From 2ea2b40c724e5083f388eb93a8b2ac56009d09ae Mon Sep 17 00:00:00 2001
From: castano <castano@95f4ed2b-212e-0410-8b90-d31948207fce>
Date: Tue, 7 Sep 2010 18:08:27 +0000
Subject: [PATCH] Fix mirror sampling fixes issue 135.

---
 ChangeLog                  |  3 ++-
 src/nvimage/FloatImage.cpp | 19 +++++++++++--------
 2 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index d7292c0..fca2564 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,7 +5,8 @@ NVIDIA Texture Tools version 2.0.9
  * Improve C# / .NET Wrapper
  * Add an XNA Game Studio 3.1 Content Processor to make it easy to utilize NVIDIA Texture Tools in XNA applications.
  * Fix single color DXT1a compressor. Fixes issue 134.
- 
+ * Fix mirror sampling. Fixes issue 135.
+
 NVIDIA Texture Tools version 2.0.8
  * Fix float to fixed image conversion. Patch provided by Alex Pfaffe. Fixes issue 121.
  * ColorBlock::isSingleColor compares only RGB channels. Fixes issue 115.
diff --git a/src/nvimage/FloatImage.cpp b/src/nvimage/FloatImage.cpp
index 0c004f2..9bf43c5 100644
--- a/src/nvimage/FloatImage.cpp
+++ b/src/nvimage/FloatImage.cpp
@@ -32,14 +32,17 @@ namespace
 		return f - floor(f);
 	}
 
-	static int mirror(int x, int w)
-	{
-		x = abs(x);
-		while (x >= w) {
-			x = 2 * w - x - 2;
-		}
-		return x;
-	}
+    static int mirror(int x, int w)
+    {
+        if (w == 1) return 0;
+
+        x = abs(x);
+        while (x >= w) {
+            x = abs(w + w - x - 2);
+        }
+
+        return x;
+    }
 }