--- ray/src/common/ccolor.c	2012/05/17 05:47:59	3.2
+++ 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 3.2 2012/05/17 05:47:59 greg Exp $";
+static const char RCSid[] = "$Id: ccolor.c,v 3.4 2012/05/18 20:43:13 greg Exp $";
 #endif
 /*
  * Spectral color handling routines
@@ -9,6 +9,18 @@ static const char RCSid[] = "$Id: ccolor.c,v 3.2 2012/
 #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;
 
@@ -57,20 +69,9 @@ static const C_COLOR	cie_zp = { 1, NULL, C_CDSPEC|C_CS
 			36057L, .0, .0,
 			};
 
-					/* Sharp primary matrix */
-static const float	toSharp[3][3] = {
-	{ 1.2694, -0.0988, -0.1706},
-	{-0.8364,  1.8006,  0.0357},
-	{ 0.0297, -0.0315,  1.0018}
-};
-					/* inverse Sharp primary matrix */
-static const float	fromSharp[3][3] = {
-	{ 0.8156,  0.0472,  0.1372},
-	{ 0.3791,  0.5769,  0.0440},
-	{-0.0123,  0.0167,  0.9955}
-};
 
-static void
+/* convert to sharpened RGB color for low-error operations */
+void
 c_toSharpRGB(C_COLOR *cin, double cieY, float cout[3])
 {
 	double	xyz[3];
@@ -81,25 +82,26 @@ c_toSharpRGB(C_COLOR *cin, double cieY, float cout[3])
 	xyz[1] = cieY;
 	xyz[2] = (1. - cin->cx - cin->cy)/cin->cy * cieY;
 
-	cout[0] = toSharp[0][0]*xyz[0] + toSharp[0][1]*xyz[1] +
-				toSharp[0][2]*xyz[2];
-	cout[1] = toSharp[1][0]*xyz[0] + toSharp[1][1]*xyz[1] +
-				toSharp[1][2]*xyz[2];
-	cout[2] = toSharp[2][0]*xyz[0] + toSharp[2][1]*xyz[1] +
-				toSharp[2][2]*xyz[2];
+	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];
 }
 
-static double
+/* convert back from sharpened RGB color */
+double
 c_fromSharpRGB(float cin[3], C_COLOR *cout)
 {
 	double	xyz[3], sf;
 
-	xyz[0] = fromSharp[0][0]*cin[0] + fromSharp[0][1]*cin[1] +
-				fromSharp[0][2]*cin[2];
-	xyz[1] = fromSharp[1][0]*cin[0] + fromSharp[1][1]*cin[1] +
-				fromSharp[1][2]*cin[2];
-	xyz[2] = fromSharp[2][0]*cin[0] + fromSharp[2][1]*cin[1] +
-				fromSharp[2][2]*cin[2];
+	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]);
 
@@ -110,6 +112,82 @@ c_fromSharpRGB(float cin[3], C_COLOR *cout)
 	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)
@@ -199,6 +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;
@@ -238,6 +318,8 @@ c_cmult(C_COLOR *cres, C_COLOR *c1, double y1, C_COLOR
 			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) {
@@ -250,7 +332,7 @@ c_cmult(C_COLOR *cres, C_COLOR *c1, double y1, C_COLOR
 		cres->flags = C_CDSPEC|C_CSSPEC;
 
 		c_ccvt(cres, C_CSEFF);			/* nasty, but true */
-		yres = (y1 * y2 * cie_yf.ssum * C_CLPWM) /
+		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) );