//C++ header - Open Scene Graph - Copyright (C) 1998-2002 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSG_TEXTURECUBEMAP
#define OSG_TEXTURECUBEMAP 1

#include <osg/Texture>

#ifndef GL_TEXTURE_CUBE_MAP
#define GL_TEXTURE_CUBE_MAP 0x8513
#endif

namespace osg {

/** TextureCubeMap state class which encapsulates OpenGl texture cubemap functionality.*/
class SG_EXPORT TextureCubeMap : public Texture
{

    public :
        
        TextureCubeMap();

        /** Copy constructor using CopyOp to manage deep vs shallow copy.*/
        TextureCubeMap(const TextureCubeMap& cm,const CopyOp& copyop=CopyOp::SHALLOW_COPY);

        META_StateAttribute(osg, TextureCubeMap,TEXTURE);
        
        /** return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs.*/
        virtual int compare(const StateAttribute& rhs) const;

        enum Face {
            POSITIVE_X=0,
            NEGATIVE_X=1,
            POSITIVE_Y=2,
            NEGATIVE_Y=3,
            POSITIVE_Z=4,
            NEGATIVE_Z=5
        };

        /** Set the texture image for specified face. */
        void setImage(Face, Image* image);

        /** Get the texture image for specified face. */
        Image* getImage(Face);

        /** Get the const texture image for specified face. */
        const Image* getImage(Face) const;


        /** Set the texture width and height. If width or height are zero then
          * the repsective size value is calculated from the source image sizes. */
        inline void setTextureSize(int width, int height) const
        {
            _textureWidth = width;
            _textureHeight = height;
        }

        /** Get the texture subload width. */
        inline void getTextureSize(int& width, int& height) const
        {
            width = _textureWidth;
            height = _textureHeight;
        }


        class SubloadCallback : public Referenced
        {
            public:
                virtual void load(const TextureCubeMap& texture,State& state) const = 0;
                virtual void subload(const TextureCubeMap& texture,State& state) const = 0;
        };
        
        void setSubloadCallback(SubloadCallback* cb) { _subloadCallback = cb;; }
        
        SubloadCallback* getSubloadCallback() { return _subloadCallback.get(); }

        const SubloadCallback* getSubloadCallback() const { return _subloadCallback.get(); }


        /** Set the number of mip map levels the the texture has been created with,
            should only be called within an osg::Texuture::apply() and custom OpenGL texture load.*/
        void setNumMipmapLevels(unsigned int num) const { _numMimpmapLevels=num; }

        /** Get the number of mip map levels the the texture has been created with.*/
        unsigned int getNumMipmapLevels() const { return _numMimpmapLevels; }        

        /** On first apply (unless already compiled), create the minmapped 
          * texture and bind it, subsequent apply will simple bind to texture.*/
        virtual void apply(State& state) const;
        
    protected :

        virtual ~TextureCubeMap();
        
        bool imagesValid() const;
        
        virtual void computeInternalFormat() const;

        mutable ref_ptr<Image> _images[6];

        // subloaded images can have different texture and image sizes.
        mutable GLsizei _textureWidth, _textureHeight;
        
        // number of mip map levels the the texture has been created with,        
        mutable GLsizei _numMimpmapLevels;

        ref_ptr<SubloadCallback> _subloadCallback;
};

}

#endif