/****************************************************************************
 *                  fnintern.cpp
 *
 * This module implements the the function type used by iso surfaces and
 * the function pattern.
 *
 * This module is based on code by D. Skarda, T. Bily and R. Suzuki.
 * It includes functions based on code first introduced by many other
 * contributors.
 *
 * from Persistence of Vision(tm) Ray Tracer version 3.6.
 * Copyright 1991-2003 Persistence of Vision Team
 * Copyright 2003-2009 Persistence of Vision Raytracer Pty. Ltd.
 *---------------------------------------------------------------------------
 * NOTICE: This source code file is provided so that users may experiment
 * with enhancements to POV-Ray and to port the software to platforms other
 * than those supported by the POV-Ray developers. There are strict rules
 * regarding how you are permitted to use this file. These rules are contained
 * in the distribution and derivative versions licenses which should have been
 * provided with this file.
 *
 * These licences may be found online, linked from the end-user license
 * agreement that is located at http://www.povray.org/povlegal.html
 *---------------------------------------------------------------------------
 * This program is based on the popular DKB raytracer version 2.12.
 * DKBTrace was originally written by David K. Buck.
 * DKBTrace Ver 2.0-2.12 were written by David K. Buck & Aaron A. Collins.
 *---------------------------------------------------------------------------
 * $File: //depot/povray/3.5/source/fnintern.cpp $
 * $Revision: #46 $
 * $Change: 4808 $
 * $DateTime: 2009/06/03 08:16:08 $
 * $Author: calimet $
 * $Log$
 *****************************************************************************/

#include "frame.h"
#include "povray.h"
#include "texture.h"
#include "vector.h"
#include "colour.h"
#include "fncode.h"
#include "fnpovfpu.h"
#include "fnintern.h"
#include "pigment.h"
#include "matrices.h"
#include "splines.h"

#include <algorithm>

BEGIN_POV_NAMESPACE

/*****************************************************************************
* Local preprocessor defines
******************************************************************************/

/*
 * IMPORTANT NOTICE
 * Never ever use any PARAM_xxx macro after a call to POVFPU_SetLocal
 * because POVFPU_SetLocal may change the stack base address and thus
 * the "ptr" passed to the functions may be invalid after the call! [trf]
 */
#define PARAM_X (ptr[0])
#define PARAM_Y (ptr[1])
#define PARAM_Z (ptr[2])
#define PARAM(index) (ptr[index + 3])
#define PARAM_N_X(offset) (ptr[offset])
#define PARAM_N_Y(offset) (ptr[offset + 1])
#define PARAM_N_Z(offset) (ptr[offset + 2])
#define PARAM_N(index,offset) (ptr[index + offset + 3])

#define ROT2D(p,d,ang) if (p>0) {x2=sqrt(x2+PARAM_Z*PARAM_Z)- d; th=ang*M_PI_180; \
    if (th!=0){ PARAM_X= x2*cos(th)-PARAM_Y*sin(th); PARAM_Y= x2*sin(th)+PARAM_Y*cos(th);} else PARAM_X=x2; \
    x2=PARAM_X*PARAM_X; y2=PARAM_Y*PARAM_Y;}


/*****************************************************************************
* Global functions
******************************************************************************/

DBL f_algbr_cyl1(DBL *ptr, unsigned int fn); // 0
DBL f_algbr_cyl2(DBL *ptr, unsigned int fn); // 1
DBL f_algbr_cyl3(DBL *ptr, unsigned int fn); // 2
DBL f_algbr_cyl4(DBL *ptr, unsigned int fn); // 3
DBL f_bicorn(DBL *ptr, unsigned int fn); // 4
DBL f_bifolia(DBL *ptr, unsigned int fn); // 5
DBL f_blob(DBL *ptr, unsigned int fn); // 6
DBL f_blob2(DBL *ptr, unsigned int fn); // 7
DBL f_boy_surface(DBL *ptr, unsigned int fn); // 8
DBL f_comma(DBL *ptr, unsigned int fn); // 9
DBL f_cross_ellipsoids(DBL *ptr, unsigned int fn); // 10
DBL f_crossed_trough(DBL *ptr, unsigned int fn); // 11
DBL f_cubic_saddle(DBL *ptr, unsigned int fn); // 12
DBL f_cushion(DBL *ptr, unsigned int fn); // 13
DBL f_devils_curve(DBL *ptr, unsigned int fn); // 14
DBL f_devils_curve_2d(DBL *ptr, unsigned int fn); // 15
DBL f_dupin_cyclid(DBL *ptr, unsigned int fn); // 16
DBL f_ellipsoid(DBL *ptr, unsigned int fn); // 17
DBL f_enneper(DBL *ptr, unsigned int fn); // 18
DBL f_flange_cover(DBL *ptr, unsigned int fn); // 19
DBL f_folium_surface(DBL *ptr, unsigned int fn); // 20
DBL f_folium_surface_2d(DBL *ptr, unsigned int fn); // 21
DBL f_glob(DBL *ptr, unsigned int fn); // 22
DBL f_heart(DBL *ptr, unsigned int fn); // 23
DBL f_helical_torus(DBL *ptr, unsigned int fn); // 24
DBL f_helix1(DBL *ptr, unsigned int fn); // 25
DBL f_helix2(DBL *ptr, unsigned int fn); // 26
DBL f_hex_x(DBL *ptr, unsigned int fn); // 27
DBL f_hex_y(DBL *ptr, unsigned int fn); // 28
DBL f_hetero_mf(DBL *ptr, unsigned int fn); // 29
DBL f_hunt_surface(DBL *ptr, unsigned int fn); // 30
DBL f_hyperbolic_torus(DBL *ptr, unsigned int fn); // 31
DBL f_isect_ellipsoids(DBL *ptr, unsigned int fn); // 32
DBL f_kampyle_of_eudoxus(DBL *ptr, unsigned int fn); // 33
DBL f_kampyle_of_eudoxus_2d(DBL *ptr, unsigned int fn); // 34
DBL f_klein_bottle(DBL *ptr, unsigned int fn); // 35
DBL f_kummer_surface_v1(DBL *ptr, unsigned int fn); // 36
DBL f_kummer_surface_v2(DBL *ptr, unsigned int fn); // 37
DBL f_lemniscate_of_gerono(DBL *ptr, unsigned int fn); // 38
DBL f_lemniscate_of_gerono_2d(DBL *ptr, unsigned int fn); // 39
DBL f_mesh1(DBL *ptr, unsigned int fn); // 40
DBL f_mitre(DBL *ptr, unsigned int fn); // 41
DBL f_nodal_cubic(DBL *ptr, unsigned int fn); // 42
DBL f_odd(DBL *ptr, unsigned int fn); // 43
DBL f_ovals_of_cassini(DBL *ptr, unsigned int fn); // 44
DBL f_paraboloid(DBL *ptr, unsigned int fn); // 45
DBL f_parabolic_torus(DBL *ptr, unsigned int fn); // 46
DBL f_ph(DBL *ptr, unsigned int fn); // 47
DBL f_pillow(DBL *ptr, unsigned int fn); // 48
DBL f_piriform(DBL *ptr, unsigned int fn); // 49
DBL f_piriform_2d(DBL *ptr, unsigned int fn); // 50
DBL f_poly4(DBL *ptr, unsigned int fn); // 51
DBL f_polytubes(DBL *ptr, unsigned int fn); // 52
DBL f_quantum(DBL *ptr, unsigned int fn); // 53
DBL f_quartic_paraboloid(DBL *ptr, unsigned int fn); // 54
DBL f_quartic_saddle(DBL *ptr, unsigned int fn); // 55
DBL f_quartic_cylinder(DBL *ptr, unsigned int fn); // 56
DBL f_r(DBL *ptr, unsigned int fn); // 57
DBL f_ridge(DBL *ptr, unsigned int fn); // 58
DBL f_ridged_mf(DBL *ptr, unsigned int fn); // 59
DBL f_rounded_box(DBL *ptr, unsigned int fn); // 60
DBL f_sphere(DBL *ptr, unsigned int fn); // 61
DBL f_spikes(DBL *ptr, unsigned int fn); // 62
DBL f_spikes_2d(DBL *ptr, unsigned int fn); // 63
DBL f_spiral(DBL *ptr, unsigned int fn); // 64
DBL f_steiners_roman(DBL *ptr, unsigned int fn); // 65
DBL f_strophoid(DBL *ptr, unsigned int fn); // 66
DBL f_strophoid_2d(DBL *ptr, unsigned int fn); // 67
DBL f_superellipsoid(DBL *ptr, unsigned int fn); // 68
DBL f_th(DBL *ptr, unsigned int fn); // 69
DBL f_torus(DBL *ptr, unsigned int fn); // 70
DBL f_torus2(DBL *ptr, unsigned int fn); // 71
DBL f_torus_gumdrop(DBL *ptr, unsigned int fn); // 72
DBL f_umbrella(DBL *ptr, unsigned int fn); // 73
DBL f_witch_of_agnesi(DBL *ptr, unsigned int fn); // 74
DBL f_witch_of_agnesi_2d(DBL *ptr, unsigned int fn); // 75
DBL f_noise3d(DBL *ptr, unsigned int fn); // 76
DBL f_pattern(DBL *ptr, unsigned int fn); // 77
DBL f_noise_generator(DBL *ptr, unsigned int fn); // 78

void f_pigment(DBL *ptr, unsigned int fn, unsigned int sp); // 0
void f_transform(DBL *ptr, unsigned int fn, unsigned int sp); // 1
void f_spline(DBL *ptr, unsigned int fn, unsigned int sp); // 2


/*****************************************************************************
* Global variables
******************************************************************************/

const Trap POVFPU_TrapTable[] =
{
	{ f_algbr_cyl1,              5 + 3 }, // 0
	{ f_algbr_cyl2,              5 + 3 }, // 1
	{ f_algbr_cyl3,              5 + 3 }, // 2
	{ f_algbr_cyl4,              5 + 3 }, // 3
	{ f_bicorn,                  2 + 3 }, // 4
	{ f_bifolia,                 2 + 3 }, // 5
	{ f_blob,                    5 + 3 }, // 6
	{ f_blob2,                   4 + 3 }, // 7
	{ f_boy_surface,             2 + 3 }, // 8
	{ f_comma,                   1 + 3 }, // 9
	{ f_cross_ellipsoids,        4 + 3 }, // 10
	{ f_crossed_trough,          1 + 3 }, // 11
	{ f_cubic_saddle,            1 + 3 }, // 12
	{ f_cushion,                 1 + 3 }, // 13
	{ f_devils_curve,            1 + 3 }, // 14
	{ f_devils_curve_2d,         6 + 3 }, // 15
	{ f_dupin_cyclid,            6 + 3 }, // 16
	{ f_ellipsoid,               3 + 3 }, // 17
	{ f_enneper,                 1 + 3 }, // 18
	{ f_flange_cover,            4 + 3 }, // 19
	{ f_folium_surface,          3 + 3 }, // 20
	{ f_folium_surface_2d,       6 + 3 }, // 21
	{ f_glob,                    1 + 3 }, // 22
	{ f_heart,                   1 + 3 }, // 23
	{ f_helical_torus,          10 + 3 }, // 24
	{ f_helix1,                  7 + 3 }, // 25
	{ f_helix2,                  7 + 3 }, // 26
	{ f_hex_x,                   1 + 3 }, // 27
	{ f_hex_y,                   1 + 3 }, // 28
	{ f_hetero_mf,               6 + 3 }, // 29
	{ f_hunt_surface,            1 + 3 }, // 30
	{ f_hyperbolic_torus,        3 + 3 }, // 31
	{ f_isect_ellipsoids,        4 + 3 }, // 32
	{ f_kampyle_of_eudoxus,      3 + 3 }, // 33
	{ f_kampyle_of_eudoxus_2d,   6 + 3 }, // 34
	{ f_klein_bottle,            1 + 3 }, // 35
	{ f_kummer_surface_v1,       1 + 3 }, // 36
	{ f_kummer_surface_v2,       4 + 3 }, // 37
	{ f_lemniscate_of_gerono,    1 + 3 }, // 38
	{ f_lemniscate_of_gerono_2d, 6 + 3 }, // 39
	{ f_mesh1,                   5 + 3 }, // 40
	{ f_mitre,                   1 + 3 }, // 41
	{ f_nodal_cubic,             1 + 3 }, // 42
	{ f_odd,                     1 + 3 }, // 43
	{ f_ovals_of_cassini,        4 + 3 }, // 44
	{ f_paraboloid,              1 + 3 }, // 45
	{ f_parabolic_torus,         3 + 3 }, // 46
	{ f_ph,                      0 + 3 }, // 47
	{ f_pillow,                  1 + 3 }, // 48
	{ f_piriform,                1 + 3 }, // 49
	{ f_piriform_2d,             7 + 3 }, // 50
	{ f_poly4,                   5 + 3 }, // 51
	{ f_polytubes,               6 + 3 }, // 52
	{ f_quantum,                 1 + 3 }, // 53
	{ f_quartic_paraboloid,      1 + 3 }, // 54
	{ f_quartic_saddle,          1 + 3 }, // 55
	{ f_quartic_cylinder,        3 + 3 }, // 56
	{ f_r,                       0 + 3 }, // 57
	{ f_ridge,                   6 + 3 }, // 58
	{ f_ridged_mf,               6 + 3 }, // 59
	{ f_rounded_box,             4 + 3 }, // 60
	{ f_sphere,                  1 + 3 }, // 61
	{ f_spikes,                  5 + 3 }, // 62
	{ f_spikes_2d,               4 + 3 }, // 63
	{ f_spiral,                  6 + 3 }, // 64
	{ f_steiners_roman,          1 + 3 }, // 65
	{ f_strophoid,               4 + 3 }, // 66
	{ f_strophoid_2d,            7 + 3 }, // 67
	{ f_superellipsoid,          2 + 3 }, // 68
	{ f_th,                      0 + 3 }, // 69
	{ f_torus,                   2 + 3 }, // 70
	{ f_torus2,                  3 + 3 }, // 71
	{ f_torus_gumdrop,           1 + 3 }, // 72
	{ f_umbrella,                1 + 3 }, // 73
	{ f_witch_of_agnesi,         2 + 3 }, // 74
	{ f_witch_of_agnesi_2d,      6 + 3 }, // 75
	{ f_noise3d,                 0 + 3 }, // 76
	{ f_pattern,                 0 + 3 }, // 77
	{ f_noise_generator,         1 + 3 }, // 78
	{ NULL, 0 }
};

const TrapS POVFPU_TrapSTable[] =
{
	{ f_pigment,                 0 + 3 }, // 0
	{ f_transform,               0 + 3 }, // 1
	{ f_spline,                  0 + 1 }, // 2
	{ NULL, 0 }
};

const unsigned int POVFPU_TrapTableSize = 79;
const unsigned int POVFPU_TrapSTableSize = 3;


/*****************************************************************************
* Functions
******************************************************************************/

DBL f_algbr_cyl1(DBL *ptr, unsigned int) // 0
{
	DBL r, x2, y2, th;

	x2 = PARAM_X * PARAM_X;
	y2 = PARAM_Y * PARAM_Y;

	ROT2D(PARAM(2),PARAM(3),PARAM(4))

	PARAM_X = fabs(PARAM_X);

	r = -(x2 * PARAM_X - x2 + y2);

	return (-min(PARAM(1), max(PARAM(0) * r, -PARAM(1))));
}

DBL f_algbr_cyl2(DBL *ptr, unsigned int) // 1
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(2),PARAM(3),PARAM(4))
  r=-( 2*x2*x2 -3*x2*PARAM_Y +y2 -2*y2*PARAM_Y +y2*y2 );
  return( min(PARAM(1), max(PARAM(0)*r,-PARAM(1))) );
}

DBL f_algbr_cyl3(DBL *ptr, unsigned int) // 2
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(2),PARAM(3),PARAM(4))
  r=-( x2*x2 +x2*y2 -2*x2*PARAM_Y -PARAM_X*y2 +y2 );
  return( min(PARAM(1), max(PARAM(0)*r,-PARAM(1))) );
}

DBL f_algbr_cyl4(DBL *ptr, unsigned int) // 3
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(2),PARAM(3),PARAM(4))
  r=-( x2*x2 +y2*y2 +2*x2*y2 +3*x2*PARAM_Y -y2*PARAM_Y );
  return( min(PARAM(1), max(PARAM(0)*r,-PARAM(1))) );
}

DBL f_bicorn(DBL *ptr, unsigned int) // 4
{
  DBL r, r2,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r = PARAM(1)*PARAM(1); 
  r2=(x2 + z2 + 2*PARAM(1)*PARAM_Y - r);
  r = ( y2*(r - (x2 + z2)) - r2*r2);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_bifolia(DBL *ptr, unsigned int) // 5
{
  DBL r, x2=PARAM_X*PARAM_X, z2=PARAM_Z*PARAM_Z;
  r=x2+PARAM_Y*PARAM_Y+z2;
  r= -(r*r - PARAM(1)*(x2 + z2)*PARAM_Y);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_blob(DBL *ptr, unsigned int) // 6
{
  DBL r,r2,y2,z2,temp;
  /*   blob  */
  y2=PARAM_Y*PARAM_Y; z2=PARAM_Z*PARAM_Z;
  r2= PARAM(0)*0.5;
  r=((PARAM_X+r2)*(PARAM_X+r2)+y2+z2)*PARAM(2)*PARAM(2);
  if (r>1.) 
    r=1.;
  temp=( (PARAM_X - r2)*(PARAM_X - r2)+y2+z2)*PARAM(4)*PARAM(4);
  if (temp>1) 
    temp=1.;
  return(-(PARAM(1) *(1.-r) *(1.-r)  +PARAM(3) *(1.-temp)*(1.-temp) ));
}

DBL f_blob2(DBL *ptr, unsigned int) // 7
{
  DBL r,x2,y2,z2;
  x2=PARAM_X*PARAM_X; y2=PARAM_Y*PARAM_Y; z2=PARAM_Z*PARAM_Z;
  /*  f= f1 + f2 */
  r=exp(-(x2+y2+z2)*PARAM(1)) + exp(-((PARAM_X-PARAM(0))*(PARAM_X-PARAM(0))+y2+z2)*PARAM(1));
  return(PARAM(3)-r*PARAM(2));
}

DBL f_boy_surface(DBL *ptr, unsigned int) // 8
{
  DBL r, r2,ph,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r2=1-PARAM_Z; ph=x2+y2;
  r= PARAM(1)*(64*r2*r2*r2*z2*PARAM_Z- 48*r2*r2*z2*(3*x2+3*y2+2*z2)+
  12*r2*PARAM_Z*(27*ph*ph-24*z2*ph+ 36*sqrt(2.0)*PARAM_Y*PARAM_Z*(y2-3*x2)+4*z2*z2)+
  (9*x2+9*y2-2*z2)*(-81*ph*ph-72*z2*ph+ 
  108*sqrt(2.0)*PARAM_X*PARAM_Z*(x2-3*y2)+4*z2*z2) );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_comma(DBL *ptr, unsigned int) // 9
{
  DBL r,th,temp;
  if ((PARAM_X==0)&&(PARAM_Z==0)) 
    PARAM_X=0.0001;
  th=atan2(PARAM_Z,PARAM_X);
  r=sqrt( (PARAM_X + PARAM(0)*0.25)*(PARAM_X + PARAM(0)*0.25) + PARAM_Z*PARAM_Z);
  temp= cos(th*0.5) * PARAM(0)*0.5 -sqrt((r- PARAM(0)*0.75)*(r - PARAM(0)*0.75)+PARAM_Y*PARAM_Y);
  temp= min(PARAM_Z, temp);
  r= PARAM(0)*0.5   - sqrt( (PARAM_X - PARAM(0)*0.5)*(PARAM_X - PARAM(0)*0.5) + PARAM_Z*PARAM_Z + PARAM_Y*PARAM_Y) ;
  return(-(DBL)max(temp,r));
}

DBL f_cross_ellipsoids(DBL *ptr, unsigned int) // 10
{
  DBL r,x2,y2,z2;
  x2=PARAM_X*PARAM_X; y2=PARAM_Y*PARAM_Y; z2=PARAM_Z*PARAM_Z;
  /*  f= max (f1, f2, f3) */
  r=max(exp(-(x2*PARAM(0)+y2*PARAM(0)+z2)*PARAM(1)), exp(-(x2*PARAM(0)+y2+z2*PARAM(0))*PARAM(1)));
  r=max(r, exp(-(x2+y2*PARAM(0)+z2*PARAM(0))*PARAM(1)));
  return(PARAM(3)-r*PARAM(2));
}

DBL f_crossed_trough(DBL *ptr, unsigned int) // 11
{
  DBL r;
  r=( PARAM_X*PARAM_X * PARAM_Z*PARAM_Z - PARAM_Y  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_cubic_saddle(DBL *ptr, unsigned int) // 12
{
  DBL r;
  r=-(PARAM_X*PARAM_X*PARAM_X - PARAM_Y*PARAM_Y*PARAM_Y - PARAM_Z);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_cushion(DBL *ptr, unsigned int) // 13
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r= (z2*x2 - z2*z2 - 2*PARAM_Z*x2 + 2*z2*PARAM_Z + x2 - z2
  -(x2 - PARAM_Z)*(x2 - PARAM_Z) - y2*y2 - 2*x2*y2 - y2*z2 + 2*y2*PARAM_Z + y2);       
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_devils_curve(DBL *ptr, unsigned int) // 14
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-(x2*x2 + 2*x2*z2 - 0.36*x2 - y2*y2 + 0.25*y2 + z2*z2);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_devils_curve_2d(DBL *ptr, unsigned int) // 15
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(3),PARAM(4),PARAM(5))
  r=-( x2 * (x2 - PARAM(1)*PARAM(1)) -  y2 * (y2 - PARAM(2)*PARAM(2)) );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_dupin_cyclid(DBL *ptr, unsigned int) // 16
{
  DBL r, r2,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z, ph,th, p1,p2,p3,p4;
  r2=PARAM(5)*PARAM(5);
  ph=PARAM(2)*PARAM(2); th=PARAM(4)*PARAM(4);
  p1= ph - th - (PARAM(3) + PARAM(1))*(PARAM(3) + PARAM(1));
  p2= ph - th - (PARAM(3) - PARAM(1))*(PARAM(3) - PARAM(1));
  p3= PARAM(3)*PARAM(3); p4=PARAM(1)*PARAM(1);
  r=-( p1*p2* (x2*x2+y2*y2+z2*z2)+ 2*(p1*p2* (x2*y2+x2*z2+y2*z2))+
  2*r2*((-th-p3 + ph+p4)* (2*PARAM_X*PARAM(3)+2*PARAM_Y*PARAM(4)-r2)-4*PARAM(4)*ph*PARAM_Y)*
  (x2+y2+z2)+ 4*r2*r2*(PARAM(3)*PARAM_X+PARAM(4)*PARAM_Y)
  *(-r2+PARAM(4)*PARAM_Y+PARAM(3)*PARAM_X)+ 4*r2*r2*p4*y2+ r2*r2*r2*r2);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_ellipsoid(DBL *ptr, unsigned int) // 17
{
  /*   sphere  */
  return(sqrt(PARAM_X*PARAM_X * PARAM(0)*PARAM(0) + PARAM_Y*PARAM_Y * PARAM(1)*PARAM(1) + PARAM_Z*PARAM_Z * PARAM(2)*PARAM(2)));  
}

DBL f_enneper(DBL *ptr, unsigned int) // 18
{
  DBL r, r2,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  if (fabs(PARAM_Z)<0.2) 
    PARAM_Z=0.2;
  r =((y2-x2)/(2*PARAM_Z)+2*z2/9+2/3);
  r2=((y2-x2)/(4*PARAM_Z)-(1/4)*(x2+y2+(8/9)*z2)+2/9);
  r=-( r*r*r -6*r2*r2) ;
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_flange_cover(DBL *ptr, unsigned int) // 19
{
  DBL r,x2,y2,z2;
  x2=PARAM_X*PARAM_X; y2=PARAM_Y*PARAM_Y; z2=PARAM_Z*PARAM_Z;
  /*  f= f1 + f2 + f3 */
  r=exp(-(x2*PARAM(0)+y2*PARAM(0)+z2)*PARAM(1)) + exp(-(x2*PARAM(0)+y2+z2*PARAM(0))*PARAM(1)) +
  exp(-(x2+y2*PARAM(0)+z2*PARAM(0))*PARAM(1));
  return(PARAM(3)-r*PARAM(2));
}

DBL f_folium_surface(DBL *ptr, unsigned int) // 20
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=((y2 + z2) * (1+(PARAM(2) - 4*PARAM(1))*PARAM_X)+x2*(1 + PARAM(2)));
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_folium_surface_2d(DBL *ptr, unsigned int) // 21
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z, th;
  ROT2D(PARAM(3),PARAM(4),PARAM(5))
  r = -( y2  * (1 + (PARAM(2) - 4*PARAM(1))*PARAM_X) + x2*(1 + PARAM(2)));
  return( min(10., max(PARAM(0)*r, -10.)) );
}

DBL f_glob(DBL *ptr, unsigned int) // 22
{
  DBL r, x2=PARAM_X*PARAM_X;
  r= ( 0.5*x2*x2*PARAM_X + 0.5*x2*x2 - (PARAM_Y*PARAM_Y + PARAM_Z*PARAM_Z)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_heart(DBL *ptr, unsigned int) // 23
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( (2*x2+y2+z2-1)*(2*x2+y2+z2-1)*(2*x2+y2+z2-1)-
  0.1*x2*z2*PARAM_Z-y2*z2*PARAM_Z  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_helical_torus(DBL *ptr, unsigned int) // 24
{
  DBL r,r2, temp,th,ph;
  r2=sqrt(PARAM_X*PARAM_X+PARAM_Z*PARAM_Z);
  if ((PARAM_X==0)&&(PARAM_Z==0)) 
    PARAM_X=0.000001;
  ph=atan2(PARAM_X,PARAM_Z);
  temp=atan2(r2 - PARAM(0), PARAM_Y);
  r=sqrt((r2-PARAM(0))*(r2-PARAM(0))+PARAM_Y*PARAM_Y);
  th=fmod(ph*PARAM(1)+temp*PARAM(2), TWO_M_PI);
  if (th<0) 
    th+=TWO_M_PI;
  temp=atan2((th-M_PI)*PARAM(8), r-PARAM(5));
  temp=cos(temp*PARAM(7)+ph*PARAM(9))*PARAM(3)+PARAM(4);
  r2=PARAM(4)+PARAM(5)-PARAM(0)-r2;
  th=th - M_PI;
  temp=temp-min(sqrt((r-PARAM(5))*(r-PARAM(5))+th*th*PARAM(6)), (r+PARAM(5)));
  return(-max(r2,temp));
}

DBL f_helix1(DBL *ptr, unsigned int) // 25
{
	DBL r, r2, temp, th, ph, x2;
	/* helix                                     *
	 *   p[0] : number of helix                  *
	 *   p[1] : frequency                        *
	 *   p[2] : minor radius                     *
	 *   p[3] : major radius                     *
	 *   p[4] : shape parameter                  *
	 *   p[5] : cross section                    *
	 *             p[5] = 1:  circle             *
	 *                  = 2:  diamond            *
	 *                  < 1:  rectangle(rounded) *
	 *   p[6] : rotation angle for p[5]<1        */

	r = sqrt(PARAM_X * PARAM_X + PARAM_Z * PARAM_Z);
	if ((PARAM_X == 0) && (PARAM_Z == 0))
		PARAM_X = 0.000001;
	th = atan2(PARAM_Z, PARAM_X);
	th = fmod(th * PARAM(0) + PARAM_Y * PARAM(1) * PARAM(0), TWO_M_PI);
	if (th < 0)
		th += TWO_M_PI;
	PARAM_Z = (th - M_PI) / PARAM(4) / (PARAM(1) * PARAM(0));

	PARAM_X = r - PARAM(3);
	if (PARAM(5) == 1)
		r2 = sqrt(PARAM_X * PARAM_X + PARAM_Z * PARAM_Z);
	else
	{
		if (PARAM(6) != 0)
		{
			th = cos(PARAM(6) * M_PI_180);
			ph = sin(PARAM(6) * M_PI_180);
			x2 = PARAM_X * th - PARAM_Z * ph;
			PARAM_Z = PARAM_X * ph + PARAM_Z * th;
			PARAM_X = x2;
		}
		if (PARAM(5) != 0)
		{
			temp = 2. / PARAM(5);
			r2 = pow((pow(fabs(PARAM_X), temp) + pow(fabs(PARAM_Z), temp)), PARAM(5) *.5);
		}
		else
			r2 = max(fabs(PARAM_X), fabs(PARAM_Z));
	}

	return (-PARAM(2) + min((PARAM(3) + r), r2));
}

DBL f_helix2(DBL *ptr, unsigned int) // 26
{
	DBL th, ph, x2, z2, r2, temp;
	/* helical shape  for (minor radius>major radius  *
	 *    cross section   p[5] same as NFUNCTION = 6      */
	th = PARAM_Y * PARAM(1);
	ph = cos(th);
	th = sin(th);
	x2 = PARAM_X - PARAM(3) * ph;
	z2 = PARAM_Z - PARAM(3) * th;
	PARAM_X = x2 * ph + z2 * th;
	PARAM_Z = (-x2 * th + z2 * ph);

	if (PARAM(5) == 1)
		return (sqrt(PARAM_X * PARAM_X + PARAM_Z * PARAM_Z) - PARAM(2));
	if (PARAM(5) != 0)
	{
		temp = 2. / PARAM(5);
		r2 = pow((pow(fabs(PARAM_X), temp) + pow(fabs(PARAM_Z), temp)), PARAM(5) *.5);
	}
	else
		r2 = max(fabs(PARAM_X), fabs(PARAM_Z));

	return (r2 - PARAM(2));
}

DBL f_hex_x(DBL *ptr, unsigned int) // 27
{
  DBL x1,y1,x2,y2, th;
  x1=fabs(fmod(fabs(PARAM_X), sqrt(3.0))-sqrt(3.0)/2);
  y1=fabs(fmod(fabs(PARAM_Y), 3)-1.5);
  x2=sqrt(3.0)/2-x1;
  y2=1.5-y1;
  if ((x1*x1+y1*y1)>(x2*x2+y2*y2)) 
  {
    x1=x2; 
    y1=y2;
  }
  if ((x1==0)&&(y1==0)) 
    PARAM_X=0.000001;
  th=atan2(y1,x1);
  if (th<M_PI/6) 
    return(x1);
  else
  {
    x1=cos(M_PI/3)*x1+sin(M_PI/3)*y1;
    return(x1);
  }
}

DBL f_hex_y(DBL *ptr, unsigned int) // 28
{
  DBL x1,y1,x2,y2, th;
  x1=fabs(fmod(fabs(PARAM_X), sqrt(3.0))-sqrt(3.0)/2);
  y1=fabs(fmod(fabs(PARAM_Y), 3)-1.5);
  x2=sqrt(3.0)/2-x1;
  y2=1.5-y1;
  if ((x1*x1+y1*y1)>(x2*x2+y2*y2)) 
  {
    x1=x2; 
    y1=y2;
  }
  if ((x1==0)&&(y1==0)) 
    PARAM_X=0.000001;
  th=atan2(y1,x1);
  if (th<M_PI/6) 
    return(y1);
  else
  {
    y1=-sin(M_PI/3)*x1+cos(M_PI/3)*y1;
    return(fabs(y1));
  }
}

DBL f_hetero_mf(DBL *ptr, unsigned int fn) // 29
{
  DBL signal;
  VECTOR V1;
  DBL rem;

  Make_Vector(V1, PARAM_X, PARAM_Y, PARAM_Z);

  TPATTERN TPat;
  TPat.Flags = (((int)PARAM(5)) & 3) << 4;

  signal = (Noise(V1, &TPat)*2.0 - 1.0) + PARAM(3);
  VScaleEq(V1, PARAM(1));

  DBL p1_2_mp0 = pow(PARAM(1), -PARAM(0)), ea = p1_2_mp0;
  for (int i = 1; i < PARAM(2); i++)
  {
     // make a noisy increment and scale it by f^(-H)
     DBL inc = ((Noise(V1,&TPat)*2.0 - 1.0) + PARAM(3)) * ea;

     // scale the increment by (the current signal)^PARAM(4) at V1
     //   so that PARAM(4)=0 gives 'straight' 1/f, PARAM(4)=1 
     // gives heterogenous fractal, etc
     for (int p = (int) PARAM(4); p > 0; --p)
        inc *= signal;

     signal += inc;
     // go to next 'octave'
     VScaleEq(V1, PARAM(1));
     ea *= p1_2_mp0;
  }

  rem = PARAM(2) - (int) PARAM(2);
  if(rem != 0.0)
  {
      // do something with fraction part of octave
      DBL inc = ((Noise(V1,&TPat)*2.0-1.0) + PARAM(3)) * ea;
      signal += rem * inc * signal;
  }

  return signal;
}

DBL f_hunt_surface(DBL *ptr, unsigned int) // 30
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( 4*(x2+y2+z2-13)*(x2+y2+z2-13)*(x2+y2+z2-13) + 
  27*(3*x2+y2-4*z2-12)*(3*x2+y2-4*z2-12)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_hyperbolic_torus(DBL *ptr, unsigned int) // 31
{
  DBL r, ph,th,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  ph=PARAM(1)*PARAM(1); th=PARAM(2)*PARAM(2);
  r=-( x2*x2 + 2*x2*y2 - 2*x2*z2 - 2*(ph+th)*x2 + y2*y2 -
  2*y2*z2 + 2*(ph-th)*y2 + z2*z2 + 2*(ph+th)*z2 + (ph-th)*(ph-th));
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_isect_ellipsoids(DBL *ptr, unsigned int) // 32
{
  DBL r,x2,y2,z2;
  x2=PARAM_X*PARAM_X; y2=PARAM_Y*PARAM_Y; z2=PARAM_Z*PARAM_Z;
  /* f= min (f1, f2, f3) */
  r=min(exp(-(x2*PARAM(0)+y2*PARAM(0)+z2)*PARAM(1)), exp(-(x2*PARAM(0)+y2+z2*PARAM(0))*PARAM(1)));
  r=min(r, exp(-(x2+y2*PARAM(0)+z2*PARAM(0))*PARAM(1)));
  return(PARAM(3)-r*PARAM(2));
}

DBL f_kampyle_of_eudoxus(DBL *ptr, unsigned int) // 33
{
  DBL r, x2=PARAM_X*PARAM_X;
  r=-( (PARAM_Y*PARAM_Y + PARAM_Z*PARAM_Z) - PARAM(2)*PARAM(2) * x2*x2 +  PARAM(2)*PARAM(2) * PARAM(1)*PARAM(1) * x2  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_kampyle_of_eudoxus_2d(DBL *ptr, unsigned int) // 34
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(3),PARAM(4),PARAM(5))
  r=-( y2  - PARAM(2)*PARAM(2) * x2*x2 +    PARAM(2)*PARAM(2) * PARAM(1)*PARAM(2) * x2  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_klein_bottle(DBL *ptr, unsigned int) // 35
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( (x2+y2+z2+2*PARAM_Y-1)*((x2+y2+z2-2*PARAM_Y-1)*(x2+y2+z2-2*PARAM_Y-1)-8*z2)+
  16*PARAM_X*PARAM_Z*(x2+y2+z2-2*PARAM_Y-1) );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_kummer_surface_v1(DBL *ptr, unsigned int) // 36
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( x2*x2+y2*y2+z2*z2-x2-y2-z2-x2*y2-x2*z2-y2*z2+1  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_kummer_surface_v2(DBL *ptr, unsigned int) // 37
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( x2*x2+y2*y2+z2*z2+PARAM(1)*(x2+y2+z2)+PARAM(2)*(x2*y2+x2*z2+y2*z2)+PARAM(3)*PARAM_X*PARAM_Y*PARAM_Z-1 );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_lemniscate_of_gerono(DBL *ptr, unsigned int) // 38
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-(  x2*x2 - x2 + y2 + z2  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_lemniscate_of_gerono_2d(DBL *ptr, unsigned int) // 39
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(3),PARAM(4),PARAM(5))
  r=-( y2 - PARAM(2)*PARAM(2) * PARAM(1)*PARAM(1) * x2 +   PARAM(2)*PARAM(2)*x2*x2  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_mesh1(DBL *ptr, unsigned int) // 40
{
	DBL th, ph, r, r2, temp;
	th = M_PI / PARAM(0);
	ph = M_PI / PARAM(1);
	r = fmod(PARAM_X, PARAM(0) * 2);
	if (r < 0)
		r += PARAM(0) * 2;
	r = fabs(r - PARAM(0)) * PARAM(2);
	r2 = (PARAM_Y - cos(PARAM_Z * ph) * PARAM(3)) * PARAM(4);
	temp = -sqrt(r2 * r2 + r * r);

	r = fmod(PARAM_X - PARAM(0), PARAM(0) * 2);
	if (r < 0)
		r += PARAM(0) * 2;
	r = fabs(r - PARAM(0)) * PARAM(2);
	r2 = (PARAM_Y + cos(PARAM_Z * ph) * PARAM(3)) * PARAM(4);
	temp = max(-sqrt(r2 * r2 + r * r), temp);

	r = fmod(PARAM_Z, PARAM(1) * 2);
	if (r < 0)
		r += PARAM(1) * 2;
	r = fabs(r - PARAM(1)) * PARAM(2);
	r2 = (PARAM_Y + cos(PARAM_X * th) * PARAM(3)) * PARAM(4);
	temp = max(-sqrt(r2 * r2 + r * r), temp);

	r = fmod(PARAM_Z - PARAM(1), PARAM(1) * 2);
	if (r < 0)
		r += PARAM(1) * 2;
	r = fabs(r - PARAM(1)) * PARAM(2);
	r2 = (PARAM_Y - cos(PARAM_X * th) * PARAM(3)) * PARAM(4);

	return (-max(-sqrt(r2 * r2 + r * r), temp));
}

DBL f_mitre(DBL *ptr, unsigned int) // 41
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( 4*x2*(x2 + y2 + z2) - y2*(1 - y2 - z2)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_nodal_cubic(DBL *ptr, unsigned int) // 42
{
  DBL r;
  r=-( PARAM_Y*PARAM_Y*PARAM_Y + PARAM_Z*PARAM_Z*PARAM_Z - 6*PARAM_Y*PARAM_Z );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_odd(DBL *ptr, unsigned int) // 43
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=( z2*x2 - z2*z2 - 2*PARAM_Z*x2 + 2*z2*PARAM_Z + x2 - z2 - 
  (x2 - PARAM_Z)*(x2 - PARAM_Z) - y2*y2 - 2*y2*x2 - y2*z2 + 2*y2*PARAM_Z + y2  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_ovals_of_cassini(DBL *ptr, unsigned int) // 44
{
  DBL r, r2,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r2 = (x2 + y2 + z2 + PARAM(1)*PARAM(1));
  r  = -(r2*r2 - PARAM(3)*PARAM(1)*PARAM(1)*(x2 + z2) - PARAM(2)*PARAM(2) );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_paraboloid(DBL *ptr, unsigned int) // 45
{
  DBL r;
  r=-( PARAM_X*PARAM_X - PARAM_Y + PARAM_Z*PARAM_Z);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_parabolic_torus(DBL *ptr, unsigned int) // 46
{
  DBL r, ph,th, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  ph=PARAM(1)*PARAM(1); th=PARAM(2)*PARAM(2);
  r=-(  x2*x2 + 2*x2*y2 - 2*x2*PARAM_Z - (ph+th)*x2 + y2*y2 - 2*y2*PARAM_Z +
  (ph-th)*y2 + z2 + (ph+th)*PARAM_Z +  (ph-th)* (ph-th)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_ph(DBL *ptr, unsigned int) // 47
{
  return( atan2(sqrt(PARAM_X*PARAM_X + PARAM_Z*PARAM_Z ),PARAM_Y) );  
}

DBL f_pillow(DBL *ptr, unsigned int) // 48
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=( x2*x2 + y2*y2 + z2*z2 - (x2 + y2 + z2)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_piriform(DBL *ptr, unsigned int) // 49
{
  DBL r, x2=PARAM_X*PARAM_X;
  r=-( (x2*x2 - x2*PARAM_X) + PARAM_Y*PARAM_Y + PARAM_Z*PARAM_Z  );
  return( -min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_piriform_2d(DBL *ptr, unsigned int) // 50
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y,th;
  ROT2D(PARAM(4),PARAM(5),PARAM(6))
  r=-( PARAM_Y*PARAM_Y - PARAM(1) * PARAM(3)* PARAM(3) * x2*PARAM_X -  PARAM(2) * PARAM(3)*PARAM(3) * x2*x2  );       
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_poly4(DBL *ptr, unsigned int) // 51
{
  /*  cylindrical shape   */
  DBL y2, temp;
  y2=PARAM_Y*PARAM_Y;
  temp=(PARAM(0)+PARAM(1)*PARAM_Y+PARAM(2)*y2 + PARAM(3)*y2*PARAM_Y +PARAM(4)*y2*y2);
  if (temp<-5.) 
    temp=-5.;
  return (-temp+sqrt(PARAM_X*PARAM_X+PARAM_Z*PARAM_Z));
}

DBL f_polytubes(DBL *ptr, unsigned int) // 52
{
  DBL x2,y2,z2,r,r2;
  int i;
  y2=PARAM_Y*PARAM_Y;
  r2=PARAM(1)+PARAM(2)*PARAM_Y+PARAM(3)*y2+PARAM(4)*y2*PARAM_Y+  PARAM(5)*y2*y2;
  r=-10000;
  for (i=0;i<(int)PARAM(0);i++)
  {
    x2 = PARAM_X - r2*sin(2*M_PI/PARAM(0)*i);
    z2 = PARAM_Z - r2*cos(2*M_PI/PARAM(0)*i);
    r= max(r,-sqrt( x2*x2 + z2*z2 ) );
  }
  return(-r);
}

DBL f_quantum(DBL *ptr, unsigned int) // 53
{
  DBL r, th,temp;
  /*  well known function in quantum mechanics */
  if ((PARAM_X==0)&&(PARAM_Z==0)) 
    PARAM_X=1e-6;
  r=sqrt(PARAM_X*PARAM_X+PARAM_Z*PARAM_Z);
  th=cos(atan2(r,PARAM_Y));
  r=sqrt(r*r+PARAM_Y*PARAM_Y)*2.;
  temp=r*r*exp(-r*0.33333333)*(3.*th*th-1);
  return (temp*temp-12.0)*(-0.1);
}

DBL f_quartic_paraboloid(DBL *ptr, unsigned int) // 54
{
  DBL r, x2=PARAM_X*PARAM_X, z2=PARAM_Z*PARAM_Z;
  r=-( x2*x2 + z2*z2 - PARAM_Y  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_quartic_saddle(DBL *ptr, unsigned int) // 55
{
  DBL r, x2=PARAM_X*PARAM_X, z2=PARAM_Z*PARAM_Z;
  r=-( x2*x2 - z2*z2 - PARAM_Y  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_quartic_cylinder(DBL *ptr, unsigned int) // 56
{
  DBL r, x2=PARAM_X*PARAM_X, z2=PARAM_Z*PARAM_Z;
  r=-( (x2 + z2) * PARAM_Y*PARAM_Y + PARAM(2)*PARAM(2) * (x2 + z2) - PARAM(2)*PARAM(2) * PARAM(1)*PARAM(1)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_r(DBL *ptr, unsigned int) // 57
{
  return( sqrt(PARAM_X*PARAM_X + PARAM_Y*PARAM_Y + PARAM_Z*PARAM_Z ) );  
}

DBL f_ridge(DBL *ptr, unsigned int) // 58
{
  VECTOR EPoint = { PARAM_X, PARAM_Y, PARAM_Z };
  int i;
  DBL Lambda, Omega, l, o;
  DBL value, v, resid, tot = 1.0, off, ridge, scale, rscale;
  VECTOR temp;
  int Octaves;
  TPATTERN TPat;
  int Tmp = PARAM(5);

  TPat.Flags = (Tmp & 3) << 4;

  Lambda = l = PARAM(0);
  Octaves = (int)PARAM(1);
  Omega = o = PARAM(2);
  off = PARAM(3);
  ridge = PARAM(4);

  rscale = 1.0 / max(ridge, 1.0 - ridge);
  scale = 1.0 / max(off, 1.0 - off);
  resid = PARAM(1) - (DBL)Octaves;

  v = fabs(Noise(EPoint,&TPat) - ridge) * rscale;
  value = (v - off);

  for (i = 2; i <= Octaves; i++)
  {
    VScale(temp,EPoint,l);
    v = fabs(Noise(temp,&TPat) - ridge) * rscale;
    value += o * (v - off);
    tot += o;
    l *= Lambda;
    o *= Omega;
  }
  if (0.0 != resid)
  {
    VScale(temp,EPoint,l);
    v = fabs(Noise(temp,&TPat) - ridge) * rscale;
    value += o * (v - off) * resid;
    tot += o * resid;
  }

  return (value * scale / tot);
}

DBL f_ridged_mf(DBL *ptr, unsigned int fn) // 59
{
  FunctionCode *f = POVFPU_GetFunction(fn);
  DBL *ea,freq,signal,weight,result;
  int i;
  VECTOR V1;
  TPATTERN TPat;
  int Tmp = PARAM(5);

  TPat.Flags = (Tmp & 3) << 4;

  V1[X]=PARAM_X;
  V1[Y]=PARAM_Y;
  V1[Z]=PARAM_Z;
  if (f->private_data == NULL) 
  {
    ea = (DBL*)POV_MALLOC((PARAM(2) + 1)*sizeof(DBL), "exponent array");
    freq = 1.0;
    for (i=0; i<=PARAM(2);i++)
    {
      ea[i]= pow(freq,-PARAM(0));
      freq *= PARAM(1);
    }
    f->private_data = (void *)ea;
  } 
  else 
  {
    ea = (DBL *)(f->private_data);
  }
  signal = Noise(V1,&TPat)*2.0-1.0;
  if (signal < 0.0 ) 
    signal = -signal;
  signal = PARAM(3) - signal;
  signal *= signal;
  result = signal;
  weight = 1.0;

  for (i=1; i<PARAM(2); i++) 
  {
    V1[X] *= PARAM(1);
    V1[Y] *= PARAM(1);
    V1[Z] *= PARAM(1);
    weight = signal * PARAM(4);
    if (weight > 1.0)
      weight = 1.0;
    if (weight < 0.0)
      weight = 0.0;
    signal = Noise(V1,&TPat)*2.0-1.0;
    if (signal < 0.0 )
      signal = -signal;
    signal = PARAM(3) - signal;
    signal *= signal;
    signal *= weight;
    result += signal * ea[i];
  }
  return (result);
}

DBL f_rounded_box(DBL *ptr, unsigned int) // 60
{
	DBL x2, y2, z2, x3, y3, z3;

	x2 = PARAM(1) - PARAM(0);
	y2 = PARAM(2) - PARAM(0);
	z2 = PARAM(3) - PARAM(0);
	x3 = (PARAM_X < x2) ? 0 : (PARAM_X - x2);
	y3 = (PARAM_Y < y2) ? 0 : (PARAM_Y - y2);
	z3 = (PARAM_Z < z2) ? 0 : (PARAM_Z - z2);
	x2 = PARAM(0) - PARAM(1);
	y2 = PARAM(0) - PARAM(2);
	z2 = PARAM(0) - PARAM(3);
	PARAM_X = (PARAM_X > x2) ? 0 : (x2 - PARAM_X);
	PARAM_Y = (PARAM_Y > y2) ? 0 : (y2 - PARAM_Y);
	PARAM_Z = (PARAM_Z > z2) ? 0 : (z2 - PARAM_Z);
	PARAM_X = max(PARAM_X, x3);
	PARAM_Y = max(PARAM_Y, y3);
	PARAM_Z = max(PARAM_Z, z3);

	return (-PARAM(0) + sqrt(PARAM_X * PARAM_X + PARAM_Y * PARAM_Y + PARAM_Z * PARAM_Z) - 1e-6);
}

DBL f_sphere(DBL *ptr, unsigned int) // 61
{
	return (-PARAM(0) + sqrt(PARAM_X * PARAM_X + PARAM_Y * PARAM_Y + PARAM_Z * PARAM_Z));
}

DBL f_spikes(DBL *ptr, unsigned int) // 62
{
  DBL r,x2,y2,z2;
  x2=PARAM_X*PARAM_X; y2=PARAM_Y*PARAM_Y; z2=PARAM_Z*PARAM_Z;
  r= exp(-(x2+y2+z2)*PARAM(3))*PARAM(4)          -exp(-(x2*PARAM(0)+y2*PARAM(0)+z2)*PARAM(1))
    -exp(-(x2*PARAM(0)+y2+z2*PARAM(0))*PARAM(1)) -exp(-(x2+y2*PARAM(0)+z2*PARAM(0))*PARAM(1));
  return(-r*PARAM(2));
}

DBL f_spikes_2d(DBL *ptr, unsigned int) // 63
{
  /*  2-D distribution */
  return(-( PARAM(0)* cos(PARAM(1)*PARAM_X) * cos(PARAM(2)*PARAM_Z) * exp(- PARAM(3)*(PARAM_X*PARAM_X+PARAM_Z*PARAM_Z)) -PARAM_Y));
}

DBL f_spiral(DBL *ptr, unsigned int) // 64
{
	DBL r, r2, th, temp;
	/* spiral shape                *
	 *                             */
	r = sqrt(PARAM_X * PARAM_X + PARAM_Z * PARAM_Z);
	if ((PARAM_X == 0) && (PARAM_Z == 0))
		PARAM_X = 0.000001;
	th = atan2(PARAM_Z, PARAM_X);
	r = r + PARAM(0) * th / TWO_M_PI;
	r2 = fmod(r, PARAM(0)) - PARAM(0) * 0.5;

	if (PARAM(5) == 1)
		r2 = sqrt(r2 * r2 + PARAM_Y * PARAM_Y);
	else if (PARAM(5) != 0)
	{
		temp = 2 / PARAM(5);
		r2 = pow((pow(fabs(r2), temp) + pow(fabs(PARAM_Y), temp)), 1. / temp);
	}
	else
		r2 = max(fabs(r2), fabs(PARAM_Y));

	r = sqrt(PARAM_X * PARAM_X + PARAM_Y * PARAM_Y + PARAM_Z * PARAM_Z);

	return (-min(PARAM(2) - r, PARAM(1) - min(r2, r)));
}

DBL f_steiners_roman(DBL *ptr, unsigned int) // 65
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( x2*y2 + x2*z2 + y2*z2 + PARAM_X*PARAM_Y*PARAM_Z  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_strophoid(DBL *ptr, unsigned int) // 66
{
  DBL r, r2,x2=PARAM_X*PARAM_X;
  r2=PARAM(3)*PARAM(3);
  r=-((PARAM(2) - PARAM_X)*(PARAM_Y*PARAM_Y + PARAM_Z*PARAM_Z) - r2*PARAM(1)*x2 - r2*x2*PARAM_X );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_strophoid_2d(DBL *ptr, unsigned int) // 67
{
  DBL r, r2,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(4),PARAM(5),PARAM(6))
  r2=PARAM(3)*PARAM(3);
  r=-( (PARAM(2) - PARAM_X)*y2  - r2*PARAM(1)*x2 -  r2*x2*PARAM_X  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_superellipsoid(DBL *ptr, unsigned int) // 68
{
	DBL p = 2 / PARAM(0), n = 1 / PARAM(1);

	return 1 - pow((pow((pow(fabs(PARAM_X), p) + pow(fabs(PARAM_Y), p)), PARAM(0) * n) + pow(fabs(PARAM_Z), 2 * n)), PARAM(1) *.5);
}

DBL f_th(DBL *ptr, unsigned int) // 69
{
  return( atan2(PARAM_X,PARAM_Z) );  
}

DBL f_torus(DBL *ptr, unsigned int) // 70
{
	PARAM_X = sqrt(PARAM_X * PARAM_X + PARAM_Z * PARAM_Z) - PARAM(0);

	return -PARAM(1) + sqrt(PARAM_X * PARAM_X + PARAM_Y * PARAM_Y);
}

DBL f_torus2(DBL *ptr, unsigned int) // 71
{
  DBL r, ph,th,x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  ph=PARAM(1)*PARAM(1); th=PARAM(2)*PARAM(2);
  r=-( x2*x2 + y2*y2 + z2*z2 + 2*x2*y2 + 2*x2*z2 + 2*y2*z2 -2* (ph + th)* x2 + 2* (ph - th)* y2 -2* (ph + th)* z2 + (ph - th)*(ph - th)  );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_torus_gumdrop(DBL *ptr, unsigned int) // 72
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, z2=PARAM_Z*PARAM_Z;
  r=-( 4*(x2*x2 + (y2 + z2)*(y2 + z2)) + 17 * x2 * (y2 + z2) - 20 * (x2 + y2 + z2) + 17);
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_umbrella(DBL *ptr, unsigned int) // 73
{
  DBL r;
  r=-( PARAM_X*PARAM_X - PARAM_Y*PARAM_Z*PARAM_Z );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_witch_of_agnesi(DBL *ptr, unsigned int) // 74
{
  DBL r;
  r=-( PARAM(1) * (PARAM_Y - 1) + (PARAM_X*PARAM_X + PARAM_Z*PARAM_Z) * PARAM_Y   );
  return( min(10., max(PARAM(0)*r,-10.)) );
}

DBL f_witch_of_agnesi_2d(DBL *ptr, unsigned int) // 75
{
  DBL r, x2=PARAM_X*PARAM_X, y2=PARAM_Y*PARAM_Y, th;
  ROT2D(PARAM(3),PARAM(4),PARAM(5))
  r=-( PARAM(1)*PARAM(1) * PARAM_Y + x2 * PARAM_Y - PARAM(2)  );
  return( min(10.0, max(PARAM(0)*r,-10.0)) );
}

DBL f_noise3d(DBL *ptr, unsigned int) // 76
{
	VECTOR Vec = { PARAM_X, PARAM_Y, PARAM_Z };
	return Noise(Vec, NULL);
}

DBL f_pattern(DBL *ptr, unsigned int fn) // 77
{
	VECTOR TPoint;
	VECTOR Vec = { PARAM_X, PARAM_Y, PARAM_Z };
	FunctionCode *f = POVFPU_GetFunction(fn);

	if(f->private_data == NULL)
		return 0.0;

	Warp_EPoint (TPoint, Vec, (TPATTERN *)(f->private_data));
	return Evaluate_TPat((TPATTERN *)(f->private_data), TPoint, NULL);
}

DBL f_noise_generator(DBL *ptr, unsigned int) // 78
{
	VECTOR Vec = { PARAM_X, PARAM_Y, PARAM_Z };
	TPATTERN TPat;
	int Tmp = PARAM(0);

	TPat.Flags = (Tmp & 3) << 4;

	return Noise(Vec, &TPat);
}

void f_pigment(DBL *ptr, unsigned int fn, unsigned int sp) // 0
{
	VECTOR Vec = { PARAM_N_X(5), PARAM_N_Y(5), PARAM_N_Z(5) };
	COLOUR Col;
	FunctionCode *f = POVFPU_GetFunction(fn);

	if(f->private_data == NULL)
	{
		POVFPU_SetLocal(sp + pRED, 0.0);
		POVFPU_SetLocal(sp + pGREEN, 0.0);
		POVFPU_SetLocal(sp + pBLUE, 0.0);
		POVFPU_SetLocal(sp + pFILTER, 0.0);
		POVFPU_SetLocal(sp + pTRANSM, 0.0);
		return;
	}

	Compute_Pigment(Col, (PIGMENT *)(f->private_data), Vec, NULL);

	POVFPU_SetLocal(sp + pRED, Col[pRED]);
	POVFPU_SetLocal(sp + pGREEN, Col[pGREEN]);
	POVFPU_SetLocal(sp + pBLUE, Col[pBLUE]);
	POVFPU_SetLocal(sp + pFILTER, Col[pFILTER]);
	POVFPU_SetLocal(sp + pTRANSM, Col[pTRANSM]);
}

void f_transform(DBL *ptr, unsigned int fn, unsigned int sp) // 1
{
	VECTOR Vec = { PARAM_N_X(3), PARAM_N_Y(3), PARAM_N_Z(3) };
	VECTOR Result;
	FunctionCode *f = POVFPU_GetFunction(fn);

	if(f->private_data == NULL)
	{
		POVFPU_SetLocal(sp + X, 0.0);
		POVFPU_SetLocal(sp + Y, 0.0);
		POVFPU_SetLocal(sp + Z, 0.0);
		return;
	}

	MTransPoint(Result, Vec, (TRANSFORM *)(f->private_data));

	POVFPU_SetLocal(sp + X, Result[X]);
	POVFPU_SetLocal(sp + Y, Result[Y]);
	POVFPU_SetLocal(sp + Z, Result[Z]);
}

void f_spline(DBL *ptr, unsigned int fn, unsigned int sp) // 2
{
	EXPRESS Result;
	FunctionCode *f = POVFPU_GetFunction(fn);
	int Terms;

	if(f->private_data == NULL)
	{
		POVFPU_SetLocal(sp + X, 0.0);
		POVFPU_SetLocal(sp + Y, 0.0);
		POVFPU_SetLocal(sp + Z, 0.0);
		return;
	}

	Terms = ((SPLINE *)(f->private_data))->Terms;

	Get_Spline_Val((SPLINE *)(f->private_data), PARAM_N_X(Terms), Result, &Terms);

	POVFPU_SetLocal(sp + X, Result[X]);
	POVFPU_SetLocal(sp + Y, Result[Y]);
	if(Terms > 2)
	{
		POVFPU_SetLocal(sp + Z, Result[Z]);
		if(Terms > 3)
		{
			POVFPU_SetLocal(sp + T, Result[T]);
			if(Terms > 4)
				POVFPU_SetLocal(sp + T + 1, Result[T + 1]);
		}
	}
}

END_POV_NAMESPACE
