Sphere.cpp

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/**
@file Sphere.cpp
*/
#include <cmath>
#include "Sphere.h"
 
void
rt::Sphere::draw( Viewer& /* viewer */ )
{
  Material m = material;
  // Taking care of south pole
  glBegin( GL_TRIANGLE_FAN );
  glColor4fv( m.ambient );
  glMaterialfv(GL_FRONT, GL_DIFFUSE, m.diffuse);
  glMaterialfv(GL_FRONT, GL_SPECULAR, m.specular);
  glMaterialf(GL_FRONT, GL_SHININESS, m.shinyness );
  Point3 south_pole = localize( -90, 0 );
  glNormal3fv( getNormal( south_pole ) );
  glVertex3fv( south_pole );
  for ( int x = 0; x <= NLON; ++x )
    {
      Point3 p = localize( -90 + 180/NLAT, x * 360 / NLON );
      glNormal3fv( getNormal( p ) );
      glVertex3fv( p );
    }
  glEnd();
  // Taking care of in-between poles
  for ( int y = 1; y < NLAT - 1; ++y )
    {
      glBegin( GL_QUAD_STRIP);
      glColor4fv( m.ambient );
      glMaterialfv(GL_FRONT, GL_DIFFUSE, m.diffuse);
      glMaterialfv(GL_FRONT, GL_SPECULAR, m.specular);
      glMaterialf(GL_FRONT, GL_SHININESS, m.shinyness );
      for ( int x = 0; x <= NLON; ++x )
        {
          Point3 p = localize( -90 + y*180/NLAT,     x * 360 / NLON );
          Point3 q = localize( -90 + (y+1)*180/NLAT, x * 360 / NLON );
          glNormal3fv( getNormal( p ) );
          glVertex3fv( p );
          glNormal3fv( getNormal( q ) );
          glVertex3fv( q );
        }
      glEnd();
    }
  // Taking care of north pole
  glBegin( GL_TRIANGLE_FAN );
  glColor4fv( m.ambient );
  glMaterialfv(GL_FRONT, GL_DIFFUSE, m.diffuse);
  glMaterialfv(GL_FRONT, GL_SPECULAR, m.specular);
  glMaterialf(GL_FRONT, GL_SHININESS, m.shinyness );
  Point3 north_pole = localize( 90, 0 );
  glNormal3fv( getNormal( north_pole ) );
  glVertex3fv( north_pole );
  for ( int x = NLON; x >= 0; --x )
    {
      Point3 p = localize( -90 + (NLAT-1)*180/NLAT, x * 360 / NLON );
      glNormal3fv( getNormal( p ) );
      glVertex3fv( p );
    }
  glEnd();
}
 
rt::Point3
rt::Sphere::localize( Real latitude, Real longitude ) const
{
  static const Real conv_deg_rad = 2.0 * M_PI / 360.0;
  latitude  *= conv_deg_rad;
  longitude *= conv_deg_rad;
  return center 
    + radius * Point3( cos( longitude ) * cos( latitude ),
                       sin( longitude ) * cos( latitude ),
                       sin( latitude ) );
}
 
rt::Vector3
rt::Sphere::getNormal( Point3 p )
{
  Vector3 u = p - center;
  Real   l2 = u.dot( u );
  if ( l2 != 0.0 ) u /= sqrt( l2 );
  return u;
}
 
rt::Material
rt::Sphere::getMaterial( Point3 /* p */ )
{
  return material; // the material is constant along the sphere.
}
 
rt::Real
rt::Sphere::rayIntersection( const Ray& ray, Point3& p )
{
  // TO DO
  return 1.0f;
}