[Scummvm-cvs-logs] CVS: scummvm/common scaler.cpp,1.30,1.31

[Max Horn]

Update of /cvsroot/scummvm/scummvm/common
In directory sc8-pr-cvs1:/tmp/cvs-serv2067

Modified Files:
	scaler.cpp 
Log Message:
undoing this optimization: despite my initial sureness about this being correct - I was wrong :-) just plug in 0xFFFFFFFF to see it (roughly spoken, we can loose the uppermost bits if we shift after the addition instead of before it)

Index: scaler.cpp
===================================================================
RCS file: /cvsroot/scummvm/scummvm/common/scaler.cpp,v
retrieving revision 1.30
retrieving revision 1.31
diff -u -d -r1.30 -r1.31
--- scaler.cpp	22 Jun 2003 15:06:48 -0000	1.30
+++ scaler.cpp	22 Jun 2003 17:29:55 -0000	1.31
@@ -96,17 +96,17 @@
 }
 
 static inline uint32 INTERPOLATE(uint32 A, uint32 B) {
-	if (A != B) {	
-		return (((A & colorMask) + (B & colorMask)) >> 1) + (A & B & lowPixelMask);
+	if (A != B) {
+		return (((A & colorMask) >> 1) + ((B & colorMask) >> 1) + (A & B & lowPixelMask));
 	} else
 		return A;
 }
 
 static inline uint32 Q_INTERPOLATE(uint32 A, uint32 B, uint32 C, uint32 D) {
-	register uint32 x = ((A & qcolorMask) + (B & qcolorMask) + (C & qcolorMask) + (D & qcolorMask))>>2;
-	register uint32 y = (A & qlowpixelMask) + (B & qlowpixelMask) + (C & qlowpixelMask) + (D & qlowpixelMask);
+	register uint32 x = ((A & qcolorMask) >> 2) + ((B & qcolorMask) >> 2) + ((C & qcolorMask) >> 2) + ((D & qcolorMask) >> 2);
+	register uint32 y = ((A & qlowpixelMask) + (B & qlowpixelMask) + (C & qlowpixelMask) + (D & qlowpixelMask)) >> 2;
 
-	y = (y >> 2) & qlowpixelMask;
+	y &= qlowpixelMask;
 	return x + y;
 }