#ifndef OSG_ALPHAFUNC
#define OSG_ALPHAFUNC 1

#include <osg/StateAttribute>
#include <osg/StateSet>

namespace osg {

/** Encapsulte OpenGL glAlphaFunc.
*/     
class SG_EXPORT AlphaFunc : public StateAttribute
{
    public :
    
    
        AlphaFunc();
        virtual bool isSameKindAs(const Object* obj) const { return dynamic_cast<const AlphaFunc*>(obj)!=0L; }
        virtual Object* clone() const { return new AlphaFunc(); }
        virtual const char* className() const { return "AlphaFunc"; }
    
        virtual const Type getType() const { return ALPHAFUNC; }
        
        virtual void setStateSetModes(StateSet& ds,const GLModeValue value) const
        {
            ds.setMode(GL_ALPHA_TEST,value);
        }

        enum ComparisonFunction {
            NEVER = GL_NEVER,
            LESS = GL_LESS,
            EQUAL = GL_EQUAL,
            LEQUAL = GL_LEQUAL,
            GREATER = GL_GREATER,
            NOTEQUAL = GL_NOTEQUAL,
            GEQUAL = GL_GEQUAL,
            ALWAYS = GL_ALWAYS
        };

        inline void setFunction(const ComparisonFunction func,const float ref)
        {
            _comparisonFunc = func;
            _referenceValue = ref;
        }
        
        inline const ComparisonFunction getFunction() const { return _comparisonFunc; }
        
        inline const float getReferenceValue() const { return _referenceValue; }
        
        virtual void apply(State& state) const;

    protected:
    
        virtual ~AlphaFunc();

        ComparisonFunction _comparisonFunc;
        float _referenceValue;

};

};

#endif