qt-everywhere-src-5.15.1/qtquick3d/src/runtimerender/resourcemanager/qssgrenderresourcetexture2d.cpp

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#include "qssgrenderresourcetexture2d_p.h"

QT_BEGIN_NAMESPACE

QSSGResourceTexture2D::QSSGResourceTexture2D(const QSSGRef<QSSGResourceManager> &mgr,
                                                 const QSSGRef<QSSGRenderTexture2D> &inTexture)
    : m_resourceManager(mgr), m_texture(inTexture)
{
    if (inTexture)
        m_textureDetails = inTexture->textureDetails();
}

QSSGResourceTexture2D::QSSGResourceTexture2D(const QSSGRef<QSSGResourceManager> &mgr,
                                                 quint32 width,
                                                 quint32 height,
                                                 QSSGRenderTextureFormat inFormat,
                                                 quint32 inSamples)
    : m_resourceManager(mgr)
{
    ensureTexture(width, height, inFormat, inSamples);
}

QSSGResourceTexture2D::~QSSGResourceTexture2D()
{
    releaseTexture();
}

// Returns true if the texture was allocated, false if nothing changed (no allocation).
bool QSSGResourceTexture2D::textureMatches(qint32 width, qint32 height, QSSGRenderTextureFormat inFormat, qint32 inSamples)
{
    Q_ASSERT(width >= 0 && height >= 0 && inSamples >= 0);
    return m_texture && m_textureDetails.width == width && m_textureDetails.height == height
            && m_textureDetails.format == inFormat && m_textureDetails.sampleCount == inSamples;
}

bool QSSGResourceTexture2D::ensureTexture(qint32 width, qint32 height, QSSGRenderTextureFormat inFormat, qint32 inSamples)
{
    Q_ASSERT(width >= 0 && height >= 0 && inSamples >= 0);
    if (textureMatches(width, height, inFormat, inSamples))
        return false;

    if (m_texture && inSamples > 1) {
        // we cannot resize MSAA textures though release first
        releaseTexture();
    }

    if (!m_texture)
        m_texture = m_resourceManager->allocateTexture2D(width, height, inFormat, inSamples);
    else {
        // multisampled textures are immuteable
        Q_ASSERT(inSamples == 1);
        m_texture->setTextureData(QSSGByteView(), 0, width, height, inFormat);
    }

    m_textureDetails = m_texture->textureDetails();
    return true;
}

void QSSGResourceTexture2D::releaseTexture()
{
    if (m_texture) {
        m_resourceManager->release(m_texture);
        forgetTexture();
    }
}

void QSSGResourceTexture2D::forgetTexture()
{
    m_texture = nullptr;
}

void QSSGResourceTexture2D::stealTexture(QSSGResourceTexture2D &inOther)
{
    releaseTexture();
    m_texture = inOther.m_texture;
    m_textureDetails = inOther.m_textureDetails;
    inOther.m_texture = nullptr;
}

void QSSGResourceTexture2D::swapTexture(QSSGResourceTexture2D &inOther)
{
    QSSGRef<QSSGRenderTexture2D> temp = inOther.m_texture;
    QSSGTextureDetails detailsTemp = inOther.m_textureDetails;
    inOther.m_texture = m_texture;
    inOther.m_textureDetails = m_textureDetails;
    m_texture = temp;
    m_textureDetails = detailsTemp;
}

QT_END_NAMESPACE