/* Last edited on 2023-02-22 20:44:25 by stolfi */

/* ---------------------------------------------------------------------- */

void irt_butterfly_from_ia_diff (IntervalDiff *fd, ia_butfly_t *ip);
  /* Computes a bounding butterfly {ip} from the ranges {fd->f} and {fd->df}
    of a function and its derivative. */

void irt_butterfly_from_ia_diff (IntervalDiff *fd, ia_butfly_t *ip)
  { ip->yxlo = ip->yxmd = ip->yxhi = fd->f;
    ip->xmd = 0.0;
    if (fd->df.lo > 0.0)
      { /* Function is strictly increasing */
        ROUND_UP;
        ip->yxlo.hi = ip->yxhi.hi - fd->df.lo;
        ROUND_DOWN;
        ip->yxhi.lo = ip->yxlo.lo + fd->df.lo;
      }
    else if (fd->df.hi < 0.0)
      { /* Function is strictly decreasing */
        ROUND_UP;
        ip->yxhi.hi = ip->yxlo.hi + fd->df.hi;
        ROUND_DOWN;
        ip->yxlo.lo = ip->yxhi.lo - fd->df.hi;
      }
    else
      { /* Function may be increasing or decreasing, can't say anything */ }
  }

/* ---------------------------------------------------------------------- */

typedef struct cmp_int_data_t {
    /* Parameters passed to irt_compute_intersection: */
    shape_t *sh;
    h3_point_t *org;
    h3_point_t *dst;
    Interval *hit;
    int *slo; int *shi;
    int print_ray;
  } cmp_int_data_t;


/* ---------------------------------------------------------------------- */
Interval zf_trapezoid_slice_yrange(Interval *xo, Interval *xi, Interval *yxlor, Interval *yxhir)
  { Float alo, ahi, blo, bhi;

    if (ip->lox.lo >= Zero)
      { ROUND_DOWN; alo = ((One - e)/Two)*ip->yxlo.lo;}
    else
      { ROUND_UP;   alo = -(((One - e)/Two)*(-ip->yxlo.lo)); }

    if (yxhi.lo >= Zero)
      { ROUND_DOWN; blo = ((One + e)/Two)*yxhi.lo;}
    else
      { ROUND_UP;   blo = -(((One + e)/Two)*(-yxhi.lo)); }

    if (ip->yxlo.hi >= Zero)
      { ROUND_UP;   ahi = ((One - e)/Two)*ip->yxlo.hi;}
    else
      { ROUND_DOWN; ahi = -(((One - e)/Two)*(-ip->yxlo.hi)); }

    if (yxhi.hi >= Zero)
      { ROUND_UP;   bhi = ((One + e)/Two)*yxhi.hi;}
    else
      { ROUND_DOWN; bhi = -(((One + e)/Two)*(-yxhi.hi)); }

    ROUND_DOWN; f_trp.lo = alo + blo;
    ROUND_UP;   f_trp.hi = ahi + bhi;
  }


/* ---------------------------------------------------------------------- */
    /* double xc = 4.25 * 72.0; */
    /* double hmin = xc - size / 2.0; */
    /* double hmax = xc + size / 2.0; */
    /* double yc = 6.50 *72.0; */
    /* double vmin = yc - size / 2.0; */
    /* double vmax = yc + size / 2.0; */

/* ---------------------------------------------------------------------- */

        else if (strcmp(t, "proc_name") == 0)
          { sc->shape.proc_name = irt_read_name(); }
        else if (strcmp(t, "print_ray") == 0)
          { sc->print_ray = irt_read_pixel_num(); }
        else if (strcmp(t, "plot_ray") == 0)
          { sc->plot_ray = irt_read_pixel_num(); }
        else if (strcmp(t, "image_width") == 0)
          { sc->view.image_width = irt_read_int32_t(); }
        else if (strcmp(t, "image_height") == 0)
          { sc->view.image_height = irt_read_int32_t(); }
        else if (strcmp(t, "pixel_size") == 0)

        if (strcmp(t, "arithmetic") == 0)
          { char *a = strtok(NULL, " ");
            if (strcmp(a, "IA") == 0) 
              { sc->arithmetic = arith_ia; }
            else if (strcmp(a, "IA/DIFF") == 0) 
              { sc->arithmetic = arith_ia_diff; }
            else if (strcmp(a, "AA") == 0)
              { sc->arithmetic = arith_aa; }
            else if (strcmp(a, "MIX") == 0)
              { sc->arithmetic = arith_mix; }
            else
              { fatalerror ("irt_read_parm_file: unknown arithmetic"); }
          }
        else

  char *proc_name;           /* Name of function that defines the scene's shape */

    char *scene_dir = o->scene_dir;
    char *scene_name = o->scene_name;
    
    o->scene_dir = argparser_get_next(pp);
    o->scene_name = argparser_get_next(pp);

     if (sc->shape.proc_name == NULL) 
      { fatalerror ("irt_read_parm_file: missing parameter proc_name"); }
    
char *irt_read_name(void);
  /* Parses an identifier. */
    
pixel_num_t irt_read_pixel_num(void);
  /* Parses a pair of pixel indices (row and col). */
 
char *irt_read_name(void)
  { return(txtcat(strtok(NULL," "), "")); }

pixel_num_t irt_read_pixel_num(void)
  { pixel_num_t p;
    p.col = irt_atoi(strtok(NULL, " "));
    p.row = irt_atoi(strtok(NULL, " "));
    return(p);
  }
        
/* ---------------------------------------------------------------------- */