1] -= m_vBoxPos[1];
    m_vEp0[2] -= m_vBoxPos[2];

    m_vEp1[0] -= m_vBoxPos[0];
    m_vEp1[1] -= m_vBoxPos[1];
    m_vEp1[2] -= m_vBoxPos[2];

    dVector3 vTemp1;
    // clip the edge to box 
    dVector4 plPlane;
    // plane 0 +x
    dMat3GetCol(m_mBoxRot,0,vTemp1);
    dConstructPlane(vTemp1,m_vBoxHalfSize[0],plPlane);
    if(!dClipEdgeToPlane( m_vEp0, m_vEp1, plPlane )) 
    { 
        return 0; 
    }

    // plane 1 +y
    dMat3GetCol(m_mBoxRot,1,vTemp1);
    dConstructPlane(vTemp1,m_vBoxHalfSize[1],plPlane);
    if(!dClipEdgeToPlane( m_vEp0, m_vEp1, plPlane )) 
    { 
        return 0; 
    }

    // plane 2 +z
    dMat3GetCol(m_mBoxRot,2,vTemp1);
    dConstructPlane(vTemp1,m_vBoxHalfSize[2],plPlane);
    if(!dClipEdgeToPlane( m_vEp0, m_vEp1, plPlane )) 
    { 
        return 0; 
    }

    // plane 3 -x
    dMat3GetCol(m_mBoxRot,0,vTemp1);
    dVector3Inv(vTemp1);
    dConstructPlane(vTemp1,m_vBoxHalfSize[0],plPlane);
    if(!dClipEdgeToPlane( m_vEp0, m_vEp1, plPlane )) 
    { 
        return 0; 
    }

    // plane 4 -y
    dMat3GetCol(m_mBoxRot,1,vTemp1);
    dVector3Inv(vTemp1);
    dConstructPlane(vTemp1,m_vBoxHalfSize[1],plPlane);
    if(!dClipEdgeToPlane( m_vEp0, m_vEp1, plPlane )) 
    { 
        return 0; 
    }

    // plane 5 -z
    dMat3GetCol(m_mBoxRot,2,vTemp1);
    dVector3Inv(vTemp1);
    dConstructPlane(vTemp1,m_vBoxHalfSize[2],plPlane);
    if(!dClipEdgeToPlane( m_vEp0, m_vEp1, plPlane )) 
    { 
        return 0; 
    }

    // calculate depths for both contact points
    m_fDepth0 = m_fBestrb + dVector3Dot(m_vEp0, m_vNormal);
    m_fDepth1 = m_fBestrb + dVector3Dot(m_vEp1, m_vNormal);

    // clamp depths to 0
    if(m_fDepth0<0) 
    {
        m_fDepth0 = REAL(0.0);
    }

    if(m_fDepth1<0) 
    {
        m_fDepth1 = REAL(0.0);
    }

    // back transform edge points from box to absolute space
    m_vEp0[0] += m_vBoxPos[0];
    m_vEp0[1] += m_vBoxPos[1];
    m_vEp0[2] += m_vBoxPos[2];

    m_vEp1[0] += m_vBoxPos[0];
    m_vEp1[1] += m_vBoxPos[1];
    m_vEp1[2] += m_vBoxPos[2];

    dContactGeom* Contact0 = SAFECONTACT(m_iFlags, m_gContact, m_nContacts, m_iSkip);
    Contact0->depth = m_fDepth0;
    dVector3Copy(m_vNormal,Contact0->normal);
    dVector3Copy(m_vEp0,Contact0->pos);
    Contact0->g1 = m_gCylinder;
    Contact0->g2 = m_gBox;
    Contact0->side1 = -1;
    Contact0->side2 = -1;
    dVector3Inv(Contact0->normal);
    m_nContacts++;

    if (m_nContacts != (m_iFlags & NUMC_MASK))
    {
        dContactGeom* Contact1 = SAFECONTACT(m_iFlags, m_gContact, m_nContacts, m_iSkip);
        Contact1->depth = m_fDepth1;
        dVector3Copy(m_vNormal,Contact1->normal);
        dVector3Copy(m_vEp1,Contact1->pos);
        Contact1->g1 = m_gCylinder;
        Contact1->g2 = m_gBox;
        Contact1->side1 = -1;
        Contact1->side2 = -1;
        dVector3Inv(Contact1->normal);
        m_nContacts++;
    }

    return 1;
}


void sCylinderBoxData::_cldClipBoxToCylinder() 
{
    dIASSERT(m_nContacts != (m_iFlags & NUMC_MASK));

    dVector3 vCylinderCirclePos, vCylinderCircleNormal_Rel;
    // check which circle from cylinder we take for clipping
    if ( dVector3Dot(m_vCylinderAxis, m_vNormal) > REAL(0.0) ) 
    {
        // get top circle
        vCylinderCirclePos[0] = m_vCylinderPos[0] + m_vCylinderAxis[0]*(m_fCylinderSize*REAL(0.5));
        vCylinderCirclePos[1] = m_vCylinderPos[1] + m_vCylinderAxis[1]*(m_fCylinderSize*REAL(0.5));
        vCylinderCirclePos[2] = m_vCylinderPos[2] + m_vCylinderAxis[2]*(m_fCylinderSize*REAL(0.5));

        vCylinderCircleNormal_Rel[0] = REAL(0.0);
        vCylinderCircleNormal_Rel[1] = REAL(0.0);
        vCylinderCircleNormal_Rel[2] = REAL(0.0);
        vCylinderCircleNormal_Rel[nCYLINDER_AXIS] = REAL(-1.0);
    }
    else 
    {
        // get bottom circle
        vCylinderCirclePos[0] = m_vCylinderPos[0] - m_vCylinderAxis[0]*(m_fCylinderSize*REAL(0.5));
        vCylinderCirclePos[1] = m_vCylinderPos[1] - m_vCylinderAxis[1]*(m_fCylinderSize*REAL(0.5));
        vCylinderCirclePos[2] = m_vCylinderPos[2] - m_vCylinderAxis[2]*(m_fCylinderSize*REAL(0.5));

        vCylinderCircleNormal_Rel[0] = REAL(0.0);
        vCylinderCircleNormal_Rel[1] = REAL(0.0);
        vCylinderCircleNormal_Rel[2] = REAL(0.0);
        vCylinderCircleNormal_Rel[nCYLINDER_AXIS] = REAL(1.0);
    }

    // vNr is normal in Box frame, pointing from Cylinder to Box
    dVector3 vNr;
    dMatrix3 mBoxInv;

    // Find a way to use quaternion
    dMatrix3Inv(m_mBoxRot,mBoxInv);
    dMultiplyMat3Vec3(mBoxInv,m_vNormal,vNr);

    dVector3 vAbsNormal;

    vAbsNormal[0] = dFabs( vNr[0] );
    vAbsNormal[1] = dFabs( vNr[1] );
    vAbsNormal[2] = dFabs( vNr[2] );

    // find which face in box is closest to cylinder
    int iB0, iB1, iB2;

    // Different from Croteam's code
    if (vAbsNormal[1] > vAbsNormal[0]) 
    {
        // 1 > 0
        if (vAbsNormal[0]> vAbsNormal[2]) 
        {
            // 0 > 2 -> 1 > 0 >2
            iB0 = 1; iB1 = 0; iB2 = 2;
        } 
        else 
        {
            // 2 > 0-> Must compare 1 and 2
            if (vAbsNormal[1] > vAbsNormal[2])
            {
                // 1 > 2 -> 1 > 2 > 0
                iB0 = 1; iB1 = 2; iB2 = 0;
            }
            else
            {
                // 2 > 1 -> 2 > 1 > 0;
                iB0 = 2; iB1 = 1; iB2 = 0;
            }			
        }
    } 
    else 
    {
        // 0 > 1
        if (vAbsNormal[1] > vAbsNormal[2]) 
        {
            // 1 > 2 -> 0 > 1 > 2
            iB0 = 0; iB1 = 1; iB2 = 2;
        }
        else 
        {
            // 2 > 1 -> Must compare 0 and 2
            if (vAbsNormal[0] > vAbsNormal[2])
            {
                // 0 > 2 -> 0 > 2 > 1;
                iB0 = 0; iB1 = 2; iB2 = 1;
            }
            else
            {
                // 2 > 0 -> 2 > 0 > 1;
                iB0 = 2; iB1 = 0; iB2 = 1;
            }		
        }
    }

    dVector3 vCenter;
    // find center of box polygon
    dVector3 vTemp;
    if (vNr[iB0] > 0) 
    {
        dMat3GetCol(m_mBoxRot,iB0,vTemp);
        vCenter[0] = m_vBoxPos[0] - m_vBoxHalfSize[iB0]*vTemp[0];
        vCenter[1] = m_vBoxPos[1] - m_vBoxHalfSize[iB0]*vTemp[1];
        vCenter[2] = m_vBoxPos[2] - m_vBoxHalfSize[iB0]*vTemp[2];
    }
    else 
    {
        dMat3GetCol(m_mBoxRot,iB0,vTemp);
        vCenter[0] = m_vBoxPos[0] + m_vBoxHalfSize[iB0]*vTemp[0];
        vCenter[1] = m_vBoxPos[1] + m_vBoxHalfSize[iB0]*vTemp[1];
        vCenter[2] = m_vBoxPos[2] + m_vBoxHalfSize[iB0]*vTemp[2];
    }

    // find the vertices of box polygon
    dVector3 avPoints[4];
    dVector3 avTempArray1[MAX_CYLBOX_CLIP_POINTS];
    dVector3 avTempArray2[MAX_CYLBOX_CLIP_POINTS];

    int i=0;
    for(i=0; i<MAX_CYLBOX_CLIP_POINTS; i++) 
    {
        avTempArray1[i][0] = REAL(0.0);
        avTempArray1[i][1] = REAL(0.0);
        avTempArray1[i][2] = REAL(0.0);

        avTempArray2[i][0] = REAL(0.0);
        avTempArray2[i][1] = REAL(0.0);
        avTempArray2[i][2] = REAL(0.0);
    }

    dVector3 vAxis1, vAxis2;

    dMat3GetCol(m_mBoxRot,iB1,vAxis1);
    dMat3GetCol(m_mBoxRot,iB2,vAxis2);

    avPoints[0][0] = vCenter[0] + m_vBoxHalfSize[iB1] * vAxis1[0] - m_vBoxHalfSize[iB2] * vAxis2[0];
    avPoints[0][1] = vCenter[1] + m_vBoxHalfSize[iB1] * vAxis1[1] - m_vBoxHalfSize[iB2] * vAxis2[1];
    avPoints[0][2] = vCenter[2] + m_vBoxHalfSize[iB1] * vAxis1[2] - m_vBoxHalfSize[iB2] * vAxis2[2];

    avPoints[1][0] = vCenter[0] - m_vBoxHalfSize[iB1] * vAxis1[0] - m_vBoxHalfSize[iB2] * vAxis2[0];
    avPoints[1][1] = vCenter[1] - m_vBoxHalfSize[iB1] * vAxis1[1] - m_vBoxHalfSize[iB2] * vAxis2[1];
    avPoints[1][2] = vCenter[2] - m_vBoxHalfSize[iB1] * vAxis1[2] - m_vBoxHalfSize[iB2] * vAxis2[2];

    avPoints[2][0] = vCenter[0] - m_vBoxHalfSize[iB1] * vAxis1[0] + m_vBoxHalfSize[iB2] * vAxis2[0];
    avPoints[2][1] = vCenter[1] - m_vBoxHalfSize[iB1] * vAxis1[1] + m_vBoxHalfSize[iB2] * vAxis2[1];
    avPoints[2][2] = vCenter[2] - m_vBoxHalfSize[iB1] * vAxis1[2] + m_vBoxHalfSize[iB2] * vAxis2[2];

    avPoints[3][0] = vCenter[0] + m_vBoxHalfSize[iB1] * vAxis1[0] + m_vBoxHalfSize[iB2] * vAxis2[0];
    avPoints[3][1] = vCenter[1] + m_vBoxHalfSize[iB1] * vAxis1[1] + m_vBoxHalfSize[iB2] * vAxis2[1];
    avPoints[3][2] = vCenter[2] + m_vBoxHalfSize[iB1] * vAxis1[2] + m_vBoxHalfSize[iB2] * vAxis2[2];

    // transform box points to space of cylinder circle
    dMatrix3 mCylinderInv;
    dMatrix3Inv(m_mCylinderRot,mCylinderInv);

    for(i=0; i<4; i++) 
    {
        dVector3Subtract(avPoints[i],vCylinderCirclePos,vTemp);
        dMultiplyMat3Vec3(mCylinderInv,vTemp,avPoints[i]);
    }

    int iTmpCounter1 = 0;
    int iTmpCounter2 = 0;
    dVector4 plPlane;

    // plane of cylinder that contains circle for intersection
    dConstructPlane(vCylinderCircleNormal_Rel,REAL(0.0),plPlane);
    dClipPolyToPlane(avPoints, 4, avTempArray1, iTmpCounter1, plPlane);


    // Body of base circle of Cylinder
    int nCircleSegment = 0;
    for (nCircleSegment = 0; nCircleSegment < nCYLINDER_SEGMENT; nCircleSegment++)
    {
        dConstructPlane(m_avCylinderNormals[nCircleSegment],m_fCylinderRadius,plPlane);

        if (0 == (nCircleSegment % 2))
        {
            dClipPolyToPlane( avTempArray1 , iTmpCounter1 , avTempArray2, iTmpCounter2, plPlane);
        }
        else
        {
            dClipPolyToPlane( avTempArray2, iTmpCounter2, avTempArray1 , iTmpCounter1 , plPlane );
        }

        dIASSERT( iTmpCounter1 >= 0 && iTmpCounter1 <= MAX_CYLBOX_CLIP_POINTS );
        dIASSERT( iTmpCounter2 >= 0 && iTmpCounter2 <= MAX_CYLBOX_CLIP_POINTS );
    }

    // back transform clipped points to absolute space
    dReal ftmpdot;	
    dReal fTempDepth;
    dVector3 vPoint;

    if (nCircleSegment % 2)
    {
        for( i=0; i<iTmpCounter2; i++)
        {
            dMultiply0_331(vPoint,m_mCylinderRot,avTempArray2[i]);
            vPoint[0] += vCylinderCirclePos[0];
            vPoint[1] += vCylinderCirclePos[1];
            vPoint[2] += vCylinderCirclePos[2];

            dVector3Subtract(vPoint,m_vCylinderPos,vTemp);
            ftmpdot	 = dVector3Dot(vTemp, m_vNormal);
            fTempDepth = m_fBestrc - ftmpdot;
            // Depth must be positive
            if (fTempDepth > REAL(0.0))
            {
                // generate contacts
                dContactGeom* Contact0 = SAFECONTACT(m_iFlags, m_gContact, m_nContacts, m_iSkip);
                Contact0->depth = fTempDepth;
                dVector3Copy(m_vNormal,Contact0->normal);
                dVector3Copy(vPoint,Contact0->pos);
                Contact0->g1 = m_gCylinder;
                Contact0->g2 = m_gBox;
                Contact0->side1 = -1;
                Contact0->side2 = -1;
                dVector3Inv(Contact0->normal);
                m_nContacts++;

                if (m_nContacts == (m_iFlags & NUMC_MASK))
                {
                    break;
                }
            }
        }
    }
    else
    {
        for( i=0; i<iTmpCounter1; i++)
        {
            dMultiply0_331(vPoint,m_mCylinderRot,avTempArray1[i]);
            vPoint[0] += vCylinderCirclePos[0];
            vPoint[1] += vCylinderCirclePos[1];
            vPoint[2] += vCylinderCirclePos[2];

            dVector3Subtract(vPoint,m_vCylinderPos,vTemp);
            ftmpdot	 = dVector3Dot(vTemp, m_vNormal);
            fTempDepth = m_fBestrc - ftmpdot;
            // Depth must be positive
            if (fTempDepth > REAL(0.0))
            {
                // generate contacts
                dContactGeom* Contact0 = SAFECONTACT(m_iFlags, m_gContact, m_nContacts, m_iSkip);
                Contact0->depth = fTempDepth;
                dVector3Copy(m_vNormal,Contact0->normal);
                dVector3Copy(vPoint,Contact0->pos);
                Contact0->g1 = m_gCylinder;
                Contact0->g2 = m_gBox;
                Contact0->side1 = -1;
                Contact0->side2 = -1;
                dVector3Inv(Contact0->normal);
                m_nContacts++;

                if (m_nContacts == (m_iFlags & NUMC_MASK))
                {
                    break;
                }
            }
        }
    }
}

int sCylinderBoxData::PerformCollisionChecking()
{
    // initialize collider
    _cldInitCylinderBox();

    // do intersection test and find best separating axis
    if ( !_cldTestSeparatingAxes() ) 
    {
        // if not found do nothing
        return 0;
    }

    // if best separation axis is not found
    if ( m_iBestAxis == 0 ) 
    {
        // this should not happen (we should already exit in that case)
        dIASSERT(0);
        // do nothing
        return 0;
    }

    dReal fdot = dVector3Dot(m_vNormal,m_vCylinderAxis);
    // choose which clipping method are we going to apply
    if (dFabs(fdot) < REAL(0.9) ) 
    {
        // clip cylinder over box
        if(!_cldClipCylinderToBox()) 
        {
            return 0;
        }
    } 
    else 
    {
        _cldClipBoxToCylinder();  
    }

    return m_nContacts;
}

// Cylinder - Box by CroTeam
// Ported by Nguyen Binh
int dCollideCylinderBox(dxGeom *o1, dxGeom *o2, int flags, dContactGeom *contact, int skip)
{
    dIASSERT (skip >= (int)sizeof(dContactGeom));
    dIASSERT (o1->type == dCylinderClass);
    dIASSERT (o2->type == dBoxClass);
    dIASSERT ((flags & NUMC_MASK) >= 1);

    sCylinderBoxData cData(o1, o2, flags, contact, skip);

    return cData.PerformCollisionChecking();
}