From f26be0155c104ca53bd600eb216f29a24c14ded5 Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 1 Apr 2015 09:37:53 +0000
Subject: [PATCH] From Lionel Largarde, "fix for the
 Image::computeNumberOfMipmapLevels method. The method did use the float
 version of the log function and the / operator. It works for most of the
 input sizes, but fails for 8192, 32768... For 8192, the method returns 13
 instead of 14."

git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/branches/OpenSceneGraph-3.2@14815 16af8721-9629-0410-8352-f15c8da7e697
---
 src/osg/Image.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/osg/Image.cpp b/src/osg/Image.cpp
index 195ec8a60..1909fd336 100644
--- a/src/osg/Image.cpp
+++ b/src/osg/Image.cpp
@@ -799,7 +799,11 @@ int Image::computeNumberOfMipmapLevels(int s,int t, int r)
 {
     int w = maximum(s, t);
     w = maximum(w, r);
-    return 1 + static_cast<int>(floor(logf(w)/logf(2.0f)));
+
+    int n = 0;
+    while (w >>= 1)
+        ++n;
+    return n+1;
 }
 
 bool Image::isCompressed() const