--- ray/src/px/pf2.c	1989/02/02 10:49:24	1.1
+++ ray/src/px/pf2.c	2023/12/08 17:56:26	2.11
@@ -1,88 +1,71 @@
-/* Copyright (c) 1986 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: pf2.c,v 2.11 2023/12/08 17:56:26 greg Exp $";
 #endif
-
 /*
  *  pf2.c - routines used by pfilt.
- *
- *     10/3/85
  */
 
-#include  <stdio.h>
-
+#include  "pfilt.h"
 #include  "random.h"
 
-#include  "color.h"
+#define	 AVGLVL		0.5	/* target mean brightness */
 
-#define  PI		3.14159265359
+double	avgbrt;			/* average picture brightness */
+long	npix;			/* # pixels in average */
 
-#define  FTINY		(1e-6)
-
-extern int  nrows, ncols;	/* number of rows and columns for output */
-
-extern int  xres, yres;		/* x and y resolution */
-
-extern int  avghot;		/* true means average in avgbrt spots */
-
-extern double  hotlvl;		/* brightness considered "hot" */
-
-extern int  npts;		/* # of points for stars */
-
-extern double  spread;		/* spread for star points */
-
-extern char  *progname;
-
-extern COLOR  exposure;		/* exposure for frame */
-
-#define  AVGLVL		0.5	/* target mean brightness */
-
-double  avgbrt;			/* average picture brightness */
-
-typedef struct  hotpix {	/* structure for avgbrt pixels */
+typedef struct	hotpix {	/* structure for avgbrt pixels */
 	struct hotpix  *next;	/* next in list */
 	COLOR  val;		/* pixel color */
 	short  x, y;		/* pixel position */
 	float  slope;		/* random slope for diffraction */
 }  HOTPIX;
 
-HOTPIX  *head;			/* head of avgbrt pixel list */
+HOTPIX	*head;			/* head of avgbrt pixel list */
 
-double  sprdfact;		/* computed spread factor */
+double	sprdfact;		/* computed spread factor */
 
+static void starpoint(SCOLOR fcol, int  x, int  y, HOTPIX	 *hp);
 
-pass1init()			/* prepare for first pass */
+
+void
+pass1init(void)			/* prepare for first pass */
 {
 	avgbrt = 0.0;
+	npix = 0;
 	head = NULL;
 }
 
 
-pass1default()			/* for single pass */
+void
+pass1default(void)			/* for single pass */
 {
-	avgbrt = AVGLVL * xres * yres;
+	avgbrt = AVGLVL;
+	npix = 1;
 	head = NULL;
 }
 
 
-pass1scan(scan, y)		/* process first pass scanline */
-register COLOR  *scan;
-int  y;
+void
+pass1scan(		/* process first pass scanline */
+	COLORV	*scan,
+	int  y
+)
 {
-	extern char  *malloc();
-	extern double  tan(), sqrt();
-	double  cbrt;
-	register int  x;
-	register HOTPIX  *hp;
+	double	cbrt;
+	int  x;
+	HOTPIX	 *hp;
 
 	for (x = 0; x < xres; x++) {
 	
-		cbrt = bright(scan[x]);
+		cbrt = (*ourbright)(scan+x*NCSAMP);
 
-		if (avghot || cbrt < hotlvl)
-			avgbrt += cbrt;
+		if (cbrt <= 0)
+			continue;
 
+		if (avghot || cbrt < hotlvl) {
+			avgbrt += cbrt;
+			npix++;
+		}
 		if (npts && cbrt >= hotlvl) {
 			hp = (HOTPIX *)malloc(sizeof(HOTPIX));
 			if (hp == NULL) {
@@ -90,10 +73,10 @@ int  y;
 						progname);
 				quit(1);
 			}
-			copycolor(hp->val, scan[x]);
+			scolor_color(hp->val, scan+x*NCSAMP);
 			hp->x = x;
 			hp->y = y;
-			hp->slope = tan(PI*(0.5-(random()%npts+0.5)/npts));
+			hp->slope = ttan(PI*(0.5-(irandom(npts)+0.5)/npts));
 			hp->next = head;
 			head = hp;
 		}
@@ -101,14 +84,15 @@ int  y;
 }
 
 
-pass2init()			/* prepare for final pass */
+void
+pass2init(void)			/* prepare for final pass */
 {
-	avgbrt /= (double)xres * yres;
-
-	if (avgbrt <= FTINY) {
-		fprintf(stderr, "%s: picture too dark\n", progname);
+	if (!npix) {
+		fprintf(stderr, "%s: picture too dark or too bright\n",
+				progname);
 		quit(1);
 	}
+	avgbrt /= (double)npix;
 
 	scalecolor(exposure,  AVGLVL/avgbrt);
 	
@@ -117,13 +101,15 @@ pass2init()			/* prepare for final pass */
 }
 
 
-pass2scan(scan, y)		/* process final pass scanline */
-register COLOR  *scan;
-int  y;
+void
+pass2scan(		/* process final pass scanline */
+	COLORV	*scan,
+	int  y
+)
 {
 	int  xmin, xmax;
-	register int  x;
-	register HOTPIX  *hp;
+	int  x;
+	HOTPIX	 *hp;
 	
 	for (hp = head; hp != NULL; hp = hp->next) {
 		if (hp->slope > FTINY) {
@@ -144,20 +130,23 @@ int  y;
 		if (xmax >= xres)
 			xmax = xres-1;
 		for (x = xmin; x <= xmax; x++)
-			starpoint(scan[x], x, y, hp);
+			starpoint(scan+x*NCSAMP, x, y, hp);
 	}
 	for (x = 0; x < xres; x++)
-		multcolor(scan[x], exposure);
+		smultcolor(scan+x*NCSAMP, exposure);
 }
 
 
-starpoint(fcol, x, y, hp)		/* pixel is on the star's point */
-COLOR  fcol;
-int  x, y;
-register HOTPIX  *hp;
+static void
+starpoint(		/* pixel is on the star's point */
+	SCOLOR  fcol,
+	int  x,
+	int  y,
+	HOTPIX	 *hp
+)
 {
 	COLOR  ctmp;
-	double  d2;
+	double	d2;
 	
 	d2 = (double)(x - hp->x)*(x - hp->x) + (double)(y - hp->y)*(y - hp->y);
 	if (d2 > sprdfact) {
@@ -166,8 +155,8 @@ register HOTPIX  *hp;
 			return;
 		copycolor(ctmp, hp->val);
 		scalecolor(ctmp, d2);
-		addcolor(fcol, ctmp);
+		saddcolor(fcol, ctmp);
 	} else if (d2 > FTINY) {
-		addcolor(fcol, hp->val);
+		saddcolor(fcol, hp->val);
 	}
 }