From: Rudolf Polzer <divverent@xonotic.org>
Date: Fri, 15 Jul 2011 11:08:46 +0000 (+0200)
Subject: make encoding of DXT3/5 "more friendly" (don't use the swapped-colors case of DXT1)
X-Git-Tag: android-x86-6.0-r1~72
X-Git-Url: http://git.osdn.net/view?p=android-x86%2Fexternal-s2tc.git;a=commitdiff_plain;h=74e3c93055a532979c3468a93c6ae6188fe07bb2

make encoding of DXT3/5 "more friendly" (don't use the swapped-colors case of DXT1)
---

diff --git a/s2tc_compressor.cpp b/s2tc_compressor.cpp
index e3312ef..aebf469 100644
--- a/s2tc_compressor.cpp
+++ b/s2tc_compressor.cpp
@@ -482,12 +482,15 @@ namespace
 			{
 				if(ca[1] < ca[0])
 				{
+					// select mode with 6 = 0, 7 = 255
 					ca[2] = ca[0];
 					ca[0] = ca[1];
 					ca[1] = ca[2];
 				}
 			}
-			if(c[1] < c[0])
+			if((dxt == DXT1) ? (c[1] < c[0]) : (c[0] < c[1]))
+			// DXT1: select mode with 3 = transparent
+			// other: don't select this mode
 			{
 				c[2] = c[0];
 				c[0] = c[1];
@@ -733,7 +736,9 @@ namespace
 					}
 				}
 			}
-			if(c[1] < c[0])
+			if((dxt == DXT1) ? (c[1] < c[0]) : (c[0] < c[1]))
+			// DXT1: select mode with 3 = transparent
+			// other: don't select this mode
 			{
 				c[2] = c[0];
 				c[0] = c[1];