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#ifndef QSGTEXTUREMANAGER_H
#define QSGTEXTUREMANAGER_H

#include "qmlscene_global.h"
#include "qsgcontext.h"

#include <QObject>
#include <QImage>

class QSGTextureManagerPrivate;

class QT_SCENEGRAPH_EXPORT QSGTexture : public QObject
{
    Q_OBJECT

public:
    enum Status {
        Null,
        Loading,
        Ready,
        Error
    };

    QSGTexture();
    ~QSGTexture();

    void setTextureId(int id) { m_texture_id = id; }
    int textureId() const { return m_texture_id; }

    void setTextureSize(const QSize &size) { m_texture_size = size; }
    QSize textureSize() const { return m_texture_size; }

    void setAlphaChannel(bool hasAlpha) { m_has_alpha = hasAlpha; }
    bool hasAlphaChannel() const { return m_has_alpha; }

    void setOwnsTexture(bool does) { m_owns_texture = does; }
    bool ownsTexture() const { return m_owns_texture; }

    void setHasMipmaps(bool has) { m_has_mipmaps = has; }
    bool hasMipmaps() const { return m_has_mipmaps; }

    void setStatus(Status s);
    Status status() const { return m_status; }

signals:
    void statusChanged(int status);

    // ### put into the private object...
public:
    Status m_status;
    int m_texture_id;
    mutable int m_ref_count;

    QSize m_texture_size;

    uint m_has_alpha : 1;
    uint m_owns_texture : 1;
    uint m_has_mipmaps : 1;

    friend class QSGTextureRef;
};


class QT_SCENEGRAPH_EXPORT QSGTextureRef
{
public:
    QSGTextureRef()
        : m_texture(0)
    {
    }

    QSGTextureRef(const QSGTexture *texture, const QRectF &subrect = QRectF(0, 0, 1, 1))
        : m_texture(texture)
        , m_sub_rect(subrect)
    {
        if (texture)
            ++texture->m_ref_count;
    }

    QSGTextureRef(const QSGTextureRef &other)
        : m_sub_rect(other.m_sub_rect)
    {
        m_texture = other.m_texture;
        ++m_texture->m_ref_count;
    }

    ~QSGTextureRef()
    {
        deref();
    }

    void setSubRect(const QRectF &subrect) { m_sub_rect = subrect; }
    QRectF subRect() const { return m_sub_rect; }

    const QSGTexture *texture() const { return m_texture; }
    const QSGTexture *operator->() const { return m_texture; }

    QSGTextureRef &operator=(const QSGTextureRef &other)
    {
        ++other.m_texture->m_ref_count;
        deref();
        m_texture = other.m_texture;
        m_sub_rect = other.m_sub_rect;

        return *this;
    }

    bool isNull() const { return m_texture == 0; }

    bool isReady() const { return m_texture != 0 && m_texture->status() == QSGTexture::Ready; }

private:
    void deref() {
        if (m_texture && !--m_texture->m_ref_count) {
            delete m_texture;
        }
    }

    const QSGTexture *m_texture;
    QRectF m_sub_rect;
};


class QT_SCENEGRAPH_EXPORT QSGTextureManager : public QObject
{
    Q_OBJECT

public:
    QSGTextureManager();

    virtual void setContext(QSGContext *context);
    QSGContext *context() const;

    virtual QSGTextureRef upload(const QImage &image);
    virtual QSGTextureRef requestUpload(const QImage &image, const QObject *listener, const char *slot);

    static void swizzleBGRAToRGBA(QImage *image);

    int maxTextureSize() const;

protected:
    void timerEvent(QTimerEvent *);

private slots:
    void processAsyncTextures();
    void textureDestroyed(QObject *texture);

private:
    QSGTextureManagerPrivate *d;
};

#endif // QSGTEXTUREMANAGER_H