/****************************************************************************
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** Copyright (C) 2016 The Qt Company Ltd.
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** This file is part of the QtGui module of the Qt Toolkit.
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** General Public License version 3 as published by the Free Software
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** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or (at your option) the GNU General
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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.
//

#ifndef QOPENGLTEXTURECACHE_P_H
#define QOPENGLTEXTURECACHE_P_H

#include <QtGui/private/qtguiglobal_p.h>
#include <QHash>
#include <QObject>
#include <QCache>
#include <private/qopenglcontext_p.h>
#include <QtCore/qmutex.h>

QT_BEGIN_NAMESPACE

class QOpenGLCachedTexture;

class Q_GUI_EXPORT QOpenGLTextureCache : public QOpenGLSharedResource
{
public:
    static QOpenGLTextureCache *cacheForContext(QOpenGLContext *context);

    QOpenGLTextureCache(QOpenGLContext *);
    ~QOpenGLTextureCache();

    enum BindOption {
        NoBindOption                            = 0x0000,
        PremultipliedAlphaBindOption            = 0x0001,
        UseRedFor8BitBindOption                 = 0x0002,
    };
    Q_DECLARE_FLAGS(BindOptions, BindOption)

    GLuint bindTexture(QOpenGLContext *context, const QPixmap &pixmap, QOpenGLTextureCache::BindOptions options = PremultipliedAlphaBindOption);
    GLuint bindTexture(QOpenGLContext *context, const QImage &image, QOpenGLTextureCache::BindOptions options = PremultipliedAlphaBindOption);

    void invalidate(qint64 key);

    void invalidateResource() Q_DECL_OVERRIDE;
    void freeResource(QOpenGLContext *ctx) Q_DECL_OVERRIDE;

private:
    GLuint bindTexture(QOpenGLContext *context, qint64 key, const QImage &image, QOpenGLTextureCache::BindOptions options);

    QMutex m_mutex;
    QCache<quint64, QOpenGLCachedTexture> m_cache;
};

Q_DECLARE_OPERATORS_FOR_FLAGS(QOpenGLTextureCache::BindOptions)

class QOpenGLCachedTexture
{
public:
    QOpenGLCachedTexture(GLuint id, QOpenGLTextureCache::BindOptions options, QOpenGLContext *context);
    ~QOpenGLCachedTexture() { m_resource->free(); }

    GLuint id() const { return m_resource->id(); }
    QOpenGLTextureCache::BindOptions options() const { return m_options; }

private:
    QOpenGLSharedResourceGuard *m_resource;
    QOpenGLTextureCache::BindOptions m_options;
};

QT_END_NAMESPACE

#endif

