From Michael Platings, To address performance bottleneck that occurs when using large number of uniforms introduced a name to uniqued ID scheme for Uniforms so comparisons can be done on a uint rather than a string.

include/osg/Program

@@ -147,8 +147,9 @@ class OSG_EXPORT Program : public osg::StateAttribute
             GLenum _type;
             GLint _size;
         };
+        typedef std::map< unsigned int, ActiveVarInfo > ActiveUniformMap;
         typedef std::map< std::string, ActiveVarInfo > ActiveVarInfoMap;
-        const ActiveVarInfoMap& getActiveUniforms(unsigned int contextID) const;
+        const ActiveUniformMap& getActiveUniforms(unsigned int contextID) const;
         const ActiveVarInfoMap& getActiveAttribs(unsigned int contextID) const;
 
     public:
@@ -189,7 +190,7 @@ class OSG_EXPORT Program : public osg::StateAttribute
                 
                 inline void apply(const Uniform& uniform) const
                 {
-                    GLint location = getUniformLocation(uniform.getName());
+                    GLint location = getUniformLocation(uniform.getNameID());
                     if (location>=0)
                     {
                         if ((unsigned int)location>=_lastAppliedUniformList.size()) _lastAppliedUniformList.resize(location+1);
@@ -211,10 +212,10 @@ class OSG_EXPORT Program : public osg::StateAttribute
                     }
                 }
 
-                const ActiveVarInfoMap& getActiveUniforms() const {return _uniformInfoMap;}
+                const ActiveUniformMap& getActiveUniforms() const {return _uniformInfoMap;}
                 const ActiveVarInfoMap& getActiveAttribs() const {return _attribInfoMap;}
 
-                inline GLint getUniformLocation( const std::string& name ) const { ActiveVarInfoMap::const_iterator itr = _uniformInfoMap.find(name); return (itr!=_uniformInfoMap.end()) ? itr->second._location : -1; }
+                inline GLint getUniformLocation( unsigned int uniformNameID ) const { ActiveUniformMap::const_iterator itr = _uniformInfoMap.find(uniformNameID); return (itr!=_uniformInfoMap.end()) ? itr->second._location : -1; }
                 inline GLint getAttribLocation( const std::string& name ) const { ActiveVarInfoMap::const_iterator itr = _attribInfoMap.find(name); return (itr!=_attribInfoMap.end()) ? itr->second._location : -1; }
 
                 inline void addShaderToAttach(Shader *shader)
@@ -243,7 +244,7 @@ class OSG_EXPORT Program : public osg::StateAttribute
                 bool _isLinked;
                 const unsigned int _contextID;
 
-                ActiveVarInfoMap _uniformInfoMap;
+                ActiveUniformMap _uniformInfoMap;
                 ActiveVarInfoMap _attribInfoMap;
                 
                 typedef std::pair<osg::ref_ptr<const osg::Uniform>, unsigned int> UniformModifiedCountPair;

include/osg/State

@@ -1253,7 +1253,7 @@ class OSG_EXPORT State : public Referenced, public Observer
         }
         inline const Program::PerContextProgram* getLastAppliedProgramObject() const { return _lastAppliedProgramObject; }
 
-        inline GLint getUniformLocation( const std::string& name ) const { return _lastAppliedProgramObject ? _lastAppliedProgramObject->getUniformLocation(name) : -1; }
+        inline GLint getUniformLocation( unsigned int uniformNameID ) const { return _lastAppliedProgramObject ? _lastAppliedProgramObject->getUniformLocation(uniformNameID) : -1; }
         inline GLint getAttribLocation( const std::string& name ) const { return _lastAppliedProgramObject ? _lastAppliedProgramObject->getAttribLocation(name) : -1; }
 
         typedef std::pair<const StateAttribute*,StateAttribute::OverrideValue>  AttributePair;

include/osg/Uniform

@@ -268,6 +268,9 @@ class OSG_EXPORT Uniform : public Object
         /** Return the internal data array type corresponding to a GLSL type */
         static GLenum getInternalArrayType( Type t );
 
+        /** Return the number that the name maps to uniquely */
+        static unsigned int getNameID(const std::string& name);
+
         /** convenient scalar (non-array) constructors w/ assignment */
         explicit Uniform( const char* name, float f );
         explicit Uniform( const char* name, int i );
@@ -472,6 +475,8 @@ class OSG_EXPORT Uniform : public Object
         inline void setModifiedCount(unsigned int mc) { _modifiedCount = mc; }
         inline unsigned int getModifiedCount() const { return _modifiedCount; }
 
+        /** Get the number that the Uniform's name maps to uniquely */
+        unsigned int getNameID() const;
 
         void apply(const GL2Extensions* ext, GLint location) const;
 
@@ -493,6 +498,8 @@ class OSG_EXPORT Uniform : public Object
 
         Type                _type;
         unsigned int        _numElements;
+        unsigned int        _nameID;
+
 
         // The internal data for osg::Uniforms are stored as an array of
         // getInternalArrayType() of length getInternalArrayNumElements().

src/osg/Program.cpp

@@ -452,7 +452,7 @@ bool Program::getGlProgramInfoLog(unsigned int contextID, std::string& log) cons
     return getPCP( contextID )->getInfoLog( log );
 }
 
-const Program::ActiveVarInfoMap& Program::getActiveUniforms(unsigned int contextID) const
+const Program::ActiveUniformMap& Program::getActiveUniforms(unsigned int contextID) const
 {
     return getPCP( contextID )->getActiveUniforms();
 }
@@ -609,7 +609,7 @@ void Program::PerContextProgram::linkProgram(osg::State& state)
             
             if( loc != -1 )
             {
-                _uniformInfoMap[reinterpret_cast<char*>(name)] = ActiveVarInfo(loc,type,size);
+                _uniformInfoMap[Uniform::getNameID(reinterpret_cast<const char*>(name))] = ActiveVarInfo(loc,type,size);
 
                 OSG_INFO << "\tUniform \"" << name << "\""
                     << " loc="<< loc

src/osg/Uniform.cpp

@@ -21,6 +21,7 @@
 #include <osg/Program>
 #include <osg/StateSet>
 
+#include <limits.h>
 #include <algorithm>
 
 using namespace osg;
@@ -30,13 +31,13 @@ using namespace osg;
 ///////////////////////////////////////////////////////////////////////////
 
 Uniform::Uniform() :
-    _type(UNDEFINED), _numElements(0), _modifiedCount(0)
+    _type(UNDEFINED), _numElements(0), _nameID(UINT_MAX), _modifiedCount(0)
 {
 }
 
 
 Uniform::Uniform( Type type, const std::string& name, int numElements ) :
-    _type(type), _numElements(0), _modifiedCount(0)
+    _type(type), _numElements(0), _nameID(UINT_MAX), _modifiedCount(0)
 {
     setName(name);
     setNumElements(numElements);
@@ -88,6 +89,7 @@ void Uniform::setName( const std::string& name )
         return;
     }
     _name = name;
+    _nameID = getNameID(name);
 }
 
 void Uniform::setNumElements( unsigned int numElements )
@@ -255,6 +257,7 @@ void Uniform::copyData(const Uniform& rhs)
 {
     // caller must ensure that _type==rhs._type
     _numElements = rhs._numElements;
+    _nameID = rhs._nameID;
     if (rhs._floatArray.valid() || rhs._intArray.valid() || rhs._uintArray.valid()) allocateDataArray();
     if( _floatArray.valid() && rhs._floatArray.valid() ) *_floatArray = *rhs._floatArray;
     if( _intArray.valid() && rhs._intArray.valid() )     *_intArray = *rhs._intArray;
@@ -601,6 +604,24 @@ GLenum Uniform::getInternalArrayType( Type t )
 }
 
 
+unsigned int Uniform::getNameID(const std::string& name)
+{
+    typedef std::map<std::string, unsigned int> UniformNameIDMap;
+    static OpenThreads::Mutex s_mutex_uniformNameIDMap;
+    static UniformNameIDMap s_uniformNameIDMap;
+
+    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(s_mutex_uniformNameIDMap);
+    UniformNameIDMap::iterator it = s_uniformNameIDMap.find(name);
+    if (it != s_uniformNameIDMap.end())
+    {
+        return it->second;
+    }
+    unsigned int id = s_uniformNameIDMap.size();
+    s_uniformNameIDMap.insert(UniformNameIDMap::value_type(name, id));
+    return id;
+}
+
+
 ///////////////////////////////////////////////////////////////////////////
 // value constructors for single-element (ie: non-array) uniforms
 
@@ -1388,6 +1409,11 @@ bool Uniform::getElement( unsigned int index, bool& b0, bool& b1, bool& b2, bool
     return true;
 }
 
+unsigned int Uniform::getNameID() const
+{
+    return _nameID;
+}
+
 ///////////////////////////////////////////////////////////////////////////
 
 void Uniform::apply(const GL2Extensions* ext, GLint location) const