--- ray/src/common/colrops.c	1990/10/19 21:31:54	1.2
+++ ray/src/common/colrops.c	2003/03/10 17:13:29	2.8
@@ -1,55 +1,91 @@
-/* Copyright (c) 1990 Regents of the University of California */
-
 #ifndef lint
-static char SCCSid[] = "$SunId$ LBL";
+static const char	RCSid[] = "$Id: colrops.c,v 2.8 2003/03/10 17:13:29 greg Exp $";
 #endif
-
 /*
  * Integer operations on COLR scanlines
  */
 
+#include "copyright.h"
+
+#include <math.h>
 #include "color.h"
 
-#define MAXGSHIFT	4		/* maximum shift for gamma table */
+extern char	*bmalloc();
 
-static BYTE	g_mant[256], g_nexp[256];
+#define MAXGSHIFT	31		/* maximum shift for gamma table */
 
-static BYTE	g_bval[MAXGSHIFT+1][256];
+static BYTE	*g_mant = NULL, *g_nexp = NULL;
 
+static BYTE	(*g_bval)[256] = NULL;
 
-setcolrgam(g)			/* set gamma conversion */
-double	g;
+
+int
+setcolrcor(f, a2)		/* set brightness correction */
+double	(*f)();
+double	a2;
 {
-	extern double	pow();
 	double	mult;
 	register int	i, j;
+					/* allocate tables */
+	if (g_bval == NULL && (g_bval =
+			(BYTE (*)[256])bmalloc((MAXGSHIFT+1)*256)) == NULL)
+		return(-1);
 					/* compute colr -> gamb mapping */
+	mult = 1.0/256.0;
 	for (i = 0; i <= MAXGSHIFT; i++) {
-		mult = pow(0.5, (double)(i+8));
 		for (j = 0; j < 256; j++)
-			g_bval[i][j] = 256.0 * pow((j+.5)*mult, 1.0/g);
+			g_bval[i][j] = 256.0 * (*f)((j+.5)*mult, a2);
+		mult *= 0.5;
 	}
+	return(0);
+}
+
+
+int
+setcolrinv(f, a2)		/* set inverse brightness correction */
+double	(*f)();
+double	a2;
+{
+	double	mult;
+	register int	i, j;
+					/* allocate tables */
+	if (g_mant == NULL && (g_mant = (BYTE *)bmalloc(256)) == NULL)
+		return(-1);
+	if (g_nexp == NULL && (g_nexp = (BYTE *)bmalloc(256)) == NULL)
+		return(-1);
 					/* compute gamb -> colr mapping */
 	i = 0;
 	mult = 256.0;
-	for (j = 255; j > 0; j--) {
-		while ((g_mant[j] = mult * pow(j/256.0, g)) < 128) {
+	for (j = 256; j--; ) {
+		while ((g_mant[j] = mult * (*f)((j+.5)/256.0, a2)) < 128) {
 			i++;
 			mult *= 2.0;
 		}
 		g_nexp[j] = i;
 	}
-	g_mant[0] = 0;
-	g_nexp[0] = COLXS;
+	return(0);
 }
 
 
+int
+setcolrgam(g)			/* set gamma conversion */
+double	g;
+{
+	if (setcolrcor(pow, 1.0/g) < 0)
+		return(-1);
+	return(setcolrinv(pow, g));
+}
+
+
+int
 colrs_gambs(scan, len)		/* convert scanline of colrs to gamma bytes */
 register COLR	*scan;
 int	len;
 {
 	register int	i, expo;
 
+	if (g_bval == NULL)
+		return(-1);
 	while (len-- > 0) {
 		expo = scan[0][EXP] - COLXS;
 		if (expo < -MAXGSHIFT) {
@@ -87,15 +123,19 @@ int	len;
 		scan[0][EXP] = COLXS;
 		scan++;
 	}
+	return(0);
 }
 
 
+int
 gambs_colrs(scan, len)		/* convert gamma bytes to colr scanline */
 register COLR	*scan;
 int	len;
 {
 	register int	nexpo;
 
+	if (g_mant == NULL | g_nexp == NULL)
+		return(-1);
 	while (len-- > 0) {
 		nexpo = g_nexp[scan[0][RED]];
 		if (g_nexp[scan[0][GRN]] < nexpo)
@@ -120,21 +160,33 @@ int	len;
 		scan[0][EXP] = COLXS - nexpo;
 		scan++;
 	}
+	return(0);
 }
 
 
+void
 shiftcolrs(scan, len, adjust)	/* shift a scanline of colors by 2^adjust */
 register COLR	*scan;
 register int	len;
 register int	adjust;
 {
+	int	minexp;
+
+	if (adjust == 0)
+		return;
+	minexp = adjust < 0 ? -adjust : 0;
 	while (len-- > 0) {
-		scan[0][EXP] += adjust;
+		if (scan[0][EXP] <= minexp)
+			scan[0][RED] = scan[0][GRN] = scan[0][BLU] =
+			scan[0][EXP] = 0;
+		else
+			scan[0][EXP] += adjust;
 		scan++;
 	}
 }
 
 
+void
 normcolrs(scan, len, adjust)	/* normalize a scanline of colrs */
 register COLR  *scan;
 int  len;