struct pickResult { vec3 pos, normal; vec2 tex; float distance; };
struct pickInfo {
  pickInfo( int f ) : flags(f) {}
  std::vector<pickResult> results;
  int flags;
  const static int F_GET_POS = 0x01;
  const static int F_GET_NORM = 0x02;
  const static int F_GET_DISTANCE = 0x04;
  const static int F_GET_ALL_OBJECTS = 0x08;
};

pickInfo bullet( F_GET_DISTANCE );
doPick( node, bullet, rayStart, rayDirection );
if( !bullet.results.empty() )
   damage = std::max(0, 100 - bullet.results.front().distance);

int castRay(NodeHandle node,
    float ox, float oy, float oz,
    float dx, float dy, float dz,
    int flags,
    int numNearest);

bool getCastRayResults(int index,
    NodeHandle *node,
    float *distance,
    float *intersection);

void clearCastRayResults();

int num = castRay(startNode, ox, oy, oz, dx, dy, dz, 0, 0)
for(int i; i < num; ++i)
{
    NodeHandle node;
    float distance;
    float intersection[3];
    getCastRayResults(i, &node, &distance, intersection);

    // do something with the result
    // ..
}
clearCastRayResult();

if(castRay(startNode, ox, oy, oz, dx, dy, dz, 0, 1))
{
    NodeHandle node;
    float distance;
    float intersection[3];
    getCastRayResult(0, &node, &distance, intersection);

    // do something with result
    // ...
}
clearCastRayResult();

enum
{
  RAYCAST_FLAG_SORT = (1<<0),
  RAYCAST_FLAG_NEAREST_RESULT_ONLY = (1<<1),
};

class RaycastResult
{
public:
  RaycastResult(NodeHandle* node, float k) : m_node(node), m_k(k) {}
  NodeHandle* Node() const { return m_node; }
  float Distance() const { return m_k }

private:
  NodeHandle* m_node;
  float m_k; // normalized distance along the ray [0-1] (could be real distance as well)
};

void myFunc()
{
  std::vector<RaycastResult> results;
 
  // cast the ray and fill in the vector with results
  rayCast(from_x, from_y, from_z, to_x, to_y, to_z, RAYCAST_FLAG_SORT, results);

  for( size_t i_intersection=0; i_intersection<results.size(); ++i_intersection )
  {
    const RaycastResult& result = results[i_intersection];
    // do whatever
  }
}