--- ray/src/cv/mgflib/context.c	1994/06/24 09:32:49	1.4
+++ ray/src/cv/mgflib/context.c	1995/03/07 14:53:20	1.18
@@ -26,19 +26,33 @@ static C_VERTEX		c_unvertex = C_DEFVERTEX;
 
 				/* the current contexts */
 C_COLOR		*c_ccolor = &c_uncolor;
+char		*c_ccname = NULL;
 C_MATERIAL	*c_cmaterial = &c_unmaterial;
+char		*c_cmname = NULL;
 C_VERTEX	*c_cvertex = &c_unvertex;
+char		*c_cvname = NULL;
 
 static LUTAB	clr_tab = LU_SINIT(free,free);	/* color lookup table */
 static LUTAB	mat_tab = LU_SINIT(free,free);	/* material lookup table */
 static LUTAB	vtx_tab = LU_SINIT(free,free);	/* vertex lookup table */
 
+				/* CIE 1931 Standard Observer */
+static C_COLOR	cie_xf = C_CIEX;
+static C_COLOR	cie_yf = C_CIEY;
+static C_COLOR	cie_zf = C_CIEZ;
 
+static int	setspectrum();
+static int	setbbtemp();
+static void	mixcolors();
+
+
 int
 c_hcolor(ac, av)		/* handle color entity */
 int	ac;
 register char	**av;
 {
+	double	w, wsum;
+	register int	i;
 	register LUENT	*lp;
 
 	switch (mg_entity(av[0])) {
@@ -48,20 +62,22 @@ register char	**av;
 		if (ac == 1) {		/* set unnamed color context */
 			c_uncolor = c_dfcolor;
 			c_ccolor = &c_uncolor;
+			c_ccname = NULL;
 			return(MG_OK);
 		}
 		lp = lu_find(&clr_tab, av[1]);	/* lookup context */
 		if (lp == NULL)
 			return(MG_EMEM);
+		c_ccname = lp->key;
+		c_ccolor = (C_COLOR *)lp->data;
 		if (ac == 2) {		/* reestablish previous context */
-			if (lp->data == NULL)
+			if (c_ccolor == NULL)
 				return(MG_EUNDEF);
-			c_ccolor = (C_COLOR *)lp->data;
 			return(MG_OK);
 		}
 		if (av[2][0] != '=' || av[2][1])
 			return(MG_ETYPE);
-		if (lp->key == NULL) {	/* create new color context */
+		if (c_ccolor == NULL) {	/* create new color context */
 			lp->key = (char *)malloc(strlen(av[1])+1);
 			if (lp->key == NULL)
 				return(MG_EMEM);
@@ -69,10 +85,14 @@ register char	**av;
 			lp->data = (char *)malloc(sizeof(C_COLOR));
 			if (lp->data == NULL)
 				return(MG_EMEM);
+			c_ccname = lp->key;
+			c_ccolor = (C_COLOR *)lp->data;
+			c_ccolor->clock = 0;
 		}
-		c_ccolor = (C_COLOR *)lp->data;
+		i = c_ccolor->clock;
 		if (ac == 3) {		/* use default template */
 			*c_ccolor = c_dfcolor;
+			c_ccolor->clock = i + 1;
 			return(MG_OK);
 		}
 		lp = lu_find(&clr_tab, av[3]);	/* lookup template */
@@ -81,20 +101,63 @@ register char	**av;
 		if (lp->data == NULL)
 			return(MG_EUNDEF);
 		*c_ccolor = *(C_COLOR *)lp->data;
-		if (ac > 4)
-			return(MG_EARGC);
+		c_ccolor->clock = i + 1;
 		return(MG_OK);
 	case MG_E_CXY:		/* assign CIE XY value */
 		if (ac != 3)
 			return(MG_EARGC);
-		if (!isflt(av[1]) || !isflt(av[2]))
+		if (!isflt(av[1]) | !isflt(av[2]))
 			return(MG_ETYPE);
 		c_ccolor->cx = atof(av[1]);
 		c_ccolor->cy = atof(av[2]);
+		c_ccolor->flags = C_CDXY|C_CSXY;
 		if (c_ccolor->cx < 0. | c_ccolor->cy < 0. |
 				c_ccolor->cx + c_ccolor->cy > 1.)
 			return(MG_EILL);
+		c_ccolor->clock++;
 		return(MG_OK);
+	case MG_E_CSPEC:	/* assign spectral values */
+		if (ac < 5)
+			return(MG_EARGC);
+		if (!isflt(av[1]) | !isflt(av[2]))
+			return(MG_ETYPE);
+		return(setspectrum(c_ccolor, atof(av[1]), atof(av[2]),
+				ac-3, av+3));
+	case MG_E_CCT:		/* assign black body spectrum */
+		if (ac != 2)
+			return(MG_EARGC);
+		if (!isflt(av[1]))
+			return(MG_ETYPE);
+		return(setbbtemp(c_ccolor, atof(av[1])));
+	case MG_E_CMIX:		/* mix colors */
+		if (ac < 5 || (ac-1)%2)
+			return(MG_EARGC);
+		if (!isflt(av[1]))
+			return(MG_ETYPE);
+		wsum = atof(av[1]);
+		if (wsum < 0.)
+			return(MG_EILL);
+		if ((lp = lu_find(&clr_tab, av[2])) == NULL)
+			return(MG_EMEM);
+		if (lp->data == NULL)
+			return(MG_EUNDEF);
+		*c_ccolor = *(C_COLOR *)lp->data;
+		for (i = 3; i < ac; i += 2) {
+			if (!isflt(av[i]))
+				return(MG_ETYPE);
+			w = atof(av[i]);
+			if (w < 0.)
+				return(MG_EILL);
+			if ((lp = lu_find(&clr_tab, av[i+1])) == NULL)
+				return(MG_EMEM);
+			if (lp->data == NULL)
+				return(MG_EUNDEF);
+			mixcolors(c_ccolor, wsum, c_ccolor,
+					w, (C_COLOR *)lp->data);
+			wsum += w;
+		}
+		c_ccolor->clock++;
+		return(MG_OK);
 	}
 	return(MG_EUNK);
 }
@@ -105,6 +168,7 @@ c_hmaterial(ac, av)		/* handle material entity */
 int	ac;
 register char	**av;
 {
+	int	i;
 	register LUENT	*lp;
 
 	switch (mg_entity(av[0])) {
@@ -114,20 +178,22 @@ register char	**av;
 		if (ac == 1) {		/* set unnamed material context */
 			c_unmaterial = c_dfmaterial;
 			c_cmaterial = &c_unmaterial;
+			c_cmname = NULL;
 			return(MG_OK);
 		}
 		lp = lu_find(&mat_tab, av[1]);	/* lookup context */
 		if (lp == NULL)
 			return(MG_EMEM);
+		c_cmname = lp->key;
+		c_cmaterial = (C_MATERIAL *)lp->data;
 		if (ac == 2) {		/* reestablish previous context */
-			if (lp->data == NULL)
+			if (c_cmaterial == NULL)
 				return(MG_EUNDEF);
-			c_cmaterial = (C_MATERIAL *)lp->data;
 			return(MG_OK);
 		}
 		if (av[2][0] != '=' || av[2][1])
 			return(MG_ETYPE);
-		if (lp->key == NULL) {	/* create new material context */
+		if (c_cmaterial == NULL) {	/* create new material */
 			lp->key = (char *)malloc(strlen(av[1])+1);
 			if (lp->key == NULL)
 				return(MG_EMEM);
@@ -135,11 +201,14 @@ register char	**av;
 			lp->data = (char *)malloc(sizeof(C_MATERIAL));
 			if (lp->data == NULL)
 				return(MG_EMEM);
+			c_cmname = lp->key;
+			c_cmaterial = (C_MATERIAL *)lp->data;
+			c_cmaterial->clock = 0;
 		}
-		c_cmaterial = (C_MATERIAL *)lp->data;
+		i = c_cmaterial->clock;
 		if (ac == 3) {		/* use default template */
 			*c_cmaterial = c_dfmaterial;
-			c_cmaterial->name = lp->key;
+			c_cmaterial->clock = i + 1;
 			return(MG_OK);
 		}
 		lp = lu_find(&mat_tab, av[3]);	/* lookup template */
@@ -148,10 +217,7 @@ register char	**av;
 		if (lp->data == NULL)
 			return(MG_EUNDEF);
 		*c_cmaterial = *(C_MATERIAL *)lp->data;
-		c_cmaterial->name = lp->key;
-		c_cmaterial->clock = 1;
-		if (ac > 4)
-			return(MG_EARGC);
+		c_cmaterial->clock = i + 1;
 		return(MG_OK);
 	case MG_E_RD:		/* set diffuse reflectance */
 		if (ac != 2)
@@ -184,11 +250,12 @@ register char	**av;
 		if (c_cmaterial->td < 0. | c_cmaterial->td > 1.)
 			return(MG_EILL);
 		c_cmaterial->td_c = *c_ccolor;
+		c_cmaterial->clock++;
 		return(MG_OK);
 	case MG_E_RS:		/* set specular reflectance */
 		if (ac != 3)
 			return(MG_EARGC);
-		if (!isflt(av[1]) || !isflt(av[2]))
+		if (!isflt(av[1]) | !isflt(av[2]))
 			return(MG_ETYPE);
 		c_cmaterial->rs = atof(av[1]);
 		c_cmaterial->rs_a = atof(av[2]);
@@ -201,7 +268,7 @@ register char	**av;
 	case MG_E_TS:		/* set specular transmittance */
 		if (ac != 3)
 			return(MG_EARGC);
-		if (!isflt(av[1]) || !isflt(av[2]))
+		if (!isflt(av[1]) | !isflt(av[2]))
 			return(MG_ETYPE);
 		c_cmaterial->ts = atof(av[1]);
 		c_cmaterial->ts_a = atof(av[2]);
@@ -211,6 +278,20 @@ register char	**av;
 		c_cmaterial->ts_c = *c_ccolor;
 		c_cmaterial->clock++;
 		return(MG_OK);
+	case MG_E_SIDES:	/* set number of sides */
+		if (ac != 2)
+			return(MG_EARGC);
+		if (!isint(av[1]))
+			return(MG_ETYPE);
+		i = atoi(av[1]);
+		if (i == 1)
+			c_cmaterial->sided = 1;
+		else if (i == 2)
+			c_cmaterial->sided = 0;
+		else
+			return(MG_EILL);
+		c_cmaterial->clock++;
+		return(MG_OK);
 	}
 	return(MG_EUNK);
 }
@@ -221,6 +302,7 @@ c_hvertex(ac, av)		/* handle a vertex entity */
 int	ac;
 register char	**av;
 {
+	int	i;
 	register LUENT	*lp;
 
 	switch (mg_entity(av[0])) {
@@ -230,20 +312,22 @@ register char	**av;
 		if (ac == 1) {		/* set unnamed vertex context */
 			c_unvertex = c_dfvertex;
 			c_cvertex = &c_unvertex;
+			c_cvname = NULL;
 			return(MG_OK);
 		}
 		lp = lu_find(&vtx_tab, av[1]);	/* lookup context */
 		if (lp == NULL)
 			return(MG_EMEM);
+		c_cvname = lp->key;
+		c_cvertex = (C_VERTEX *)lp->data;
 		if (ac == 2) {		/* reestablish previous context */
-			if (lp->data == NULL)
+			if (c_cvertex == NULL)
 				return(MG_EUNDEF);
-			c_cvertex = (C_VERTEX *)lp->data;
 			return(MG_OK);
 		}
 		if (av[2][0] != '=' || av[2][1])
 			return(MG_ETYPE);
-		if (lp->key == NULL) {	/* create new vertex context */
+		if (c_cvertex == NULL) {	/* create new vertex context */
 			lp->key = (char *)malloc(strlen(av[1])+1);
 			if (lp->key == NULL)
 				return(MG_EMEM);
@@ -251,10 +335,13 @@ register char	**av;
 			lp->data = (char *)malloc(sizeof(C_VERTEX));
 			if (lp->data == NULL)
 				return(MG_EMEM);
+			c_cvname = lp->key;
+			c_cvertex = (C_VERTEX *)lp->data;
 		}
-		c_cvertex = (C_VERTEX *)lp->data;
+		i = c_cvertex->clock;
 		if (ac == 3) {		/* use default template */
 			*c_cvertex = c_dfvertex;
+			c_cvertex->clock = i + 1;
 			return(MG_OK);
 		}
 		lp = lu_find(&vtx_tab, av[3]);	/* lookup template */
@@ -263,27 +350,28 @@ register char	**av;
 		if (lp->data == NULL)
 			return(MG_EUNDEF);
 		*c_cvertex = *(C_VERTEX *)lp->data;
-		if (ac > 4)
-			return(MG_EARGC);
+		c_cvertex->clock = i + 1;
 		return(MG_OK);
 	case MG_E_POINT:	/* set point */
 		if (ac != 4)
 			return(MG_EARGC);
-		if (!isflt(av[1]) || !isflt(av[2]) || !isflt(av[3]))
+		if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
 			return(MG_ETYPE);
 		c_cvertex->p[0] = atof(av[1]);
 		c_cvertex->p[1] = atof(av[2]);
 		c_cvertex->p[2] = atof(av[3]);
+		c_cvertex->clock++;
 		return(MG_OK);
 	case MG_E_NORMAL:	/* set normal */
 		if (ac != 4)
 			return(MG_EARGC);
-		if (!isflt(av[1]) || !isflt(av[2]) || !isflt(av[3]))
+		if (!isflt(av[1]) | !isflt(av[2]) | !isflt(av[3]))
 			return(MG_ETYPE);
 		c_cvertex->n[0] = atof(av[1]);
 		c_cvertex->n[1] = atof(av[2]);
 		c_cvertex->n[2] = atof(av[3]);
 		(void)normalize(c_cvertex->n);
+		c_cvertex->clock++;
 		return(MG_OK);
 	}
 	return(MG_EUNK);
@@ -295,16 +383,31 @@ c_clearall()			/* empty context tables */
 {
 	c_uncolor = c_dfcolor;
 	c_ccolor = &c_uncolor;
+	c_ccname = NULL;
 	lu_done(&clr_tab);
 	c_unmaterial = c_dfmaterial;
 	c_cmaterial = &c_unmaterial;
+	c_cmname = NULL;
 	lu_done(&mat_tab);
 	c_unvertex = c_dfvertex;
 	c_cvertex = &c_unvertex;
+	c_cvname = NULL;
 	lu_done(&vtx_tab);
 }
 
 
+C_MATERIAL *
+c_getmaterial(name)		/* get a named material */
+char	*name;
+{
+	register LUENT	*lp;
+
+	if ((lp = lu_find(&mat_tab, name)) == NULL)
+		return(NULL);
+	return((C_MATERIAL *)lp->data);
+}
+
+
 C_VERTEX *
 c_getvert(name)			/* get a named vertex */
 char	*name;
@@ -315,3 +418,233 @@ char	*name;
 		return(NULL);
 	return((C_VERTEX *)lp->data);
 }
+
+
+C_COLOR *
+c_getcolor(name)		/* get a named color */
+char	*name;
+{
+	register LUENT	*lp;
+
+	if ((lp = lu_find(&clr_tab, name)) == NULL)
+		return(NULL);
+	return((C_COLOR *)lp->data);
+}
+
+
+int
+c_isgrey(clr)			/* check if color is grey */
+register C_COLOR	*clr;
+{
+	if (!(clr->flags & (C_CSXY|C_CSSPEC)))
+		return(1);		/* no settings == grey */
+	c_ccvt(clr, C_CSXY);
+	return(clr->cx >= .323 && clr->cx <= .343 &&
+			clr->cy >= .323 && clr->cy <= .343);
+}
+
+
+void
+c_ccvt(clr, fl)			/* convert color representations */
+register C_COLOR	*clr;
+int	fl;
+{
+	double	x, y, z;
+	register int	i;
+
+	fl &= ~clr->flags;			/* ignore what's done */
+	if (!fl)				/* everything's done! */
+		return;
+	if (!(clr->flags & (C_CSXY|C_CSSPEC)))	/* nothing set! */
+		*clr = c_dfcolor;
+	if (fl & C_CSXY) {		/* cspec -> cxy */
+		x = y = z = 0.;
+		for (i = 0; i < C_CNSS; i++) {
+			x += cie_xf.ssamp[i] * clr->ssamp[i];
+			y += cie_yf.ssamp[i] * clr->ssamp[i];
+			z += cie_zf.ssamp[i] * clr->ssamp[i];
+		}
+		x /= (double)cie_xf.ssum;
+		y /= (double)cie_yf.ssum;
+		z /= (double)cie_zf.ssum;
+		z += x + y;
+		clr->cx = x / z;
+		clr->cy = y / z;
+		clr->flags |= C_CSXY;
+	} else if (fl & C_CSSPEC) {	/* cxy -> cspec */
+		z = (cie_xf.ssum + cie_yf.ssum + cie_zf.ssum) / 3.;
+		x = clr->cx * z / cie_xf.ssum;
+		y = clr->cy * z / cie_yf.ssum;
+		z = (1. - clr->cx - clr->cy) * z / cie_zf.ssum;
+		clr->ssum = 0;
+		for (i = 0; i < C_CNSS; i++)
+			clr->ssum += clr->ssamp[i] =
+					x * cie_xf.ssamp[i] +
+					y * cie_yf.ssamp[i] +
+					z * cie_zf.ssamp[i] + .5;
+		clr->flags |= C_CSSPEC;
+	}
+	if (fl & C_CSEFF) {		/* compute efficacy */
+		if (clr->flags & C_CDSPEC) {		/* from spectrum */
+			y = 0.;
+			for (i = 0; i < C_CNSS; i++)
+				y += cie_yf.ssamp[i] * clr->ssamp[i];
+			clr->eff = C_CLPWM * y / clr->ssum;
+		} else /* clr->flags & C_CDXY */ {	/* from (x,y) */
+			clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff +
+					(1. - clr->cx - clr->cy)*cie_zf.eff;
+		}
+		clr->flags |= C_CSEFF;
+	}
+}
+
+
+static int
+setspectrum(clr, wlmin, wlmax, ac, av)	/* convert a spectrum */
+register C_COLOR	*clr;
+double	wlmin, wlmax;
+int	ac;
+char	**av;
+{
+	double	scale;
+	float	va[C_CNSS];
+	register int	i, pos;
+	int	n, imax;
+	int	wl;
+	double	wl0, wlstep;
+					/* check bounds */
+	if (wlmax <= C_CMINWL | wlmax <= wlmin | wlmin >= C_CMAXWL)
+		return(MG_EILL);
+	wlstep = (wlmax - wlmin)/(ac-1);
+	while (wlmin < C_CMINWL) {
+		wlmin += wlstep;
+		ac--; av++;
+	}
+	while (wlmax > C_CMAXWL) {
+		wlmax -= wlstep;
+		ac--;
+	}
+	if (ac < 2)
+		return(MG_EILL);
+	imax = ac;			/* box filter if necessary */
+	if (wlstep < C_CWLI) {
+		wlstep = C_CWLI;
+		imax = (wlmax - wlmin)/wlstep;
+	}
+	scale = 0.;			/* get values and maximum */
+	pos = 0;
+	for (i = 0; i < imax; i++) {
+		va[i] = 0.; n = 0;
+		while (pos < (i+.5)*ac/imax) {
+			if (!isflt(av[pos]))
+				return(MG_ETYPE);
+			va[i] += atof(av[pos++]);
+			n++;
+		}
+		if (n > 1)
+			va[i] /= (double)n;
+		if (va[i] < 0.)
+			return(MG_EILL);
+		if (va[i] > scale)
+			scale = va[i];
+	}
+	if (scale == 0.)
+		return(MG_EILL);
+	scale = C_CMAXV / scale;
+	clr->ssum = 0;			/* convert to our spacing */
+	wl0 = wlmin;
+	pos = 0;
+	for (i = 0, wl = C_CMINWL; i < C_CNSS; i++, wl += C_CWLI)
+		if (wl < wlmin | wl > wlmax)
+			clr->ssamp[i] = 0;
+		else {
+			while (wl0 + wlstep < wl+FTINY) {
+				wl0 += wlstep;
+				pos++;
+			}
+			if (wl+FTINY >= wl0 & wl-FTINY <= wl0)
+				clr->ssamp[i] = scale*va[pos] + .5;
+			else		/* interpolate if necessary */
+				clr->ssamp[i] = .5 + scale / wlstep *
+						( va[pos]*(wl0+wlstep - wl) +
+							va[pos+1]*(wl - wl0) );
+			clr->ssum += clr->ssamp[i];
+		}
+	clr->flags = C_CDSPEC|C_CSSPEC;
+	clr->clock++;
+	return(MG_OK);
+}
+
+
+static void
+mixcolors(cres, w1, c1, w2, c2)	/* mix two colors according to weights given */
+register C_COLOR	*cres, *c1, *c2;
+double	w1, w2;
+{
+	double	scale;
+	float	cmix[C_CNSS];
+	register int	i;
+
+	if ((c1->flags|c2->flags) & C_CDSPEC) {		/* spectral mixing */
+		c_ccvt(c1, C_CSSPEC|C_CSEFF);
+		c_ccvt(c2, C_CSSPEC|C_CSEFF);
+		w1 /= c1->eff*c1->ssum;
+		w2 /= c2->eff*c2->ssum;
+		scale = 0.;
+		for (i = 0; i < C_CNSS; i++) {
+			cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i];
+			if (cmix[i] > scale)
+				scale = cmix[i];
+		}
+		scale = C_CMAXV / scale;
+		cres->ssum = 0;
+		for (i = 0; i < C_CNSS; i++)
+			cres->ssum += cres->ssamp[i] = scale*cmix[i] + .5;
+		cres->flags = C_CDSPEC|C_CSSPEC;
+	} else {					/* CIE xy mixing */
+		c_ccvt(c1, C_CSXY);
+		c_ccvt(c2, C_CSXY);
+		scale = 1. / (w1/c1->cy + w2/c2->cy);
+		cres->cx = (c1->cx*w1/c1->cy + c2->cx*w2/c2->cy) * scale;
+		cres->cy = (w1 + w2) * scale;
+		cres->flags = C_CDXY|C_CSXY;
+	}
+}
+
+
+#define	C1		3.741832e-16	/* W-m^2 */
+#define C2		1.4388e-2	/* m-K */
+
+#define bbsp(l,t)	(C1/((l)*(l)*(l)*(l)*(l)*(exp(C2/((t)*(l)))-1.)))
+#define bblm(t)		(C2/5./(t))
+
+static int
+setbbtemp(clr, tk)		/* set black body spectrum */
+register C_COLOR	*clr;
+double	tk;
+{
+	double	sf, wl;
+	register int	i;
+
+	if (tk < 1000)
+		return(MG_EILL);
+	wl = bblm(tk);			/* scalefactor based on peak */
+	if (wl < C_CMINWL*1e-9)
+		wl = C_CMINWL*1e-9;
+	else if (wl > C_CMAXWL*1e-9)
+		wl = C_CMAXWL*1e-9;
+	sf = C_CMAXV/bbsp(wl,tk);
+	clr->ssum = 0;
+	for (i = 0; i < C_CNSS; i++) {
+		wl = (C_CMINWL + i*C_CWLI)*1e-9;
+		clr->ssum += clr->ssamp[i] = sf*bbsp(wl,tk) + .5;
+	}
+	clr->flags = C_CDSPEC|C_CSSPEC;
+	clr->clock++;
+	return(MG_OK);
+}
+
+#undef	C1
+#undef	C2
+#undef	bbsp
+#undef	bblm