sphere()

int sphere

(

struct geometry *

geom

)

Sphere geometry generation.

Parameters

[in,out]

geom

geometry structure

                                 {
  DOUBLE pi,invpi,mulrad;
  DOUBLE phi,theta;
  DOUBLE dphi,dtheta;
  int i,j;
  int inodb,ielmb,nelmb,ivbase;
  struct sphere_geom* spheregeom;

  int i1,i2;

  logger(LOG_DEBUG," building sphere\n");
  spheregeom  = (struct sphere_geom*) geom->ptrgeom; // allocation
  // utility vars
  pi = 4.0*atanl(1.0); 
  invpi = 1.0/pi;      
  mulrad = pi/180.0;

  //steps
  dphi   = 180.0*mulrad/(spheregeom->rings);
  dtheta = 360.0*mulrad/(spheregeom->segments);

  inodb=0;
  phi = pi/2;
  theta = 0.0;
  /* building geometry */
  for(j=0;j<(spheregeom->segments+1);j++){
    phi = 0;
    for(i=0;i<(spheregeom->rings+1);i++){
      geometry->nodes[inodb + _g_inodb].x = spheregeom->radius * SIN(phi) * COS(theta);
      geometry->nodes[inodb + _g_inodb].y = spheregeom->radius * SIN(phi) * SIN(theta);
      geometry->nodes[inodb + _g_inodb].z = spheregeom->radius * COS(phi);
    
      phi += dphi;
      inodb++;
    }
    theta += dtheta;
  }

  /* building topology */
  nelmb = (spheregeom->rings)*(spheregeom->segments);
  ivbase=0;
  for(ielmb=0;ielmb<nelmb;ielmb++){
    i1 = (ielmb)/(spheregeom->rings);
    i2 = i1+1;

    geometry->jnodb[ivbase+0 + _g_ielmb] = ielmb + i1 + 1;
    geometry->jnodb[ivbase+1 + _g_ielmb] = ielmb + i1 + 1 + spheregeom->rings + 1;
    geometry->jnodb[ivbase+2 + _g_ielmb] = ielmb + i1     + spheregeom->rings + 1;
    geometry->jnodb[ivbase+3 + _g_ielmb] = ielmb + i1;

    ivbase +=4;
  }

   geom_fill(geom); // filling geometry

   // adding to global vars
  _g_icntr += geom->ncntr;
  _g_inodb += geom->nnodb;
  _g_ielmb += geom->nelmb;


  logger(LOG_DEBUG," sphere built\n");
 return 1;

}