/* Copyright (C) 1992-1998 The Geometry Center
 * Copyright (C) 1998-2000 Stuart Levy, Tamara Munzner, Mark Phillips
 *
 * This file is part of Geomview.
 * 
 * Geomview is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published
 * by the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 * 
 * Geomview is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with Geomview; see the file COPYING.  If not, write
 * to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA, or visit http://www.gnu.org.
 */
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include <math.h>
#include <stdio.h>

#define	MAXDIM	20	/* Max allowed dimension */


#ifndef COLORDEFS
typedef struct Color {
  float r,g,b;
} Color;
#endif

typedef struct _vertex			/* A single vertex */
{
  struct _vertex	*next;		/* Pointer to next vertex */

  float		*coord;			/* My coordinates for ND case. */

  Color		c;			/* Vertex color if any */
  int		clip;			/* Have I been clipped or not? */
  float		val;			/* Function value at this vertex */
  int		num;			/* Reference number of vertex in array */
} vertex;

typedef struct _vertex_list		/* Global list of shared vertices */
{
  int		numvtx;			/* Number of vertices */

/* private */
  vertex	*head;			/* pointer to head of list */
  vertex	*point;			/* pointer used while traversing list */

} vertex_list;

typedef struct _pvtx			/* vertex holder for vertex list */
					/* of each polygon */
{
  int		num;			/* reference number of vertex in array */
  struct _vertex *me;			/* Pointer to actual (shared) vertex. */
  struct _pvtx	*next;			/* Pointer to next pvtx in polyvtx_list */

} pvtx;

typedef struct _polyvtx_list		/* vertex list for each polygon */
{
  int numvtx;				/* number of vertices in polygon */

  pvtx		*head;			/* head of polygon vertex list */
  pvtx		*point;			/* pointer used while traversing list */
} polyvtx_list;

 
typedef struct _poly			/* A polygon */
{
  int		numvtx;			/* Number of vertices */
  int		clipped;		/* has the whole polygon been cut away? */
					/* 1 if it has been cut away, 0 if some */
					/* or all of the polygon remains */
  polyvtx_list	*me;			/* Vertex list of polygon */
  Color		c;			/* Color of this polygon if doing per */
					/* face coloring. */
  struct _poly	*next;			/* Next polygon in list of polys. */
} poly;

typedef struct _poly_list				/* List of polygons */
{
  int		numpoly;		/* number of polygons */

#define	HAS_VN	0x1
#define HAS_VC	0x4
#define	HAS_PC	0x8
  int		has;			/* bit mask of associated data */

  poly		*head;			/* head of list of polys */
  poly		*point;			/* pointer for traversing list */

} poly_list;

#define NEWLINE '\n'
#define SPACE	' '


typedef struct clip {
    poly_list polyhedron;
    vertex_list polyvertex;
    int side;	/* side to cut... 0 -- less than   1 -- greater than */
    int dim;	/* Are we working in N Dimensions. */
    float	surf[MAXDIM];	/* Surface parameters.
				/* For a plane, the plane normal vector */
				/* (or, other parameters for non-planar clip) */

    float	(*clipfunc)();	/* Clipping function, whose value is zero
				 * along the surface where we should clip.
				 */
    int		nonlinear;	/* Is clipfunc an affine function of position?*/
    float	level;		/* Value of clipfunc at clipping surface */

} Clip;

/*
 * Typical usage:
 *    Have a "Clip" variable;
 *    clip_init(&clip);
 *    setGeom(&clip, oogl-geometry-object);
 *    setSide(&clip, CLIP_xx);
 *    // Possibly change clip.clipfunc; clip_init sets planar clipping.
 *    setClipPlane(&clip, coeffs[], threshold);
 *    do_clip(&clip);
 *    g = getGeom(&clip);
 *    // Must call setGeom() before another do_clip; the internal data
 *    // structures can't handle successive clips against the same object.
 *    // Could simply setGeom(&clip, g) if that's intended.
 *    clip_destroy(&clip);
 */
void setClipPlane(Clip *, float coeffs[], float level);

enum clip_side { CLIP_LE, CLIP_GE };
void setSide(Clip *, int side);	/* 0->negative, 1->positive side */

void setGeom(Clip *, void *g);
void *getGeom(Clip *);
void clip_init(Clip *);
void clip_destroy(Clip *);
void do_clip(Clip *);