box.cpp

Beginning Direct3D Game Programming源代码Part3chapter12

/*   ColDet - C++ 3D Collision Detection Library
 *   Copyright (C) 2000   Amir Geva
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 * 
 * 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 GNU
 * Library General Public License for more details.
 * 
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * Any comments, questions and bug reports send to:
 *   [e-mail]
 *
 * Or visit the home page: http://photoneffect.com/coldet/
 */
#include "sysdep.h"
#include "box.h"
#include "mytritri.h"

__CD__BEGIN
////////////////////////////////////////////////////
// code from here is used in detection process

int BoxTreeInnerNode::getTrianglesNumber()
{
  return m_Boxes.size();
}

BoxedTriangle* BoxTreeInnerNode::getTriangle(int which)
{
  if (which<0 || which>=getTrianglesNumber()) return NULL;
  return m_Boxes[which];
}

RotationState::RotationState(const Matrix3D& transform)
: t(transform)
{
  N[0]=Vector3D(t(0,0),t(0,1),t(0,2));
  N[1]=Vector3D(t(1,0),t(1,1),t(1,2));
  N[2]=Vector3D(t(2,0),t(2,1),t(2,2));
}

inline float DotWithCol(const Vector3D& v, const Matrix3& m, int col)
{
  return v.x*m(0,col) + v.y*m(1,col) + v.z*m(2,col);
}

bool Box::intersect(const Vector3D& O, float radius)
{
  Vector3D mx=m_Pos+m_Size;
  float dist=0.0f;
  for(int i=0;i<3;i++)
  {
    if (O[i] < m_Pos[i])
    {
      float d=O[i]-m_Pos[i];
      dist+=d*d;
    }
    else
    if (O[i] > mx[i])
    {
      float d=O[i]-mx[i];
      dist+=d*d;
    }
  }
  return (dist <= (radius*radius));
}

bool Box::intersect(const Vector3D& O, const Vector3D& D,
                    float segmax)
{
  if (segmax>3e30f) return intersect(O,D); // infinite ray
  Vector3D abs_segdir, abs_diff, abs_cross; 

  Vector3D segdir=0.5f*segmax*D;
  Vector3D seg_center=O+segdir;
  Vector3D diff=seg_center - getCenter();
  int i;
  for(i=0;i<3;i++)
  {
    abs_segdir[i]=flabs(segdir[i]);
    abs_diff[i]=flabs(diff[i]);
    float f=getSize()[i] + abs_segdir[i];
    if (abs_diff[i] > f) return false;
  }
  Vector3D cross=CrossProduct(segdir,diff);
  int idx[] = {0,1,2,0,1};
  for(i=0;i<3;i++)
  {
    int i1=idx[i+1];
    int i2=idx[i+2];
    abs_cross[i] = flabs(cross[i]);
    float f = getSize()[i1]*abs_segdir[i2] + getSize()[i2]*abs_segdir[i1];
    if ( abs_cross[i] > f ) return false;
  }
  return true;
}

bool Box::intersect(const Vector3D& O, const Vector3D& D)
{
    Vector3D abs_segdir, abs_cross;
    float f;
    Vector3D diff = O - getCenter();

    for(int i=0;i<3;i++)
    {
      abs_segdir[i] = flabs(D[i]);
      if ( flabs(diff[i])>m_Size[i] && diff[i]*D[i]>=0.0f )
        return false;
    }

    Vector3D cross = CrossProduct(D,diff);

    abs_cross[0] = flabs(cross[0]);
    f = m_Size[1]*abs_segdir[2] + m_Size[2]*abs_segdir[1];
    if ( abs_cross[0] > f )
        return false;

    abs_cross[1] = flabs(cross[1]);
    f = m_Size[0]*abs_segdir[2] + m_Size[2]*abs_segdir[0];
    if ( abs_cross[1] > f )
        return false;

    abs_cross[2] = flabs(cross[2]);
    f = m_Size[0]*abs_segdir[1] + m_Size[1]*abs_segdir[0];
    if ( abs_cross[2] > f )
        return false;

    return true;
}

bool Box::intersect(const Box& b, RotationState& rs)
{
  const Vector3D bCenter=Transform(b.getCenter(),rs.t);
  Vector3D EA=0.5f*getSize();
  Vector3D EB=0.5f*b.getSize();
  Vector3D distance=bCenter-getCenter();
  Matrix3 C,abs_C;
  float   R0,R1,R,R01;
  int i;

  for(i=0;i<3;i++)
  {
    C(i,0)=rs.N[0][i];
    C(i,1)=rs.N[1][i];
    C(i,2)=rs.N[2][i];
    abs_C(i,0)=flabs(C(i,0));
    abs_C(i,1)=flabs(C(i,1));
    abs_C(i,2)=flabs(C(i,2));
    R=flabs(distance[i]);
    R1=EB*abs_C.baseRow(i);
    R01=EA[i]+R1;
    if (R>R01) return false;
  }
  for(i=0;i<3;i++)
  {
    R=flabs(rs.N[i]*distance);
    R0=DotWithCol(EA,abs_C,i);
    R01=R0+EB[i];
    if (R>R01) return false;
  }

  R=flabs(distance.z*C(1,0) - distance.y*C(2,0));
  R0=EA.y*abs_C(2,0) + EA.z*abs_C(1,0);
  R1=EB.y*abs_C(0,2) + EB.z*abs_C(0,1);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.z*C(1,1) - distance.y*C(2,1));
  R0=EA.y*abs_C(2,1) + EA.z*abs_C(1,1);
  R1=EB.x*abs_C(0,2) + EB.z*abs_C(0,0);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.z*C(1,2) - distance.y*C(2,2));
  R0=EA.y*abs_C(2,2) + EA.z*abs_C(1,2);
  R1=EB.x*abs_C(0,1) + EB.y*abs_C(0,0);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.x*C(2,0) - distance.z*C(0,0));
  R0=EA.x*abs_C(2,0) + EA.z*abs_C(0,0);
  R1=EB.y*abs_C(1,2) + EB.z*abs_C(1,1);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.x*C(2,1) - distance.z*C(0,1));
  R0=EA.x*abs_C(2,1) + EA.z*abs_C(0,1);
  R1=EB.x*abs_C(1,2) + EB.z*abs_C(1,0);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.x*C(2,2) - distance.z*C(0,2));
  R0=EA.x*abs_C(2,2) + EA.z*abs_C(0,2);
  R1=EB.x*abs_C(1,1) + EB.y*abs_C(1,0);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.y*C(0,0) - distance.x*C(1,0));
  R0=EA.x*abs_C(1,0) + EA.y*abs_C(0,0);
  R1=EB.y*abs_C(2,2) + EB.z*abs_C(2,1);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.y*C(0,1) - distance.x*C(1,1));
  R0=EA.x*abs_C(1,1) + EA.y*abs_C(0,1);
  R1=EB.x*abs_C(2,2) + EB.z*abs_C(2,0);
  R01=R0+R1;
  if (R>R01) return false;

  R=flabs(distance.y*C(0,2) - distance.x*C(1,2));
  R0=EA.x*abs_C(1,2) + EA.y*abs_C(0,2);
  R1=EB.x*abs_C(2,1) + EB.y*abs_C(2,0);
  R01=R0+R1;
  if (R>R01) return false;

  return true;
}

extern "C" { 
int tri_tri_intersect(float V0[3],float V1[3],float V2[3],
                      float U0[3],float U1[3],float U2[3]);
};

Triangle::Triangle(const Vector3D& _1, const Vector3D& _2, const Vector3D& _3)
: v1(_1), v2(_2), v3(_3), center((1.0f/3.0f)*(_1+_2+_3)) 
{}

bool Triangle::intersect(const Vector3D& O, const Vector3D& D, Vector3D& cp, 
                         float& tparm, float segmax)
{
  Plane p(v1,v2,v3);
  float denom=p.normal*D;
  if (IsZero(denom)) return false;
  float t=-(p.d+p.normal*O)/denom;
  if (t<=0.0f) return false;
  if (t>segmax) return false;
  TriangleDesc td(*this,p);
  cp=O+t*D;
  if (td.pointInTri(cp))
  {
    tparm=t;
    return true;
  }
  return false;
}

bool Triangle::intersect(const Vector3D& O, float radius, Vector3D& cp)
{
  Plane p(v1,v2,v3);
  float dist=p.Classify(O);
  if (flabs(dist) > radius) return false;
  Vector3D point=O-dist*p.normal;
  TriangleDesc td(*this,p);
  if (td.pointInTri(point))
  {
    cp=point;
    return true;
  }
  return false;
}

bool Triangle::intersect(const Triangle& t) const
{
  return (tri_tri_intersect((float*)&v1.x,
                            (float*)&v2.x,
                            (float*)&v3.x,
                            (float*)&t.v1.x,
                            (float*)&t.v2.x,
                            (float*)&t.v3.x) != 0);
}

__CD__END