--- ray/src/px/pinterp.c	1989/12/10 17:34:13	1.1
+++ ray/src/px/pinterp.c	1990/01/02 17:22:07	1.7
@@ -17,6 +17,8 @@ static char SCCSid[] = "$SunId$ LBL";
 #define pscan(y)	(ourpict+(y)*ourview.hresolu)
 #define zscan(y)	(ourzbuf+(y)*ourview.hresolu)
 
+#define ABS(x)		((x)>0?(x):-(x))
+
 VIEW	ourview = STDVIEW(512);		/* desired view */
 
 double	zeps = 0.001;			/* allowed z epsilon */
@@ -29,7 +31,9 @@ char	*progname;
 VIEW	theirview = STDVIEW(512);	/* input view */
 int	gotview;			/* got input view? */
 
+double	theirs2ours[4][4];		/* transformation matrix */
 
+
 main(argc, argv)			/* interpolate pictures */
 int	argc;
 char	*argv[];
@@ -47,6 +51,14 @@ char	*argv[];
 			check(2,1);
 			zeps = atof(argv[++i]);
 			break;
+		case 'x':				/* x resolution */
+			check(2,1);
+			ourview.hresolu = atoi(argv[++i]);
+			break;
+		case 'y':				/* y resolution */
+			check(2,1);
+			ourview.vresolu = atoi(argv[++i]);
+			break;
 		case 'v':				/* view */
 			switch (argv[i][2]) {
 			case 't':				/* type */
@@ -189,6 +201,8 @@ char	*pfile, *zfile;
 		fprintf(stderr, "%s: %s\n", pfile, err);
 		exit(1);
 	}
+					/* compute transformation */
+	pixform(theirs2ours, &theirview, &ourview);
 					/* allocate scanlines */
 	scanin = (COLR *)malloc(xres*sizeof(COLR));
 	zin = (float *)malloc(xres*sizeof(float));
@@ -216,32 +230,82 @@ char	*pfile, *zfile;
 }
 
 
+pixform(xfmat, vw1, vw2)		/* compute view1 to view2 matrix */
+register double	xfmat[4][4];
+register VIEW	*vw1, *vw2;
+{
+	double	m4t[4][4];
+
+	setident4(xfmat);
+	xfmat[0][0] = vw1->vhinc[0];
+	xfmat[0][1] = vw1->vhinc[1];
+	xfmat[0][2] = vw1->vhinc[2];
+	xfmat[1][0] = vw1->vvinc[0];
+	xfmat[1][1] = vw1->vvinc[1];
+	xfmat[1][2] = vw1->vvinc[2];
+	xfmat[2][0] = vw1->vdir[0];
+	xfmat[2][1] = vw1->vdir[1];
+	xfmat[2][2] = vw1->vdir[2];
+	xfmat[3][0] = vw1->vp[0];
+	xfmat[3][1] = vw1->vp[1];
+	xfmat[3][2] = vw1->vp[2];
+	setident4(m4t);
+	m4t[0][0] = vw2->vhinc[0]/vw2->vhn2;
+	m4t[1][0] = vw2->vhinc[1]/vw2->vhn2;
+	m4t[2][0] = vw2->vhinc[2]/vw2->vhn2;
+	m4t[3][0] = -DOT(vw2->vp,vw2->vhinc)/vw2->vhn2;
+	m4t[0][1] = vw2->vvinc[0]/vw2->vvn2;
+	m4t[1][1] = vw2->vvinc[1]/vw2->vvn2;
+	m4t[2][1] = vw2->vvinc[2]/vw2->vvn2;
+	m4t[3][1] = -DOT(vw2->vp,vw2->vvinc)/vw2->vvn2;
+	m4t[0][2] = vw2->vdir[0];
+	m4t[1][2] = vw2->vdir[1];
+	m4t[2][2] = vw2->vdir[2];
+	m4t[3][2] = -DOT(vw2->vp,vw2->vdir);
+	multmat4(xfmat, xfmat, m4t);
+}
+
+
 addscanline(y, pline, zline)		/* add scanline to output */
 int	y;
 COLR	*pline;
 float	*zline;
 {
-	FVECT	p, dir;
-	double	xnew, ynew, znew;
+	extern double	sqrt();
+	double	pos[3];
 	register int	x;
 	register int	xpos, ypos;
 
 	for (x = 0; x < theirview.hresolu; x++) {
-		rayview(p, dir, &theirview, x+.5, y+.5);
-		p[0] += zline[x]*dir[0];
-		p[1] += zline[x]*dir[1];
-		p[2] += zline[x]*dir[2];
-		pixelview(&xnew, &ynew, &znew, &ourview, p);
-		if (znew <= 0.0 || xnew < 0 || xnew > ourview.hresolu
-				|| ynew < 0 || ynew > ourview.vresolu)
+		pos[0] = x - .5*(theirview.hresolu-1);
+		pos[1] = y - .5*(theirview.vresolu-1);
+		pos[2] = zline[x];
+		if (theirview.type == VT_PER) {
+			pos[2] /= sqrt( 1.
+					+ pos[0]*pos[0]*theirview.vhn2
+					+ pos[1]*pos[1]*theirview.vvn2 );
+			pos[0] *= pos[2];
+			pos[1] *= pos[2];
+		}
+		multp3(pos, pos, theirs2ours);
+		if (pos[2] <= 0.0)
 			continue;
-					/* check current value at position */
-		xpos = xnew;
-		ypos = ynew;
+		if (ourview.type == VT_PER) {
+			pos[0] /= pos[2];
+			pos[1] /= pos[2];
+		}
+		pos[0] += .5*ourview.hresolu;
+		pos[1] += .5*ourview.vresolu;
+		if (pos[0] < 0 || pos[0] >= ourview.hresolu
+				|| pos[1] < 0 || pos[1] >= ourview.vresolu)
+			continue;
+					/* check current value at pos */
+		xpos = pos[0];
+		ypos = pos[1];
 		if (zscan(ypos)[xpos] <= 0.0
-				|| zscan(ypos)[xpos] - znew
+				|| zscan(ypos)[xpos] - pos[2]
 					> zeps*zscan(ypos)[xpos]) {
-			zscan(ypos)[xpos] = znew;
+			zscan(ypos)[xpos] = pos[2];
 			copycolr(pscan(ypos)[xpos], pline[x]);
 		}
 	}
@@ -250,31 +314,74 @@ float	*zline;
 
 fillpicture()				/* fill in empty spaces */
 {
+	int	*yback, xback;
 	int	y;
-	COLR	cfill;
-	register int	x, xblank;
-	
+	COLR	pfill;
+	register int	x, i;
+							/* get back buffer */
+	yback = (int *)malloc(ourview.hresolu*sizeof(int));
+	if (yback == NULL) {
+		perror(progname);
+		return;
+	}
+	for (x = 0; x < ourview.hresolu; x++)
+		yback[x] = -2;
+	/*
+	 * Xback and yback are the pixel locations of suitable
+	 * background values in each direction.
+	 * A value of -2 means unassigned, and -1 means
+	 * that there is no suitable background in this direction.
+	 */
+							/* fill image */
 	for (y = 0; y < ourview.vresolu; y++) {
-		xblank = -1;
+		xback = -2;
 		for (x = 0; x < ourview.hresolu; x++)
-			if (zscan(y)[x] <= 0.0) {
-				if (xblank < 0)
-					xblank = x;
-			} else if (xblank >= 0) {
-				if (xblank == 0 || zscan(y)[xblank-1] < zscan(y)[x])
-					copycolr(cfill, pscan(y)[x]);
+			if (zscan(y)[x] <= 0.0) {	/* empty pixel */
+				/*
+				 * First, find background from above or below.
+				 * (farthest assigned pixel)
+				 */
+				if (yback[x] == -2) {
+					for (i = y+1; i < ourview.vresolu; i++)
+						if (zscan(i)[x] > 0.0)
+							break;
+					if (i < ourview.vresolu
+				&& (y <= 0 || zscan(y-1)[x] < zscan(i)[x]))
+						yback[x] = i;
+					else
+						yback[x] = y-1;
+				}
+				/*
+				 * Next, find background from left or right.
+				 */
+				if (xback == -2) {
+					for (i = x+1; x < ourview.hresolu; i++)
+						if (zscan(y)[i] > 0.0)
+							break;
+					if (i < ourview.hresolu
+				&& (x <= 0 || zscan(y)[x-1] < zscan(y)[i]))
+						xback = i;
+					else
+						xback = x-1;
+				}
+				if (xback < 0 && yback[x] < 0)
+					continue;	/* no background */
+				/*
+				 * Compare, and use the background that is
+				 * farther, unless one of them is next to us.
+				 */
+				if (yback[x] < 0 || ABS(x-xback) <= 1
+					|| ( ABS(y-yback[x]) > 1
+				&& zscan(yback[x])[x] < zscan(y)[xback] ))
+					copycolr(pscan(y)[x],pscan(y)[xback]);
 				else
-					copycolr(cfill, pscan(y)[xblank-1]);
-				for ( ; xblank < x; xblank++)
-					copycolr(pscan(y)[xblank], cfill);
-				xblank = -1;
+					copycolr(pscan(y)[x],pscan(yback[x])[x]);
+			} else {				/* full pixel */
+				yback[x] = -2;
+				xback = -2;
 			}
-		if (xblank > 0) {
-			copycolr(cfill, pscan(y)[xblank-1]);
-			for ( ; xblank < ourview.hresolu; xblank++)
-				copycolr(pscan(y)[xblank], cfill);
-		}
 	}
+	free((char *)yback);
 }