/* Reading OBJ files. */

#ifndef obj_H
#define obj_H

#include <stdint.h>
#include <stdio.h>

/* This module does NOT make common assumptions is that faces are
  3 or 4 in size or that all vertices are declared always before than the normals.
  
  The data is read as a stream, rather than loading it all in memory.
  
  TO DO: do not support materials, parameter space vertices (free form geometry), 
  smooth shading. */

typedef struct obj_vertex_t {
  float x, y, z, w;
} obj_vertex_t;

typedef struct obj_texture_coord_t {
  float u, v, w;
} obj_texture_coord_t;

typedef struct obj_normal_t{
  float x, y, z;
} obj_normal_t;

typedef enum obj_face_components_t {
  OBJ_HAS_ONLY_VERTEX = 0,
  OBJ_HAS_NORMAL  = 1,
  OBJ_HAS_TEXTURE = 2
} obj_face_components_t;

typedef struct obj_face_desc_t{
  size_t n_indices;
  obj_face_components_t components;
} obj_face_desc_t;

typedef struct obj_format_t{
  obj_vertex_t* vertices;
  obj_texture_coord_t* textures;
  obj_normal_t* normals;
  int* face_indices;
  obj_face_desc_t* face_descs;
} obj_format_t;

void obj_create(obj_format_t* obj);
  /* Allocates memory for {triangle_count} in a previous allocated struct* {obj}  */

void obj_destroy(obj_format_t const* obj);
  /* destroy the object {obj}. */

void obj_write(obj_format_t const* obj, FILE* out, int binary);
  /* Writed in the {out} file the obj file format described by {obj} with binary description if {binary} > 0. */

int obj_read(obj_format_t* obj, FILE* in);
  /* Read the {in} obj file and populates {obj}. If the file cannot be read or understand, the {obj->vertices}
    will be null after this functions returns. */

#endif