cylinder()

cylinder

(

struct geometry *

geom

)

Cylinder geometry generation.

Parameters

[in,out]

geom

geometry structure

                                   {
  DOUBLE start_rad, end_rad, radius, dr;                        // gp mod
  DOUBLE pi,invpi,mulrad;
  DOUBLE theta;
  DOUBLE dtheta;
  int i,j;
  int inodb,ielmb,nelmb,ivbase;
  struct cylinder_geom* cylgeom;
  DOUBLE l,dl;

  int i1,i2;

  logger(LOG_DEBUG,"building cylinder\n");
  cylgeom  = (struct cylinder_geom*) geom->ptrgeom; // allocation
  start_rad = cylgeom->start_radius;                            // gp mod
  end_rad = cylgeom->end_radius;                                        // gp mod

  // utility vars
  pi = 4.0*atanl(1.0);
  invpi = 1.0/pi;
  mulrad = pi/180.0;

  // steps
  dl   = cylgeom->length/(cylgeom->rings);
  dtheta = 360.0*mulrad/(cylgeom->segments);
  dr = (end_rad-start_rad)/(cylgeom->rings +1);         // gp mod

  inodb=0;
 // l = cylgeom->length/2;   // gp ???
  theta = 0.0;
  l = 0.0;
  radius = start_rad;
  /* building geometry */

/*  for(j=0;j<(cylgeom->segments+1);j++){
    l = 0;
    for(i=0;i<(cylgeom->rings+1);i++){
      geometry->nodes[inodb + _g_inodb].x = COS(theta);
      geometry->nodes[inodb + _g_inodb].y = SIN(theta);
      geometry->nodes[inodb + _g_inodb].z = l;
    
      l += dl;
      inodb++;
    }
    theta += dtheta;
  }
*/ //old version

  for(j=0;j<(cylgeom->rings +1);j++){
    for(i=0;i<(cylgeom->segments +1);i++){
      geometry->nodes[inodb + _g_inodb].x = radius*COS(theta);
      geometry->nodes[inodb + _g_inodb].y = radius*SIN(theta);
      geometry->nodes[inodb + _g_inodb].z = l;
      theta += dtheta;
      inodb++;
        }
    l += dl;
    radius += dr;
  }

  /* building topology */
  nelmb = (cylgeom->rings)*(cylgeom->segments);
  ivbase=0;

  /*for(ielmb=0;ielmb<nelmb;ielmb++){
    i1 = (ielmb)/(cylgeom->rings);
    i2 = i1+1;

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

    ivbase +=4;
  }
*/      // OLD VERSION

  for(ielmb=0;ielmb<nelmb;ielmb++){
        i1 = (ielmb)/(cylgeom->segments);
        //i2 = i1+1;
    geometry->jnodb[ivbase+0 + _g_ielmb] = ielmb + i1     + cylgeom->segments + 1;
    geometry->jnodb[ivbase+1 + _g_ielmb] = ielmb + i1;
    geometry->jnodb[ivbase+2 + _g_ielmb] = ielmb + i1 + 1;
    geometry->jnodb[ivbase+3 + _g_ielmb] = ielmb + i1 + 1 + cylgeom->segments + 1;

    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,"cylinder built\n");

 return 1;

}