source: trunk/tools/qmeegographicssystemhelper/qmeegofencesync.h@ 953

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#ifndef QMEEGOFENCESYNC_H
#define QMEEGOFENCESYNC_H

#include <QWidget>

class QMeeGoFenceSyncPrivate;

//! A synchronization helper for GL pipeline.
/*!
 Fence syncs provide a mechanism for synchronizing access to certain GL primitives
 and make it possible for the application developer to be sure that a certain point
 in the GL processing pipeline has been already executed before continuing operation.

 Currently fence syncs are only useful in conjunction with QMeeGoLivePixmaps.
 \code
 ...
 // In your paint/expose event:
 QImage *image = livePixmap->lock(&someGlobalFenceSync);
 // Modify the image...
 livePixmap->release(image);

 painter->drawPixmap(0, 0, *livePixmap);
 someGlobalFenceSync.setSyncPoint();
 ...
 \endcode

 Assuming the paint/expose events come repeatedly, the lock operation
 will block till the previous event completed painting the livePixmap.
*/

class Q_DECL_EXPORT QMeeGoFenceSync : public QObject
{
public:
    //! Constructs a new fence sync.
    /*!
     The fence sync is created without a sync point. You need to set the sync point manually.
    */
    QMeeGoFenceSync(QWidget *parent = 0);

    //! Destructor for the fence sync.
    virtual ~QMeeGoFenceSync();

    //! Sets the fence sync.
    /*!
      The fence sync synchronization point should be set after all drawing has been scheduled.
      Setting a synchronization point always overrides the previous point -- whetver is was
      used (waited upon) or not.
    */
    void setSyncPoint();

private:
    Q_DISABLE_COPY(QMeeGoFenceSync)
    Q_DECLARE_PRIVATE(QMeeGoFenceSync)

protected:
    QScopedPointer<QMeeGoFenceSyncPrivate> d_ptr; //! Private bits.
    friend class QMeeGoLivePixmap;
};

#endif