C++ Hit::getT方法代码示例

Hit BVH::BVHNode::trace(const AABB_Ray & aabb_ray, const Ray & ray, Amount minT)
{
   Hit retHit(ray);
   //First check to see if this hit intersects with this node.
   Amount thisT = getBox().intersect(aabb_ray);

   if(thisT > 0 && (thisT < minT || minT < 0))
   {
      if(this->left != nullptr)
      {
         Hit hLeft = this->left->trace(aabb_ray,ray,minT);
         if(hLeft.didHit() && (hLeft.getT() < minT || minT < 0))
         {
            retHit = hLeft;
            minT = hLeft.getT();
         }
      }
      if(this->right != nullptr)
      {
         Hit hRight = this->right->trace(aabb_ray,ray,minT);
         if(hRight.didHit() && (hRight.getT() < minT || minT < 0))
         {
            retHit = hRight;
         }
      }
   }


   return retHit;
}

bool Face::plane_intersect(const Ray &r, Hit &h, bool intersect_backfacing, bool* backfacing_hit) {

	// insert the explicit equation for the ray into the implicit equation of the plane

	// equation for a plane
	// ax + by + cz = d;
	// normal . p + direction = 0
	// plug in ray
	// origin + direction * t = p(t)
	// origin . normal + t * direction . normal = d;
	// t = d - origin.normal / direction.normal;

	Vec3f normal = computeNormal();
	double d = normal.Dot3((*this)[0]->get());

	double numer = d - r.getOrigin().Dot3(normal);
	double denom = r.getDirection().Dot3(normal);

	if (denom == 0) return 0;	// parallel to plane

	if (!intersect_backfacing && normal.Dot3(r.getDirection()) >= 0) 
		return 0; // hit the backside

	double t = numer / denom;
	if (t > EPSILON && t < h.getT()) {
		h.set(t,this->getMaterial(),normal,this);
		assert (h.getT() >= EPSILON);
		//hit the backside but that's okay in this case
		if (normal.Dot3(r.getDirection()) >= 0){
			*backfacing_hit = true;
		}
		return 1;
	}
	return 0;
}

Vec3f RayTracer::shadow(const Vec3f &point,
			const Vec3f &pointOnLight,
			const Face *f,
			const Ray &ray,
			const Hit &hit) const
{
        const Vec3f normal(hit.getNormal());
        const Material *m = hit.getMaterial();

	Vec3f dirToLight = pointOnLight - point;
	dirToLight.Normalize();
	/* If dot product < 0, surface is not facing light */
	if (normal.Dot3(dirToLight) > 0) {
		Ray rayToLight(point, dirToLight);
		Hit hLight;
		bool blocked = CastRay(rayToLight, hLight, false);
		while (std::fabs(hLight.getT()) < SURFACE_EPSILON &&
				std::fabs((pointOnLight - point).Length()) > SURFACE_EPSILON) {
			rayToLight = Ray(rayToLight.pointAtParameter(SURFACE_EPSILON),
					dirToLight);
			blocked = CastRay(rayToLight, hLight, false);
		}
		if (hLight.getT() == FLT_MAX || hLight.getMaterial() != f->getMaterial()) {
			return Vec3f(0, 0, 0);
		}

		const Vec3f lightColor = 0.2 * f->getMaterial()->getEmittedColor() * f->getArea();
		return m->Shade(ray,hit,dirToLight,lightColor,args);
	}
	return Vec3f(0, 0, 0);
}

bool Sphere::intersect(const Ray &r, Hit &h, float tmin)
{
	Vec3f v = center - r.getOrigin();
	float tp = v.Dot3(r.getDirection());
	float det = tp*tp - v.Dot3(v) + radius*radius;
	//intersect
	if(det > 0)
	{
		//t'
		det = sqrtf(det); 

		float t1 = tp - det;
		float t2 = tp + det;

		if(t1 > tmin && t1 < h.getT())
		{
			Vec3f normal = (r.pointAtParameter(t1) - center);
			normal /= radius;
			normal.Normalize();
			h.set(t1,material,normal,r);
			return 1;
		}
		else if(t2 > tmin && t2 < h.getT())
		{
			//sphere's normal
			Vec3f normal = (r.pointAtParameter(t2) - center);
			normal /= radius;
			normal.Normalize();
			h.set(t2,material,normal,r);
			return 1;
		}
	}
	return 0;
}

bool Face::plane_intersect(const Ray &r, Hit &h, bool intersect_backfacing) const {

  // insert the explicit equation for the ray into the implicit equation of the plane

  // equation for a plane
  // ax + by + cz = d;
  // normal . p + direction = 0
  // plug in ray
  // origin + direction * t = p(t)
  // origin . normal + t * direction . normal = d;
  // t = d - origin.normal / direction.normal;

  glm::vec3 normal = computeNormal();
  float d = glm::dot(normal,(*this)[0]->get());

  float numer = d - glm::dot(r.getOrigin(),normal);
  float denom = glm::dot(r.getDirection(),normal);

  if (denom == 0) return 0;  // parallel to plane

  if (!intersect_backfacing && glm::dot(normal,r.getDirection()) >= 0) 
    return 0; // hit the backside

  float t = numer / denom;
  if (t > EPSILON && t < h.getT()) {
    h.set(t,this->getMaterial(),normal);
    assert (h.getT() >= EPSILON);
    return 1;
  }
  return 0;
}

bool Transform::Intersect(const Ray &r, Hit &h, float tmin) const
{
  bool result = false;
  
  Matrix m = m_matrix;
  if ( m.Inverse() )
    {
      Vec3f org = r.getOrigin();
      Vec3f dir = r.getDirection();
      m.Transform(org);
      m.TransformDirection(dir);
      Ray r2 (dir, org);
      result = m_pObject->Intersect(r2, h, tmin);
      
      if (result)
	{
	  Matrix m1 = m;
	  m1.Transpose();
	  Vec3f n = h.getNormal();
	  m1.TransformDirection(n);
	  n.Normalize();
	  h.set(h.getT(), h.getMaterial(), n, r);
	}
    }
  return result;
}

bool Plane::intersect(const Ray & r, Hit & h, float tmin)
{
	assert (tmin >= 0.0f);

	Vec3f org = r.getOrigin();
	Vec3f dir = r.getDirection();

	if (dir.Dot3(normal) < 1.0e-7 && dir.Dot3(normal) > -1.0e-7) {
		return false;
	}					// Appromately parrell to plane

	float tempT = (offset - org.Dot3(normal)) / dir.Dot3(normal);
	if (tempT <= 1e-6) {
		return false;
	}
	else if (tempT >= tmin && tempT < h.getT()) 
	{
		// Update Hit Point
		normal.Normalize();
		h.set(tempT, NULL, normal, color, r);

		return true;
	}
	
	return false;
}

/*
The intersect routine will first transform the ray, 
then delegate to the intersect routine of the contained 
object. Make sure to correctly transform the resulting 
normal according to the rule seen in lecture. You may 
choose to normalize the direction of the transformed ray 
or leave it un-normalized. If you decide not to normalize 
the direction, you might need to update some of your intersection code.
*/
bool Transform::intersect(const Ray &r, Hit &h, float tmin)
{
	Vec3f r0 = r.getOrigin();
	Vec3f rd = r.getDirection();
	Matrix inv;
	matrix.Inverse(inv);
	inv.Transform(r0);
	inv.TransformDirection(rd);
	if (object != NULL)
	{
		//这里的h是有问题的，作如下修改：
		bool judge = object->intersect(Ray(r0,rd), h, tmin);
		Vec3f normal = h.getNormal();
		//这里很奇怪，normal的方向没有修正，然而结果却是对的
		//改了之后反而是错的！！
		//这里确定normal没有错，那么就是之后应用normal的
		//问题
		//好吧，就是这里的问题
		//经过把图形摆正，发现求的法向量没有问题，但是没有单位化…………！
		matrix.TransformDirection(normal);
		normal.Normalize();
		//or：
		//Matrix change,res;
		//matrix.Inverse(change);
		//change.Transpose(res);
		//res.TransformDirection(normal);
		h.set(h.getT(), h.getMaterial(), normal, r);
		return judge;
	}
	return false;
}

bool Sphere::intersect(const Ray &r, Hit &h, float tmin)
{
	//直线方程 P = t*D + R    ①
	//圆方程  ||P||= raduis   ②
	//将①带入②, 由点乘的性质(满足分配率，交换律)，求得t^2+2RDt+R^2-r^2=0
	//得t = -RD±sqrt(RD^2-R^2+r^2)
	//选择距离较近的那个点t = -RD-sqrt(RD^2-R^2+r^2)
	Vec3f D = r.getDirection();
	Vec3f R = r.getOrigin()-center;


	float R2 = R.Dot3(R);
	float RD = R.Dot3(D);
	
	float b2_4ac = RD*RD-R2+radius*radius;//R2 RD RDRD这些其实可以存在ray里，但是算法研究以程序清晰为要
	if(b2_4ac<0)return 0;
	float t;
	t = -RD - sqrt(b2_4ac);
	if(t<0){
		t = -RD + sqrt(b2_4ac);
		if(t < 0)return 0;
	}
	if(t<h.getT())
	{
		h.set(t, &color, r);
	}

	return 1;
}

bool Sphere::intersect(const Ray &r, Hit &h, float tmin){

	/*Vector equation for sphere
	P*P - r^2 = 0
	((R0-c) + td)*((R0-c) + td) - r^2 = 0
	(td)^2 + 2R0-c)td + (R0-c)^2 - r^2 =0
	Use quadratic equation solve for t
	a = (d^2)
	b = 2(R0-c)d
    c = ((R0-c)^2 - r^2)
	*/

	Vec3f rayOrigin, rayDirection,segment,Q;
	float tpos,tneg,a,b,c,discriminant;

	rayOrigin = r.getOrigin();
	rayDirection = r.getDirection();
	segment = rayOrigin - _center;

	a = rayDirection.Dot3(rayDirection);
	b = 2*segment.Dot3(rayDirection);
	c = segment.Dot3(segment) - _radius*_radius;

	discriminant = sqrt(b*b - 4*a*c); 

	tpos = (-b + discriminant)/(2*a);
	tneg = (-b - discriminant)/(2*a);

	if (tneg > tmin && tneg < h.getT()){
			Q = r.pointAtParameter(tneg);
			Q = Q - _center;
			Q.Normalize();
			h.set(tneg, _material,Q,r);
			return true;
		}
	else if (tpos > tmin && tpos < h.getT()){
			Q = r.pointAtParameter(tpos);
			Q = Q - _center;
			Q.Normalize();
			h.set(tpos,_material,Q,r);
			return true;
		}
	return false;

}

void PhotonMapping::TracePhoton(const Vec3f &position, const Vec3f &direction, 
				const Vec3f &energy, int iter) {
  
  if(iter>args->num_bounces){
    return;
  }

  Hit h = Hit();
  Ray R = Ray(position, direction);
  bool intersect = raytracer->CastRay(R, h, false);
  if(!intersect){
    return;
  }
  Material *m = h.getMaterial();
  Vec3f normal = h.getNormal();
  Vec3f point = R.pointAtParameter(h.getT());
  Vec3f opDirec = direction;
  opDirec.Negate();
  opDirec.Normalize();
  Vec3f diffuse = m->getDiffuseColor(), reflec = m->getReflectiveColor();
  double diffuseAnswer = diffuse.x()+diffuse.y()+diffuse.z();
  double reflecAnswer = reflec.x()+reflec.y()+reflec.z();
  double total = reflecAnswer+diffuseAnswer;
  diffuseAnswer /= total;
  reflecAnswer /= total;
  double seed = GLOBAL_mtrand.rand();
  if(seed <= diffuseAnswer && seed >= 0){
    Vec3f newEnergy = energy * diffuse;
    Vec3f newPosition = point;
    Vec3f newDirection = Vec3f(GLOBAL_mtrand.rand(),GLOBAL_mtrand.rand(),GLOBAL_mtrand.rand());
    newDirection.Normalize();
    Photon answer = Photon(point,opDirec,newEnergy,iter+1);
    kdtree->AddPhoton(answer);
    TracePhoton(newPosition, newDirection, newEnergy, iter+1);
  }
  else if(seed>diffuseAnswer && seed <= 1){
    Vec3f newEnergy = energy * reflec;
    Vec3f newPosition = point;
    Vec3f newDirection = direction - 2 * direction.Dot3(normal) * normal;
    Photon answer = Photon(point,opDirec,newEnergy,iter+1);
    kdtree->AddPhoton(answer);
    TracePhoton(newPosition, newDirection, newEnergy, iter+1);
  }
  // ==============================================
  // ASSIGNMENT: IMPLEMENT RECURSIVE PHOTON TRACING
  // ==============================================

  // Trace the photon through the scene.  At each diffuse or
  // reflective bounce, store the photon in the kd tree.

  // One optimization is to *not* store the first bounce, since that
  // direct light can be efficiently computed using classic ray
  // tracing.



}

Vec3f RayTracer::shadows(const Ray &ray, const Hit &hit) const
{
	Vec3f answer(0, 0, 0);

	const int num_lights = mesh->getLights().size();
	if (args->num_shadow_samples == 0) {
		for (int i = 0; i < num_lights; ++i) {

			const Face *f = mesh->getLights()[i];
			Vec3f pointOnLight = f->computeCentroid();
			const Vec3f point(ray.pointAtParameter(hit.getT()));
			Vec3f dirToLight = pointOnLight - point;
			dirToLight.Normalize();
			const Vec3f lightColor = 0.2 * f->getMaterial()->getEmittedColor() * f->getArea();
			return hit.getMaterial()->Shade(ray,hit,dirToLight,lightColor,args);
		}
	}

	// ----------------------------------------------
	// add contributions from each light that is not in shadow

	for (int i = 0; i < num_lights; i++) {
		const Face *f = mesh->getLights()[i];
		Vec3f pointOnLight = f->computeCentroid();
		const Vec3f point(ray.pointAtParameter(hit.getT()));

		double answerx = 0, answery = 0, answerz = 0;
		{
			for (int s = 0; s <= args->num_shadow_samples; ++s) {
				const Vec3f sh = shadow(point, pointOnLight, f, ray, hit);
				answerx += sh.x();
				answery += sh.y();
				answerz += sh.z();
				pointOnLight = f->RandomPoint();
			}
		}
		answer += Vec3f(answerx, answery, answerz);
	}
	answer *= static_cast<double>(1) / ((args->num_shadow_samples + 1) * num_lights);
	return answer;
}

void PhotonMapping::TracePhoton(const Vec3f &position, const Vec3f &direction, 
				const Vec3f &energy, int iter) {


  // ==============================================
  // ASSIGNMENT: IMPLEMENT RECURSIVE PHOTON TRACING
  // ==============================================

  // Trace the photon through the scene.  At each diffuse or
  // reflective bounce, store the photon in the kd tree.

  // One optimization is to *not* store the first bounce, since that
  // direct light can be efficiently computed using classic ray
  // tracing.

  //do ray cast
  Ray r(position,direction*(1/direction.Length()));
  Hit h;
  raytracer->CastRay(r,h,true);
  if (h.getT()>1000)
	  return;
  MTRand mtrand;
  Vec3f refl = h.getMaterial()->getReflectiveColor();
  Vec3f diff = h.getMaterial()->getDiffuseColor();
  double ran=mtrand.rand();
  if (iter==0)
	  ran= mtrand.rand(refl.Length()+diff.Length());
  //std::cout<<iter<<" "<<h.getT()<<" "<<refl.Length()+diff.Length()<<std::endl;
  //send reflective photon
  if (iter<args->num_bounces&&ran<=refl.Length())
	  TracePhoton(r.pointAtParameter(h.getT()),r.getDirection()-2*(r.getDirection().Dot3(h.getNormal()))*h.getNormal(),energy,iter+1);
  else if (iter<args->num_bounces&&ran<=refl.Length()+diff.Length())
	  TracePhoton(r.pointAtParameter(h.getT()),RandomDiffuseDirection(h.getNormal()),energy,iter+1);
  else
  {
	  Photon p(position,direction,energy,iter);
	  kdtree->AddPhoton(p);
  }


}

Vec3f RayTracer::reflection(const Ray &start_ray, int bounce_count) const
{
	Ray ray(start_ray);
	Hit h;
	Vec3f answer = TraceRay(ray, h, bounce_count);
	while (h.getT() < SURFACE_EPSILON) {
		ray = Ray(ray.pointAtParameter(SURFACE_EPSILON),
				ray.getDirection());
		answer = TraceRay(ray, h, bounce_count);
	}
	return answer;
}

bool Triangle::intersect( const Ray& r , Hit& h , float tmin){

	Vector3f R_o = r.getOrigin();
	Vector3f R_d = r.getDirection();

	Matrix3f A( this->a.x()-this->b.x() , this->a.x()-this->c.x() , R_d.x() ,
		    this->a.y()-this->b.y() , this->a.y()-this->c.y() , R_d.y() ,
		    this->a.z()-this->b.z() , this->a.z()-this->c.z() , R_d.z()  );

	Matrix3f BetaM( this->a.x()-R_o.x() , this->a.x()-this->c.x() , R_d.x() ,
		        this->a.y()-R_o.y() , this->a.y()-this->c.y() , R_d.y() ,
		        this->a.z()-R_o.z() , this->a.z()-this->c.z() , R_d.z()  );
	
	float beta = BetaM.determinant() / A.determinant();

	Matrix3f GammaM( this->a.x()-this->b.x() , this->a.x()-R_o.x() , R_d.x() ,
		         this->a.y()-this->b.y() , this->a.y()-R_o.y() , R_d.y() ,
		         this->a.z()-this->b.z() , this->a.z()-R_o.z() , R_d.z()  );
	
	float gamma = GammaM.determinant() / A.determinant();

	float alpha = 1.0f - beta - gamma;

	Matrix3f tM( this->a.x()-this->b.x() , this->a.x()-this->c.x() , this->a.x()-R_o.x() ,
		     this->a.y()-this->b.y() , this->a.y()-this->c.y() , this->a.y()-R_o.y() ,
		     this->a.z()-this->b.z() , this->a.z()-this->c.z() , this->a.z()-R_o.z()  );
	
	float t = tM.determinant() / A.determinant();

	if (beta + gamma > 1){
	    return false;
	} 
	if (beta < 0){
	    return false;
	} 
	if (gamma < 0){
	    return false;
	} 

	if (t > tmin && t < h.getT()){

	    Vector3f newNormal = (alpha*this->normals[0] + beta*this->normals[1] + gamma*this->normals[2]).normalized();
	    h.set(t, this->material, newNormal);

	    Vector2f newTexCoord = (alpha*this->texCoords[0] + beta*this->texCoords[1] + gamma*this->texCoords[2]);
	    h.setTexCoord(newTexCoord);

	    return true;	
	} 
	else{
	    return false;
	} 
}