--- ray/src/rt/rpict.c	1996/06/08 21:16:06	2.47
+++ ray/src/rt/rpict.c	1998/06/17 13:29:55	2.51
@@ -53,6 +53,8 @@ int  psample = 4;			/* pixel sample size */
 double	maxdiff = .05;			/* max. difference for interpolation */
 double	dstrpix = 0.67;			/* square pixel distribution */
 
+double  mblur = 0.;			/* motion blur parameter */
+
 double	dstrsrc = 0.0;			/* square source distribution */
 double	shadthresh = .05;		/* shadow threshold */
 double	shadcert = .5;			/* shadow certainty */
@@ -104,6 +106,8 @@ extern unsigned long  nrays;		/* number of rays traced
 
 int  hres, vres;			/* resolution for this frame */
 
+static VIEW	lastview;		/* the previous view input */
+
 extern char  *mktemp();
 
 double	pixvalue();
@@ -228,6 +232,7 @@ char  *pout, *zout, *prvr;
 		for ( ; seq < rn; seq++)
 			if (nextview(stdin) == EOF)
 				error(USER, "unexpected EOF on view input");
+		setview(&ourview);
 		prvr = fbuf;			/* mark for renaming */
 	}
 	if (pout != NULL & prvr != NULL) {
@@ -269,6 +274,7 @@ char  *pout, *zout, *prvr;
 						fbuf);
 					error(USER, errmsg);
 				}
+				setview(&ourview);
 				continue;		/* don't clobber */
 			}
 			if (freopen(fbuf, "w", stdout) == NULL) {
@@ -331,6 +337,7 @@ FILE  *fp;
 {
 	char  linebuf[256];
 
+	copystruct(&lastview, &ourview);
 	while (fgets(linebuf, sizeof(linebuf), fp) != NULL)
 		if (isview(linebuf) && sscanview(&ourview, linebuf) > 0)
 			return(0);
@@ -341,7 +348,6 @@ FILE  *fp;
 render(zfile, oldfile)				/* render the scene */
 char  *zfile, *oldfile;
 {
-	extern long  lseek();
 	COLOR  *scanbar[MAXDIV+1];	/* scanline arrays of pixel values */
 	float  *zbar[MAXDIV+1];		/* z values */
 	char  *sampdens;		/* previous sample density */
@@ -394,7 +400,7 @@ char  *zfile, *oldfile;
 	if (i >= vres)
 		goto alldone;
 	if (zfd != -1 && i > 0 &&
-			lseek(zfd, (long)i*hres*sizeof(float), 0) == -1)
+			lseek(zfd, (long)i*hres*sizeof(float), 0) < 0)
 		error(SYSTEM, "z-file seek error in render");
 	pctdone = 100.0*i/vres;
 	if (ralrm > 0)			/* report init stats */
@@ -404,7 +410,8 @@ char  *zfile, *oldfile;
 #endif
 	signal(SIGCONT, report);
 	ypos = vres-1 - i;			/* initialize sampling */
-	init_drawsources(psample);
+	if (directvis)
+		init_drawsources(psample);
 	fillscanline(scanbar[0], zbar[0], sampdens, hres, ypos, hstep);
 						/* compute scanlines */
 	for (ypos -= ystep; ypos > -ystep; ypos -= ystep) {
@@ -424,8 +431,8 @@ char  *zfile, *oldfile;
 				hres, ypos, hstep);
 							/* fill bar */
 		fillscanbar(scanbar, zbar, hres, ypos, ystep);
-							/* add bitty sources */
-		drawsources(scanbar, zbar, 0, hres, ypos, ystep);
+		if (directvis)				/* add bitty sources */
+			drawsources(scanbar, zbar, 0, hres, ypos, ystep);
 							/* write it out */
 #ifndef	 BSD
 		signal(SIGCONT, SIG_IGN);	/* don't interrupt writes */
@@ -602,17 +609,36 @@ pixvalue(col, x, y)		/* compute pixel value */
 COLOR  col;			/* returned color */
 int  x, y;			/* pixel position */
 {
-	static RAY  thisray;
-
-	if ((thisray.rmax = viewray(thisray.rorg, thisray.rdir, &ourview,
-			(x+pixjitter())/hres, (y+pixjitter())/vres)) < -FTINY) {
+	RAY  thisray;
+	FVECT	lorg, ldir;
+	double	hpos, vpos, lmax, d;
+						/* compute view ray */
+	hpos = (x+pixjitter())/hres;
+	vpos = (y+pixjitter())/vres;
+	if ((thisray.rmax = viewray(thisray.rorg, thisray.rdir,
+					&ourview, hpos, vpos)) < -FTINY) {
 		setcolor(col, 0.0, 0.0, 0.0);
 		return(0.0);
 	}
 
-	rayorigin(&thisray, NULL, PRIMARY, 1.0);
-
 	samplendx = pixnumber(x,y,hres,vres);	/* set pixel index */
+
+						/* optional motion blur */
+	if (lastview.type && mblur > FTINY && (lmax = viewray(lorg, ldir,
+					&lastview, hpos, vpos)) >= -FTINY) {
+		register int	i;
+		register double  d = mblur*(.5-urand(281+samplendx));
+
+		thisray.rmax = (1.-d)*thisray.rmax + d*lmax;
+		for (i = 3; i--; ) {
+			thisray.rorg[i] = (1.-d)*thisray.rorg[i] + d*lorg[i];
+			thisray.rdir[i] = (1.-d)*thisray.rdir[i] + d*ldir[i];
+		}
+		if (normalize(thisray.rdir) == 0.0)
+			return(0.0);
+	}
+
+	rayorigin(&thisray, NULL, PRIMARY, 1.0);
 
 	rayvalue(&thisray);			/* trace ray */