#ifndef WH_MODEL_H_aecb277c_
#define WH_MODEL_H_aecb277c_

#include <stdio.h>

/*
 * Model description uses these data types:
 *	UINT	An unsigned integer, a la "%u".
 *	FLOAT	A floating-point number, a la "%g".
 *	XYZ	Three whitespace-separated FLOATs: x, y, z.
 *	RGB	Three whitespace-separated FLOATs: r, g, b.
 *	STR	Text string.  This consists of all non-whitespace
 *		  characters or quoted characters up to the next
 *		  unquoted whitespace (", ', and \ quoting can be
 *		  used).
 *	CHAR	Single nonblank character
 *
 * A model consists of four sections.  The model begins with a format
 *  identifier, then one number per section, giving the number of
 *  entries in the sections:
 *
 *	STR	Format version ID, the string ModelV2
 *	UINT	Number of materials
 *	UINT	Number of locations
 *	UINT	Number of points
 *	UINT	Number of triangles
 *	UINT	Number of objects
 *
 * This is followed by the data for the sections.  Each section is a
 *  stream of the appropriate number of entries; each entry conforms to
 *  the description below.  References from one section to another are
 *  by number.
 *
 * Material definition:
 *	STR	Material name (cannot be zero-length)
 *	RGB	Self-luminosity colour of the material
 *	RGB	Diffuse reflective colour of the material
 *	FLOAT	Specularity exponent
 *	FLOAT	Specularity multiplier
 *
 * Location:
 *	XYZ	Location
 *
 * Point:
 *	UINT	Location number
 *	CHAR	Point type:
 *		's'	Smooth surface internal point, normal follows
 *		'c'	Corner/edge point, use triangle's normal
 *	If 's':
 *		XYZ	Surface normal vector
 *	If 'c':
 *		(nothing)
 *
 * Triangle:
 *	UINT	Material number
 *	UINT	Point number of corner 1
 *	UINT	Point number of corner 2
 *	UINT	Point number of corner 3
 *
 * Object:
 *	UINT	Number of triangles
 *	UINT...	That many triangle numbers
 *
 * The inx member of MATERIAL, LOCATION, POINT, TRIANGLE, and OBJECT is
 *  the number that must be passed to get_material, get_location, etc,
 *  to get that particular MATERIAL, LOCATION, etc.
 */

typedef struct xyz XYZ;
typedef struct rgb RGB;
typedef struct location LOCATION;
typedef struct material MATERIAL;
typedef struct point POINT;
typedef struct triangle TRIANGLE;
typedef struct model MODEL;
typedef struct object OBJECT;

struct xyz {
  double x;
  double y;
  double z;
  } ;

struct rgb {
  double r;
  double g;
  double b;
  } ;

struct location {
  int inx;
  XYZ l;
  } ;

struct material {
  int inx;
  char *name;
  RGB selflum;
  RGB reflect;
  double spec_exp;
  double spec_mul;
  } ;

struct point {
  int inx;
  int loc;
  unsigned char type;
#define PT_UNSET '\0'
#define PT_SURFACE 's'
#define PT_CORNER 'c'
  XYZ normal; /* valid only for PT_SURFACE, scratch for PT_CORNER */
  } ;

struct triangle {
  int inx;
  int material;
  int corner[3];
  } ;

/*
 * load_model arranges for triangles to point to at least ntriangles
 *  ints; save_model assumes it does so; free_model and del_object free
 *  it.  Various of the other calls make similar assumptions.  Provided
 *  client code ensures that triangles is freeable whenever free_model
 *  is called and whenever object is called for the OBJECT in question,
 *  and that triangles[0..ntriangles-1] is the correct list of triangle
 *  numbers for the object whenever it calls into any of the other
 *  entry points, it can do whatever it wants here.  In particular,
 *  client code may realloc it freely, or even free the provided vector
 *  and point it at a non-freeable array provided care is taken to
 *  reset it to something freeable (such as a nil pointer) before
 *  deleting the object or freeing the model.
 *
 * The library modifies the triangle numbers whenever it has occasion
 *  to renumber triangles, but otherwise does not follow the triangles
 *  pointer except as mentioned above.  Client code may even point
 *  triangles to unwriteable memory provided it never gives the library
 *  reason to renumber any of the listed triangles.
 */
struct object {
  int inx;
  int ntriangles;
  int *triangles;
  } ;

extern MODEL *load_model(FILE *, void (*)(const char *));
extern MODEL *new_model(void);
extern void save_model(MODEL *, FILE *);
extern void free_model(MODEL *);

extern int n_materials(MODEL *);
extern int n_locations(MODEL *);
extern int n_points(MODEL *);
extern int n_triangles(MODEL *);
extern int n_objects(MODEL *);
extern MATERIAL *get_material(MODEL *, int);
extern LOCATION *get_location(MODEL *, int);
extern POINT *get_point(MODEL *, int);
extern TRIANGLE *get_triangle(MODEL *, int);
extern OBJECT *get_object(MODEL *, int);
extern int new_material(MODEL *);
extern int new_location(MODEL *);
extern int new_point(MODEL *);
extern int new_triangle(MODEL *);
extern int new_object(MODEL *);
extern int del_material(MODEL *, int);
extern int del_location(MODEL *, int);
extern int del_point(MODEL *, int);
extern int del_triangle(MODEL *, int);
extern int del_object(MODEL *, int);

#endif