Example #1
0
//intersect sphere with a ray
bool Sphere::intersect(const Ray &ray, IntersectionData* iData) {
  //=== EXERCISE 1.3.2 ===
  //Resolving the problem algebraicaly, we get the following coefficients of a quadratic equation in t:
  double a=ray.direction.dot(ray.direction);
  double b=2*(ray.point.dot(ray.direction) - m_center.dot(ray.direction));
  double c=m_center.dot(m_center)+ray.point.dot(ray.point) - 2.0*m_center.dot(ray.point) - m_radius*m_radius;

  double discriminant = b*b - 4.0*a*c;
  if (discriminant<0)
  {
    return false;

  }else{
    double t1=(-b+sqrt(discriminant))/(2.0*a);
    double t2=(-b-sqrt(discriminant))/(2.0*a);

    bool b1= (t1>=ray.min_t && t1<=ray.max_t) && t1<iData->t ;
    bool b2= (t2>=ray.min_t && t2<=ray.max_t) && t2<iData->t ;

    if (b1||b2)
    {

      if(b1)
        iData->t=t1;

      if(b2)
        iData->t=t2;

      if (b1 && b2)
      {
        iData->t=(t2<t1?t2:t1);
      }

      iData->position=ray.getPointOnRay(iData->t);
      iData->color=getColor();
      iData->material=getMaterial();
      iData->sourcePosition=ray.point;
      iData->normal=(ray.getPointOnRay(iData->t) - m_center).normalize();

      iData->reflectionPercentage=getReflectionPercentage();
      iData->refractionIndex=getRefractionIndex();
      iData->refractionPercentage=getRefractionPercentage();
      iData->rayEntersObject= (ray.direction.dot(iData->normal)<0.0);

	  iData->reflectionPercentage = getReflectionPercentage();

      return true;
    }
  }

  return false;
}
Example #2
0
//intersect triangle with a ray
bool Triangle::intersect(const Ray &ray, IntersectionData* iData) {

  //=== EXERCISE 1.4.2 ===
	Vector3 n = (m_p3 - m_p1).cross(m_p2 - m_p1);
	if (ray.direction.dot(n) == 0)
	{
		// no solution
		return false;
	}else{
		// compute the solution
		double t = - ((ray.point - m_p1).dot(n))/(ray.direction.dot(n));

		// check if solution is valid for our problem
		bool b = (t>=ray.min_t && t<=ray.max_t) && t<iData->t;
		if(b){

			// normal vector of small triangles
			Vector3 x = ray.getPointOnRay(t);
			Vector3 n_s1 = (m_p2 - m_p3).cross(x - m_p3);
			Vector3 n_s2 = (m_p1 - m_p2).cross(x - m_p2);
			Vector3 n_s3 = (m_p3 - m_p1).cross(x - m_p1);

			// compute s1 s2 s3 (normalise)
			double s1 = (n.dot(n_s1))/(n.x*n.x + n.y*n.y + n.z*n.z);
			double s2 = (n.dot(n_s2))/(n.x*n.x + n.y*n.y + n.z*n.z);
			double s3 = (n.dot(n_s3))/(n.x*n.x + n.y*n.y + n.z*n.z);

			// test if p is in triangle
			if(1-ray.epsilon_t < s1+s2+s3 && s1+s2+s3 < 1+ray.epsilon_t && 0 < s1 && s1<1 && 0<s2 && s2<1 && 0<s3 && s3<1){
				iData->t=t;
		
			//Intersection information
			iData->position=ray.getPointOnRay(iData->t);
			iData->color=getColor();
			iData->sourcePosition=ray.point;
			return true;
			}else{
				return false;
			}
		}else{

		return false;
		}
	}

	return false;
}
Example #3
0
//intersect triangle with a ray
bool Triangle::intersect(const Ray &ray, IntersectionData* iData) {


//=== EXERCISE 1.4.2 ===
	Vector3 n = (m_p3 - m_p1).cross(m_p2 - m_p1);
	if (ray.direction.dot(n) == 0)
	{
		// no solution
		return false;
	}else{
		// compute the solution
		double t = - ((ray.point - m_p1).dot(n))/(ray.direction.dot(n));

		// check if solution is valid for our problem
		bool b = (t>=ray.min_t && t<=ray.max_t) && t<iData->t;
		if(b){

			// normal vector of small triangles
			Vector3 x = ray.getPointOnRay(t);
			Vector3 n_s1 = (m_p2 - m_p3).cross(x - m_p3);
			Vector3 n_s2 = (m_p1 - m_p2).cross(x - m_p2);
			Vector3 n_s3 = (m_p3 - m_p1).cross(x - m_p1);

			// compute s1 s2 s3 (normalise)
			double s1 = (n.dot(n_s1))/(n.x*n.x + n.y*n.y + n.z*n.z);
			double s2 = (n.dot(n_s2))/(n.x*n.x + n.y*n.y + n.z*n.z);
			double s3 = (n.dot(n_s3))/(n.x*n.x + n.y*n.y + n.z*n.z);

			// test if p is in triangle
			if(1-ray.epsilon_t < s1+s2+s3 && s1+s2+s3 < 1+ray.epsilon_t && 0 < s1 && s1<1 && 0<s2 && s2<1 && 0<s3 && s3<1){
				iData->t=t;
		
			//Intersection information
			iData->position=ray.getPointOnRay(iData->t);
			iData->color=getColor();
			iData->sourcePosition=ray.point;
			iData->reflectionPercentage = getReflectionPercentage();


			// Exercice 2.1.1
			iData->material = getMaterial();
			//Normal interpolation
			Vector3 normal1 = m_n1.operator*(s1);
			Vector3 normal2 = m_n2.operator*(s3);
			Vector3 normal3 = m_n3.operator*(s2); // s2 and s3 are inverted du to the typing error on the triangle in slide

			Vector3 normal = (normal1+normal2+normal3).normalize(); // get the interpolated normal in x
			iData->normal = normal;
			return true;
			}else{
				return false;
			}
		}else{

		return false;
		}
	}
  return false;



}