--- ray/src/rt/rpict.c	1989/10/03 12:17:09	1.10
+++ ray/src/rt/rpict.c	1989/12/10 13:42:45	1.11
@@ -53,7 +53,9 @@ extern long  nrays;			/* number of rays traced */
 
 #define  pixjitter()	(.5+dstrpix*(.5-frandom()))
 
+double  pixvalue();
 
+
 quit(code)			/* quit program */
 int  code;
 {
@@ -89,12 +91,15 @@ report()		/* report progress */
 }
 
 
-render(oldfile)				/* render the scene */
-char  *oldfile;
+render(zfile, oldfile)				/* render the scene */
+char  *zfile, *oldfile;
 {
 	COLOR  *scanbar[MAXDIV+1];	/* scanline arrays of pixel values */
+	float  *zbar[MAXDIV+1];		/* z values */
 	int  ypos;			/* current scanline */
+	FILE  *zfp;
 	COLOR  *colptr;
+	float  *zptr;
 	register int  i;
 					/* check sampling */
 	if (psample < 1)
@@ -105,13 +110,32 @@ char  *oldfile;
 	for (i = 0; i <= psample; i++) {
 		scanbar[i] = (COLOR *)malloc(ourview.hresolu*sizeof(COLOR));
 		if (scanbar[i] == NULL)
-			error(SYSTEM, "out of memory in render");
+			goto memerr;
 	}
+					/* open z file */
+	if (zfile != NULL) {
+		if ((zfp = fopen(zfile, "a+")) == NULL) {
+			sprintf(errmsg, "cannot open z file \"%s\"", zfile);
+			error(SYSTEM, errmsg);
+		}
+		for (i = 0; i <= psample; i++) {
+			zbar[i] = (float *)malloc(ourview.hresolu*sizeof(float));
+			if (zbar[i] == NULL)
+				goto memerr;
+		}
+	} else {
+		zfp = NULL;
+		for (i = 0; i <= psample; i++)
+			zbar[i] = NULL;
+	}
 					/* write out boundaries */
 	fputresolu(YMAJOR|YDECR, ourview.hresolu, ourview.vresolu, stdout);
 					/* recover file and compute first */
-	ypos = ourview.vresolu-1 - salvage(oldfile);
-	fillscanline(scanbar[0], ourview.hresolu, ypos, psample);
+	i = salvage(oldfile);
+	if (zfp != NULL && fseek(zfp, (long)i*ourview.hresolu*sizeof(float), 0) == EOF)
+		error(SYSTEM, "z file seek error in render");
+	ypos = ourview.vresolu-1 - i;
+	fillscanline(scanbar[0], zbar[0], ourview.hresolu, ypos, psample);
 						/* compute scanlines */
 	for (ypos -= psample; ypos >= 0; ypos -= psample) {
 	
@@ -120,14 +144,22 @@ char  *oldfile;
 		colptr = scanbar[psample];		/* move base to top */
 		scanbar[psample] = scanbar[0];
 		scanbar[0] = colptr;
+		zptr = zbar[psample];
+		zbar[psample] = zbar[0];
+		zbar[0] = zptr;
 							/* fill base line */
-		fillscanline(scanbar[0], ourview.hresolu, ypos, psample);
+		fillscanline(scanbar[0], zbar[0], ourview.hresolu, ypos, psample);
 							/* fill bar */
-		fillscanbar(scanbar, ourview.hresolu, ypos, psample);
+		fillscanbar(scanbar, zbar, ourview.hresolu, ypos, psample);
 							/* write it out */
-		for (i = psample; i > 0; i--)
-			if (fwritescan(scanbar[i], ourview.hresolu, stdout) < 0)
+		for (i = psample; i > 0; i--) {
+			if (zfp != NULL && fwrite(zbar[i],sizeof(float),ourview.hresolu,zfp) != ourview.hresolu)
 				goto writerr;
+			if (fwritescan(scanbar[i],ourview.hresolu,stdout) < 0)
+				goto writerr;
+		}
+		if (zfp != NULL && fflush(zfp) == EOF)
+			goto writerr;
 		if (fflush(stdout) == EOF)
 			goto writerr;
 	}
@@ -135,79 +167,113 @@ char  *oldfile;
 	colptr = scanbar[psample];
 	scanbar[psample] = scanbar[0];
 	scanbar[0] = colptr;
+	zptr = zbar[psample];
+	zbar[psample] = zbar[0];
+	zbar[0] = zptr;
 	if (ypos > -psample) {
-		fillscanline(scanbar[-ypos], ourview.hresolu,
+		fillscanline(scanbar[-ypos], zbar[-ypos], ourview.hresolu,
 				0, psample);
-		fillscanbar(scanbar-ypos, ourview.hresolu,
+		fillscanbar(scanbar-ypos, zbar-ypos, ourview.hresolu,
 				0, psample+ypos);
 	}
-	for (i = psample; i+ypos >= 0; i--)
+	for (i = psample; i+ypos >= 0; i--) {
+		if (zfp != NULL && fwrite(zbar[i],sizeof(float),ourview.hresolu,zfp) != ourview.hresolu)
+			goto writerr;
 		if (fwritescan(scanbar[i], ourview.hresolu, stdout) < 0)
 			goto writerr;
+	}
+						/* clean up */
+	if (zfp != NULL) {
+		if (fclose(zfp) == EOF)
+			goto writerr;
+		for (i = 0; i <= psample; i++)
+			free((char *)zbar[i]);
+	}
 	if (fflush(stdout) == EOF)
 		goto writerr;
-	pctdone = 100.0;
-						/* free scanlines */
 	for (i = 0; i <= psample; i++)
 		free((char *)scanbar[i]);
+	pctdone = 100.0;
 	return;
 writerr:
 	error(SYSTEM, "write error in render");
+memerr:
+	error(SYSTEM, "out of memory in render");
 }
 
 
-fillscanline(scanline, xres, y, xstep)		/* fill scan line at y */
+fillscanline(scanline, zline, xres, y, xstep)	/* fill scan line at y */
 register COLOR  *scanline;
+register float  *zline;
 int  xres, y, xstep;
 {
 	int  b = xstep;
+	double  z;
 	register int  i;
 	
-	pixvalue(scanline[0], 0, y);
+	z = pixvalue(scanline[0], 0, y);
+	if (zline) zline[0] = z;
 
 	for (i = xstep; i < xres; i += xstep) {
 	
-		pixvalue(scanline[i], i, y);
+		z = pixvalue(scanline[i], i, y);
+		if (zline) zline[i] = z;
 		
-		b = fillsample(scanline+i-xstep, i-xstep, y, xstep, 0, b/2);
+		b = fillsample(scanline+i-xstep, zline ? zline+i-xstep : NULL,
+				i-xstep, y, xstep, 0, b/2);
 	}
 	if (i-xstep < xres-1) {
-		pixvalue(scanline[xres-1], xres-1, y);
-		fillsample(scanline+i-xstep, i-xstep, y,
-				xres-1-(i-xstep), 0, b/2);
+		z = pixvalue(scanline[xres-1], xres-1, y);
+		if (zline) zline[xres-1] = z;
+		fillsample(scanline+i-xstep, zline ? zline+i-xstep : NULL,
+				i-xstep, y, xres-1-(i-xstep), 0, b/2);
 	}
 }
 
 
-fillscanbar(scanbar, xres, y, ysize)		/* fill interior */
+fillscanbar(scanbar, zbar, xres, y, ysize)	/* fill interior */
 register COLOR  *scanbar[];
+register float  *zbar[];
 int  xres, y, ysize;
 {
 	COLOR  vline[MAXDIV+1];
+	float  zline[MAXDIV+1];
 	int  b = ysize;
+	double  z;
 	register int  i, j;
 	
 	for (i = 0; i < xres; i++) {
 		
 		copycolor(vline[0], scanbar[0][i]);
 		copycolor(vline[ysize], scanbar[ysize][i]);
+		if (zbar[0]) {
+			zline[0] = zbar[0][i];
+			zline[ysize] = zbar[ysize][i];
+		}
 		
-		b = fillsample(vline, i, y, 0, ysize, b/2);
+		b = fillsample(vline, zbar[0] ? zline : NULL,
+				i, y, 0, ysize, b/2);
 		
 		for (j = 1; j < ysize; j++)
 			copycolor(scanbar[j][i], vline[j]);
+		if (zbar[0])
+			for (j = 1; j < ysize; j++)
+				zbar[j][i] = zline[j];
 	}
 }
 
 
 int
-fillsample(colline, x, y, xlen, ylen, b)	/* fill interior points */
+fillsample(colline, zline, x, y, xlen, ylen, b)	/* fill interior points */
 register COLOR  *colline;
+register float  *zline;
 int  x, y;
 int  xlen, ylen;
 int  b;
 {
+	extern double  fabs();
 	double  ratio;
+	double  z;
 	COLOR  ctmp;
 	int  ncut;
 	register int  len;
@@ -220,9 +286,12 @@ int  b;
 	if (len <= 1)			/* limit recursion */
 		return(0);
 	
-	if (b > 0 || bigdiff(colline[0], colline[len], maxdiff)) {
+	if (b > 0
+	|| (zline && 2.*fabs(zline[0]-zline[len]) > maxdiff*(zline[0]+zline[len]))
+			|| bigdiff(colline[0], colline[len], maxdiff)) {
 	
-		pixvalue(colline[len>>1], x + (xlen>>1), y + (ylen>>1));
+		z = pixvalue(colline[len>>1], x + (xlen>>1), y + (ylen>>1));
+		if (zline) zline[len>>1] = z;
 		ncut = 1;
 		
 	} else {					/* interpolate */
@@ -230,22 +299,26 @@ int  b;
 		copycolor(colline[len>>1], colline[len]);
 		ratio = (double)(len>>1) / len;
 		scalecolor(colline[len>>1], ratio);
-		copycolor(ctmp, colline[0]);
+		if (zline) zline[len>>1] = zline[len] * ratio;
 		ratio = 1.0 - ratio;
+		copycolor(ctmp, colline[0]);
 		scalecolor(ctmp, ratio);
 		addcolor(colline[len>>1], ctmp);
+		if (zline) zline[len>>1] += zline[0] * ratio;
 		ncut = 0;
 	}
 							/* recurse */
-	ncut += fillsample(colline, x, y, xlen>>1, ylen>>1, (b-1)/2);
+	ncut += fillsample(colline, zline, x, y, xlen>>1, ylen>>1, (b-1)/2);
 	
-	ncut += fillsample(colline + (len>>1), x + (xlen>>1), y + (ylen>>1),
-				xlen - (xlen>>1), ylen - (ylen>>1), b/2);
+	ncut += fillsample(colline+(len>>1), zline ? zline+(len>>1) : NULL,
+			x+(xlen>>1), y+(ylen>>1),
+			xlen-(xlen>>1), ylen-(ylen>>1), b/2);
 
 	return(ncut);
 }
 
 
+double
 pixvalue(col, x, y)		/* compute pixel value */
 COLOR  col;			/* returned color */
 int  x, y;			/* pixel position */
@@ -260,6 +333,8 @@ int  x, y;			/* pixel position */
 	rayvalue(&thisray);			/* trace ray */
 
 	copycolor(col, thisray.rcol);		/* return color */
+	
+	return(thisray.rot);			/* return distance */
 }