QSGNode ¶

概要 ¶

详细描述 ¶

QSGNode class can be used as a child container. Children are added with the appendChildNode() , prependChildNode() , insertChildNodeBefore() and insertChildNodeAfter() . The order of nodes is important as geometry nodes are rendered according to their ordering in the scene graph.

The scene graph nodes contains a mechanism to describe which parts of the scene has changed. This includes the combined matrices, accumulated opacity, changes to the node hierarchy, and so on. This information can be used for optimizations inside the scene graph renderer. For the renderer to properly render the nodes, it is important that users call markDirty() with the correct flags when nodes are changed. Most of the functions on the node classes will implicitly call markDirty() 。例如， appendChildNode() will call markDirty() passing in DirtyNodeAdded .

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

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

注意

All classes with QSG prefix should be used solely on the scene graph’s rendering thread. See 场景图形和渲染 了解更多信息。

class QSGNode ¶

QSGNode(type)

param type

NodeType

Constructs a new node

Constructs a new node with the given node type.

PySide2.QtQuick.QSGNode. NodeType ¶

Can be used to figure out the type of node.

常量	描述
QSGNode.BasicNodeType	The type of QSGNode
QSGNode.GeometryNodeType	The type of QSGGeometryNode
QSGNode.TransformNodeType	The type of QSGTransformNode
QSGNode.ClipNodeType	The type of QSGClipNode
QSGNode.OpacityNodeType	The type of QSGOpacityNode
QSGNode.RenderNodeType	The type of QSGRenderNode

另请参阅

type()

PySide2.QtQuick.QSGNode. Flag ¶

The enum describes flags on the QSGNode

常量	描述
QSGNode.OwnedByParent	The node is owned by its parent and will be deleted when the parent is deleted.
QSGNode.UsePreprocess	The node’s virtual preprocess() function will be called before rendering starts.
QSGNode.OwnsGeometry	Only valid for QSGGeometryNode and QSGClipNode . The node has ownership over the QSGGeometry instance and will delete it when the node is destroyed or a geometry is assigned.
QSGNode.OwnsMaterial	Only valid for QSGGeometryNode . The node has ownership over the material and will delete it when the node is destroyed or a material is assigned.
QSGNode.OwnsOpaqueMaterial	Only valid for QSGGeometryNode . The node has ownership over the opaque material and will delete it when the node is destroyed or a material is assigned.
QSGNode.InternalReserved	Reserved for internal use.

PySide2.QtQuick.QSGNode. DirtyStateBit ¶

用于 markDirty() to indicate how the scene graph has changed.

常量	描述
QSGNode.DirtyMatrix	The matrix in a QSGTransformNode 已改变。
QSGNode.DirtyNodeAdded	A node was added.
QSGNode.DirtyNodeRemoved	A node was removed.
QSGNode.DirtyGeometry	The geometry of a QSGGeometryNode 已改变。
QSGNode.DirtyMaterial	The material of a QSGGeometryNode 已改变。
QSGNode.DirtyOpacity	The opacity of a QSGOpacityNode 已改变。
QSGNode.DirtySubtreeBlocked	The subtree has been blocked.

另请参阅

markDirty()

PySide2.QtQuick.QSGNode. appendChildNode ( node ) ¶

参数

node – QSGNode

追加 node to this node’s list of children.

Ordering of nodes is important as geometry nodes will be rendered in the order they are added to the scene graph.

PySide2.QtQuick.QSGNode. childAtIndex ( i ) ¶

参数

i – int

返回类型

QSGNode

Returns the child at index i .

Children are stored internally as a linked list, so iterating over the children via the index is suboptimal.

PySide2.QtQuick.QSGNode. childCount ( ) ¶

返回类型

int

Returns the number of child nodes.

PySide2.QtQuick.QSGNode. clearDirty ( ) ¶

注意

此函数被弃用。

PySide2.QtQuick.QSGNode. dirtyState ( ) ¶

返回类型

DirtyState

注意

此函数被弃用。

PySide2.QtQuick.QSGNode. firstChild ( ) ¶

返回类型

QSGNode

Returns the first child of this node.

The children are stored in a linked list.

PySide2.QtQuick.QSGNode. flags ( ) ¶

返回类型

标志

Returns the set of flags for this node.

另请参阅

setFlags()

PySide2.QtQuick.QSGNode. insertChildNodeAfter ( node , after ) ¶

参数

• node – QSGNode

• after – QSGNode

插入 node to this node’s list of children after the node specified with after .

Ordering of nodes is important as geometry nodes will be rendered in the order they are added to the scene graph.

PySide2.QtQuick.QSGNode. insertChildNodeBefore ( node , before ) ¶

参数

• node – QSGNode

• before – QSGNode

插入 node to this node’s list of children before the node specified with before .

Ordering of nodes is important as geometry nodes will be rendered in the order they are added to the scene graph.

PySide2.QtQuick.QSGNode. isSubtreeBlocked ( ) ¶

返回类型

bool

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.

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

PySide2.QtQuick.QSGNode. lastChild ( ) ¶

返回类型

QSGNode

Returns the last child of this node.

The children are stored as a linked list.

PySide2.QtQuick.QSGNode. markDirty ( bits ) ¶

参数

bits – DirtyState

Notifies all connected renderers that the node has dirty bits .

PySide2.QtQuick.QSGNode. nextSibling ( ) ¶

返回类型

QSGNode

Returns the node after this in the parent’s list of children.

The children are stored as a linked list.

PySide2.QtQuick.QSGNode. parent ( ) ¶

返回类型

QSGNode

Returns the parent node of this node.

PySide2.QtQuick.QSGNode. prependChildNode ( node ) ¶

参数

node – QSGNode

前置 node to this node’s the list of children.

Ordering of nodes is important as geometry nodes will be rendered in the order they are added to the scene graph.

PySide2.QtQuick.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 UsePreprocess . The flag needs to be set before the node is added to the scene graph and will cause the function to be called for every frame the node is rendered.

警告

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.

PySide2.QtQuick.QSGNode. previousSibling ( ) ¶

返回类型

QSGNode

Returns the node before this in the parent’s list of children.

The children are stored as a linked list.

PySide2.QtQuick.QSGNode. removeAllChildNodes ( ) ¶

Removes all child nodes from this node’s list of children.

PySide2.QtQuick.QSGNode. removeChildNode ( node ) ¶

参数

node – QSGNode

移除 node from this node’s list of children.

PySide2.QtQuick.QSGNode. reparentChildNodesTo ( newParent ) ¶

参数

newParent – QSGNode

Reparents all nodes of this node to newParent .

PySide2.QtQuick.QSGNode. setFlag ( arg__1 [ , arg__2=true ] ) ¶

参数

• arg__1 – Flag

• arg__2 – bool

Sets the flag f on this node if enabled 为 true；否则清零标志。

另请参阅

flags()

PySide2.QtQuick.QSGNode. setFlags ( arg__1 [ , arg__2=true ] ) ¶

参数

• arg__1 – 标志

• arg__2 – bool

Sets the flags f on this node if enabled is true; otherwise clears the flags.

另请参阅

flags()

PySide2.QtQuick.QSGNode. type ( ) ¶

返回类型

NodeType

Returns the type of this node. The node type must be one of the predefined types defined in NodeType and can safely be used to cast to the corresponding class.