C++ ray::getDirection方法代码示例

        //! Intersect ray and sphere, returning true if there is an intersection.
        bool intersect(const ray<Type>& r, Type& tmin, Type& tmax) const
        {
            const vec3<Type> r_to_s = r.getOrigin() - m_center;

            //Compute A, B and C coefficients
            const Type A = r.getDirection().sqrLength();
            const Type B = 2.0f * r_to_s.dot(r.getDirection());
            const Type C = r_to_s.sqrLength() - m_radius * m_radius;

            //Find discriminant
            Type disc = B * B - 4.0 * A * C;

            // if discriminant is negative there are no real roots
            if (disc < 0.0)
                return false;

            disc = (Type)std::sqrt((double)disc);

            tmin = (-B + disc) / (2.0 * A);
            tmax = (-B - disc) / (2.0 * A);

            // check if we're inside it
            if ((tmin < 0.0 && tmax > 0) || (tmin > 0 && tmax < 0))
                return false;

            if (tmin > tmax)
                std::swap(tmin, tmax);

            return (tmin > 0);
        }

Segments CSGNode::intersectLocal(const ray& r) const{
	Segments ret;
	if (isLeaf){
		SegmentPoint pNear, pFar;
		isect i;
		ray backR(r.at(-10000), r.getDirection());
		if(!item->intersect(backR, i))return ret;
		pNear.t = i.t - 10000;
		pNear.normal = i.N;
		pNear.isRight = false;
		ray contiR(r.at(pNear.t+RAY_EPSILON*10),r.getDirection());
		if (!item->intersect(contiR, i))pFar = pNear;
		else {
			pFar.t = i.t + pNear.t;
			pFar.normal = i.N;
		}
		pFar.isRight = true;
		ret.addPoint(pNear);
		ret.addPoint(pFar);
		return ret;
	}
	else {
		if (!lchild || !rchild)return ret;
		Segments leftSeg, rightSeg;
		leftSeg = lchild->intersectLocal(r);
		rightSeg = rchild->intersectLocal(r);
		leftSeg.Merge(rightSeg,relation);
		return leftSeg;
	}
}

bool Cone::intersectBody( const ray& r, isect& i ) const
{
	vec3f d = r.getDirection();
	vec3f p = r.getPosition();

	double a = (d[0]*d[0]) + (d[1]*d[1]) - (C*d[2]*d[2]);
	double b = 2.0 * (d[0]*p[0] + d[1]*p[1] - C*d[2]*p[2]) - B*d[2];
	double c = (p[0]*p[0]) + (p[1]*p[1]) - A - (B*p[2]) - (C*p[2]*p[2]);

	double disc = b*b - 4.0*a*c;

	if( disc <= 0.0 ) {
		return false;
	}

	disc = sqrt( disc );

	double t1 = (-b - disc) / (2.0 * a);
	double t2 = (-b + disc) / (2.0 * a);

	if( t2 < RAY_EPSILON ) {
		return false;
	}

	if( t1 > RAY_EPSILON ) {
		// Two intersections.
		vec3f P = r.at( t1 );
		double z = P[2];
		if( z >= 0.0 && z <= height ) {
			// It's okay.
			i.t = t1;
			double p3 = -C*P[2] + (b_radius - t_radius)*b_radius / height;
			i.N = vec3f(P[0], P[1], p3).normalize();
#ifdef _DEBUG
			printf("two intersections!\n");
#endif
			return true;
		}
	}

	vec3f P = r.at( t2 );
	double z = P[2];
	if( z >= 0.0 && z <= height ) {
		i.t = t2;
		double p3 = -C*P[2] + (b_radius - t_radius)*b_radius / height;
		i.N = vec3f(P[0], P[1], p3).normalize();
		// In case we are _inside_ the _uncapped_ cone, we need to flip the normal.
		// Essentially, the cone in this case is a double-sided surface
		// and has _2_ normals
	
		if( !capped && (i.N).dot( r.getDirection() ) > 0 )
				i.N = -i.N;
#ifdef _DEBUG
		printf("one intersection!\n");
#endif
        return true;
	}

	return false;
}

// Intersect ray r with the triangle abc.  If it hits returns true,
// and puts the t parameter, barycentric coordinates, normal, object id,
// and object material in the isect object
bool TrimeshFace::intersectLocal( const ray& r, isect& i ) const
{
  const Vec3d& a = parent->vertices[ids[0]];
  const Vec3d& b = parent->vertices[ids[1]];
  const Vec3d& c = parent->vertices[ids[2]];

  // tangent vectors
  Vec3d t1 = b - a;
  Vec3d t2 = c - a;
  
  Vec3d n = crossProd(t1,t2);

  double D = -n*a;

  // if the surface is parallel to the ray there is no intersection
  if(r.getDirection()*n == 0)
  {
    return false;
  }  

  double t = -(n*r.getPosition() + D)/(n*r.getDirection() );
  if (t <= RAY_EPSILON)
    return false;

  // point of intersection with the same plane (doesn't mean intersection with triangle) p(t)=p+t*d
  Vec3d p = r.at(t);

  // triangle area
  double A = n.length()/2.0;

  // barycentric coords
  double wa = crossProd(c-b, p-b).length() / (2.0*A);
  double wb = crossProd(a-c, p-c).length() / (2.0*A);
  double wc = crossProd(b-a, p-a).length() / (2.0*A);

  if((wa >= 0.0) && (wb >= 0.0) && (wc >= 0.0) && (wa+wb+wc-1.0 <= 0.00001)) {
    i.setT(t);
    i.setBary(wa, wb, wc);
    if (parent->normals.size() == 0) {
      i.setN(n);
    } else {
      Vec3d inter_n = wa*parent->normals[ids[0]] + wb*parent->normals[ids[1]]
                    + wc*parent->normals[ids[2]];
      inter_n.normalize();
      i.setN(inter_n);
    }
    i.setObject(this);
    if (parent->materials.size() == 0) {
      i.setMaterial(this->getMaterial() );
    } else {
      Material inter_m = wa*(*parent->materials[ids[0]]);
      inter_m += wb*(*parent->materials[ids[1]]);
      inter_m += wc*(*parent->materials[ids[2]]);
      i.setMaterial(inter_m);
    }
    return true;
  }

  return false;
}

// Apply the Blinn-Phong model to this point on the surface of the object, 
//  returning the color of that point.
Vec3d Material::shade( Scene *scene, const ray& r, const isect& i ) const
{
	// YOUR CODE HERE

		// For now, this method just returns the diffuse color of the object.
		// This gives a single matte color for every distinct surface in the
		// scene, and that's it.  Simple, but enough to get you started.
		// (It's also inconsistent with the Phong model...)

		// Your mission is to fill in this method with the rest of the phong
		// shading model, including the contributions of all the light sources.
		// You will need to call both distanceAttenuation() and shadowAttenuation()
		// somewhere in your code in order to compute shadows and light falloff.
		if (debugMode)
			std::cout << "Debugging the Phong code (or lack thereof...)" << std::endl;

		// When you're iterating through the lights,
		// you'll want to use code that looks something
		// like this:
		Vec3d light = ke(i);
		Vec3d normal = i.N;
		Vec3d iDot = r.at(i.t);
		if (r.getDirection() * normal > 0) {
			normal = -normal;
			light += prod(prod(scene->ambient(), ka(i)), kt(i));
		}
		else {
			light += prod(scene->ambient(), ka(i));
		}

		for (vector<Light*>::const_iterator litr = scene->beginLights();
			litr != scene->endLights();
			++litr)
		{
			Light* pLight = *litr;

			double distAttenuation = pLight->distanceAttenuation(iDot);
			Vec3d shadowAttenuation = pLight->shadowAttenuation(iDot);
			Vec3d atten = distAttenuation * shadowAttenuation;
			Vec3d L = pLight->getDirection(iDot);


			if (L * normal > 0) {
				Vec3d H = (L + -1 * r.getDirection());
				if (H.length() != 0)
					H.normalize();

				double sDot = max(0.0, normal * H);
				Vec3d dTerm = kd(i) * (normal * L);
				Vec3d sTerm = ks(i) * (pow(sDot, shininess(i)));
				Vec3d newLight = dTerm + sTerm;
				newLight = prod(newLight, pLight->getColor());

				light += prod(atten, newLight);
			}
		}

	return light;
}

bool Cone::intersectBody( const ray& r, isect& i ) const
{
	vec3f d = r.getDirection();
	vec3f p = r.getPosition();

	double a = (d[0]*d[0]) + (d[1]*d[1]) - (C*d[2]*d[2]);
	double b = 2.0 * (d[0]*p[0] + d[1]*p[1] - C*d[2]*p[2]) - B*d[2];
	double c = (p[0]*p[0]) + (p[1]*p[1]) - A - (B*p[2]) - (C*p[2]*p[2]);

	double disc = b*b - 4.0*a*c;

	if( disc <= 0.0 ) {
		return false;
	}

	disc = sqrt( disc );

	double t1 = (-b - disc) / (2.0 * a);
	double t2 = (-b + disc) / (2.0 * a);

	if( t2 < RAY_EPSILON ) {
		return false;
	}

	if( t1 > RAY_EPSILON ) {
		// Two intersections.
		vec3f P = r.at( t1 );
		double z = P[2];
		if( z >= 0.0 && z <= height ) {
			double n3 = -C*P[2] + (b_radius - t_radius)*b_radius / height;
			i.t = t1;
            i.N = vec3f( P[0], P[1], n3).normalize();
				
			if (!capped && (i.N).dot(r.getDirection()) > 0)
				i.N = -i.N;

			return true;
		}
	}

	vec3f P = r.at( t2 );
	double z = P[2];
	if( z >= 0.0 && z <= height ) {
		double n3 = -C*P[2] + (b_radius - t_radius)*b_radius / height;
		i.t = t2;
        i.N = vec3f( P[0], P[1], n3).normalize();
	
		if( !capped && (i.N).dot( r.getDirection() ) > 0 )
				i.N = -i.N;

        return true;
	}

	return false;
}

bool intersectCircle(const ray& r0, double& tnear, double& tfar, const vec3f& center)
{
	ray r(r0.getPosition() - center, r0.getDirection());

	vec3f v = -r.getPosition();
	double b = v.dot(r.getDirection());
	double discriminant = b*b - v.dot(v) + 1;

	if (discriminant < 0.0) {
		return false;
	}

	discriminant = sqrt(discriminant);
	double t2 = b + discriminant;

	if (t2 <= RAY_EPSILON) {
		return false;
	}



	double t1 = b - discriminant;

	if (t1 > RAY_EPSILON) {
		tnear = t1;
		tfar = t2;
	}
	else {
		tnear = 0;
		tfar = t2;
	}

	return true;
}

bool Square::intersectLocal( const ray& r, isect& i ) const
{
	vec3f p = r.getPosition();
	vec3f d = r.getDirection();

	if( d[2] == 0.0 ) {
		return false;
	}

	double t = -p[2]/d[2];

	if( t <= RAY_EPSILON ) {
		return false;
	}

	vec3f P = r.at( t );

	if( P[0] < -0.5 || P[0] > 0.5 ) {	
		return false;
	}

	if( P[1] < -0.5 || P[1] > 0.5 ) {	
		return false;
	}

	i.obj = this;
	i.t = t;
	if( d[2] > 0.0 ) {
		i.N = vec3f( 0.0, 0.0, -1.0 );
	} else {
		i.N = vec3f( 0.0, 0.0, 1.0 );
	}

	return true;
}

// Apply the phong model to this point on the surface of the object, returning
// the color of that point. Uses shaddowAttenuation which sends a shadow ray
// to check if there is an intersection that blocks the light sources.
Vec3d Material::shade( Scene *scene, const ray& r, const isect& i ) const
{
  Vec3d retVal = ke(i) + prod(ka(i), scene->ambient());
  
  // Applies calculations for each light source
  for (vector<Light*>::const_iterator litr = scene->beginLights(); 
       litr != scene->endLights(); ++litr) {
    Vec3d point = r.getPosition() + r.getDirection() * i.t;
    Light* pLight = *litr;
  
    Vec3d reflectionAngle = 2 * (i.N * pLight->getDirection(point)) * i.N - pLight->getDirection(point);

    Vec3d diffIntensity = kd(i) * (max(0, i.N * pLight->getDirection(point)));

    Vec3d viewerAngle = scene->getCamera().getEye() - point;
    viewerAngle.normalize();
    Vec3d specIntensity = ks(i) * pow(max(0, viewerAngle * reflectionAngle), shininess(i));

    Vec3d lcolor = pLight->getColor(point);

    Vec3d totalColor = prod(diffIntensity + specIntensity, lcolor);
    totalColor = totalColor * pLight->distanceAttenuation(point);
    totalColor = prod(totalColor, pLight->shadowAttenuation(point));

    retVal = retVal + totalColor;	
  }
  return retVal;
}

bool CSGTree::intersect(const ray& r, isect& i) const{
	if (!root)return false;
	Segments inters = root->intersectLocal(r);
	SegmentPoint sp;
	if(!inters.firstPositive(sp))return false;
	i.t = sp.t;
	if (sp.isRight){//right - out
		if (sp.normal*r.getDirection() > RAY_EPSILON)i.N = sp.normal;
		else i.N = -sp.normal;
	}
	else {//left - in
		if (sp.normal*r.getDirection() > RAY_EPSILON)i.N = -sp.normal;
		else i.N = sp.normal;
	}
	return true;
}

bool Sphere::intersectLocal( const ray& r, isect& i ) const
{
	Vec3d v = -r.getPosition();
	double b = v * r.getDirection();
	double discriminant = b*b - v*v + 1;

	if( discriminant < 0.0 ) {
		return false;
	}

	discriminant = sqrt( discriminant );
	double t2 = b + discriminant;

	if( t2 <= RAY_EPSILON ) {
		return false;
	}

	i.obj = this;

	double t1 = b - discriminant;

	if( t1 > RAY_EPSILON ) {
		i.t = t1;
		i.N = r.at( t1 );
		i.N.normalize();
	} else {
		i.t = t2;
		i.N = r.at( t2 );
		i.N.normalize();
	}

	return true;
}

bool Cylinder::intersectCaps( const ray& r, isect& i ) const
{
	if( !capped ) {
		return false;
	}

	double pz = r.getPosition()[2];
	double dz = r.getDirection()[2];

	if( 0.0 == dz ) {
		return false;
	}

	double t1;
	double t2;

	if( dz > 0.0 ) {
		t1 = (-pz)/dz;
		t2 = (1.0-pz)/dz;
	} else {
		t1 = (1.0-pz)/dz;
		t2 = (-pz)/dz;
	}

	if( t2 < RAY_EPSILON ) {
		return false;
	}

	if( t1 >= RAY_EPSILON ) {
		vec3f p( r.at( t1 ) );
		if( (p[0]*p[0] + p[1]*p[1]) <= 1.0 ) {
			i.t = t1;
			if( dz > 0.0 ) {
				// Intersection with cap at z = 0.
				i.N = vec3f( 0.0, 0.0, -1.0 );
			} else {
				i.N = vec3f( 0.0, 0.0, 1.0 );
			}
			return true;
		}
	}

	vec3f p( r.at( t2 ) );
	if( (p[0]*p[0] + p[1]*p[1]) <= 1.0 ) {
		i.t = t2;
		if( dz > 0.0 ) {
			// Intersection with cap at z = 1.
			i.N = vec3f( 0.0, 0.0, 1.0 );
		} else {
			i.N = vec3f( 0.0, 0.0, -1.0 );
		}
		return true;
	}

	return false;
}

// Apply the phong model to this point on the surface of the object, returning
// the color of that point.
Vec3d Material::shade(Scene *scene, const ray& r, const isect& i) const
{
  const Material& m = i.getMaterial();

  Vec3d I = m.ke(i) + prod(m.ka(i) ,scene->ambient());
  Vec3d R = 2*(-r.getDirection() * i.N)*i.N +r.getDirection();

  for ( vector<Light*>::const_iterator litr = scene->beginLights(); 
  		litr != scene->endLights(); 
  		++litr )
  {
  		Vec3d atten = (*litr)->distanceAttenuation(r.at(i.t)) * (*litr)->shadowAttenuation(r,r.at(i.t));
      I += prod(atten,(m.kd(i)*max((i.N * (*litr)->getDirection(r.at(i.t)) ), 0.0) + m.ks(i) * max(((scene->getCamera().getEye() - r.at(i.t)) *R),0.0)));
  }

  // You will need to call both the distanceAttenuation() and
  // shadowAttenuation() methods for each light source in order to
  // compute shadows and light falloff.

  return I;
}

bool Metaball::intersectLocal(const ray& r, isect& i) const
{
	bool inside = false;
	if (calvalue(r.getPosition(), ball1pos, ball2pos)>threshold)inside = true;

	//determine possible intersect range
	double t11=0, t12=0, t21=0, t22=0;
	double tmin, tmax;
	bool i1, i2;
	i1 = intersectCircle(r, t11, t12, ball1pos);
	i2 = intersectCircle(r, t21, t22, ball2pos);
	if (!i1 && !i2) return false;
	else if (!i1 && i2)
	{
		tmin = t21;
		tmax = t22;
	}
	else if (i1 && !i2)
	{
		tmin = t11;
		tmax = t12;
	}
	else
	{
		tmin = min(t11, t21);
		tmax = max(t12, t22);
	}

	for (double t = tmin; t < tmax; t += 0.001)
	{
		vec3f point = r.getPosition() + t * r.getDirection();
		double value = calvalue(point, ball1pos, ball2pos);

		if ((!inside && value > threshold) || (inside && value < threshold))
		{
			// prevent fake intersect
			if (inside && t < 0.01)return false;

			vec3f normal;
			normal += 2 * (point - ball1pos) / ((point - ball1pos).length()*(point - ball1pos).length());
			normal += 2 * (point - ball2pos) / ((point - ball2pos).length()*(point - ball2pos).length());
			normal = normal.normalize();
			i.t = t;
			i.N = normal;
			i.obj = this;
			return true;
		}
	}
	return false;
}

// Apply the phong model to this point on the surface of the object, returning
// the color of that point.
vec3f Material::shade( Scene *scene, const ray& r, const isect& i ) const
{
	// YOUR CODE HERE

	// For now, this method just returns the diffuse color of the object.
	// This gives a single matte color for every distinct surface in the
	// scene, and that's it.  Simple, but enough to get you started.
	// (It's also inconsistent with the phong model...)

	// Your mission is to fill in this method with the rest of the phong
	// shading model, including the contributions of all the light sources.
    // You will need to call both distanceAttenuation() and shadowAttenuation()
    // somewhere in your code in order to compute shadows and light falloff.
	
	//intersection point
	vec3f point = r.at(i.t);
	bool istransmissive = abs(index - 1.0) > NORMAL_EPSILON || !kt.iszero();
	vec3f rate = vec3f(1, 1, 1) - kt;

	vec3f I = ke;

	//ambient
	if (istransmissive) I += scene->ambient.time(ka).time(rate).clamp();
	else I += scene->ambient.time(ka).clamp();

	list<Light*>::const_iterator begin = scene->beginLights();
	list<Light*>::const_iterator end = scene->endLights();
	while (begin != end)
	{
		vec3f atten = (*begin)->shadowAttenuation(point) * (*begin)->distanceAttenuation(point);
		vec3f L = (*begin)->getDirection(point);
		double NL = i.N.dot(L);

		//diffuse
		if (istransmissive) I += (atten * NL).time(kd).time(rate).clamp();
		else I += (atten * NL).time(kd).clamp();

		//specular
		vec3f R = i.N * (2 * NL) - L;
		double RV = -R.dot(r.getDirection());
		
		//TODO: where is n£¿
		double n = 64;
		I += (atten * pow(RV, n)).time(ks).clamp();

		begin++;
	}

	return I;
}