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image.c

#ifndef lint
static const char RCSid[] = "$Id: image.c,v 2.33 2006/11/19 01:14:31 greg Exp $";
#endif
/*
 *  image.c - routines for image generation.
 *
 *  External symbols declared in view.h
 */

#include "copyright.h"

#include  <ctype.h>
#include  "rtio.h"
#include  "rtmath.h"
#include  "paths.h"
#include  "view.h"


#define  FEQ(x,y) (fabs((x)-(y)) <= FTINY)
#define  VEQ(v,w) (FEQ((v)[0],(w)[0]) && FEQ((v)[1],(w)[1]) \
                        && FEQ((v)[2],(w)[2]))

VIEW  stdview = STDVIEW;            /* default view parameters */

static gethfunc gethview;


char *
setview(v)        /* set hvec and vvec, return message on error */
register VIEW  *v;
{
      static char  ill_horiz[] = "illegal horizontal view size";
      static char  ill_vert[] = "illegal vertical view size";
      
      if (v->vaft < -FTINY || (v->vaft > FTINY && v->vaft <= v->vfore))
            return("illegal fore/aft clipping plane");

      if (v->vdist <= FTINY)
            return("illegal view distance");
      v->vdist *= normalize(v->vdir);           /* normalize direction */
      if (v->vdist == 0.0)
            return("zero view direction");

      if (normalize(v->vup) == 0.0)       /* normalize view up */
            return("zero view up vector");

      fcross(v->hvec, v->vdir, v->vup);   /* compute horiz dir */

      if (normalize(v->hvec) == 0.0)
            return("view up parallel to view direction");

      fcross(v->vvec, v->hvec, v->vdir);  /* compute vert dir */

      if (v->horiz <= FTINY)
            return(ill_horiz);
      if (v->vert <= FTINY)
            return(ill_vert);

      switch (v->type) {
      case VT_PAR:                        /* parallel view */
            v->hn2 = v->horiz;
            v->vn2 = v->vert;
            break;
      case VT_PER:                        /* perspective view */
            if (v->horiz >= 180.0-FTINY)
                  return(ill_horiz);
            if (v->vert >= 180.0-FTINY)
                  return(ill_vert);
            v->hn2 = 2.0 * tan(v->horiz*(PI/180.0/2.0));
            v->vn2 = 2.0 * tan(v->vert*(PI/180.0/2.0));
            break;
      case VT_CYL:                        /* cylindrical panorama */
            if (v->horiz > 360.0+FTINY)
                  return(ill_horiz);
            if (v->vert >= 180.0-FTINY)
                  return(ill_vert);
            v->hn2 = v->horiz * (PI/180.0);
            v->vn2 = 2.0 * tan(v->vert*(PI/180.0/2.0));
            break;
      case VT_ANG:                        /* angular fisheye */
            if (v->horiz > 360.0+FTINY)
                  return(ill_horiz);
            if (v->vert > 360.0+FTINY)
                  return(ill_vert);
            v->hn2 = v->horiz * (PI/180.0);
            v->vn2 = v->vert * (PI/180.0);
            break;
      case VT_HEM:                        /* hemispherical fisheye */
            if (v->horiz > 180.0+FTINY)
                  return(ill_horiz);
            if (v->vert > 180.0+FTINY)
                  return(ill_vert);
            v->hn2 = 2.0 * sin(v->horiz*(PI/180.0/2.0));
            v->vn2 = 2.0 * sin(v->vert*(PI/180.0/2.0));
            break;
      default:
            return("unknown view type");
      }
      if (v->type != VT_ANG) {
            if (v->type != VT_CYL) {
                  v->hvec[0] *= v->hn2;
                  v->hvec[1] *= v->hn2;
                  v->hvec[2] *= v->hn2;
            }
            v->vvec[0] *= v->vn2;
            v->vvec[1] *= v->vn2;
            v->vvec[2] *= v->vn2;
      }
      v->hn2 *= v->hn2;
      v->vn2 *= v->vn2;

      return(NULL);
}


void
normaspect(va, ap, xp, yp)          /* fix pixel aspect or resolution */
double  va;             /* view aspect ratio */
double  *ap;                  /* pixel aspect in (or out if 0) */
int  *xp, *yp;                /* x and y resolution in (or out if *ap!=0) */
{
      if (*ap <= FTINY)
            *ap = va * *xp / *yp;         /* compute pixel aspect */
      else if (va * *xp > *ap * *yp)
            *xp = *yp / va * *ap + .5;    /* reduce x resolution */
      else
            *yp = *xp * va / *ap + .5;    /* reduce y resolution */
}


double
viewray(orig, direc, v, x, y)       /* compute ray origin and direction */
FVECT  orig, direc;
register VIEW  *v;
double  x, y;
{
      double      d, z;
      
      x += v->hoff - 0.5;
      y += v->voff - 0.5;

      switch(v->type) {
      case VT_PAR:                  /* parallel view */
            orig[0] = v->vp[0] + v->vfore*v->vdir[0]
                        + x*v->hvec[0] + y*v->vvec[0];
            orig[1] = v->vp[1] + v->vfore*v->vdir[1]
                        + x*v->hvec[1] + y*v->vvec[1];
            orig[2] = v->vp[2] + v->vfore*v->vdir[2]
                        + x*v->hvec[2] + y*v->vvec[2];
            VCOPY(direc, v->vdir);
            return(v->vaft > FTINY ? v->vaft - v->vfore : 0.0);
      case VT_PER:                  /* perspective view */
            direc[0] = v->vdir[0] + x*v->hvec[0] + y*v->vvec[0];
            direc[1] = v->vdir[1] + x*v->hvec[1] + y*v->vvec[1];
            direc[2] = v->vdir[2] + x*v->hvec[2] + y*v->vvec[2];
            orig[0] = v->vp[0] + v->vfore*direc[0];
            orig[1] = v->vp[1] + v->vfore*direc[1];
            orig[2] = v->vp[2] + v->vfore*direc[2];
            d = normalize(direc);
            return(v->vaft > FTINY ? (v->vaft - v->vfore)*d : 0.0);
      case VT_HEM:                  /* hemispherical fisheye */
            z = 1.0 - x*x*v->hn2 - y*y*v->vn2;
            if (z < 0.0)
                  return(-1.0);
            z = sqrt(z);
            direc[0] = z*v->vdir[0] + x*v->hvec[0] + y*v->vvec[0];
            direc[1] = z*v->vdir[1] + x*v->hvec[1] + y*v->vvec[1];
            direc[2] = z*v->vdir[2] + x*v->hvec[2] + y*v->vvec[2];
            orig[0] = v->vp[0] + v->vfore*direc[0];
            orig[1] = v->vp[1] + v->vfore*direc[1];
            orig[2] = v->vp[2] + v->vfore*direc[2];
            return(v->vaft > FTINY ? v->vaft - v->vfore : 0.0);
      case VT_CYL:                  /* cylindrical panorama */
            d = x * v->horiz * (PI/180.0);
            z = cos(d);
            x = sin(d);
            direc[0] = z*v->vdir[0] + x*v->hvec[0] + y*v->vvec[0];
            direc[1] = z*v->vdir[1] + x*v->hvec[1] + y*v->vvec[1];
            direc[2] = z*v->vdir[2] + x*v->hvec[2] + y*v->vvec[2];
            orig[0] = v->vp[0] + v->vfore*direc[0];
            orig[1] = v->vp[1] + v->vfore*direc[1];
            orig[2] = v->vp[2] + v->vfore*direc[2];
            d = normalize(direc);
            return(v->vaft > FTINY ? (v->vaft - v->vfore)*d : 0.0);
      case VT_ANG:                  /* angular fisheye */
            x *= v->horiz/180.0;
            y *= v->vert/180.0;
            d = x*x + y*y;
            if (d > 1.0)
                  return(-1.0);
            d = sqrt(d);
            z = cos(PI*d);
            d = d <= FTINY ? PI : sqrt(1 - z*z)/d;
            x *= d;
            y *= d;
            direc[0] = z*v->vdir[0] + x*v->hvec[0] + y*v->vvec[0];
            direc[1] = z*v->vdir[1] + x*v->hvec[1] + y*v->vvec[1];
            direc[2] = z*v->vdir[2] + x*v->hvec[2] + y*v->vvec[2];
            orig[0] = v->vp[0] + v->vfore*direc[0];
            orig[1] = v->vp[1] + v->vfore*direc[1];
            orig[2] = v->vp[2] + v->vfore*direc[2];
            return(v->vaft > FTINY ? v->vaft - v->vfore : 0.0);
      }
      return(-1.0);
}


void
viewloc(ip, v, p)       /* find image location for point */
FVECT  ip;
register VIEW  *v;
FVECT  p;
{
      double  d, d2;
      FVECT  disp;

      disp[0] = p[0] - v->vp[0];
      disp[1] = p[1] - v->vp[1];
      disp[2] = p[2] - v->vp[2];

      switch (v->type) {
      case VT_PAR:                  /* parallel view */
            ip[2] = DOT(disp,v->vdir) - v->vfore;
            break;
      case VT_PER:                  /* perspective view */
            d = DOT(disp,v->vdir);
            ip[2] = VLEN(disp);
            if (d < 0.0) {          /* fold pyramid */
                  ip[2] = -ip[2];
                  d = -d;
            }
            if (d > FTINY) {
                  d = 1.0/d;
                  disp[0] *= d;
                  disp[1] *= d;
                  disp[2] *= d;
            }
            ip[2] *= (1.0 - v->vfore*d);
            break;
      case VT_HEM:                  /* hemispherical fisheye */
            d = normalize(disp);
            if (DOT(disp,v->vdir) < 0.0)
                  ip[2] = -d;
            else
                  ip[2] = d;
            ip[2] -= v->vfore;
            break;
      case VT_CYL:                  /* cylindrical panorama */
            d = DOT(disp,v->hvec);
            d2 = DOT(disp,v->vdir);
            ip[0] = 180.0/PI * atan2(d,d2) / v->horiz + 0.5 - v->hoff;
            d = 1.0/sqrt(d*d + d2*d2);
            ip[1] = DOT(disp,v->vvec)*d/v->vn2 + 0.5 - v->voff;
            ip[2] = VLEN(disp);
            ip[2] *= (1.0 - v->vfore*d);
            return;
      case VT_ANG:                  /* angular fisheye */
            ip[0] = 0.5 - v->hoff;
            ip[1] = 0.5 - v->voff;
            ip[2] = normalize(disp) - v->vfore;
            d = DOT(disp,v->vdir);
            if (d >= 1.0-FTINY)
                  return;
            if (d <= -(1.0-FTINY)) {
                  ip[0] += 180.0/v->horiz;
                  return;
            }
            d = acos(d)/PI / sqrt(1.0 - d*d);
            ip[0] += DOT(disp,v->hvec)*d*180.0/v->horiz;
            ip[1] += DOT(disp,v->vvec)*d*180.0/v->vert;
            return;
      }
      ip[0] = DOT(disp,v->hvec)/v->hn2 + 0.5 - v->hoff;
      ip[1] = DOT(disp,v->vvec)/v->vn2 + 0.5 - v->voff;
}


void
pix2loc(loc, rp, px, py)      /* compute image location from pixel pos. */
RREAL  loc[2];
register RESOLU  *rp;
int  px, py;
{
      register int  x, y;

      if (rp->rt & YMAJOR) {
            x = px;
            y = py;
      } else {
            x = py;
            y = px;
      }
      if (rp->rt & XDECR)
            x = rp->xr-1 - x;
      if (rp->rt & YDECR)
            y = rp->yr-1 - y;
      loc[0] = (x+.5)/rp->xr;
      loc[1] = (y+.5)/rp->yr;
}


void
loc2pix(pp, rp, lx, ly)       /* compute pixel pos. from image location */
int  pp[2];
register RESOLU  *rp;
double  lx, ly;
{
      register int  x, y;

      x = lx * rp->xr;
      y = ly * rp->yr;
      if (rp->rt & XDECR)
            x = rp->xr-1 - x;
      if (rp->rt & YDECR)
            y = rp->yr-1 - y;
      if (rp->rt & YMAJOR) {
            pp[0] = x;
            pp[1] = y;
      } else {
            pp[0] = y;
            pp[1] = x;
      }
}


int
getviewopt(v, ac, av)               /* process view argument */
register VIEW  *v;
int  ac;
register char  *av[];
{
#define check(c,l)      if ((av[0][c]&&av[0][c]!=' ') || \
                  badarg(ac-1,av+1,l)) return(-1)

      if (ac <= 0 || av[0][0] != '-' || av[0][1] != 'v')
            return(-1);
      switch (av[0][2]) {
      case 't':               /* type */
            if (!av[0][3] || av[0][3]==' ')
                  return(-1);
            check(4,"");
            v->type = av[0][3];
            return(0);
      case 'p':               /* point */
            check(3,"fff");
            v->vp[0] = atof(av[1]);
            v->vp[1] = atof(av[2]);
            v->vp[2] = atof(av[3]);
            return(3);
      case 'd':               /* direction */
            check(3,"fff");
            v->vdir[0] = atof(av[1]);
            v->vdir[1] = atof(av[2]);
            v->vdir[2] = atof(av[3]);
            v->vdist = 1.;
            return(3);
      case 'u':               /* up */
            check(3,"fff");
            v->vup[0] = atof(av[1]);
            v->vup[1] = atof(av[2]);
            v->vup[2] = atof(av[3]);
            return(3);
      case 'h':               /* horizontal size */
            check(3,"f");
            v->horiz = atof(av[1]);
            return(1);
      case 'v':               /* vertical size */
            check(3,"f");
            v->vert = atof(av[1]);
            return(1);
      case 'o':               /* fore clipping plane */
            check(3,"f");
            v->vfore = atof(av[1]);
            return(1);
      case 'a':               /* aft clipping plane */
            check(3,"f");
            v->vaft = atof(av[1]);
            return(1);
      case 's':               /* shift */
            check(3,"f");
            v->hoff = atof(av[1]);
            return(1);
      case 'l':               /* lift */
            check(3,"f");
            v->voff = atof(av[1]);
            return(1);
      default:
            return(-1);
      }
#undef check
}


int
sscanview(vp, s)              /* get view parameters from string */
VIEW  *vp;
register char  *s;
{
      int  ac;
      char  *av[4];
      int  na;
      int  nvopts = 0;

      while (isspace(*s))
            if (!*s++)
                  return(0);
      while (*s) {
            ac = 0;
            do {
                  if (ac || *s == '-')
                        av[ac++] = s;
                  while (*s && !isspace(*s))
                        s++;
                  while (isspace(*s))
                        s++;
            } while (*s && ac < 4);
            if ((na = getviewopt(vp, ac, av)) >= 0) {
                  if (na+1 < ac)
                        s = av[na+1];
                  nvopts++;
            } else if (ac > 1)
                  s = av[1];
      }
      return(nvopts);
}


void
fprintview(vp, fp)                  /* write out view parameters */
register VIEW  *vp;
FILE  *fp;
{
      fprintf(fp, " -vt%c", vp->type);
      fprintf(fp, " -vp %.6g %.6g %.6g", vp->vp[0], vp->vp[1], vp->vp[2]);
      fprintf(fp, " -vd %.6g %.6g %.6g", vp->vdir[0]*vp->vdist,
                                    vp->vdir[1]*vp->vdist,
                                    vp->vdir[2]*vp->vdist);
      fprintf(fp, " -vu %.6g %.6g %.6g", vp->vup[0], vp->vup[1], vp->vup[2]);
      fprintf(fp, " -vh %.6g -vv %.6g", vp->horiz, vp->vert);
      fprintf(fp, " -vo %.6g -va %.6g", vp->vfore, vp->vaft);
      fprintf(fp, " -vs %.6g -vl %.6g", vp->hoff, vp->voff);
}


char *
viewopt(vp)                   /* translate to minimal view string */
register VIEW  *vp;
{
      static char  vwstr[128];
      register char  *cp = vwstr;

      *cp = '\0';
      if (vp->type != stdview.type) {
            sprintf(cp, " -vt%c", vp->type);
            cp += strlen(cp);
      }
      if (!VEQ(vp->vp,stdview.vp)) {
            sprintf(cp, " -vp %.6g %.6g %.6g",
                        vp->vp[0], vp->vp[1], vp->vp[2]);
            cp += strlen(cp);
      }
      if (!FEQ(vp->vdist,stdview.vdist) || !VEQ(vp->vdir,stdview.vdir)) {
            sprintf(cp, " -vd %.6g %.6g %.6g",
                        vp->vdir[0]*vp->vdist,
                        vp->vdir[1]*vp->vdist,
                        vp->vdir[2]*vp->vdist);
            cp += strlen(cp);
      }
      if (!VEQ(vp->vup,stdview.vup)) {
            sprintf(cp, " -vu %.6g %.6g %.6g",
                        vp->vup[0], vp->vup[1], vp->vup[2]);
            cp += strlen(cp);
      }
      if (!FEQ(vp->horiz,stdview.horiz)) {
            sprintf(cp, " -vh %.6g", vp->horiz);
            cp += strlen(cp);
      }
      if (!FEQ(vp->vert,stdview.vert)) {
            sprintf(cp, " -vv %.6g", vp->vert);
            cp += strlen(cp);
      }
      if (!FEQ(vp->vfore,stdview.vfore)) {
            sprintf(cp, " -vo %.6g", vp->vfore);
            cp += strlen(cp);
      }
      if (!FEQ(vp->vaft,stdview.vaft)) {
            sprintf(cp, " -va %.6g", vp->vaft);
            cp += strlen(cp);
      }
      if (!FEQ(vp->hoff,stdview.hoff)) {
            sprintf(cp, " -vs %.6g", vp->hoff);
            cp += strlen(cp);
      }
      if (!FEQ(vp->voff,stdview.voff)) {
            sprintf(cp, " -vl %.6g", vp->voff);
            cp += strlen(cp);
      }
      return(vwstr);
}


int
isview(s)                     /* is this a view string? */
char  *s;
{
      static char  *altname[]={NULL,VIEWSTR,"rpict","rview","rvu","rpiece","pinterp",NULL};
      extern char  *progname;
      register char  *cp;
      register char  **an;
                              /* add program name to list */
      if (altname[0] == NULL) {
            for (cp = progname; *cp; cp++)
                  ;
            while (cp > progname && !ISDIRSEP(cp[-1]))
                  cp--;
            altname[0] = cp;
      }
                              /* skip leading path */
      cp = s;
      while (*cp && *cp != ' ')
            cp++;
      while (cp > s && !ISDIRSEP(cp[-1]))
            cp--;
      for (an = altname; *an != NULL; an++)
            if (!strncmp(*an, cp, strlen(*an)))
                  return(1);
      return(0);
}


struct myview {
      VIEW  *hv;
      int   ok;
};


static int
gethview(                     /* get view from header */
      char  *s,
      void  *v
)
{
      if (isview(s) && sscanview(((struct myview*)v)->hv, s) > 0)
            ((struct myview*)v)->ok++;
      return(0);
}


int
viewfile(fname, vp, rp)             /* get view from file */
char  *fname;
VIEW  *vp;
RESOLU  *rp;
{
      struct myview     mvs;
      FILE  *fp;

      if (fname == NULL || !strcmp(fname, "-"))
            fp = stdin;
      else if ((fp = fopen(fname, "r")) == NULL)
            return(-1);

      mvs.hv = vp;
      mvs.ok = 0;

      getheader(fp, gethview, &mvs);

      if (rp != NULL && !fgetsresolu(rp, fp))
            mvs.ok = 0;

      fclose(fp);

      return(mvs.ok);
}

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