qwindowsd3d11texturereadback.cpp

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// Copyright (C) 2026 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

#include "qwindowsd3d11texturereadback_p.h"

#include <QtCore/qloggingcategory.h>

#include <QtCore/private/qsystemerror_p.h>

QT_BEGIN_NAMESPACE

namespace QtMultimediaPrivate {

namespace {

Q_LOGGING_CATEGORY(lcD3D11TextureReadback, "qt.multimedia.windows.d3d11texturereadback");

QAbstractVideoBuffer::MapData

QWindowsD3D11TextureReadback::map(const ComPtr<ID3D11Device> &device,

                                  const ComPtr<ID3D11Texture2D> &texture, const QSize &frameSize)

    Q_ASSERT(device);

    Q_ASSERT(texture);

    if (m_mapped)

        return {};

    device->GetImmediateContext(&m_stagingCtx);

    CD3D11_TEXTURE2D_DESC desc;

    texture->GetDesc(&desc);

    desc.Usage = D3D11_USAGE_STAGING;

    desc.BindFlags = 0;

    desc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;

    desc.MiscFlags = 0;

    if (const HRESULT hr = device->CreateTexture2D(&desc, nullptr, &m_stagingTex); FAILED(hr)) {

        qCWarning(lcD3D11TextureReadback)

                << "CreateTexture2D failed:" << QSystemError::windowsComString(hr);

        return {};

    m_stagingCtx->CopyResource(m_stagingTex.Get(), texture.Get());

    D3D11_MAPPED_SUBRESOURCE mapped = {};

    if (const HRESULT hr = m_stagingCtx->Map(m_stagingTex.Get(), 0, D3D11_MAP_READ, 0, &mapped);

        FAILED(hr)) {

        qCWarning(lcD3D11TextureReadback) << "Map failed:" << QSystemError::windowsComString(hr);

        m_stagingTex.Reset();

        m_stagingCtx.Reset();

        return {};

    m_mapped = true;

    QAbstractVideoBuffer::MapData data;

    data.planeCount = 1;

    data.bytesPerLine[0] = static_cast<int>(mapped.RowPitch);

    data.data[0] = static_cast<uchar *>(mapped.pData);

    data.dataSize[0] = static_cast<int>(mapped.RowPitch) * frameSize.height();

    return data;

void QWindowsD3D11TextureReadback::unmap()

    if (!m_mapped)

        return;

    m_stagingCtx->Unmap(m_stagingTex.Get(), 0);

    m_stagingTex.Reset();

    m_stagingCtx.Reset();

    m_mapped = false;

} // namespace QtMultimediaPrivate

QT_END_NAMESPACE