Sphere.cxx

   1 #include "Sphere.hxx"
   2
   3 Sphere::Sphere(const Vec3f& center, float radius, Shader* shader)
   4   : Primitive(shader),
   5     m_center(center),
   6     m_radius(radius)
   7 {
   8 }
   9
  10 Sphere::~Sphere()
  11 {
  12 }
  13
  14 bool
  15 Sphere::Intersect(Ray& ray)
  16 {
  17   float A = ray.direction().dot(ray.direction());
  18   float C = (ray.origin()-m_center).dot(ray.origin()-m_center) - m_radius*m_radius;
  19   float B = 2 * ray.direction().dot(ray.origin()-m_center);
  20
  21   if( B*B-4*A*C < 0 )
  22     return false;
  23
  24   float root = sqrtf(B*B-4*A*C);
  25   float t = (-B-root)/(2.0f*A);
  26   if(t > ray.t())
  27     return false;
  28
  29   if( t < Epsilon )
  30     {
  31       t = (-B+root)/(2.0f*A);
  32       if( t < Epsilon || t > ray.t())
  33         return false;
  34     }
  35
  36   ray.setT(t);
  37   ray.setHit(this);
  38
  39   return true;
  40 }
  41
  42 Vec3f
  43 Sphere::GetNormal(Ray& ray)
  44 {
  45   Vec3f p = ray.origin()+ray.direction()*ray.t();
  46   Vec3f N = (p-m_center);
  47   N.normalize();
  48
  49   return N;
  50 }
  51
  52 Box
  53 Sphere::CalcBounds()
  54 {
  55   Vec3f min(m_center[0] - m_radius/2, m_center[1] - m_radius/2,
  56     m_center[2] - m_radius/2);
  57   Vec3f max(m_center[0] + m_radius/2, m_center[1] + m_radius/2,
  58     m_center[2] + m_radius/2);
  59   return Box(min, max);
  60 }
  61
  62 bool
  63 Sphere::InVoxel(const Box& box)
  64 {
  65   return CalcBounds().Overlaps(box);
  66 }