#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

GLubyte *grid_rgb_value(GLubyte *data, int width, int height, double xd, double yd);
GLfloat grid_value(GLubyte *data, int width, int height, double x, double y);

typedef struct {
  int w;
  int h;
  GLfloat data[];
} grid_t;


grid_t *sample_grid(GLubyte *data, int width, int height, int nx, int ny);

void grid_bounds_check(grid_t *, int x, int y);

#define GRID_VALUE(grid,x,y) \
  (grid_bounds_check(grid,x,y), (grid)->data[ ((grid)->w) * (y) + (x) ])


GLfloat *normal(GLfloat *a, GLfloat *b, GLfloat *c);


/* ********************************************************************** */

#include "queue.h"

struct face_t;
struct vertex_t;

typedef TAILQ_HEAD(facelist_t, face_t) facelist_t;
typedef TAILQ_HEAD(vertexlist_t, vertex_t) vertexlist_t;

typedef struct triangulation_t {
  facelist_t flist;
  vertexlist_t vlist;
} triangulation_t;

typedef struct vertex_t {
  GLfloat pt[3];
  facelist_t vfl;				/* faces */
  TAILQ_ENTRY(vertex_t) vlist_link;	/* list of vertices */
  GLfloat normal[3];
} vertex_t;

typedef struct face_t {
  vertex_t *vertices[3];
  TAILQ_ENTRY(face_t) vfl_link; /* faces of vertex */
  TAILQ_ENTRY(face_t) flist_link; /* list of faces */
  GLfloat normal[3];
} face_t;



triangulation_t *grid2triangulation(grid_t *grid);
void trFree(triangulation_t *);