C++ AABB::Intersection方法代码示例

void UnCollide(GameObject* go, const Vec3f& oldPos, const AABB& aabb)
{
  /* 
  Move back so not interpenetrating:
  Boxes now intersect in all axes. Moving away by penetration depth in any
  axis will resolve the intersection. To choose which axis, use the previous
  position. E.g. if previously not intersecting in X, move away in X axis.
  */

  // Intersecton region
  AABB ir = aabb.Intersection(go->GetAABB());
  Vec3f goPos = go->GetPos();

  AABB oldBox = go->GetAABB();
  Vec3f move = oldPos - goPos;
  oldBox.Translate(move);
  // Oldbox should NOT be intersecting in one or more axes

  Vec3f penDist(
    ir.GetMax(0) - ir.GetMin(0), 
    ir.GetMax(1) - ir.GetMin(1),
    ir.GetMax(2) - ir.GetMin(2));
  penDist *= 1.01f; // move away a bit more to be sure of clearing the collision

  if (oldBox.GetMax(0) < aabb.GetMin(0))
  {
    // Old box to left of box, so move away to the left
    goPos.x -= penDist.x; 
  }
  else if (oldBox.GetMin(0) > aabb.GetMax(0))
  {
    goPos.x += penDist.x;
  }
  /*
  else if (oldBox.GetMax(1) < aabb.GetMin(1))
  {
    goPos.y -= penDist.y;
  }
  else if (oldBox.GetMin(1) > aabb.GetMax(1))
  {
    goPos.y += penDist.y;
  }
  */
  else if (oldBox.GetMax(2) < aabb.GetMin(2))
  {
    goPos.z -= penDist.z;
  }
  else if (oldBox.GetMin(2) > aabb.GetMax(2))
  {
    goPos.z += penDist.z;
  }

  go->SetPos(goPos);
}

// recursive construction algorithm
//void Kdtree::construct(unsigned int fn, const AABB& box, const std::list<unsigned int>& triList, AABB * bounds, unsigned int depth)
//void Kdtree::construct(unsigned int fn, AABB& box, std::list<IPrimitive*>& primList, AABB * bounds, unsigned int depth)
void Kdtree::construct(unsigned int fn, AABB& box, unsigned int size,
                       unsigned int depth, bool isLeft, unsigned int rIndex, 
                       unsigned int pre_size, bool dsize, int tries)
{
    //BSPNode *node = &m_pTree[fn];
    //printf("max num: %i\n", m_pTree.max_size());
    //m_pTree.assign(BSPNode(), fn);
    BSPNode *node = &m_pTree[fn];

    //unsigned int size = (unsigned int)primList.size();
    //std::list<IPrimitive*>::iterator p;

    //printf(".");
    // if end condition met
    // if(abs(previous size - size) <= 3 ...
    if((int)abs((int)(pre_size-size)) <= 3)
    {
        dsize = true;
        tries++;
    }
    else
    {
        dsize = false;
        tries = 0;
    }
    if(size <= m_MaxItemPerNode || depth >= m_MaxDepth || (dsize && tries == 3))
    {
        IPrimitive** myList = 0;
        if(size > 0)
            myList = new IPrimitive*[size];
        //std::list<IPrimitive*>* myList = new std::list<IPrimitive*>;
        if(depth == 0)
        {
            std::list<IPrimitive*>::iterator tit;
            int i = 0;
            for(tit = m_PrimList.begin(); tit != m_PrimList.end(); tit++, i++)
                myList[i] = (*tit);
        }
        else if(isLeft)
        {
            for(unsigned int i = 0; i < size; i++)
                myList[i] = leftBOX[i];
        }
        else
        {
            for(unsigned int i = 0; i < size; i++)
                myList[i] = rightBOX[rIndex+i];
        }
        node->initLeaf(size, myList);

        // increment counts
        m_TotalTreeTri += size;
        totalLeaf++;
        return; // leaf with triangle
    }

    // each node must have a split axis and split position
    int axis = 0;
    float splitpos = 0;
    unsigned int i;

#ifdef SAH    

    AABB tbox;
    // build up information of bounding box and edges
    if(depth == 0)
    {
        i = 0;
        std::list<IPrimitive*>::iterator tit;
        for(tit = m_PrimList.begin(); tit != m_PrimList.end(); tit++, i++)
        {
            tbox = (*tit)->getAABB();
            AABB* mybox = &(box.Intersection(tbox)); // get intersection of triangle box + bounding box of this node
            Point3 minp = mybox->getPos();
            Point3 maxp = minp + mybox->getSize();

            // add x position to the list
            edge[0][i*2].set(minp.X(), (*tit), true); 
            edge[0][i*2+1].set(maxp.X(), (*tit), false); 			
            // add y
            edge[1][i*2].set(minp.Y(), (*tit), true); 
            edge[1][i*2+1].set(maxp.Y(), (*tit), false);
            // add z
            edge[2][i*2].set(minp.Z(), (*tit), true); 
            edge[2][i*2+1].set(maxp.Z(), (*tit), false);
        }
    }
    else if(isLeft)
    {
        for(i = 0; i < size; i++)
        {
            tbox = leftBOX[i]->getAABB();
            AABB* mybox = &(box.Intersection(tbox)); // get intersection of triangle box + bounding box of this node
            Point3 minp = mybox->getPos();
            Point3 maxp = minp + mybox->getSize();

            // add x position to the list
//.........这里部分代码省略.........