source: trunk/VUT/GtpVisibilityPreprocessor/src/Ray.h @ 176

#ifndef __RAY_H__
#define __RAY_H__

#include <vector>
#include "Matrix4x4.h"
#include "Vector3.h"

// forward declarations
class Plane3;
class Intersectable;
class KdLeaf;
class MeshInstance;


// -------------------------------------------------------------------
// CRay class.  A ray is defined by a location and a direction.
// The direction is always normalized (length == 1).
// -------------------------------------------------------------------

class Ray
{
public:
  enum RayType { LOCAL_RAY, GLOBAL_RAY };

  enum { NO_INTERSECTION=0, INTERSECTION_OUT_OF_LIMITS, INTERSECTION };

  struct RayIntersection {
    // the point of intersection
    float mT;

    // can be either mesh or a viewcell
    Intersectable *mObject;

    // the face of the intersectable
    int mFace;

    RayIntersection(const float t,
                    Intersectable *object,
                    const int face):mT(t), mObject(object), mFace(face) {}

    RayIntersection() {}

    bool operator<(
                   const RayIntersection &b) const {
      return 
        mT
        <
        b.mT;
    }
    
  };
  
  // I should have some abstract cell data type !!! here
  // corresponds to the spatial elementary cell
  /** intersection with the source object if any */
  RayIntersection sourceObject;
  
  vector<RayIntersection> intersections;
  vector<KdLeaf *> leaves;
  vector<MeshInstance *> meshes;

  // constructors
  Ray(const Vector3 &wherefrom,
      const Vector3 &whichdir,
      const int _type,
      const void *_originCell = NULL) {
    loc = wherefrom;
    dir = Normalize(whichdir);
    mType = _type;
    depth = 0;
    Init();
  }
  // dummy constructor
  Ray() {}

  
  // Inititalize the ray again when already constructed
  void Init(const Vector3 &wherefrom, const Vector3 &whichdir,
            const int _type, 
            bool dirNormalized = false) {
    loc = wherefrom;
    dir = (dirNormalized) ? whichdir: Normalize(whichdir) ;
    mType = _type;
    depth = 0;
    Init();
  }

  // --------------------------------------------------------
  // Extrapolate ray given a signed distance, returns a point
  // --------------------------------------------------------
  Vector3 Extrap(float t) const {
    return loc + dir * t;
  }

  // -----------------------------------
  // Return parameter given point on ray
  // -----------------------------------
  float Interp(Vector3 &x) const {
    for (int i = 0; i < 3; i++)
      if (Abs(dir[i]) > Limits::Small)
        return (x[i] - loc[i]) / dir[i];
    return 0;
  }

  // -----------------------------------
  // Reflects direction of reflection for the ray, 
  // given the normal to the surface.
  // -----------------------------------
  Vector3 ReflectRay(const Vector3 &N) const {
    return N * 2.0 * DotProd(N, -dir) + dir;
  }
  void ReflectRay(Vector3 &result, const Vector3 &N) const {
    result =  N * 2.0 * DotProd(N, -dir) + dir;
  }

  // Computes the inverted direction of the ray, used optionally by
  // a ray traversal algorithm.
  void ComputeInvertedDir() const;

  // Given the matrix 4x4, transforms the ray to another space
  void ApplyTransform(const Matrix4x4 &tform) {
    loc = tform * loc;
    dir = RotateOnly(tform, dir);
    // note that normalization to the unit size of the direction
    // is NOT computed -- this is what we want.
    Precompute();
  }

  // returns ID of this ray (use for mailboxes)
  int GetID() const { return ID; }

  // returns the transfrom ID of the ray (use for ray transformations)
  int GetTransformID() const { return transfID; }

  // copy the transform ID from an input ray
  void CopyTransformID(const Ray &ray) { transfID = ray.transfID; }
  
  // set unique ID for a given ray - always avoid setting to zero
  void SetID() {
    if ((ID = ++genID) == 0)
      ID = ++genID;
    transfID = ID;
  }
  // set ID to explicit value - it can be even 0 for rays transformed
  // to the canonical object space to supress the mailbox failure.
  void SetID(int newID) {
    ID = newID;
    // note that transfID is not changed!
  }


  // the object on which the ray starts at
  const RayIntersection* GetStartObject() const { return &intersections[0]; }
  const RayIntersection* GetStopObject() const { return &intersections[intersections.size()-1]; }
  
  
  void SetLoc(const Vector3 &l);
  Vector3& GetLoc() { return loc; }
  Vector3  GetLoc() const { return loc; }

  float  GetLoc(const int axis) const { return loc[axis]; }

  void SetDir(const Vector3 &ndir) { dir = ndir;} 
  Vector3& GetDir() { return dir; }
  Vector3  GetDir() const { return dir; }
  float  GetDir(const int axis) const { return dir[axis]; }

  int GetType() const { return mType; }
  
  // make such operation to slightly change the ray direction
  // in case any component of ray direction is zero.
  void CorrectZeroComponents();

  // the depth of the ray - primary rays are in the depth 0
  int GetDepth() const { return depth;}
  void SetDepth(int newDepth) { depth = newDepth;}
  
private:
  Vector3 loc, dir;             // Describes ray origin and vector
  
  // The inverted direction of the ray components. It is computed optionally
  // by the ray traversal algorithm using function ComputeInvertedDir();
  mutable Vector3 invDir;

  // Type of the ray: primary, shadow, dummy etc., see ERayType above
  int mType;
 
  
  // unique ID of a ray for the use in the mailboxes
  int ID;
  
  // unique ID of a ray for the use with a transformations - this one
  // never can be changed that allows the nesting of transformations
  // and caching the transformed rays correctly
  int transfID;
  
  // the ID generator fo each ray instantiated
  static int genID;  

  // When ray shot from the source(camera/light), this number is equal
  // to the number of bounces of the ray, also called the depth of the
  // ray (primary ray has its depth zero)
  int      depth;
  
  
  void Init();

  // precompute some values that are necessary
  void Precompute();

  friend class AxisAlignedBox3;
  friend class Plane;

  // for CKDR GEMS
  friend float DistanceToXPlane(const Vector3 &vec, const Ray &ray);
  friend float DistanceToYPlane(const Vector3 &vec, const Ray &ray);
  friend float DistanceToZPlane(const Vector3 &vec, const Ray &ray);
  friend int MakeIntersectLine(const Plane3 &p, const Plane3 &q, Ray &ray);
};




#endif