--- ray/src/common/ccolor.c	2011/02/18 00:40:25	3.1
+++ ray/src/common/ccolor.c	2012/05/18 20:43:13	3.4
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: ccolor.c,v 3.1 2011/02/18 00:40:25 greg Exp $";
+static const char RCSid[] = "$Id: ccolor.c,v 3.4 2012/05/18 20:43:13 greg Exp $";
 #endif
 /*
  * Spectral color handling routines
@@ -9,30 +9,42 @@ static const char RCSid[] = "$Id: ccolor.c,v 3.1 2011/
 #include <math.h>
 #include "ccolor.h"
 
+					/* Sharp primary matrix */
+float	XYZtoSharp[3][3] = {
+	{ 1.2694, -0.0988, -0.1706},
+	{-0.8364,  1.8006,  0.0357},
+	{ 0.0297, -0.0315,  1.0018}
+};
+					/* inverse Sharp primary matrix */
+float	XYZfromSharp[3][3] = {
+	{ 0.8156,  0.0472,  0.1372},
+	{ 0.3791,  0.5769,  0.0440},
+	{-0.0123,  0.0167,  0.9955}
+};
 
 C_COLOR		c_dfcolor = C_DEFCOLOR;
 
 				/* CIE 1931 Standard Observer curves */
-static C_COLOR	cie_xf = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
+static const C_COLOR	cie_xf = { 1, NULL, 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, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
+static const C_COLOR	cie_yf = { 1, NULL, 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, NULL, C_CDSPEC|C_CSSPEC|C_CSXY|C_CSEFF,
+static const C_COLOR	cie_zf = { 1, NULL, 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, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
+static const C_COLOR	cie_xp = { 1, NULL, 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,
@@ -40,7 +52,7 @@ static C_COLOR	cie_xp = { 1, NULL, C_CDSPEC|C_CSSPEC|C
 			8336,8336,8336,8336,8336,8336},
 			127424L, 1., .0,
 			};
-static C_COLOR	cie_yp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
+static const C_COLOR	cie_yp = { 1, NULL, 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,
@@ -48,7 +60,7 @@ static C_COLOR	cie_yp = { 1, NULL, C_CDSPEC|C_CSSPEC|C
 			-4066,-4066,-4066,-4066,-4066,-4066},
 			-23035L, .0, 1.,
 			};
-static C_COLOR	cie_zp = { 1, NULL, C_CDSPEC|C_CSSPEC|C_CSXY,
+static const C_COLOR	cie_zp = { 1, NULL, 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,
@@ -57,6 +69,125 @@ static C_COLOR	cie_zp = { 1, NULL, C_CDSPEC|C_CSSPEC|C
 			36057L, .0, .0,
 			};
 
+
+/* convert to sharpened RGB color for low-error operations */
+void
+c_toSharpRGB(C_COLOR *cin, double cieY, float cout[3])
+{
+	double	xyz[3];
+
+	c_ccvt(cin, C_CSXY);
+
+	xyz[0] = cin->cx/cin->cy * cieY;
+	xyz[1] = cieY;
+	xyz[2] = (1. - cin->cx - cin->cy)/cin->cy * cieY;
+
+	cout[0] = XYZtoSharp[0][0]*xyz[0] + XYZtoSharp[0][1]*xyz[1] +
+				XYZtoSharp[0][2]*xyz[2];
+	cout[1] = XYZtoSharp[1][0]*xyz[0] + XYZtoSharp[1][1]*xyz[1] +
+				XYZtoSharp[1][2]*xyz[2];
+	cout[2] = XYZtoSharp[2][0]*xyz[0] + XYZtoSharp[2][1]*xyz[1] +
+				XYZtoSharp[2][2]*xyz[2];
+}
+
+/* convert back from sharpened RGB color */
+double
+c_fromSharpRGB(float cin[3], C_COLOR *cout)
+{
+	double	xyz[3], sf;
+
+	xyz[0] = XYZfromSharp[0][0]*cin[0] + XYZfromSharp[0][1]*cin[1] +
+				XYZfromSharp[0][2]*cin[2];
+	xyz[1] = XYZfromSharp[1][0]*cin[0] + XYZfromSharp[1][1]*cin[1] +
+				XYZfromSharp[1][2]*cin[2];
+	xyz[2] = XYZfromSharp[2][0]*cin[0] + XYZfromSharp[2][1]*cin[1] +
+				XYZfromSharp[2][2]*cin[2];
+				
+	sf = 1./(xyz[0] + xyz[1] + xyz[2]);
+
+	cout->cx = xyz[0] * sf;
+	cout->cy = xyz[1] * sf;
+	cout->flags = C_CDXY|C_CSXY;
+	
+	return(xyz[1]);
+}
+
+/* assign arbitrary spectrum */
+double
+c_sset(C_COLOR *clr, double wlmin, double wlmax, const float spec[], int nwl)
+{
+	double	yval, scale;
+	float	va[C_CNSS];
+	int	i, pos, n, imax, wl;
+	double	wl0, wlstep;
+	double	boxpos, boxstep;
+					/* check arguments */
+	if ((nwl <= 1) | (spec == NULL) | (wlmin >= C_CMAXWL) |
+			(wlmax <= C_CMINWL) | (wlmin >= wlmax))
+		return(0.);
+	wlstep = (wlmax - wlmin)/(nwl-1);
+	while (wlmin < C_CMINWL) {
+		wlmin += wlstep;
+		--nwl; ++spec;
+	}
+	while (wlmax > C_CMAXWL) {
+		wlmax -= wlstep;
+		--nwl;
+	}
+	imax = nwl;			/* box filter if necessary */
+	boxpos = 0;
+	boxstep = 1;
+	if (wlstep < C_CWLI) {
+		imax = (wlmax - wlmin)/C_CWLI + 1e-7;
+		boxpos = (wlmin - C_CMINWL)/C_CWLI;
+		boxstep = wlstep/C_CWLI;
+		wlstep = C_CWLI;
+	}
+	scale = 0.;			/* get values and maximum */
+	yval = 0.;
+	pos = 0;
+	for (i = 0; i < imax; i++) {
+		va[i] = 0.; n = 0;
+		while (boxpos < i+.5 && pos < nwl) {
+			va[i] += spec[pos++];
+			n++;
+			boxpos += boxstep;
+		}
+		if (n > 1)
+			va[i] /= (double)n;
+		if (va[i] > scale)
+			scale = va[i];
+		else if (va[i] < -scale)
+			scale = -va[i];
+		yval += va[i] * cie_yf.ssamp[i];
+	}
+	if (scale <= 1e-7)
+		return(0.);
+	yval /= (double)cie_yf.ssum;
+	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+1e-7) {
+				wl0 += wlstep;
+				pos++;
+			}
+			if ((wl+1e-7 >= wl0) & (wl-1e-7 <= 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;
+	return(yval);
+}
+
 /* check if color is grey */
 int
 c_isgrey(C_COLOR *clr)
@@ -127,15 +258,16 @@ c_ccvt(C_COLOR *clr, int fl)
 	}
 }
 
-/* mix two colors according to weights given -- cres can be c1 or c2 */
+/* mix two colors according to weights given -- cres may be c1 or c2 */
 void
 c_cmix(C_COLOR *cres, double w1, C_COLOR *c1, double w2, C_COLOR *c2)
 {
 	double	scale;
-	float	cmix[C_CNSS];
 	int	i;
 
 	if ((c1->flags|c2->flags) & C_CDSPEC) {		/* spectral mixing */
+		float	cmix[C_CNSS];
+
 		c_ccvt(c1, C_CSSPEC|C_CSEFF);
 		c_ccvt(c2, C_CSSPEC|C_CSEFF);
 		w1 /= c1->eff*c1->ssum;
@@ -145,6 +277,8 @@ c_cmix(C_COLOR *cres, double w1, C_COLOR *c1, double w
 			cmix[i] = w1*c1->ssamp[i] + w2*c2->ssamp[i];
 			if (cmix[i] > scale)
 				scale = cmix[i];
+			else if (cmix[i] < -scale)
+				scale = -cmix[i];
 		}
 		scale = C_CMAXV / scale;
 		cres->ssum = 0;
@@ -168,11 +302,58 @@ c_cmix(C_COLOR *cres, double w1, C_COLOR *c1, double w
 	}
 }
 
+/* multiply two colors -- cres may be c1 or c2 */
+double
+c_cmult(C_COLOR *cres, C_COLOR *c1, double y1, C_COLOR *c2, double y2)
+{
+	double	yres;
+	int	i;
+
+	if ((c1->flags|c2->flags) & C_CDSPEC) {
+		long	cmix[C_CNSS], cmax = 0;		/* spectral multiply */
+
+		c_ccvt(c1, C_CSSPEC|C_CSEFF);
+		c_ccvt(c2, C_CSSPEC|C_CSEFF);
+		for (i = 0; i < C_CNSS; i++) {
+			cmix[i] = c1->ssamp[i] * c2->ssamp[i];
+			if (cmix[i] > cmax)
+				cmax = cmix[i];
+			else if (cmix[i] < -cmax)
+				cmax = -cmix[i];
+		}
+		cmax /= C_CMAXV;
+		if (!cmax) {
+			*cres = c_dfcolor;
+			return(0.);
+		}
+		cres->ssum = 0;
+		for (i = 0; i < C_CNSS; i++)
+			cres->ssum += cres->ssamp[i] = cmix[i] / cmax;
+		cres->flags = C_CDSPEC|C_CSSPEC;
+
+		c_ccvt(cres, C_CSEFF);			/* nasty, but true */
+		yres = y1 * y2 * cie_yf.ssum * C_CLPWM /
+			(c1->eff*c1->ssum * c2->eff*c2->ssum) *
+			cres->eff*( cres->ssum*(double)cmax +
+						C_CNSS/2.0*(cmax-1) );
+	} else {
+		float	rgb1[3], rgb2[3];		/* CIE xy multiply */
+
+		c_toSharpRGB(c1, y1, rgb1);
+		c_toSharpRGB(c2, y2, rgb2);
+		
+		rgb2[0] *= rgb1[0]; rgb2[1] *= rgb1[1]; rgb2[2] *= rgb1[2];
+
+		yres = c_fromSharpRGB(rgb2, cres);
+	}
+	return(yres);
+}
+
 #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))
+#define bblm(t)		(C2*0.2/(t))
 
 /* set black body spectrum */
 int