--- ray/src/common/tonemap.c	2005/01/07 22:05:30	3.18
+++ ray/src/common/tonemap.c	2006/03/23 22:01:43	3.22
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char	RCSid[] = "$Id: tonemap.c,v 3.18 2005/01/07 22:05:30 greg Exp $";
+static const char	RCSid[] = "$Id: tonemap.c,v 3.22 2006/03/23 22:01:43 greg Exp $";
 #endif
 /*
  * Tone mapping functions.
@@ -171,6 +171,8 @@ int	len
 {
 	static const char funcName[] = "tmCvColors";
 	static COLOR	csmall = {.5*MINLUM, .5*MINLUM, .5*MINLUM};
+	static BYTE	gamtab[1024];
+	static double	curgam = .0;
 	COLOR	cmon;
 	double	lum, slum;
 	double	d;
@@ -180,6 +182,11 @@ int	len
 		returnErr(TM_E_TMINVAL);
 	if ((ls == NULL) | (scan == NULL) | (len < 0))
 		returnErr(TM_E_ILLEGAL);
+	if (cs != TM_NOCHROM && fabs(tms->mongam - curgam) > .02) {
+		curgam = tms->mongam;			/* (re)build table */
+		for (i = 1024; i--; )
+			gamtab[i] = (int)(256.*pow((i+.5)/1024., 1./curgam));
+	}
 	for (i = len; i--; ) {
 		if (tmNeedMatrix(tms)) {		/* get monitor RGB */
 			colortrans(cmon, tms->cmat, scan[i]);
@@ -188,6 +195,11 @@ int	len
 			cmon[GRN] = tms->inpsf*scan[i][GRN];
 			cmon[BLU] = tms->inpsf*scan[i][BLU];
 		}
+#ifdef isnan
+		if (isnan(cmon[RED]) || isinf(cmon[RED])) cmon[RED] = .0f;
+		if (isnan(cmon[GRN]) || isinf(cmon[GRN])) cmon[GRN] = .0f;
+		if (isnan(cmon[BLU]) || isinf(cmon[BLU])) cmon[BLU] = .0f;
+#endif
 							/* world luminance */
 		lum =	tms->clf[RED]*cmon[RED] +
 			tms->clf[GRN]*cmon[GRN] +
@@ -226,16 +238,29 @@ int	len
 			cmon[RED] = cmon[GRN] = cmon[BLU] = lum;
 		}
 		d = tms->clf[RED]*cmon[RED]/lum;
-		cs[3*i  ] = d>=.999 ? 255 :
-				(int)(256.*pow(d, 1./tms->mongam));
+		cs[3*i  ] = d>=.999 ? 255 : gamtab[(int)(1024.*d)];
 		d = tms->clf[GRN]*cmon[GRN]/lum;
-		cs[3*i+1] = d>=.999 ? 255 :
-				(int)(256.*pow(d, 1./tms->mongam));
+		cs[3*i+1] = d>=.999 ? 255 : gamtab[(int)(1024.*d)];
 		d = tms->clf[BLU]*cmon[BLU]/lum;
-		cs[3*i+2] = d>=.999 ? 255 :
-				(int)(256.*pow(d, 1./tms->mongam));
+		cs[3*i+2] = d>=.999 ? 255 : gamtab[(int)(1024.*d)];
 	}
 	returnOK;
+}
+
+
+TMbright
+tmCvLuminance(				/* convert a single luminance */
+double	lum
+)
+{
+	double	d;
+
+	if (lum <= TM_NOLUM)
+		return(TM_NOBRT);
+	d = TM_BRTSCALE*log(lum);
+	if (d > 0.)
+		return((TMbright)(d+.5));
+	return((TMbright)(d-.5));
 }