qhwvideobuffer_p.h

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// Copyright (C) 2024 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#ifndef QHWVIDEOBUFFER_P_H
#define QHWVIDEOBUFFER_P_H
 
//
//  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 "qabstractvideobuffer.h"
#include "qvideoframe.h"
 
#include <QtGui/qmatrix4x4.h>
 
#include <optional>
 
QT_BEGIN_NAMESPACE
 
class QRhi;
class QRhiTexture;
class QVideoFrame;
 
/**
 * @brief QVideoFrameTexturesHandles is the base class, providing texture handles for frame planes.
 *        Instances of the class may own textures, share ownership, or refer to inner hw textures
 *        of QVideoFrame. Referencing to inner frame's textures without shared ownership is
 *        not recommended, we strive to get around it; if texture are referencing,
 *        the source frame is kept in the QVideoFrameTextures instance via its
 *        constructor-provided source frame.
 */
class Q_MULTIMEDIA_EXPORT QVideoFrameTexturesHandles
{
public:
    virtual ~QVideoFrameTexturesHandles();
 
    virtual quint64 textureHandle(QRhi &, int /*plane*/) { return 0; }
 
    // Set when the textures don't have the layout of the frame's pixel format, e.g. a
    // single-image import, which exposes one texture for a multi-plane frame.
    virtual std::optional<QVideoFrameFormat::PixelFormat> texturePixelFormat() const { return {}; }
};
using QVideoFrameTexturesHandlesUPtr = std::unique_ptr<QVideoFrameTexturesHandles>;
 
/**
 * @brief QVideoFrameTextures is the base class representing an abstraction layer
 *        between QVideoFrame's texture(s) and rhi's plane textures.
 *        QVideoFrameTextures must own the inner rhi textures or
 *        share ownership. QVideoFrameTextures instances are propagated to
 *        QVideoFrameTexturesPool, where their lifetime is managed
 *        according to results of QRhi::currentFrameSlot upon rendering.
 *
 */
class Q_MULTIMEDIA_EXPORT QVideoFrameTextures
{
public:
    explicit QVideoFrameTextures(QVideoFrame sourceFrame = {});
    virtual ~QVideoFrameTextures();
    virtual QRhiTexture *texture(uint plane) const = 0;
 
    /**
     * @brief The virtual method should be invoked after QRhi::endFrame to unmap and free
     *        internal resources that are not needed anymore.
     */
    virtual void onFrameEndInvoked() { }
 
    virtual QVideoFrameTexturesHandlesUPtr takeHandles() { return nullptr; }
 
private:
    QVideoFrame m_sourceFrame;
};
using QVideoFrameTexturesUPtr = std::unique_ptr<QVideoFrameTextures>;
 
class Q_MULTIMEDIA_EXPORT QHwVideoBuffer : public QAbstractVideoBuffer,
                                           public QVideoFrameTexturesHandles
{
public:
    QHwVideoBuffer();
 
    ~QHwVideoBuffer() override;
 
    // returns rhi in the current thread that has been associated with the frame
    // during texture mapping or texture converter initialization.
    virtual QRhi *associatedCurrentThreadRhi() const { return nullptr; }
 
    QVideoFrameFormat format() const final
    {
        // invalid by design: we have to go through QVideoFramePrivate::createFrame
        return {};
    }
 
    virtual QMatrix4x4 externalTextureMatrix() const { return {}; }
 
    virtual QVideoFrameTexturesUPtr mapTextures(QRhi &rhi,
                                                QVideoFrameTexturesUPtr & /*oldTextures*/)
    {
        return mapTextures(rhi);
    }
    virtual QVideoFrameTexturesUPtr mapTextures(QRhi &) { return nullptr; }
 
    virtual void initTextureConverter(QRhi &) { }
 
    virtual bool isDmaBuf() const { return false; }
};
 
QT_END_NAMESPACE
 
#endif // QHWVIDEOBUFFER_P_H