From 87ec916c2e75f090ba99dea83851a965cdb9000a Mon Sep 17 00:00:00 2001
From: kaetemi <kaetemi@gmail.com>
Date: Sat, 19 Mar 2016 22:13:38 +0100
Subject: [PATCH] Fix random thunder activation caused by rounding error in
 setup interpolation

---
 code/nel/src/misc/bitmap.cpp | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/code/nel/src/misc/bitmap.cpp b/code/nel/src/misc/bitmap.cpp
index 11a27e67e..5574a8597 100644
--- a/code/nel/src/misc/bitmap.cpp
+++ b/code/nel/src/misc/bitmap.cpp
@@ -3106,11 +3106,17 @@ bool CBitmap::blit(const CBitmap *src, sint32 x, sint32 y)
 // Private :
 float CBitmap::getColorInterp (float x, float y, float colorInXY00, float colorInXY10, float colorInXY01, float colorInXY11) const
 {
+	if (colorInXY00 == colorInXY10
+		&& colorInXY00 == colorInXY01
+		&& colorInXY00 == colorInXY11)
+		return colorInXY00; // Fix rounding error for alpha 255...
+
 	float res =	colorInXY00*(1.0f-x)*(1.0f-y) +
 				colorInXY10*(     x)*(1.0f-y) +
 				colorInXY01*(1.0f-x)*(     y) +
 				colorInXY11*(     x)*(     y);
-	clamp (res, 0.0f, 255.0f);
+	clamp(res, 0.0f, 255.0f);
+
 	return res;
 }