/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
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** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
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****************************************************************************/

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QMultiHash>
#include <QObject>
#include <QtOpenGL/QtOpenGL>
#include <private/qgl_p.h>

QT_BEGIN_NAMESPACE

class QGL2GradientCache
{
    struct CacheInfo
    {
        inline CacheInfo(QGradientStops s, qreal op, QGradient::InterpolationMode mode) :
            stops(s), opacity(op), interpolationMode(mode) {}

        GLuint texId;
        QGradientStops stops;
        qreal opacity;
        QGradient::InterpolationMode interpolationMode;
    };

    typedef QMultiHash<quint64, CacheInfo> QGLGradientColorTableHash;

public:
    static QGL2GradientCache *cacheForContext(const QGLContext *context);

    QGL2GradientCache() { }
    ~QGL2GradientCache() {cleanCache();}

    GLuint getBuffer(const QGradient &gradient, qreal opacity);
    inline int paletteSize() const { return 1024; }

protected:
    inline int maxCacheSize() const { return 60; }
    inline void generateGradientColorTable(const QGradient& gradient,
                                           uint *colorTable,
                                           int size, qreal opacity) const;
    GLuint addCacheElement(quint64 hash_val, const QGradient &gradient, qreal opacity);

    void cleanCache();

    QGLGradientColorTableHash cache;
};

QT_END_NAMESPACE