/*****************************************************************
 KWin - the KDE window manager
 This file is part of the KDE project.

Copyright (C) 2006-2007 Rivo Laks <rivolaks@hot.ee>

You can Freely distribute this program under the GNU General Public
License. See the file "COPYING" for the exact licensing terms.
******************************************************************/

#ifndef KWIN_GLUTILS_H
#define KWIN_GLUTILS_H

#include <config.h>

#ifdef HAVE_OPENGL
#include <GL/gl.h>
#include <GL/glx.h>
#include <fixx11h.h>
#endif

#include <QPixmap>
#include <QString>
#include <QImage>
#include <QSize>

#include <kwinglutils_funcs.h>


template< class K, class V > class QHash;


namespace KWin
{


// Initializes GLX function pointers
void KWIN_EXPORT initGLX();
// Initializes OpenGL stuff. This includes resolving function pointers as
//  well as checking for GL version and extensions
//  Note that GL context has to be created by the time this function is called
void KWIN_EXPORT initGL();


// Number of supported texture units
extern KWIN_EXPORT int glTextureUnitsCount;


bool KWIN_EXPORT hasGLVersion(int major, int minor, int release = 0);
bool KWIN_EXPORT hasGLXVersion(int major, int minor, int release = 0);
// use for both OpenGL and GLX extensions
bool KWIN_EXPORT hasGLExtension(const QString& extension);

inline bool KWIN_EXPORT isPowerOfTwo( int x ) { return (( x & ( x - 1 )) == 0 ); }
int KWIN_EXPORT nearestPowerOfTwo( int x );

#ifdef HAVE_OPENGL

class KWIN_EXPORT GLTexture
    {
    public:
        GLTexture();
        GLTexture( const QImage& image, GLenum target = GL_TEXTURE_2D );
        GLTexture( const QPixmap& pixmap, GLenum target = GL_TEXTURE_2D );
        GLTexture( const QString& fileName );
        virtual ~GLTexture();

        bool isNull() const;

        virtual bool load( const QImage& image, GLenum target = GL_TEXTURE_2D );
        virtual bool load( const QPixmap& pixmap, GLenum target = GL_TEXTURE_2D );
        virtual bool load( const QString& fileName );
        virtual void discard();
        virtual void bind();
        virtual void unbind();
        void enableUnnormalizedTexCoords();
        void disableUnnormalizedTexCoords();

        GLuint texture() const;
        GLenum target() const;
        GLenum filter() const;
        virtual bool isDirty() const;
        void setTexture( GLuint texture );
        void setTarget( GLenum target );
        void setFilter( GLenum filter );
        virtual void setDirty();

        static void initStatic();
        static bool NPOTTextureSupported()  { return mNPOTTextureSupported; }
        static bool framebufferObjectSupported()  { return mFramebufferObjectSupported; }
        static bool saturationSupported()  { return mSaturationSupported; }

    protected:
        void enableFilter();
        QImage convertToGLFormat( const QImage& img ) const;

        GLuint mTexture;
        GLenum mTarget;
        GLenum mFilter;
        QSize mSize;
        QSizeF mScale; // to un-normalize GL_TEXTURE_2D
        bool y_inverted; // texture has y inverted
        bool can_use_mipmaps;
        bool has_valid_mipmaps;

    private:
        void init();

        static bool mNPOTTextureSupported;
        static bool mFramebufferObjectSupported;
        static bool mSaturationSupported;
    };

class KWIN_EXPORT GLShader
    {
    public:
        GLShader(const QString& vertexfile, const QString& fragmentfile);

        bool isValid() const  { return mValid; }
        void bind();
        void unbind();

        int uniformLocation(const QString& name);
        bool setUniform(const QString& name, float value);
        bool setUniform(const QString& name, int value);
        int attributeLocation(const QString& name);
        bool setAttribute(const QString& name, float value);


        static void initStatic();
        static bool fragmentShaderSupported()  { return mFragmentShaderSupported; }
        static bool vertexShaderSupported()  { return mVertexShaderSupported; }


    protected:
        bool loadFromFiles(const QString& vertexfile, const QString& fragmentfile);
        bool load(const QString& vertexsource, const QString& fragmentsource);


    private:
        unsigned int mProgram;
        bool mValid;
        QHash< QString, int >* mVariableLocations;
        static bool mFragmentShaderSupported;
        static bool mVertexShaderSupported;
    };

#endif

} // namespace

#endif