diff --git a/include/osg/Array b/include/osg/Array
index d4769843b..7d4b81a4e 100644
--- a/include/osg/Array
+++ b/include/osg/Array
@@ -10,11 +10,13 @@
 #include <osg/Vec2>
 #include <osg/Vec3>
 #include <osg/Vec4>
+#include <osg/UByte4>
 
 #include <vector>
 
 namespace osg {
 
+class ArrayVisitor;
 
 class SG_EXPORT Array : public Object
 {
@@ -51,6 +53,8 @@ class SG_EXPORT Array : public Object
         virtual bool isSameKindAs(const Object* obj) const { return dynamic_cast<const Array*>(obj)!=NULL; }
         virtual const char* libraryName() const { return "osg"; }
         virtual const char* className() const;
+        
+        virtual void accept(ArrayVisitor&) {}
 
 
         Type                    getType() const { return _arrayType; }
@@ -88,33 +92,49 @@ class TemplateArray : public Array, public std::vector<T>
             Array(ARRAYTYPE,DataSize,DataType),
             std::vector<T>(ptr,ptr+no) {}
 
-
         template <class InputIterator>
         TemplateArray(InputIterator first,InputIterator last) : 
             Array(ARRAYTYPE,DataSize,DataType),
             std::vector<T>(first,last) {}        
 
-//         TemplateArray(T* first,T* last) : 
-//             Array(ARRAYTYPE,DataSize,DataType),
-//             std::vector<T>(first,last) {}
-
         virtual Object* cloneType() const { return osgNew TemplateArray(); }
         virtual Object* clone(const CopyOp& copyop) const { return osgNew TemplateArray(*this,copyop); }        
+        virtual void accept(ArrayVisitor& av) { av.apply(*this); }
 
         virtual const GLvoid*   dataPointer() const { if (!empty()) return &front(); else return 0; }
 };
 
-typedef TemplateArray<char,Array::ByteArrayType,1,GL_BYTE>                       ByteArray;
-typedef TemplateArray<short,Array::ShortArrayType,1,GL_SHORT>                    ShortArray;
-typedef TemplateArray<int,Array::IntArrayType,1,GL_INT>                          IntArray;
-typedef TemplateArray<unsigned char,Array::UByteArrayType,1,GL_UNSIGNED_BYTE>    UByteArray;
-typedef TemplateArray<unsigned short,Array::UShortArrayType,1,GL_UNSIGNED_SHORT> UShortArray;
-typedef TemplateArray<unsigned int,Array::UIntArrayType,1,GL_UNSIGNED_INT>       UIntArray;
-typedef TemplateArray<unsigned int,Array::UByte4ArrayType,4,GL_UNSIGNED_BYTE>    UByte4Array;
-typedef TemplateArray<float,Array::FloatArrayType,1,GL_FLOAT>                    FloatArray;
-typedef TemplateArray<Vec2,Array::Vec2ArrayType,2,GL_FLOAT>                      Vec2Array;
-typedef TemplateArray<Vec3,Array::Vec3ArrayType,3,GL_FLOAT>                      Vec3Array;
-typedef TemplateArray<Vec4,Array::Vec4ArrayType,4,GL_FLOAT>                      Vec4Array;
+typedef TemplateArray<GLbyte,Array::ByteArrayType,1,GL_BYTE>                    ByteArray;
+typedef TemplateArray<GLshort,Array::ShortArrayType,1,GL_SHORT>                 ShortArray;
+typedef TemplateArray<GLint,Array::IntArrayType,1,GL_INT>                       IntArray;
+typedef TemplateArray<GLubyte,Array::UByteArrayType,1,GL_UNSIGNED_BYTE>         UByteArray;
+typedef TemplateArray<GLushort,Array::UShortArrayType,1,GL_UNSIGNED_SHORT>      UShortArray;
+typedef TemplateArray<GLuint,Array::UIntArrayType,1,GL_UNSIGNED_INT>            UIntArray;
+typedef TemplateArray<UByte4,Array::UByte4ArrayType,4,GL_UNSIGNED_BYTE>         UByte4Array;
+typedef TemplateArray<float,Array::FloatArrayType,1,GL_FLOAT>                   FloatArray;
+typedef TemplateArray<Vec2,Array::Vec2ArrayType,2,GL_FLOAT>                     Vec2Array;
+typedef TemplateArray<Vec3,Array::Vec3ArrayType,3,GL_FLOAT>                     Vec3Array;
+typedef TemplateArray<Vec4,Array::Vec4ArrayType,4,GL_FLOAT>                     Vec4Array;
+
+class ArrayVisitor
+{
+    public:
+        ArrayVisitor() {}
+        
+        virtual void apply(Array&) {}
+        virtual void apply(ByteArray&) {}
+        virtual void apply(ShortArray&) {}
+        virtual void apply(IntArray&) {}
+        virtual void apply(UByteArray&) {}
+        virtual void apply(UShortArray&) {}
+        virtual void apply(UIntArray&) {}
+        virtual void apply(UByte4Array&) {}
+        virtual void apply(FloatArray&) {}
+        virtual void apply(Vec2Array&) {}
+        virtual void apply(Vec3Array&) {}
+        virtual void apply(Vec4Array&) {}
+    
+};
 
 }
 
diff --git a/include/osg/UByte4 b/include/osg/UByte4
new file mode 100644
index 000000000..747575acd
--- /dev/null
+++ b/include/osg/UByte4
@@ -0,0 +1,155 @@
+//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
+//Distributed under the terms of the GNU Library General Public License (LGPL)
+//as published by the Free Software Foundation.
+
+#ifndef OSG_UBYTE4
+#define OSG_UBUTE 1
+
+#include <osg/Vec3>
+
+#include <iostream>
+
+namespace osg {
+
+/** General purpose float quad, uses include representation
+    of colour coordinates.
+    No support yet added for float * UByte4 - is it necessary?
+    Need to define a non-member non-friend operator*  etc.
+   			     UByte4 * float is okay
+*/
+class UByte4
+{
+    public:
+
+	// Methods are defined here so that they are implicitly inlined
+
+        UByte4() { _v[0]=0; _v[1]=0; _v[2]=0; _v[3]=0;}
+        
+        UByte4(unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+        {
+            _v[0]=r; _v[1]=g; _v[2]=b; _v[3]=a;
+        }
+
+        unsigned char _v[4];
+
+        inline const bool operator == (const UByte4& v) const { return _v[0]==v._v[0] && _v[1]==v._v[1] && _v[2]==v._v[2] && _v[3]==v._v[3]; }
+
+        inline const bool operator != (const UByte4& v) const { return _v[0]!=v._v[0] || _v[1]!=v._v[1] || _v[2]!=v._v[2] || _v[3]!=v._v[3]; }
+
+        inline const bool operator <  (const UByte4& v) const
+        {
+            if (_v[0]<v._v[0]) return true;
+            else if (_v[0]>v._v[0]) return false;
+            else if (_v[1]<v._v[1]) return true;
+            else if (_v[1]>v._v[1]) return false;
+            else if (_v[2]<v._v[2]) return true;
+            else if (_v[2]>v._v[2]) return false;
+            else return (_v[3]<v._v[3]);
+        }
+
+        inline unsigned char* ptr() { return _v; }
+        inline const unsigned char* ptr() const { return _v; }
+
+        inline void set(unsigned char r, unsigned char g, unsigned char b, unsigned char a)
+        {
+            _v[0]=r; _v[1]=g; _v[2]=b; _v[3]=a;
+        }
+
+        inline unsigned char& operator [] (const int i) { return _v[i]; }
+        inline unsigned char operator [] (const int i) const { return _v[i]; }
+
+        inline unsigned char& r() { return _v[0]; }
+        inline unsigned char& g() { return _v[1]; }
+        inline unsigned char& b() { return _v[2]; }
+        inline unsigned char& a() { return _v[3]; }
+
+        inline unsigned char r() const { return _v[0]; }
+        inline unsigned char g() const { return _v[1]; }
+        inline unsigned char b() const { return _v[2]; }
+        inline unsigned char a() const { return _v[3]; }
+
+        /// multiply by scalar
+        inline UByte4 operator * (const float rhs) const
+        {
+            UByte4 col(*this);
+            col *= rhs;
+            return col;
+        }
+
+        /// unary multiply by scalar
+        inline UByte4& operator *= (const float rhs)
+        {
+            _v[0]=(unsigned char)((float)_v[0]*rhs);
+            _v[1]=(unsigned char)((float)_v[1]*rhs);
+            _v[2]=(unsigned char)((float)_v[2]*rhs);
+            _v[3]=(unsigned char)((float)_v[3]*rhs);
+            return *this;
+        }
+
+        /// divide by scalar
+        inline UByte4 operator / (const float rhs) const
+        {
+            UByte4 col(*this);
+            col /= rhs;
+            return col;
+        }
+
+        /// unary divide by scalar
+        inline UByte4& operator /= (const float rhs)
+        {
+            float div = 1.0f/rhs;
+            *this *= div;
+            return *this;
+        }
+
+        /// binary vector add
+        inline UByte4 operator + (const UByte4& rhs) const
+        {
+            return UByte4(_v[0]+rhs._v[0], _v[1]+rhs._v[1],
+		        _v[2]+rhs._v[2], _v[3]+rhs._v[3]);
+        }
+
+        /** unary vector add.  Slightly more efficient because no temporary
+            intermediate object*/
+        inline UByte4& operator += (const UByte4& rhs)
+        {
+            _v[0] += rhs._v[0];
+            _v[1] += rhs._v[1];
+            _v[2] += rhs._v[2];
+            _v[3] += rhs._v[3];
+            return *this;
+        }
+
+        /// binary vector subtract
+        inline UByte4 operator - (const UByte4& rhs) const
+        {
+            return UByte4(_v[0]-rhs._v[0], _v[1]-rhs._v[1],
+		        _v[2]-rhs._v[2], _v[3]-rhs._v[3] );
+        }
+
+        /// unary vector subtract
+        inline UByte4& operator -= (const UByte4& rhs)
+        {
+            _v[0]-=rhs._v[0];
+            _v[1]-=rhs._v[1];
+            _v[2]-=rhs._v[2];
+            _v[3]-=rhs._v[3];
+            return *this;
+        }
+
+        friend inline std::ostream& operator << (std::ostream& output, const UByte4& vec)
+        {
+	    output << vec._v[0] << " "
+                   << vec._v[1] << " "
+                   << vec._v[2] << " "
+                   << vec._v[3];
+	    return output; 	// to enable cascading
+	}
+
+};	// end of class UByte4
+
+
+
+}	// end of namespace osg
+
+#endif
diff --git a/include/osg/Vec4 b/include/osg/Vec4
index 0dbdbb436..012bfca3d 100644
--- a/include/osg/Vec4
+++ b/include/osg/Vec4
@@ -96,7 +96,6 @@ class Vec4
                    (unsigned long)clampTo((_v[0]*255.0f),0.0f,255.0f);
         }
 
-
         inline const bool valid() const { return !isNaN(); }
         inline const bool isNaN() const { return osg::isNaN(_v[0]) || osg::isNaN(_v[1]) || osg::isNaN(_v[2]) || osg::isNaN(_v[3]); }
 
@@ -110,13 +109,13 @@ class Vec4
         }
 
         /// multiply by scalar
-        inline Vec4 operator * (const float& rhs) const
+        inline Vec4 operator * (const float rhs) const
         {
             return Vec4(_v[0]*rhs, _v[1]*rhs, _v[2]*rhs, _v[3]*rhs);
         }
 
         /// unary multiply by scalar
-        inline Vec4& operator *= (const float& rhs)
+        inline Vec4& operator *= (const float rhs)
         {
             _v[0]*=rhs;
             _v[1]*=rhs;
@@ -126,13 +125,13 @@ class Vec4
         }
 
         /// divide by scalar
-        inline Vec4 operator / (const float& rhs) const
+        inline Vec4 operator / (const float rhs) const
         {
             return Vec4(_v[0]/rhs, _v[1]/rhs, _v[2]/rhs, _v[3]/rhs);
         }
 
         /// unary divide by scalar
-        inline Vec4& operator /= (const float& rhs)
+        inline Vec4& operator /= (const float rhs)
         {
             _v[0]/=rhs;
             _v[1]/=rhs;