--- ray/src/common/color.c	1989/09/13 16:35:14	1.5
+++ ray/src/common/color.c	1990/08/30 09:13:21	1.11
@@ -45,7 +45,7 @@ static BYTE  chroma[3][NINC] = {
 };
 
 
-spec_rgb(col, s, e)		/* comput RGB color from spectral range */
+spec_rgb(col, s, e)		/* compute RGB color from spectral range */
 COLOR  col;
 int  s, e;
 {
@@ -354,7 +354,7 @@ colr_color(col, clr)		/* convert short to float color 
 register COLOR  col;
 register COLR  clr;
 {
-	double  ldexp(), f;
+	double  f;
 	
 	if (clr[EXP] == 0)
 		col[RED] = col[GRN] = col[BLU] = 0.0;
@@ -364,4 +364,60 @@ register COLR  clr;
 		col[GRN] = (clr[GRN] + 0.5)*f;
 		col[BLU] = (clr[BLU] + 0.5)*f;
 	}
+}
+
+
+normcolrs(scan, len, adjust)	/* normalize a scanline of colrs */
+register COLR  *scan;
+int  len;
+int  adjust;
+{
+	register int  c;
+	register int  shift;
+
+	while (len-- > 0) {
+		shift = scan[0][EXP] + adjust - COLXS;
+		if (shift > 0) {
+			if (shift > 8) {
+				scan[0][RED] =
+				scan[0][GRN] =
+				scan[0][BLU] = 255;
+			} else {
+				shift--;
+				c = (scan[0][RED]<<1 | 1) << shift;
+				scan[0][RED] = c > 255 ? 255 : c;
+				c = (scan[0][GRN]<<1 | 1) << shift;
+				scan[0][GRN] = c > 255 ? 255 : c;
+				c = (scan[0][BLU]<<1 | 1) << shift;
+				scan[0][BLU] = c > 255 ? 255 : c;
+			}
+		} else if (shift < 0) {
+			if (shift < -8) {
+				scan[0][RED] =
+				scan[0][GRN] =
+				scan[0][BLU] = 0;
+			} else {
+				shift = -1-shift;
+				scan[0][RED] = ((scan[0][RED]>>shift)+1)>>1;
+				scan[0][GRN] = ((scan[0][GRN]>>shift)+1)>>1;
+				scan[0][BLU] = ((scan[0][BLU]>>shift)+1)>>1;
+			}
+		}
+		scan[0][EXP] = COLXS - adjust;
+		scan++;
+	}
+}
+
+
+bigdiff(c1, c2, md)			/* c1 delta c2 > md? */
+register COLOR  c1, c2;
+double  md;
+{
+	register int  i;
+
+	for (i = 0; i < 3; i++)
+		if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) ||
+			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
+			return(1);
+	return(0);
 }