--- ray/src/rt/m_mist.c	1995/12/11 11:19:33	2.3
+++ ray/src/rt/m_mist.c	2003/07/27 22:12:03	2.14
@@ -1,15 +1,15 @@
-/* Copyright (c) 1995 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char RCSid[] = "$Id";
 #endif
-
 /*
  * Mist volumetric material.
  */
 
-#include  "ray.h"
+#include "copyright.h"
 
+#include <string.h>
+
+#include  "ray.h"
 #include  "source.h"
 
 /*
@@ -33,23 +33,24 @@ static char SCCSid[] = "$SunId$ LBL";
  *
  *  Up to five real arguments may be given for MAT_MIST:
  *
- *	[ext_r  ext_g  ext_b  [albedo [gecc]]]
+ *	[ext_r  ext_g  ext_b  [albedo_r albedo_g albedo_b [gecc]]]
  *
  *  The primaries indicate medium extinction per unit length (absorption
- *  plus scattering).  The albedo is the ratio of scattering to extinction,
+ *  plus scattering), which is added to the global extinction coefficient, set
+ *  by the -me option.  The albedo is the ratio of scattering to extinction,
  *  and is set globally by the -ma option (salbedo) and overridden here.
  *  The Heyney-Greenstein eccentricity parameter (-mg seccg) indicates how much
  *  scattering favors the forward direction.  A value of 0 means isotropic
  *  scattering.  A value approaching 1 indicates strong forward scattering.
  */
 
+#ifndef  MAXSLIST
+#define  MAXSLIST	32	/* maximum sources to check */
+#endif
+
 #define RELAYDELIM	'>'		/* relay delimiter character */
 
-extern COLOR  cextinction;		/* global coefficient of extinction */
-extern double  salbedo;			/* global scattering albedo */
-extern double  seccg;			/* global scattering eccentricity */
 
-
 static int
 inslist(sl, n)		/* return index of source n if it's in list sl */
 register int  *sl;
@@ -69,10 +70,9 @@ srcmatch(sp, id)	/* check for an id match on a light s
 register SRCREC  *sp;
 register char  *id;
 {
-	extern char  *index();
 	register char  *cp;
 						/* check for relay sources */
-	while ((cp = index(id, RELAYDELIM)) != NULL) {
+	while ((cp = strchr(id, RELAYDELIM)) != NULL) {
 		if (!(sp->sflags & SVIRTUAL) || sp->so == NULL)
 			return(0);
 		if (strncmp(id, sp->so->oname, cp-id) || sp->so->oname[cp-id])
@@ -86,7 +86,7 @@ register char  *id;
 }
 
 
-static
+static void
 add2slist(r, sl)	/* add source list to ray's */
 register RAY  *r;
 register int  *sl;
@@ -101,12 +101,14 @@ register int  *sl;
 	for (i = sl[0]; i > 0; i--)
 		if (!inslist(r->slights, sl[i])) {
 			if (r->slights[0] >= MAXSLIST)
-				error(USER, "scattering source list overflow");
+				error(INTERNAL,
+					"scattering source list overflow");
 			r->slights[++r->slights[0]] = sl[i];
 		}
 }
 
 
+int
 m_mist(m, r)		/* process a ray entering or leaving some mist */
 OBJREC  *m;
 register RAY  *r;
@@ -118,13 +120,12 @@ register RAY  *r;
 	double  re, ge, be;
 	register int  i, j;
 					/* check arguments */
-	if (m->oargs.nfargs > 5)
+	if (m->oargs.nfargs > 7)
 		objerror(m, USER, "bad arguments");
 					/* get source indices */
-	if (!(r->crtype & SHADOW) && m->oargs.nsargs > 0 &&
-			(myslist = (int *)m->os) == NULL) {
+	if (m->oargs.nsargs > 0 && (myslist = (int *)m->os) == NULL) {
 		if (m->oargs.nsargs > MAXSLIST)
-			objerror(m, USER, "too many sources in list");
+			objerror(m, INTERNAL, "too many sources in list");
 		myslist = (int *)malloc((m->oargs.nsargs+1)*sizeof(int));
 		if (myslist == NULL)
 			goto memerr;
@@ -166,38 +167,44 @@ register RAY  *r;
 		p.slights[0] = 0;
 	if (r->rod > 0.) {			/* entering ray */
 		addcolor(p.cext, mext);
-		if (m->oargs.nfargs > 3)
-			p.albedo = m->oargs.farg[3];
-		if (m->oargs.nfargs > 4)
-			p.gecc = m->oargs.farg[4];
+		if (m->oargs.nfargs > 5)
+			setcolor(p.albedo, m->oargs.farg[3],
+					m->oargs.farg[4], m->oargs.farg[5]);
+		if (m->oargs.nfargs > 6)
+			p.gecc = m->oargs.farg[6];
 		add2slist(&p, myslist);			/* add to list */
 	} else {				/* leaving ray */
 		if (myslist != NULL) {			/* delete from list */
 			for (j = myslist[0]; j > 0; j--)
-				if (i = inslist(p.slights, myslist[j]))
+				if ( (i = inslist(p.slights, myslist[j])) )
 					p.slights[i] = -1;
 			for (i = 0, j = 1; j <= p.slights[0]; j++)
 				if (p.slights[j] != -1)
 					p.slights[++i] = p.slights[j];
 			if (p.slights[0] - i < myslist[0]) {	/* fix old */
 				addcolor(r->cext, mext);
-				if (m->oargs.nfargs > 3)
-					r->albedo = m->oargs.farg[3];
-				if (m->oargs.nfargs > 4)
-					r->gecc = m->oargs.farg[4];
+				if (m->oargs.nfargs > 5)
+					setcolor(r->albedo, m->oargs.farg[3],
+					m->oargs.farg[4], m->oargs.farg[5]);
+				if (m->oargs.nfargs > 6)
+					r->gecc = m->oargs.farg[6];
 				add2slist(r, myslist);
 			}
 			p.slights[0] = i;
 		}
-		re = colval(r->cext,RED) - colval(mext,RED);
-		ge = colval(r->cext,GRN) - colval(mext,GRN);
-		be = colval(r->cext,BLU) - colval(mext,BLU);
-		setcolor(p.cext, re<0. ? 0. : re,
-				ge<0. ? 0. : ge,
-				be<0. ? 0. : be);
-		if (m->oargs.nfargs > 3)
-			p.albedo = salbedo;
-		if (m->oargs.nfargs > 4)
+		if ((re = colval(r->cext,RED) - colval(mext,RED)) <
+				colval(cextinction,RED))
+			re = colval(cextinction,RED);
+		if ((ge = colval(r->cext,GRN) - colval(mext,GRN)) <
+				colval(cextinction,GRN))
+			ge = colval(cextinction,GRN);
+		if ((be = colval(r->cext,BLU) - colval(mext,BLU)) <
+				colval(cextinction,BLU))
+			be = colval(cextinction,BLU);
+		setcolor(p.cext, re, ge, be);
+		if (m->oargs.nfargs > 5)
+			copycolor(p.albedo, salbedo);
+		if (m->oargs.nfargs > 6)
 			p.gecc = seccg;
 	}
 	rayvalue(&p);				/* calls rayparticipate() */