path: root/src/declarative/scenegraph/coreapi/qsgnode.cpp

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#include "qsgnode.h"
#include "qsgrenderer_p.h"
#include "qsgnodeupdater_p.h"
#include "qsgmaterial.h"

#include "limits.h"

QT_BEGIN_NAMESPACE

#ifndef QT_NO_DEBUG
static int qt_node_count = 0;

static void qt_print_node_count()
{
    qDebug("Number of leaked nodes: %i", qt_node_count);
    qt_node_count = -1;
}
#endif

/*!
    \class QSGNode
    \bried The QSGNode class is the base class for all nodes in the scene graph.

    The QSGNode class can be used as a child container. Children are added with
    the appendChildNode(), prependChildNode(), insertChildNodeBefore() and
    insertChildNodeAfter(). Ordering is important as nodes are rendered in
    order. Actually, the scene may reorder nodes freely, but the resulting visual
    order is still guaranteed.

    If nodes change every frame, the preprocess() function can be used to
    apply changes to a node for every frame its rendered. The use of preprocess()
    must be explicitly enabled by setting the QSGNode::UsePreprocess flag
    on the node.

    The virtual isSubtreeBlocked() function can be used to disable a subtree all
    together. Nodes in a blocked subtree will not be preprocessed() and not
    rendered.

    Anything related to QSGNode should happen on the scene graph rendering thread.
 */

QSGNode::QSGNode()
    : m_parent(0)
    , m_nodeFlags(OwnedByParent)
    , m_flags(0)
{
#ifndef QT_NO_DEBUG
    ++qt_node_count;
    static bool atexit_registered = false;
    if (!atexit_registered) {
        atexit(qt_print_node_count);
        atexit_registered = true;
    }
#endif

}

QSGNode::~QSGNode()
{
#ifndef QT_NO_DEBUG
    --qt_node_count;
    if (qt_node_count < 0)
        qDebug("Material destroyed after qt_print_node_count() was called.");
#endif
    destroy();
}


/*!
    \fn void QSGNode::preprocess()

    Override this function to do processing on the node before it is rendered.

    Preprocessing needs to be explicitly enabled by setting the flag
    QSGNode::UsePreprocess. The flag needs to be set before the node is added
    to the scene graph and will cause the preprocess() function to be called
    for every frame the node is rendered.

    The preprocess function is called before the update pass that propegates
    opacity and transformations through the scene graph. That means that
    functions like QSGOpacityNode::combinedOpacity() and
    QSGTransformNode::combinedMatrix() will not contain up-to-date values.
    If such values are changed during the preprocess, these changes will be
    propegated through the scene graph before it is rendered.

    \warning Beware of deleting nodes while they are being preprocessed. It is
    possible, with a small performance hit, to delete a single node during its
    own preprocess call. Deleting a subtree which has nodes that also use
    preprocessing may result in a segmentation fault. This is done for
    performance reasons.
 */




/*!
    \fn bool QSGNode::isSubtreeBlocked() const

    Returns whether this node and its subtree is available for use.

    Blocked subtrees will not get their dirty states updated and they
    will not be rendered.

    The QSGOpacityNode will return a blocked subtree when accumulated opacity
    is 0, for instance.
 */


void QSGNode::destroy()
{
    if (m_parent) {
        m_parent->removeChildNode(this);
        Q_ASSERT(m_parent == 0);
    }
    for (int ii = m_children.count() - 1; ii >= 0; --ii) {
        QSGNode *child = m_children.at(ii);
        removeChildNode(child);
        Q_ASSERT(child->m_parent == 0);
        if (child->flags() & OwnedByParent)
            delete child;
    }
    Q_ASSERT(m_children.isEmpty());
}

void QSGNode::prependChildNode(QSGNode *node)
{
    Q_ASSERT_X(!m_children.contains(node), "QSGNode::prependChildNode", "QSGNode is already a child!");
    Q_ASSERT_X(!node->m_parent, "QSGNode::prependChildNode", "QSGNode already has a parent");

#ifndef QT_NO_DEBUG
    if (node->type() == QSGNode::GeometryNodeType) {
        QSGGeometryNode *g = static_cast<QSGGeometryNode *>(node);
        Q_ASSERT_X(g->material(), "QSGNode::prependChildNode", "QSGGeometryNode is missing material");
        Q_ASSERT_X(g->geometry(), "QSGNode::prependChildNode", "QSGGeometryNode is missing geometry");
    }
#endif

    m_children.prepend(node);
    node->m_parent = this;

    node->markDirty(DirtyNodeAdded);
}

void QSGNode::appendChildNode(QSGNode *node)
{
    Q_ASSERT_X(!m_children.contains(node), "QSGNode::appendChildNode", "QSGNode is already a child!");
    Q_ASSERT_X(!node->m_parent, "QSGNode::appendChildNode", "QSGNode already has a parent");

#ifndef QT_NO_DEBUG
    if (node->type() == QSGNode::GeometryNodeType) {
        QSGGeometryNode *g = static_cast<QSGGeometryNode *>(node);
        Q_ASSERT_X(g->material(), "QSGNode::appendChildNode", "QSGGeometryNode is missing material");
        Q_ASSERT_X(g->geometry(), "QSGNode::appendChildNode", "QSGGeometryNode is missing geometry");
    }
#endif

    m_children.append(node);
    node->m_parent = this;

    node->markDirty(DirtyNodeAdded);
}

void QSGNode::insertChildNodeBefore(QSGNode *node, QSGNode *before)
{
    Q_ASSERT_X(!m_children.contains(node), "QSGNode::insertChildNodeBefore", "QSGNode is already a child!");
    Q_ASSERT_X(!node->m_parent, "QSGNode::insertChildNodeBefore", "QSGNode already has a parent");
    Q_ASSERT_X(node->type() != RootNodeType, "QSGNode::insertChildNodeBefore", "RootNodes cannot be children of other nodes");

#ifndef QT_NO_DEBUG
    if (node->type() == QSGNode::GeometryNodeType) {
        QSGGeometryNode *g = static_cast<QSGGeometryNode *>(node);
        Q_ASSERT_X(g->material(), "QSGNode::insertChildNodeBefore", "QSGGeometryNode is missing material");
        Q_ASSERT_X(g->geometry(), "QSGNode::insertChildNodeBefore", "QSGGeometryNode is missing geometry");
    }
#endif

    int idx = before?m_children.indexOf(before):-1;
    if (idx == -1)
        m_children.append(node);
    else
        m_children.insert(idx, node);
    node->m_parent = this;

    node->markDirty(DirtyNodeAdded);
}

void QSGNode::insertChildNodeAfter(QSGNode *node, QSGNode *after)
{
    Q_ASSERT_X(!m_children.contains(node), "QSGNode::insertChildNodeAfter", "QSGNode is already a child!");
    Q_ASSERT_X(!node->m_parent, "QSGNode::insertChildNodeAfter", "QSGNode already has a parent");
    Q_ASSERT_X(node->type() != RootNodeType, "QSGNode::insertChildNodeAfter", "RootNodes cannot be children of other nodes");

#ifndef QT_NO_DEBUG
    if (node->type() == QSGNode::GeometryNodeType) {
        QSGGeometryNode *g = static_cast<QSGGeometryNode *>(node);
        Q_ASSERT_X(g->material(), "QSGNode::insertChildNodeAfter", "QSGGeometryNode is missing material");
        Q_ASSERT_X(g->geometry(), "QSGNode::insertChildNodeAfter", "QSGGeometryNode is missing geometry");
    }
#endif

    int idx = after?m_children.indexOf(after):-1;
    if (idx == -1)
        m_children.append(node);
    else
        m_children.insert(idx + 1, node);
    node->m_parent = this;

    node->markDirty(DirtyNodeAdded);
}

void QSGNode::removeChildNode(QSGNode *node)
{
    Q_ASSERT(m_children.contains(node));
    Q_ASSERT(node->parent() == this);

    m_children.removeOne(node);

    node->markDirty(DirtyNodeRemoved);
    node->m_parent = 0;
}


/*!
    Sets the flag \a f on this node if \a enabled is true;
    otherwise clears the flag.

    \sa flags()
*/

void QSGNode::setFlag(Flag f, bool enabled)
{
    if (enabled)
        m_nodeFlags |= f;
    else
        m_nodeFlags &= ~f;
}


/*!
    Sets the flags \a f on this node if \a enabled is true;
    otherwise clears the flags.

    \sa flags()
*/

void QSGNode::setFlags(Flags f, bool enabled)
{
    if (enabled)
        m_nodeFlags |= f;
    else
        m_nodeFlags &= ~f;
}


void QSGNode::markDirty(DirtyFlags flags)
{
    m_flags |= (flags & DirtyPropagationMask);

    DirtyFlags subtreeFlags = DirtyFlags((flags & DirtyPropagationMask) << 16);
    QSGNode *p = m_parent;
    while (p) {
        p->m_flags |= subtreeFlags;
        if (p->type() == RootNodeType)
            static_cast<QSGRootNode *>(p)->notifyNodeChange(this, flags);
        p = p->m_parent;
    }
}

QSGBasicGeometryNode::QSGBasicGeometryNode()
    : m_geometry(0)
    , m_matrix(0)
    , m_clip_list(0)
{
}

QSGBasicGeometryNode::~QSGBasicGeometryNode()
{
    destroy();
    if (flags() & OwnsGeometry)
        delete m_geometry;
}

void QSGBasicGeometryNode::setGeometry(QSGGeometry *geometry)
{
    if (flags() & OwnsGeometry)
        delete m_geometry;
    m_geometry = geometry;
    markDirty(DirtyGeometry);
}


QSGGeometryNode::QSGGeometryNode()
    : m_render_order(0)
    , m_material(0)
    , m_opaque_material(0)
    , m_opacity(1)
{
}

QSGGeometryNode::~QSGGeometryNode()
{
    destroy();
    if (flags() & OwnsMaterial)
        delete m_material;
    if (flags() & OwnsOpaqueMaterial)
        delete m_opaque_material;
}

/*!
    Sets the render order of this node to be \a order.

    GeometryNodes are rendered in an order that visually looks like
    low order nodes are rendered prior to high order nodes. For opaque
    geometry there is little difference as z-testing will handle
    the discard, but for translucent objects, the rendering should
    normally be specified in the order of back-to-front.

    The default render order is 0.

    \internal
  */
void QSGGeometryNode::setRenderOrder(int order)
{
    m_render_order = order;
}



/*!
    Sets the material of this geometry node to \a material.

    GeometryNodes must have a material before they can be added to the
    scene graph.
 */
void QSGGeometryNode::setMaterial(QSGMaterial *material)
{
    if (flags() & OwnsMaterial)
        delete m_material;
    m_material = material;
#ifndef QT_NO_DEBUG
    if (m_material != 0 && m_opaque_material == m_material)
        qWarning("QSGGeometryNode: using same material for both opaque and translucent");
#endif
    markDirty(DirtyMaterial);
}



/*!
    Sets the opaque material of this geometry to \a material.

    The opaque material will be preferred by the renderer over the
    default material, as returned by the material() function, if
    it is not null and the geometry item has an inherited opacity of
    1.

    The opaqueness refers to scene graph opacity, the material is still
    allowed to set QSGMaterial::Blending to true and draw transparent
    pixels.
 */
void QSGGeometryNode::setOpaqueMaterial(QSGMaterial *material)
{
    if (flags() & OwnsOpaqueMaterial)
        delete m_opaque_material;
    m_opaque_material = material;
#ifndef QT_NO_DEBUG
    if (m_opaque_material != 0 && m_opaque_material == m_material)
        qWarning("QSGGeometryNode: using same material for both opaque and translucent");
#endif

    markDirty(DirtyMaterial);
}



/*!
    Returns the material which should currently be used for geometry node.

    If the inherited opacity of the node is 1 and there is an opaque material
    set on this node, it will be returned; otherwise, the default material
    will be returned.

    \warning This function requires the scene graph above this item to be
    completely free of dirty states, so it can only be called during rendering

    \internal

    \sa setMaterial, setOpaqueMaterial
 */
QSGMaterial *QSGGeometryNode::activeMaterial() const
{
    Q_ASSERT_X(dirtyFlags() == 0, "QSGGeometryNode::activeMaterial()", "function assumes that all dirty states are cleaned up");
    if (m_opaque_material && m_opacity > 0.999)
        return m_opaque_material;
    return m_material;
}


/*!
    Sets the inherited opacity of this geometry to \a opacity.

    This function is meant to be called by the node preprocessing
    prior to rendering the tree, so it will not mark the tree as
    dirty.

    \internal
  */
void QSGGeometryNode::setInheritedOpacity(qreal opacity)
{
    Q_ASSERT(opacity >= 0 && opacity <= 1);
    m_opacity = opacity;
}



QSGClipNode::QSGClipNode()
{
}

QSGClipNode::~QSGClipNode()
{
    destroy();
}

/*!
    Sets whether this clip node has a rectangular clip to \a rectHint.
 */
void QSGClipNode::setIsRectangular(bool rectHint)
{
    m_is_rectangular = rectHint;
}


/*!
    Sets the clip rect of this clip node to \a rect.

    When a rectangular clip is set in combination with setIsRectangular
    the renderer may in some cases use a more optimal clip method.
 */
void QSGClipNode::setClipRect(const QRectF &rect)
{
    m_clip_rect = rect;
}


QSGTransformNode::QSGTransformNode()
{
}

QSGTransformNode::~QSGTransformNode()
{
    destroy();
}

void QSGTransformNode::setMatrix(const QMatrix4x4 &matrix)
{
    m_matrix = matrix;
    markDirty(DirtyMatrix);
}


/*!
    Sets the combined matrix of this matrix to \a transform.

    This function is meant to be called by the node preprocessing
    prior to rendering the tree, so it will not mark the tree as
    dirty.

    \internal
  */
void QSGTransformNode::setCombinedMatrix(const QMatrix4x4 &matrix)
{
    m_combined_matrix = matrix;
}



QSGRootNode::~QSGRootNode()
{
    while (!m_renderers.isEmpty())
        m_renderers.last()->setRootNode(0);
    destroy();
}


void QSGRootNode::notifyNodeChange(QSGNode *node, DirtyFlags flags)
{
    for (int i=0; i<m_renderers.size(); ++i) {
        m_renderers.at(i)->nodeChanged(node, flags);
    }
}

/*!
    Constructs an opacity node with a default opacity of 1.

    Opacity accumulate downwards in the scene graph so a node with two
    QSGOpacityNode instances above it, both with opacity of 0.5, will have
    effective opacity of 0.25.

    The default opacity of nodes is 1.
  */
QSGOpacityNode::QSGOpacityNode()
    : m_opacity(1)
    , m_combined_opacity(1)
{
}


QSGOpacityNode::~QSGOpacityNode()
{
    destroy();
}


/*!
    Sets the opacity of this node to \a opacity.

    Before rendering the graph, the renderer will do an update pass
    over the subtree to propegate the opacity to its children.

    The value will be bounded to the range 0 to 1.
 */
void QSGOpacityNode::setOpacity(qreal opacity)
{
    opacity = qBound<qreal>(0, opacity, 1);
    if (m_opacity == opacity)
        return;
    m_opacity = opacity;
    markDirty(DirtyOpacity);
}


/*!
    Sets the combined opacity of this node to \a opacity.

    This function is meant to be called by the node preprocessing
    prior to rendering the tree, so it will not mark the tree as
    dirty.

    \internal
 */
void QSGOpacityNode::setCombinedOpacity(qreal opacity)
{
    m_combined_opacity = opacity;
}


bool QSGOpacityNode::isSubtreeBlocked() const
{
    return m_combined_opacity < 0.001;
}


QSGNodeVisitor::~QSGNodeVisitor()
{

}


void QSGNodeVisitor::visitNode(QSGNode *n)
{
    switch (n->type()) {
    case QSGNode::TransformNodeType: {
        QSGTransformNode *t = static_cast<QSGTransformNode *>(n);
        enterTransformNode(t);
        visitChildren(t);
        leaveTransformNode(t);
        break; }
    case QSGNode::GeometryNodeType: {
        QSGGeometryNode *g = static_cast<QSGGeometryNode *>(n);
        enterGeometryNode(g);
        visitChildren(g);
        leaveGeometryNode(g);
        break; }
    case QSGNode::ClipNodeType: {
        QSGClipNode *c = static_cast<QSGClipNode *>(n);
        enterClipNode(c);
        visitChildren(c);
        leaveClipNode(c);
        break; }
    case QSGNode::OpacityNodeType: {
        QSGOpacityNode *o = static_cast<QSGOpacityNode *>(n);
        enterOpacityNode(o);
        visitChildren(o);
        leaveOpacityNode(o);
        break; }
    default:
        visitChildren(n);
        break;
    }
}

void QSGNodeVisitor::visitChildren(QSGNode *n)
{
    int count = n->childCount();
    for (int i=0; i<count; ++i) {
        visitNode(n->childAtIndex(i));
    }
}



#ifndef QT_NO_DEBUG_STREAM
QDebug operator<<(QDebug d, const QSGGeometryNode *n)
{
    if (!n) {
        d << "QSGGeometryNode(null)";
        return d;
    }
    d << "QSGGeometryNode(" << hex << (void *) n << dec;

    const QSGGeometry *g = n->geometry();

    if (!g) {
        d << "no geometry";
    } else {

        switch (g->drawingMode()) {
        case GL_TRIANGLE_STRIP: d << "strip"; break;
        case GL_TRIANGLE_FAN: d << "fan"; break;
        case GL_TRIANGLES: d << "triangles"; break;
        default: break;
        }

         d << g->vertexCount();

         if (g->attributeCount() > 0 && g->attributes()->type == GL_FLOAT) {
             float x1 = 1e10, x2 = -1e10, y1=1e10, y2=-1e10;
             int stride = g->stride();
             for (int i = 0; i < g->vertexCount(); ++i) {
                 float x = ((float *)((char *)const_cast<QSGGeometry *>(g)->vertexData() + i * stride))[0];
                 float y = ((float *)((char *)const_cast<QSGGeometry *>(g)->vertexData() + i * stride))[1];

                 x1 = qMin(x1, x);
                 x2 = qMax(x2, x);
                 y1 = qMin(y1, y);
                 y2 = qMax(y2, y);
             }

             d << "x1=" << x1 << "y1=" << y1 << "x2=" << x2 << "y2=" << y2;
         }
    }

    d << "order=" << n->renderOrder();
    if (n->material())
        d << "effect=" << n->material() << "type=" << n->material()->type();


    d << ")";
#ifdef QML_RUNTIME_TESTING
    d << n->description;
#endif
    d << "dirty=" << hex << (int) n->dirtyFlags() << dec;
    return d;
}

QDebug operator<<(QDebug d, const QSGClipNode *n)
{
    if (!n) {
        d << "QSGClipNode(null)";
        return d;
    }
    d << "QSGClipNode(" << hex << (void *) n << dec;

    if (n->childCount())
        d << "children=" << n->childCount();

    d << "is rect?" << (n->isRectangular() ? "yes" : "no");

    d << ")";
#ifdef QML_RUNTIME_TESTING
    d << n->description;
#endif
    d << "dirty=" << hex << (int) n->dirtyFlags() << dec << (n->isSubtreeBlocked() ? "*BLOCKED*" : "");
    return d;
}

QDebug operator<<(QDebug d, const QSGTransformNode *n)
{
    if (!n) {
        d << "QSGTransformNode(null)";
        return d;
    }
    const QMatrix4x4 m = n->matrix();
    d << "QSGTransformNode(";
    d << hex << (void *) n << dec;
    if (m.isIdentity())
        d << "identity";
    else if (m.determinant() == 1 && m(0, 0) == 1 && m(1, 1) == 1 && m(2, 2) == 1)
        d << "translate" << m(0, 3) << m(1, 3) << m(2, 3);
    else
        d << "det=" << n->matrix().determinant();
#ifdef QML_RUNTIME_TESTING
    d << n->description;
#endif
    d << "dirty=" << hex << (int) n->dirtyFlags() << dec << (n->isSubtreeBlocked() ? "*BLOCKED*" : "");
    d << ")";
    return d;
}

QDebug operator<<(QDebug d, const QSGOpacityNode *n)
{
    if (!n) {
        d << "QSGOpacityNode(null)";
        return d;
    }
    d << "QSGOpacityNode(";
    d << hex << (void *) n << dec;
    d << "opacity=" << n->opacity()
      << "combined=" << n->combinedOpacity()
      << (n->isSubtreeBlocked() ? "*BLOCKED*" : "");
#ifdef QML_RUNTIME_TESTING
    d << n->description;
#endif
    d << "dirty=" << hex << (int) n->dirtyFlags() << dec;
    d << ")";
    return d;
}


QDebug operator<<(QDebug d, const QSGRootNode *n)
{
    if (!n) {
        d << "QSGRootNode(null)";
        return d;
    }
    d << "QSGRootNode" << hex << (void *) n << "dirty=" << (int) n->dirtyFlags() << dec
      << (n->isSubtreeBlocked() ? "*BLOCKED*" : "");
#ifdef QML_RUNTIME_TESTING
    d << n->description;
#endif
    d << ")";
    return d;
}



QDebug operator<<(QDebug d, const QSGNode *n)
{
    if (!n) {
        d << "QSGNode(null)";
        return d;
    }
    switch (n->type()) {
    case QSGNode::GeometryNodeType:
        d << static_cast<const QSGGeometryNode *>(n);
        break;
    case QSGNode::TransformNodeType:
        d << static_cast<const QSGTransformNode *>(n);
        break;
    case QSGNode::ClipNodeType:
        d << static_cast<const QSGClipNode *>(n);
        break;
    case QSGNode::RootNodeType:
        d << static_cast<const QSGRootNode *>(n);
        break;
    case QSGNode::OpacityNodeType:
        d << static_cast<const QSGOpacityNode *>(n);
        break;
    default:
        d << "QSGNode(" << hex << (void *) n << dec
          << "dirty=" << hex << (int) n->dirtyFlags() << dec
          << (n->isSubtreeBlocked() ? "*BLOCKED*" : "");
#ifdef QML_RUNTIME_TESTING
        d << n->description;
#endif
        d << ")";
        break;
    }
    return d;
}

void QSGNodeDumper::dump(QSGNode *n)
{
    QSGNodeDumper dump;
    dump.visitNode(n);
}

void QSGNodeDumper::visitNode(QSGNode *n)
{
    if (n->isSubtreeBlocked())
        return;
    qDebug() << QString(m_indent * 2, QLatin1Char(' ')) << n;
    QSGNodeVisitor::visitNode(n);
}

void QSGNodeDumper::visitChildren(QSGNode *n)
{
    ++m_indent;
    QSGNodeVisitor::visitChildren(n);
    --m_indent;
}

#endif

QT_END_NAMESPACE