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#include <QtQuick/private/qsgcontext_p.h>
#include <QtQuick/private/qsgbatchrenderer_p.h>
#include <QtQuick/private/qsgdistancefieldutil_p.h>
#include <QtQuick/private/qsgdefaultdistancefieldglyphcache_p.h>
#include <QtQuick/private/qsgdefaultrectanglenode_p.h>
#include <QtQuick/private/qsgdefaultimagenode_p.h>
#include <QtQuick/private/qsgdefaultglyphnode_p.h>
#include <QtQuick/private/qsgdistancefieldglyphnode_p.h>
#include <QtQuick/private/qsgdistancefieldglyphnode_p_p.h>
#include <QtQuick/private/qsgshareddistancefieldglyphcache_p.h>
#include <QtQuick/private/qsgatlastexture_p.h>

#include <QtQuick/private/qsgtexture_p.h>
#include <QtQuick/private/qquickpixmapcache_p.h>

#include <QGuiApplication>
#include <QOpenGLContext>
#include <QQuickWindow>
#include <QtGui/qopenglframebufferobject.h>

#include <private/qqmlglobal_p.h>

#include <QtQuick/private/qsgtexture_p.h>
#include <QtGui/private/qguiapplication_p.h>
#include <qpa/qplatformintegration.h>

#include <qpa/qplatformsharedgraphicscache.h>

#include <private/qobject_p.h>
#include <qmutex.h>

#include <private/qqmlprofilerservice_p.h>

DEFINE_BOOL_CONFIG_OPTION(qmlDisableDistanceField, QML_DISABLE_DISTANCEFIELD)

/*
    Comments about this class from Gunnar:

    The QSGContext class is right now two things.. The first is the
    adaptation layer and central storage ground for all the things
    in the scene graph, like textures and materials. This part really
    belongs inside the scene graph coreapi.

    The other part is the QML adaptation classes, like how to implement
    rectangle nodes. This is not part of the scene graph core API, but
    more part of the QML adaptation of scene graph.

    If we ever move the scene graph core API into its own thing, this class
    needs to be split in two. Right now its one because we're lazy when it comes
    to defining plugin interfaces..
*/

QT_BEGIN_NAMESPACE

class QSGContextPrivate : public QObjectPrivate
{
public:
    QSGContextPrivate()
        : antialiasingMethod(QSGContext::UndecidedAntialiasing)
        , distanceFieldDisabled(qmlDisableDistanceField())
        , distanceFieldAntialiasing(
#if !defined(QT_OPENGL_ES) || defined(QT_OPENGL_ES_2_ANGLE)
              QSGGlyphNode::HighQualitySubPixelAntialiasing
#else
              QSGGlyphNode::GrayAntialiasing
#endif
              )
    {
    }

    ~QSGContextPrivate()
    {
    }

    QMutex mutex;
    QSGContext::AntialiasingMethod antialiasingMethod;
    bool distanceFieldDisabled;
    QSGDistanceFieldGlyphNode::AntialiasingMode distanceFieldAntialiasing;

    static QOpenGLContext *sharedOpenGLContext;
};

QOpenGLContext *QSGContextPrivate::sharedOpenGLContext = 0;

class QSGTextureCleanupEvent : public QEvent
{
public:
    QSGTextureCleanupEvent(QSGTexture *t) : QEvent(QEvent::User), texture(t) { }
    ~QSGTextureCleanupEvent() { delete texture; }
    QSGTexture *texture;
};

namespace QSGMultisampleAntialiasing {
    class ImageNode : public QSGDefaultImageNode {
    public:
        void setAntialiasing(bool) { }
    };


    class RectangleNode : public QSGDefaultRectangleNode {
    public:
        void setAntialiasing(bool) { }
    };
}


/*!
    \class QSGContext

    \brief The QSGContext holds the scene graph entry points for one QML engine.

    The context is not ready for use until it has a QOpenGLContext. Once that happens,
    the scene graph population can start.

    \internal
 */

QSGContext::QSGContext(QObject *parent) :
    QObject(*(new QSGContextPrivate), parent)
{
    Q_D(QSGContext);
    QByteArray mode = qgetenv("QSG_DISTANCEFIELD_ANTIALIASING");
    if (mode == "subpixel")
        d->distanceFieldAntialiasing = QSGGlyphNode::HighQualitySubPixelAntialiasing;
    else if (mode == "subpixel-lowq")
        d->distanceFieldAntialiasing = QSGGlyphNode::LowQualitySubPixelAntialiasing;
    else if (mode == "gray")
        d->distanceFieldAntialiasing = QSGGlyphNode::GrayAntialiasing;
}


QSGContext::~QSGContext()
{
}

/*!
 * This function is used by the Qt WebEngine to set up context sharing
 * across multiple windows. Do not use it for any other purpose.
 */
void QSGContext::setSharedOpenGLContext(QOpenGLContext *context)
{
    QSGContextPrivate::sharedOpenGLContext = context;
}

QOpenGLContext *QSGContext::sharedOpenGLContext()
{
    return QSGContextPrivate::sharedOpenGLContext;
}

void QSGContext::renderContextInitialized(QSGRenderContext *renderContext)
{
    Q_D(QSGContext);

    d->mutex.lock();
    if (d->antialiasingMethod == UndecidedAntialiasing) {
        QByteArray aaType = qgetenv("QSG_ANTIALIASING_METHOD");
        if (aaType == "msaa") {
            d->antialiasingMethod = MsaaAntialiasing;
        } else if (aaType == "vertex") {
            d->antialiasingMethod = VertexAntialiasing;
        } else {
            if (renderContext->openglContext()->format().samples() > 0)
                d->antialiasingMethod = MsaaAntialiasing;
            else
                d->antialiasingMethod = VertexAntialiasing;
        }
    }

    static bool dumped = false;
    if (!dumped && qEnvironmentVariableIsSet("QSG_INFO")) {
        dumped = true;
        qDebug() << "GL_VENDOR:     " << (const char *) glGetString(GL_VENDOR);
        qDebug() << "GL_RENDERER:   " << (const char *) glGetString(GL_RENDERER);
        qDebug() << "GL_VERSION:    " << (const char *) glGetString(GL_VERSION);
        qDebug() << "GL_EXTENSIONS:\n   " << QByteArray((const char *) glGetString(GL_EXTENSIONS)).replace(" ", "\n    ").constData();
    }

    d->mutex.unlock();
}

void QSGContext::renderContextInvalidated(QSGRenderContext *)
{
}

/*!
    Factory function for scene graph backends of the Rectangle element.
 */
QSGRectangleNode *QSGContext::createRectangleNode()
{
    Q_D(QSGContext);
    return d->antialiasingMethod == MsaaAntialiasing
            ? new QSGMultisampleAntialiasing::RectangleNode
            : new QSGDefaultRectangleNode;
}

/*!
    Factory function for scene graph backends of the Image element.
 */
QSGImageNode *QSGContext::createImageNode()
{
    Q_D(QSGContext);
    return d->antialiasingMethod == MsaaAntialiasing
            ? new QSGMultisampleAntialiasing::ImageNode
            : new QSGDefaultImageNode;
}

/*!
    Factory function for scene graph backends of the Text elements which supports native
    text rendering. Used in special cases where native look and feel is a main objective.
*/
QSGGlyphNode *QSGContext::createNativeGlyphNode(QSGRenderContext *rc)
{
#if defined(QT_OPENGL_ES) && !defined(QT_OPENGL_ES_2_ANGLE)
    Q_D(QSGContext);
    if (d->distanceFieldDisabled)
        return new QSGDefaultGlyphNode;
    else
        return createGlyphNode(rc);
#else
    Q_UNUSED(rc);
    return new QSGDefaultGlyphNode;
#endif
}

/*!
    Factory function for scene graph backends of the Text elements;
 */
QSGGlyphNode *QSGContext::createGlyphNode(QSGRenderContext *rc)
{
    Q_D(QSGContext);

    if (d->distanceFieldDisabled) {
        return createNativeGlyphNode(rc);
    } else {
        QSGDistanceFieldGlyphNode *node = new QSGDistanceFieldGlyphNode(rc);
        node->setPreferredAntialiasingMode(d->distanceFieldAntialiasing);
        return node;
    }
}

QSurfaceFormat QSGContext::defaultSurfaceFormat() const
{
    QSurfaceFormat format;
    format.setDepthBufferSize(24);
    format.setStencilBufferSize(8);
    if (QQuickWindow::hasDefaultAlphaBuffer())
        format.setAlphaBufferSize(8);
    format.setSwapBehavior(QSurfaceFormat::DoubleBuffer);
    return format;
}

/*!
    Returns the minimum supported framebuffer object size.
 */

QSize QSGContext::minimumFBOSize() const
{
#ifdef Q_OS_MAC
    return QSize(33, 33);
#else
    return QSize(1, 1);
#endif
}



/*!
    Sets whether or not the scene graph should use the distance field technique to render text
  */
void QSGContext::setDistanceFieldEnabled(bool enabled)
{
    d_func()->distanceFieldDisabled = !enabled;
}


/*!
    Returns true if the scene graph uses the distance field technique to render text
 */
bool QSGContext::isDistanceFieldEnabled() const
{
    return !d_func()->distanceFieldDisabled;
}



/*!
    Creates a new animation driver.
 */

QAnimationDriver *QSGContext::createAnimationDriver(QObject *parent)
{
    return new QAnimationDriver(parent);
}

QSGRenderContext::QSGRenderContext(QSGContext *context)
    : m_gl(0)
    , m_sg(context)
    , m_atlasManager(0)
    , m_depthStencilManager(0)
    , m_distanceFieldCacheManager(0)
    , m_brokenIBOs(false)
    , m_serializedRender(false)
{
}

QSGRenderContext::~QSGRenderContext()
{
    invalidate();
}

static QBasicMutex qsg_framerender_mutex;

void QSGRenderContext::renderNextFrame(QSGRenderer *renderer, GLuint fboId)
{
    if (m_serializedRender)
        qsg_framerender_mutex.lock();

    if (fboId) {
        QSGBindableFboId bindable(fboId);
        renderer->renderScene(bindable);
    } else {
        renderer->renderScene();
    }

    if (m_serializedRender)
        qsg_framerender_mutex.unlock();

}

/*!
    Factory function for scene graph backends of the distance-field glyph cache.
 */
QSGDistanceFieldGlyphCache *QSGRenderContext::distanceFieldGlyphCache(const QRawFont &font)
{
    if (!m_distanceFieldCacheManager)
        m_distanceFieldCacheManager = new QSGDistanceFieldGlyphCacheManager;

    QSGDistanceFieldGlyphCache *cache = m_distanceFieldCacheManager->cache(font);
    if (!cache) {
        QPlatformIntegration *platformIntegration = QGuiApplicationPrivate::platformIntegration();
        if (platformIntegration != 0
            && platformIntegration->hasCapability(QPlatformIntegration::SharedGraphicsCache)) {
            QFontEngine *fe = QRawFontPrivate::get(font)->fontEngine;
            if (!fe->faceId().filename.isEmpty()) {
                QByteArray keyName = fe->faceId().filename;
                if (font.style() != QFont::StyleNormal)
                    keyName += QByteArray(" I");
                if (font.weight() != QFont::Normal)
                    keyName += ' ' + QByteArray::number(font.weight());
                keyName += QByteArray(" DF");
                QPlatformSharedGraphicsCache *sharedGraphicsCache =
                        platformIntegration->createPlatformSharedGraphicsCache(keyName);

                if (sharedGraphicsCache != 0) {
                    sharedGraphicsCache->ensureCacheInitialized(keyName,
                                                                QPlatformSharedGraphicsCache::OpenGLTexture,
                                                                QPlatformSharedGraphicsCache::Alpha8);

                    cache = new QSGSharedDistanceFieldGlyphCache(keyName,
                                                                 sharedGraphicsCache,
                                                                 m_distanceFieldCacheManager,
                                                                 openglContext(),
                                                                 font);
                }
            }
        }
        if (!cache)
            cache = new QSGDefaultDistanceFieldGlyphCache(m_distanceFieldCacheManager, openglContext(), font);
        m_distanceFieldCacheManager->insertCache(font, cache);
    }

    return cache;
}

#define QSG_RENDERCONTEXT_PROPERTY "_q_sgrendercontext"

QSGRenderContext *QSGRenderContext::from(QOpenGLContext *context)
{
    return qobject_cast<QSGRenderContext *>(context->property(QSG_RENDERCONTEXT_PROPERTY).value<QObject *>());
}

void QSGRenderContext::registerFontengineForCleanup(QFontEngine *engine)
{
    m_fontEnginesToClean << engine;
}

/*!
    Initializes the scene graph render context with the GL context \a context. This also
    emits the ready() signal so that the QML graph can start building scene graph nodes.
 */
void QSGRenderContext::initialize(QOpenGLContext *context)
{
    // Sanity check the surface format, in case it was overridden by the application
    QSurfaceFormat requested = m_sg->defaultSurfaceFormat();
    QSurfaceFormat actual = context->format();
    if (requested.depthBufferSize() > 0 && actual.depthBufferSize() <= 0)
        qWarning("QSGContext::initialize: depth buffer support missing, expect rendering errors");
    if (requested.stencilBufferSize() > 0 && actual.stencilBufferSize() <= 0)
        qWarning("QSGContext::initialize: stencil buffer support missing, expect rendering errors");

    if (!m_atlasManager)
        m_atlasManager = new QSGAtlasTexture::Manager();

    Q_ASSERT_X(!m_gl, "QSGRenderContext::initialize", "already initialized!");
    m_gl = context;
    m_gl->setProperty(QSG_RENDERCONTEXT_PROPERTY, QVariant::fromValue(this));
    m_sg->renderContextInitialized(this);

#ifdef Q_OS_LINUX
    const char *vendor = (const char *) glGetString(GL_VENDOR);
    if (strstr(vendor, "nouveau"))
        m_brokenIBOs = true;
    const char *renderer = (const char *) glGetString(GL_RENDERER);
    if (strstr(renderer, "llvmpipe"))
        m_serializedRender = true;
#endif

    emit initialized();
}

void QSGRenderContext::invalidate()
{
    if (!m_gl)
        return;

    qDeleteAll(m_textures.values());
    m_textures.clear();

    /* The cleanup of the atlas textures is a bit intriguing.
       As part of the cleanup in the threaded render loop, we
       do:
       1. call this function
       2. call QCoreApp::sendPostedEvents() to immediately process
          any pending deferred deletes.
       3. delete the GL context.

       As textures need the atlas manager while cleaning up, the
       manager needs to be cleaned up after the textures, so
       we post a deleteLater here at the very bottom so it gets
       deferred deleted last.

       Another alternative would be to use a QPointer in
       QSGAtlasTexture::Texture, but this seemed simpler.
     */
    m_atlasManager->invalidate();
    m_atlasManager->deleteLater();
    m_atlasManager = 0;

    // The following piece of code will read/write to the font engine's caches,
    // potentially from different threads. However, this is safe because this
    // code is only called from QQuickWindow's shutdown which is called
    // only when the GUI is blocked, and multiple threads will call it in
    // sequence. (see qsgdefaultglyphnode_p.cpp's init())
    for (QSet<QFontEngine *>::const_iterator it = m_fontEnginesToClean.constBegin(),
         end = m_fontEnginesToClean.constEnd(); it != end; ++it) {
        (*it)->clearGlyphCache(m_gl);
    }
    m_fontEnginesToClean.clear();

    delete m_depthStencilManager;
    m_depthStencilManager = 0;

    delete m_distanceFieldCacheManager;
    m_distanceFieldCacheManager = 0;

    m_gl->setProperty(QSG_RENDERCONTEXT_PROPERTY, QVariant());
    m_gl = 0;

    m_sg->renderContextInvalidated(this);
    emit invalidated();
}

/*!
    Returns a shared pointer to a depth stencil buffer that can be used with \a fbo.
  */
QSharedPointer<QSGDepthStencilBuffer> QSGRenderContext::depthStencilBufferForFbo(QOpenGLFramebufferObject *fbo)
{
    if (!m_gl)
        return QSharedPointer<QSGDepthStencilBuffer>();
    QSGDepthStencilBufferManager *manager = depthStencilBufferManager();
    QSGDepthStencilBuffer::Format format;
    format.size = fbo->size();
    format.samples = fbo->format().samples();
    format.attachments = QSGDepthStencilBuffer::DepthAttachment | QSGDepthStencilBuffer::StencilAttachment;
    QSharedPointer<QSGDepthStencilBuffer> buffer = manager->bufferForFormat(format);
    if (buffer.isNull()) {
        buffer = QSharedPointer<QSGDepthStencilBuffer>(new QSGDefaultDepthStencilBuffer(m_gl, format));
        manager->insertBuffer(buffer);
    }
    return buffer;
}

/*!
    Returns a pointer to the context's depth/stencil buffer manager. This is useful for custom
    implementations of \l depthStencilBufferForFbo().
  */
QSGDepthStencilBufferManager *QSGRenderContext::depthStencilBufferManager()
{
    if (!m_gl)
        return 0;
    if (!m_depthStencilManager)
        m_depthStencilManager = new QSGDepthStencilBufferManager(m_gl);
    return m_depthStencilManager;
}


/*!
    Factory function for texture objects.

    If \a image is a valid image, the QSGTexture::setImage function
    will be called with \a image as argument.
 */

QSGTexture *QSGRenderContext::createTexture(const QImage &image) const
{
    QSGTexture *t = m_atlasManager->create(image);
    if (t)
        return t;
    return createTextureNoAtlas(image);
}

QSGTexture *QSGRenderContext::createTextureNoAtlas(const QImage &image) const
{
    QSGPlainTexture *t = new QSGPlainTexture();
    if (!image.isNull())
        t->setImage(image);
    return t;
}

/*!
    Factory function for the scene graph renderers.

    The renderers are used for the toplevel renderer and once for every
    QQuickShaderEffectSource used in the QML scene.
 */
QSGRenderer *QSGRenderContext::createRenderer()
{
    return new QSGBatchRenderer::Renderer(this);
}

QSGTexture *QSGRenderContext::textureForFactory(QQuickTextureFactory *factory, QQuickWindow *window)
{
    if (!factory)
        return 0;

    m_mutex.lock();
    QSGTexture *texture = m_textures.value(factory);
    m_mutex.unlock();

    if (!texture) {
        if (QQuickDefaultTextureFactory *dtf = qobject_cast<QQuickDefaultTextureFactory *>(factory))
            texture = createTexture(dtf->image());
        else
            texture = factory->createTexture(window);

        m_mutex.lock();
        m_textures.insert(factory, texture);
        m_mutex.unlock();

        connect(factory, SIGNAL(destroyed(QObject *)), this, SLOT(textureFactoryDestroyed(QObject *)), Qt::DirectConnection);
    }
    return texture;
}

void QSGRenderContext::textureFactoryDestroyed(QObject *o)
{
    m_mutex.lock();
    QSGTexture *t = m_textures.take(static_cast<QQuickTextureFactory *>(o));
    m_mutex.unlock();
    if (t)
        t->deleteLater();
}

QT_END_NAMESPACE
