--- ray/src/px/pinterp.c	1990/03/06 11:14:36	1.25
+++ ray/src/px/pinterp.c	1990/09/04 21:16:25	1.29
@@ -16,8 +16,6 @@ static char SCCSid[] = "$SunId$ LBL";
 
 #include "color.h"
 
-#include "random.h"
-
 #ifndef BSD
 #define vfork		fork
 #endif
@@ -25,10 +23,6 @@ static char SCCSid[] = "$SunId$ LBL";
 #define pscan(y)	(ourpict+(y)*hresolu)
 #define zscan(y)	(ourzbuf+(y)*hresolu)
 
-#define PMASK		0xfffffff	/* probability mask */
-#define sampval(x)	(long)((x)*(PMASK+1)+.5)
-#define samp(p)		((p) > (random()&PMASK))
-
 #define F_FORE		1		/* fill foreground */
 #define F_BACK		2		/* fill background */
 
@@ -53,7 +47,7 @@ float	*ourzbuf;			/* corresponding z-buffer */
 char	*progname;
 
 int	fillo = F_FORE|F_BACK;		/* selected fill options */
-long	sampprob = 0;			/* sample probability */
+int	fillsamp = 0;			/* sample separation (0 == inf) */
 extern int	backfill(), rcalfill();	/* fill functions */
 int	(*fillfunc)() = backfill;	/* selected fill function */
 COLR	backcolr = BLKCOLR;		/* background color */
@@ -121,7 +115,7 @@ char	*argv[];
 				break;
 			case 's':				/* sample */
 				check(3,1);
-				sampprob = sampval(atof(argv[++i]));
+				fillsamp = atoi(argv[++i]);
 				break;
 			case 'c':				/* color */
 				check(3,3);
@@ -200,7 +194,7 @@ char	*argv[];
 		addpicture(argv[i], argv[i+1]);
 							/* fill in spaces */
 	if (fillo&F_BACK)
-		backpicture(fillfunc, sampprob);
+		backpicture(fillfunc, fillsamp);
 	else
 		fillpicture(fillfunc);
 							/* close calculation */
@@ -460,7 +454,11 @@ double	z;
 		y1 = p0->y + c1*s1y/l1;
 		for (c2 = l2; c2-- > 0; ) {
 			x = x1 + c2*s2x/l2;
+			if (x < 0 || x >= hresolu)
+				continue;
 			y = y1 + c2*s2y/l2;
+			if (y < 0 || y >= vresolu)
+				continue;
 			if (zscan(y)[x] <= 0 || zscan(y)[x]-z
 						> zeps*zscan(y)[x]) {
 				zscan(y)[x] = z;
@@ -471,9 +469,9 @@ double	z;
 }
 
 
-backpicture(fill, prob)			/* background fill algorithm */
+backpicture(fill, samp)			/* background fill algorithm */
 int	(*fill)();
-long	prob;
+int	samp;
 {
 	int	*yback, xback;
 	int	y;
@@ -524,29 +522,40 @@ long	prob;
 						xback = x-1;
 				}
 				/*
-				 * Check to see if we have no background for
-				 * this pixel.  If not, or sampling was
-				 * requested, use the given fill function.
+				 * If we have no background for this pixel,
+				 * use the given fill function.
 				 */
-				if ((xback < 0 && yback[x] < 0) || samp(prob)) {
-					(*fill)(x,y);
-					continue;
-				}
+				if (xback < 0 && yback[x] < 0)
+					goto fillit;
 				/*
 				 * Compare, and use the background that is
 				 * farther, unless one of them is next to us.
+				 * If the background is too distant, call
+				 * the fill function.
 				 */
 				if ( yback[x] < 0
 					|| (xback >= 0 && ABS(x-xback) <= 1)
 					|| ( ABS(y-yback[x]) > 1
 						&& zscan(yback[x])[x]
 						< zscan(y)[xback] ) ) {
+					if (samp > 0 && ABS(x-xback) >= samp)
+						goto fillit;
 					copycolr(pscan(y)[x],pscan(y)[xback]);
 					zscan(y)[x] = zscan(y)[xback];
 				} else {
+					if (samp > 0 && ABS(y-yback[x]) > samp)
+						goto fillit;
 					copycolr(pscan(y)[x],pscan(yback[x])[x]);
 					zscan(y)[x] = zscan(yback[x])[x];
 				}
+				continue;
+			fillit:
+				(*fill)(x,y);
+				if (fill == rcalfill) {		/* use it */
+					clearqueue();
+					xback = x;
+					yback[x] = y;
+				}
 			} else {				/* full pixel */
 				yback[x] = -2;
 				xback = -2;
@@ -599,10 +608,10 @@ char	*fname;
 		if (donorm) {
 			double	vx, yzn2;
 			register int	x;
-			yzn2 = y - .5*(vresolu-1);
+			yzn2 = (y+.5)/vresolu + ourview.voff - .5;
 			yzn2 = 1. + yzn2*yzn2*ourview.vn2;
 			for (x = 0; x < hresolu; x++) {
-				vx = x - .5*(hresolu-1);
+				vx = (x+.5)/hresolu + ourview.hoff - .5;
 				zout[x] = zscan(y)[x]
 					* sqrt(vx*vx*ourview.hn2 + yzn2);
 			}