--- ray/src/cv/mgflib/context.c	1995/03/07 14:53:20	1.18
+++ ray/src/cv/mgflib/context.c	1995/03/13 13:00:34	1.19
@@ -36,10 +36,50 @@ static LUTAB	clr_tab = LU_SINIT(free,free);	/* color l
 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;
+				/* CIE 1931 Standard Observer curves */
+static C_COLOR	cie_xf = { 1, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
+			{14,42,143,435,1344,2839,3483,3362,2908,1954,956,
+			320,49,93,633,1655,2904,4334,5945,7621,9163,10263,
+			10622,10026,8544,6424,4479,2835,1649,874,468,227,
+			114,58,29,14,7,3,2,1,0}, 106836L, .467, .368, 362.230
+			};
+static C_COLOR	cie_yf = { 1, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
+			{0,1,4,12,40,116,230,380,600,910,1390,2080,3230,
+			5030,7100,8620,9540,9950,9950,9520,8700,7570,6310,
+			5030,3810,2650,1750,1070,610,320,170,82,41,21,10,
+			5,2,1,1,0,0}, 106856L, .398, .542, 493.525
+			};
+static C_COLOR	cie_zf = { 1, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
+			{65,201,679,2074,6456,13856,17471,17721,16692,
+			12876,8130,4652,2720,1582,782,422,203,87,39,21,17,
+			11,8,3,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0},
+			106770L, .147, .077, 54.363
+			};
+				/* Derived CIE 1931 Primaries (imaginary) */
+static C_COLOR	cie_xp = { 1, C_CDSPEC|C_CSSPEC|C_CSXY,
+			{-174,-198,-195,-197,-202,-213,-235,-272,-333,
+			-444,-688,-1232,-2393,-4497,-6876,-6758,-5256,
+			-3100,-815,1320,3200,4782,5998,6861,7408,7754,
+			7980,8120,8199,8240,8271,8292,8309,8283,8469,
+			8336,8336,8336,8336,8336,8336},
+			127424L, 1., .0,
+			};
+static C_COLOR	cie_yp = { 1, C_CDSPEC|C_CSSPEC|C_CSXY,
+			{-451,-431,-431,-430,-427,-417,-399,-366,-312,
+			-204,57,691,2142,4990,8810,9871,9122,7321,5145,
+			3023,1123,-473,-1704,-2572,-3127,-3474,-3704,
+			-3846,-3927,-3968,-3999,-4021,-4038,-4012,-4201,
+			-4066,-4066,-4066,-4066,-4066,-4066},
+			-23035L, .0, 1.,
+			};
+static C_COLOR	cie_zp = { 1, C_CDSPEC|C_CSSPEC|C_CSXY,
+			{4051,4054,4052,4053,4054,4056,4059,4064,4071,
+			4074,4056,3967,3677,2933,1492,313,-440,-795,
+			-904,-918,-898,-884,-869,-863,-855,-855,-851,
+			-848,-847,-846,-846,-846,-845,-846,-843,-845,
+			-845,-845,-845,-845,-845},
+			36057L, .0, .0,
+			};
 
 static int	setspectrum();
 static int	setbbtemp();
@@ -472,25 +512,27 @@ int	fl;
 		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;
+		x = clr->cx;
+		y = clr->cy;
+		z = 1. - x - y;
 		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;
+		for (i = 0; i < C_CNSS; i++) {
+			clr->ssamp[i] = x*cie_xp.ssamp[i] + y*cie_yp.ssamp[i]
+					+ z*cie_zp.ssamp[i] + .5;
+			if (clr->ssamp[i] < 0)		/* out of gamut! */
+				clr->ssamp[i] = 0;
+			else
+				clr->ssum += clr->ssamp[i];
+		}
 		clr->flags |= C_CSSPEC;
 	}
 	if (fl & C_CSEFF) {		/* compute efficacy */
-		if (clr->flags & C_CDSPEC) {		/* from spectrum */
+		if (clr->flags & C_CSSPEC) {		/* 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) */
+		} else /* clr->flags & C_CSXY */ {	/* from (x,y) */
 			clr->eff = clr->cx*cie_xf.eff + clr->cy*cie_yf.eff +
 					(1. - clr->cx - clr->cy)*cie_zf.eff;
 		}