--- ray/src/rt/m_mirror.c	1995/08/26 15:15:51	2.5
+++ ray/src/rt/m_mirror.c	2014/05/10 17:43:01	2.16
@@ -1,17 +1,15 @@
-/* Copyright (c) 1995 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: m_mirror.c,v 2.16 2014/05/10 17:43:01 greg Exp $";
 #endif
-
 /*
  * Routines for mirror material supporting virtual light sources
  */
 
-#include  "ray.h"
+#include "copyright.h"
 
+#include  "ray.h"
 #include  "otypes.h"
-
+#include  "rtotypes.h"
 #include  "source.h"
 
 /*
@@ -25,36 +23,44 @@ static char SCCSid[] = "$SunId$ LBL";
  * part of the direct calculation.
  */
 
+static int mir_proj(MAT4  pm, OBJREC  *o, SRCREC  *s, int  n);
+static void mirrorproj(MAT4  m, FVECT  nv, double  offs);
 
-int  mir_proj();
 VSMATERIAL  mirror_vs = {mir_proj, 1};
 
 
-m_mirror(m, r)			/* shade mirrored ray */
-register OBJREC  *m;
-register RAY  *r;
+int
+m_mirror(			/* shade mirrored ray */
+	OBJREC  *m,
+	RAY  *r
+)
 {
 	COLOR  mcolor;
 	RAY  nr;
-	register int  i;
+	int  rpure = 1;
+	int  i;
 					/* check arguments */
 	if (m->oargs.nfargs != 3 || m->oargs.nsargs > 1)
 		objerror(m, USER, "bad number of arguments");
 					/* check for substitute material */
-	if (m->oargs.nsargs > 0 &&
+					/* but avoid double-counting */
+	if (m->oargs.nsargs > 0 && !(r->crtype & (AMBIENT|SPECULAR)) &&
 			(r->rsrc < 0 || source[r->rsrc].so != r->ro)) {
 		if (!strcmp(m->oargs.sarg[0], VOIDID)) {
 			raytrans(r);
 			return(1);
 		}
-		return(rayshade(r, modifier(m->oargs.sarg[0])));
+		return(rayshade(r, lastmod(objndx(m), m->oargs.sarg[0])));
 	}
 					/* check for bad source ray */
 	if (r->rsrc >= 0 && source[r->rsrc].so != r->ro)
 		return(1);
 
-	if (r->rod < 0.)		/* back is black */
+	if (r->rod < 0.) {		/* back is black */
+		if (!backvis)
+			raytrans(r);	/* unless back visibility is off */
 		return(1);
+	}
 					/* get modifiers */
 	raytexture(r, m->omod);
 					/* assign material color */
@@ -64,7 +70,7 @@ register RAY  *r;
 	multcolor(mcolor, r->pcol);
 					/* compute reflected ray */
 	if (r->rsrc >= 0) {			/* relayed light source */
-		rayorigin(&nr, r, REFLECTED, 1.);
+		rayorigin(&nr, REFLECTED, r, mcolor);
 					/* ignore textures */
 		for (i = 0; i < 3; i++)
 			nr.rdir[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
@@ -74,44 +80,60 @@ register RAY  *r;
 		FVECT  pnorm;
 		double  pdot;
 
-		if (rayorigin(&nr, r, REFLECTED, bright(mcolor)) < 0)
+		if (rayorigin(&nr, REFLECTED, r, mcolor) < 0)
 			return(1);
-		pdot = raynormal(pnorm, r);	/* use textures */
-		for (i = 0; i < 3; i++)
-			nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
+		if (!(r->crtype & AMBIENT) &&
+				DOT(r->pert,r->pert) > FTINY*FTINY) {
+			pdot = raynormal(pnorm, r);	/* use textures */
+			for (i = 0; i < 3; i++)
+				nr.rdir[i] = r->rdir[i] + 2.*pdot*pnorm[i];
+			rpure = 0;
+		}
 						/* check for penetration */
-		if (DOT(nr.rdir, r->ron) <= FTINY)
+		if (rpure || DOT(nr.rdir, r->ron) <= FTINY)
 			for (i = 0; i < 3; i++)
 				nr.rdir[i] = r->rdir[i] + 2.*r->rod*r->ron[i];
 	}
+	checknorm(nr.rdir);
 	rayvalue(&nr);
-	multcolor(nr.rcol, mcolor);
+	multcolor(nr.rcol, nr.rcoef);
 	addcolor(r->rcol, nr.rcol);
+	if (rpure && r->ro != NULL && isflat(r->ro->otype))
+		r->rt = r->rot + nr.rt;
 	return(1);
 }
 
 
-mir_proj(pm, o, s, n)		/* compute a mirror's projection */
-MAT4  pm;
-register OBJREC  *o;
-SRCREC  *s;
-int  n;
+static int
+mir_proj(		/* compute a mirror's projection */
+	MAT4  pm,
+	OBJREC  *o,
+	SRCREC  *s,
+	int  n
+)
 {
+	double	corr = 1.;
 	FVECT  nv, sc;
-	double  od;
-	register int  i, j;
+	double  od, offs;
+	int  i;
 				/* get surface normal and offset */
-	od = getplaneq(nv, o);
-				/* check for extreme point for behind */
+	offs = od = getplaneq(nv, o);
+	if (s->sflags & SDISTANT)
+		offs = 0.;
+				/* check for extreme point behind */
+	if (s->sflags & SCIR) {
+		if (s->sflags & (SFLAT|SDISTANT))
+			corr = 1.12837917;	/* correct setflatss() */
+		else
+			corr = 1.0/0.7236;	/* correct sphsetsrc() */
+	}
 	VCOPY(sc, s->sloc);
 	for (i = s->sflags & SFLAT ? SV : SW; i >= 0; i--)
-		if (DOT(nv, s->ss[i]) > 0.)
-			for (j = 0; j < 3; j++)
-				sc[j] += s->ss[i][j];
+		if (DOT(nv, s->ss[i]) > offs)
+			VSUM(sc, sc, s->ss[i], corr);
 		else
-			for (j = 0; j < 3; j++)
-				sc[j] -= s->ss[i][j];
-	if (DOT(sc, nv) <= (s->sflags & SDISTANT ? FTINY : od+FTINY))
+			VSUM(sc, sc, s->ss[i], -corr);
+	if (DOT(sc, nv) <= offs+FTINY)
 		return(0);
 				/* everything OK -- compute projection */
 	mirrorproj(pm, nv, od);
@@ -119,12 +141,14 @@ int  n;
 }
 
 
-mirrorproj(m, nv, offs)		/* get mirror projection for surface */
-register MAT4  m;
-FVECT  nv;
-double  offs;
+static void
+mirrorproj(		/* get mirror projection for surface */
+	MAT4  m,
+	FVECT  nv,
+	double  offs
+)
 {
-	register int  i, j;
+	int  i, j;
 					/* assign matrix */
 	setident4(m);
 	for (j = 0; j < 3; j++) {