From Wojciech Lewandowski, "Here are my changes:

- osg::Texture sets GL_MAX_TEXTURE_LEVEL if image uses fewer mipmaps than
number from computeNumberOfMipmaps (and it works!)
- DDS fix to read only available mipmaps
- DDS fixes to read / save 3D textures with mipmaps ( packing == 1 is
required)
- Few cosmetic DDS modifications and comments to make code cleaner (I hope)

Added _isTextureMaxLevelSupported variable to texture extensions. It
could be removed if OSG requires OpenGL version 1.2 by default.

Added simple ComputeImageSizeInBytes function in DDSReaderWrites. In
my opinion it would be better if similar static method was defined for
Image. Then it could be used not only in DDS but other modules as well (I
noticed that Texture/Texture2D do similar computations).

Also attached is an example test.osg model with DDS without last mipmaps to
demonstrate the problem. When loaded into Viewer with current code and moved
far away, so that cube occupies 4 pixels, cube becomes red due to the issue
I described in earlier post. When you patch DDS reader writer with attched
code but no osg::Texture yet, cube becomes blank (at least on my
Windows/NVidia)  When you also merge osg::Texture patch cube will look right
and mipmaps will be correct."

include/osg/Texture

@@ -621,6 +621,9 @@ class OSG_EXPORT Texture : public osg::StateAttribute
                 void setShadowAmbientSupported(bool flag) { _isShadowAmbientSupported = flag; }
                 bool isShadowAmbientSupported() const { return _isShadowAmbientSupported; }
 
+                void setTextureMaxLevelSupported(bool flag) { _isTextureMaxLevelSupported = flag; }
+                bool isTextureMaxLevelSupported() const { return _isTextureMaxLevelSupported; }
+
                 void setMaxTextureSize(GLint maxsize) { _maxTextureSize=maxsize; }
                 GLint maxTextureSize() const { return _maxTextureSize; }
 
@@ -667,6 +670,7 @@ class OSG_EXPORT Texture : public osg::StateAttribute
                 bool    _isNonPowerOfTwoTextureMipMappedSupported;
                 bool    _isNonPowerOfTwoTextureNonMipMappedSupported;
                 bool    _isTextureIntegerEXTSupported;
+                bool    _isTextureMaxLevelSupported;
 
                 GLint   _maxTextureSize;
                 GLint   _numTextureUnits;