bool_t pix_debug = FALSE;
        if (debug)
          { double dx = pR->c[0] - (ix_DEBUG + 0.5);
            double dy = pR->c[1] - (iy_DEBUG + 0.5);
            pix_debug = (fabs(dx) < 0.9999) && (fabs(dy) < 0.9999);
          }

        if (pix_debug)
          { fprintf(stderr, "    sampling point {pR} = ");
            r3_gen_print(stderr, pR, "%10.4f", "( ", " ", " )"); 
            fprintf(stderr, " ray direction {dR} = ");
            r3_gen_print(stderr, dR, "%+9.6f", "( ", " ", " )"); 
            fprintf(stderr, " hit point {pHit} = ");
            r3_gen_print(stderr, &pHit, "%10.4f", "( ", " ", " )\n"); 
          }
          
        if (verbose)
          { double dx = pR->c[0] - pR_debug.c[0];
            double dy = pR->c[1] - pR_debug.c[1];
            pix_debug = (fabs(dx) < 0.55) && (fabs(dy) < 0.55);
          }

/* ---------------------------------------------------------------------- */
/* report_ray, report_pixel */

            if (verbose_frame) 
              { multifok_raytrace_show_ray_data
                  ( stderr, 6, iPix, pixSize, 
                    iSmp, step, wSmp, pRay, dRay, wRay, pHit, hHit, vBlr, sNrm, NC, sVal
                  ); 
              }
 
        multifok_raytrace_show_pixel_data
          ( stderr, 4, iPix, pixSize, pCtr, zFoc, zDep,
            shrp, hAvg, hDev, sNrm, NC, sVal
          );