--- ray/src/px/pinterp.c	1993/04/01 11:21:18	2.10
+++ ray/src/px/pinterp.c	1994/12/23 17:23:05	2.17
@@ -1,4 +1,4 @@
-/* Copyright (c) 1993 Regents of the University of California */
+/* Copyright (c) 1994 Regents of the University of California */
 
 #ifndef lint
 static char SCCSid[] = "$SunId$ LBL";
@@ -34,6 +34,11 @@ static char SCCSid[] = "$SunId$ LBL";
 
 struct position {int x,y; float z;};
 
+#define NSTEPS		64		/* number steps in overlap prescan */
+#define MINSTEP		4		/* minimum worthwhile preview step */
+
+struct bound {int min,max;};
+
 VIEW	ourview = STDVIEW;		/* desired view */
 int	hresolu = 512;			/* horizontal resolution */
 int	vresolu = 512;			/* vertical resolution */
@@ -186,7 +191,7 @@ char	*argv[];
 	if (fillsamp == 1)
 		fillo &= ~F_BACK;
 						/* set view */
-	if (err = setview(&ourview)) {
+	if ((err = setview(&ourview)) != NULL) {
 		fprintf(stderr, "%s: %s\n", progname, err);
 		exit(1);
 	}
@@ -197,6 +202,8 @@ char	*argv[];
 	if (ourpict == NULL || ourzbuf == NULL)
 		syserror(progname);
 	bzero((char *)ourzbuf, hresolu*vresolu*sizeof(float));
+							/* new header */
+	newheader("RADIANCE", stdout);
 							/* get input */
 	for ( ; i < argc; i += 2)
 		addpicture(argv[i], argv[i+1]);
@@ -207,6 +214,8 @@ char	*argv[];
 		fillpicture(fillfunc);
 							/* close calculation */
 	caldone();
+							/* aft clipping */
+	clipaft();
 							/* add to header */
 	printargs(argc, argv, stdout);
 	if (gotvfile) {
@@ -241,8 +250,9 @@ char	*s;
 {
 	char	fmt[32];
 
-	if (isformat(s)) {
-		formatval(fmt, s);
+	if (isheadid(s))
+		return;
+	if (formatval(fmt, s)) {
 		wrongformat = strcmp(fmt, COLRFMT);
 		return;
 	}
@@ -267,6 +277,7 @@ char	*pfile, *zspec;
 	COLR	*scanin;
 	float	*zin;
 	struct position	*plast;
+	struct bound	*xlim, ylim;
 	int	y;
 					/* open picture file */
 	if ((pfp = fopen(pfile, "r")) == NULL)
@@ -290,38 +301,59 @@ char	*pfile, *zspec;
 	}
 					/* compute transformation */
 	hasmatrix = pixform(theirs2ours, &theirview, &ourview);
-					/* allocate scanlines */
-	scanin = (COLR *)malloc(scanlen(&tresolu)*sizeof(COLR));
+					/* get z specification or file */
 	zin = (float *)malloc(scanlen(&tresolu)*sizeof(float));
-	plast = (struct position *)calloc(scanlen(&tresolu),
-			sizeof(struct position));
-	if (scanin == NULL || zin == NULL || plast == NULL)
+	if (zin == NULL)
 		syserror(progname);
-					/* get z specification or file */
 	if ((zfd = open(zspec, O_RDONLY)) == -1) {
 		double	zvalue;
 		register int	x;
 		if (!isfloat(zspec) || (zvalue = atof(zspec)) <= 0.0)
 			syserror(zspec);
-			exit(1);
 		for (x = scanlen(&tresolu); x-- > 0; )
 			zin[x] = zvalue;
 	}
-					/* load image */
-	for (y = 0; y < numscans(&tresolu); y++) {
+					/* compute transferrable perimeter */
+	xlim = (struct bound *)malloc(numscans(&tresolu)*sizeof(struct bound));
+	if (xlim == NULL)
+		syserror(progname);
+	if (!getperim(xlim, &ylim, zin, zfd)) {	/* overlapping area? */
+		free((char *)zin);
+		free((char *)xlim);
+		if (zfd != -1)
+			close(zfd);
+		fclose(pfp);
+		return;
+	}
+					/* allocate scanlines */
+	scanin = (COLR *)malloc(scanlen(&tresolu)*sizeof(COLR));
+	plast = (struct position *)calloc(scanlen(&tresolu),
+			sizeof(struct position));
+	if (scanin == NULL | plast == NULL)
+		syserror(progname);
+					/* skip to starting point */
+	for (y = 0; y < ylim.min; y++)
 		if (freadcolrs(scanin, scanlen(&tresolu), pfp) < 0) {
 			fprintf(stderr, "%s: read error\n", pfile);
 			exit(1);
 		}
-		if (zfd != -1 && read(zfd,(char *)zin,
-				scanlen(&tresolu)*sizeof(float))
-				< scanlen(&tresolu)*sizeof(float)) {
-			fprintf(stderr, "%s: read error\n", zspec);
+	if (zfd != -1 && lseek(zfd,
+			(long)ylim.min*scanlen(&tresolu)*sizeof(float), 0) < 0)
+		syserror(zspec);
+					/* load image */
+	for (y = ylim.min; y <= ylim.max; y++) {
+		if (freadcolrs(scanin, scanlen(&tresolu), pfp) < 0) {
+			fprintf(stderr, "%s: read error\n", pfile);
 			exit(1);
 		}
-		addscanline(y, scanin, zin, plast);
+		if (zfd != -1 && read(zfd, (char *)zin,
+				scanlen(&tresolu)*sizeof(float))
+				< scanlen(&tresolu)*sizeof(float))
+			syserror(zspec);
+		addscanline(xlim+y, y, scanin, zin, plast);
 	}
 					/* clean up */
+	free((char *)xlim);
 	free((char *)scanin);
 	free((char *)zin);
 	free((char *)plast);
@@ -372,7 +404,8 @@ register VIEW	*vw1, *vw2;
 }
 
 
-addscanline(y, pline, zline, lasty)	/* add scanline to output */
+addscanline(xl, y, pline, zline, lasty)	/* add scanline to output */
+struct bound	*xl;
 int	y;
 COLR	*pline;
 float	*zline;
@@ -383,7 +416,7 @@ struct position	*lasty;		/* input/output */
 	register int	x;
 
 	lastx.z = 0;
-	for (x = scanlen(&tresolu); x-- > 0; ) {
+	for (x = xl->max; x >= xl->min; x--) {
 		pix2loc(pos, &tresolu, x, y);
 		pos[2] = zline[x];
 		if (movepixel(pos) < 0) {
@@ -463,21 +496,107 @@ double	z;
 }
 
 
+getperim(xl, yl, zline, zfd)		/* compute overlapping image area */
+register struct bound	*xl;
+struct bound	*yl;
+float	*zline;
+int	zfd;
+{
+	int	step;
+	FVECT	pos;
+	register int	x, y;
+						/* set up step size */
+	if (scanlen(&tresolu) < numscans(&tresolu))
+		step = scanlen(&tresolu)/NSTEPS;
+	else
+		step = numscans(&tresolu)/NSTEPS;
+	if (step < MINSTEP) {			/* not worth cropping? */
+		yl->min = 0;
+		yl->max = numscans(&tresolu) - 1;
+		x = scanlen(&tresolu) - 1;
+		for (y = numscans(&tresolu); y--; ) {
+			xl[y].min = 0;
+			xl[y].max = x;
+		}
+		return(1);
+	}
+	yl->min = 32000; yl->max = 0;		/* search for points on image */
+	for (y = step - 1; y < numscans(&tresolu); y += step) {
+		if (zfd != -1) {
+			if (lseek(zfd, (long)y*scanlen(&tresolu)*sizeof(float),
+					0) < 0)
+				syserror("lseek");
+			if (read(zfd, (char *)zline,
+					scanlen(&tresolu)*sizeof(float))
+					< scanlen(&tresolu)*sizeof(float))
+				syserror("read");
+		}
+		xl[y].min = 32000; xl[y].max = 0;		/* x max */
+		for (x = scanlen(&tresolu); (x -= step) > 0; ) {
+			pix2loc(pos, &tresolu, x, y);
+			pos[2] = zline[x];
+			if (movepixel(pos) == 0 && pos[0] >= 0 &&
+					pos[0] < 1 && pos[1] >= 0 &&
+					pos[1] < 1) {
+				xl[y].max = x + step - 1;
+				xl[y].min = x - step + 1;	/* x min */
+				if (xl[y].min < 0)
+					xl[y].min = 0;
+				for (x = step - 1; x < xl[y].max; x += step) {
+					pix2loc(pos, &tresolu, x, y);
+					pos[2] = zline[x];
+					if (movepixel(pos) == 0 &&
+							pos[0] >= 0 &&
+							pos[0] < 1 &&
+							pos[1] >= 0 &&
+							pos[1] < 1) {
+						xl[y].min = x - step + 1;
+						break;
+					}
+				}
+				if (y < yl->min)		/* y limits */
+					yl->min = y - step + 1;
+				yl->max = y + step - 1;
+				break;
+			}
+		}
+							/* fill in between */
+		if (xl[y].min < xl[y-step].min)
+			xl[y-1].min = xl[y].min;
+		else
+			xl[y-1].min = xl[y-step].min;
+		if (xl[y].max > xl[y-step].max)
+			xl[y-1].max = xl[y].max;
+		else
+			xl[y-1].max = xl[y-step].max;
+		for (x = 2; x < step; x++)
+			copystruct(xl+y-x, xl+y-1);
+	}
+	if (yl->max >= numscans(&tresolu))
+		yl->max = numscans(&tresolu) - 1;
+	for (x = numscans(&tresolu) - 1; x > y; x--)	/* fill bottom rows */
+		copystruct(xl+x, xl+y);
+	return(yl->max >= yl->min);
+}
+
+
 movepixel(pos)				/* reposition image point */
 FVECT	pos;
 {
+	double	d0, d1;
 	FVECT	pt, direc;
 	
 	if (pos[2] <= 0)		/* empty pixel */
 		return(-1);
+	if (normdist && theirview.type == VT_PER) {	/* adjust distance */
+		d0 = pos[0] + theirview.hoff - .5;
+		d1 = pos[1] + theirview.voff - .5;
+		pos[2] /= sqrt(1. + d0*d0*theirview.hn2 + d1*d1*theirview.vn2);
+	}
 	if (hasmatrix) {
 		pos[0] += theirview.hoff - .5;
 		pos[1] += theirview.voff - .5;
 		if (theirview.type == VT_PER) {
-			if (normdist)	/* adjust for eye-ray distance */
-				pos[2] /= sqrt( 1.
-					+ pos[0]*pos[0]*theirview.hn2
-					+ pos[1]*pos[1]*theirview.vn2 );
 			pos[0] *= pos[2];
 			pos[1] *= pos[2];
 		}
@@ -492,7 +611,7 @@ FVECT	pos;
 		pos[1] += .5 - ourview.voff;
 		return(0);
 	}
-	if (viewray(pt, direc, &theirview, pos[0], pos[1]) < 0)
+	if (viewray(pt, direc, &theirview, pos[0], pos[1]) < -FTINY)
 		return(-1);
 	pt[0] += direc[0]*pos[2];
 	pt[1] += direc[1]*pos[2];
@@ -611,6 +730,37 @@ int	(*fill)();
 }
 
 
+clipaft()			/* perform aft clipping as indicated */
+{
+	register int	x, y;
+	double	tstdist;
+	double	yzn2, vx;
+
+	if (ourview.vaft <= FTINY)
+		return;
+	tstdist = ourview.vaft - ourview.vfore;
+	for (y = 0; y < vresolu; y++) {
+		if (ourview.type == VT_PER) {		/* adjust distance */
+			yzn2 = (y+.5)/vresolu + ourview.voff - .5;
+			yzn2 = 1. + yzn2*yzn2*ourview.vn2;
+			tstdist = (ourview.vaft - ourview.vfore)*sqrt(yzn2);
+		}
+		for (x = 0; x < hresolu; x++)
+			if (zscan(y)[x] > tstdist) {
+				if (ourview.type == VT_PER) {
+					vx = (x+.5)/hresolu + ourview.hoff - .5;
+					if (zscan(y)[x] <= (ourview.vaft -
+							ourview.vfore) *
+						sqrt(vx*vx*ourview.hn2 + yzn2))
+						continue;
+				}
+				bzero(pscan(y)[x], sizeof(COLR));
+				zscan(y)[x] = 0.0;
+			}
+	}
+}
+
+
 writepicture()				/* write out picture */
 {
 	int	y;
@@ -696,14 +846,14 @@ char	*prog, *args;
 	cp = combuf;
 	wp = argv;
 	for ( ; ; ) {
-		while (isspace(*cp)) cp++;
-		if (!*cp) break;
-		*wp++ = cp;
-		while (!isspace(*cp))
-			if (!*cp++) goto done;
-		*cp++ = '\0';
+		while (isspace(*cp))	/* nullify spaces */
+			*cp++ = '\0';
+		if (!*cp)		/* all done? */
+			break;
+		*wp++ = cp;		/* add argument to list */
+		while (*++cp && !isspace(*cp))
+			;
 	}
-done:
 	*wp = NULL;
 						/* start process */
 	if ((rval = open_process(PDesc, argv)) < 0)