static void
circle( /* indicate a solid angle on image */
FVECT dir,
double dom
)
{
FVECT start, cur;
XPoint pt[NSEG+1];
FVECT pp;
int ip[2];
register int i;
fcross(cur, dir, ourview.vup);
if (normalize(cur) == 0.0)
goto fail;
spinvector(start, dir, cur, acos(1.-dom/(2.*PI)));
for (i = 0; i <= NSEG; i++) {
spinvector(cur, start, dir, 2.*PI*i/NSEG);
cur[0] += ourview.vp[0];
cur[1] += ourview.vp[1];
cur[2] += ourview.vp[2];
viewloc(pp, &ourview, cur);
if (pp[2] <= 0.0)
goto fail;
loc2pix(ip, &pres, pp[0], pp[1]);
pt[i].x = ip[0];
pt[i].y = ip[1];
}
XDrawLines(theDisplay, gwind, vecGC, pt, NSEG+1, CoordModeOrigin);
return;
fail:
fprintf(stderr, "%s: cannot draw source at (%f,%f,%f)\n",
progname, dir[0], dir[1], dir[2]);
}
static int
strtoipt( /* convert string x y z to image point */
int ipt[2],
char *str
)
{
FVECT im_pt, pt;
if (!sscanvec(str, pt))
return(-1);
if (DOT(pt,pt) <= FTINY) /* origin is really infinity */
ipt[0] = ipt[1] = -1; /* null vector */
else {
viewloc(im_pt, &ourview, pt);
loc2pix(ipt, &ourres, im_pt[0], im_pt[1]);
}
return(0);
}
static void
value( /* print value on image */
FVECT dir,
double v
)
{
FVECT pos;
FVECT pp;
int ip[2];
char buf[32];
pos[0] = ourview.vp[0] + dir[0];
pos[1] = ourview.vp[1] + dir[1];
pos[2] = ourview.vp[2] + dir[2];
viewloc(pp, &ourview, pos);
if (pp[2] <= 0.0)
return;
loc2pix(ip, &pres, pp[0], pp[1]);
sprintf(buf, "%.0f", v);
XDrawImageString(theDisplay, gwind, strGC,
ip[0], ip[1], buf, strlen(buf));
}
static int
sourcepoly( /* compute image polygon for source */
int sn,
RREAL sp[MAXVERT][2]
)
{
static short cubeord[8][6] = {{1,3,2,6,4,5},{0,4,5,7,3,2},
{0,1,3,7,6,4},{0,1,5,7,6,2},
{0,2,6,7,5,1},{0,4,6,7,3,1},
{0,2,3,7,5,4},{1,5,4,6,2,3}};
register SRCREC *s = source + sn;
FVECT ap, ip;
RREAL pt[6][2];
int dir;
register int i, j;
if (s->sflags & (SDISTANT|SFLAT)) {
if (s->sflags & SDISTANT) {
if (ourview.type == VT_PAR)
return(0); /* all or nothing case */
if (s->srad >= 0.05)
return(0); /* should never be a problem */
}
if (s->sflags & SFLAT) {
for (i = 0; i < 3; i++)
ap[i] = s->sloc[i] - ourview.vp[i];
if (DOT(ap, s->snorm) >= 0.)
return(0); /* source faces away */
}
for (j = 0; j < 4; j++) { /* four corners */
for (i = 0; i < 3; i++) {
ap[i] = s->sloc[i];
if ((j==1)|(j==2)) ap[i] += s->ss[SU][i];
else ap[i] -= s->ss[SU][i];
if ((j==2)|(j==3)) ap[i] += s->ss[SV][i];
else ap[i] -= s->ss[SV][i];
if (s->sflags & SDISTANT) {
ap[i] *= 1. + ourview.vfore;
ap[i] += ourview.vp[i];
}
}
viewloc(ip, &ourview, ap); /* find image point */
if (ip[2] <= 0.)
return(0); /* in front of view */
sp[j][0] = ip[0]; sp[j][1] = ip[1];
}
return(4);
}
/* identify furthest corner */
for (i = 0; i < 3; i++)
ap[i] = s->sloc[i] - ourview.vp[i];
dir = (DOT(ap,s->ss[SU])>0.) |
(DOT(ap,s->ss[SV])>0.)<<1 |
(DOT(ap,s->ss[SW])>0.)<<2 ;
/* order vertices based on this */
for (j = 0; j < 6; j++) {
for (i = 0; i < 3; i++) {
ap[i] = s->sloc[i];
if (cubeord[dir][j] & 1) ap[i] += s->ss[SU][i];
else ap[i] -= s->ss[SU][i];
if (cubeord[dir][j] & 2) ap[i] += s->ss[SV][i];
else ap[i] -= s->ss[SV][i];
if (cubeord[dir][j] & 4) ap[i] += s->ss[SW][i];
else ap[i] -= s->ss[SW][i];
}
viewloc(ip, &ourview, ap); /* find image point */
if (ip[2] <= 0.)
return(0); /* in front of view */
pt[j][0] = ip[0]; pt[j][1] = ip[1];
}
return(convex_hull(pt, 6, sp)); /* make sure it's convex */
}
