/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield 
 *
 * This library is open source and may be redistributed and/or modified under  
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or 
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSG_CULLFACE
#define OSG_CULLFACE 1

#include <osg/GL>
#include <osg/StateAttribute>

namespace osg {

/** Class to globally enable/disable OpenGL's polygon culling mode.
 */     
class OSG_EXPORT CullFace : public StateAttribute
{
    public :
    
        enum Mode {
            FRONT = GL_FRONT,
            BACK = GL_BACK,
            FRONT_AND_BACK = GL_FRONT_AND_BACK
        };
    
        CullFace(Mode mode=BACK):
            _mode(mode) {}

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        CullFace(const CullFace& cf,const CopyOp& copyop=CopyOp::SHALLOW_COPY):
            StateAttribute(cf,copyop),
            _mode(cf._mode) {}

        META_StateAttribute(osg, CullFace, CULLFACE);
        
        /** return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs.*/
        virtual int compare(const StateAttribute& sa) const
        {
            // check the types are equal and then create the rhs variable
            // used by the COMPARE_StateAttribute_Parameter macro's below.
            COMPARE_StateAttribute_Types(CullFace,sa)

            // compare each parameter in turn against the rhs.
            COMPARE_StateAttribute_Parameter(_mode)

            return 0; // passed all the above comparison macro's, must be equal.
        }

        virtual bool getModeUsage(ModeUsage& usage) const
        {
            usage.usesMode(GL_CULL_FACE);
            return true;
        }

        inline void setMode(Mode mode) { _mode = mode; }

        inline Mode getMode() const { return _mode; }
    
        virtual void apply(State& state) const;
        
    protected:
    
        virtual ~CullFace();
        
        Mode _mode;

};

}

#endif