#include <qquick3dscenerenderer_p.h>

Inheritance diagram for QQuick3DSGRenderNode:

Collaboration diagram for QQuick3DSGRenderNode:

Public Member Functions
	~QQuick3DSGRenderNode ()
void	prepare () override
	Called from the frame preparation phase.
StateFlags	changedStates () const override
	This function should return a mask where each bit represents graphics states changed by the \l render() function.
void	render (const RenderState *state) override
	This function is called by the renderer and should paint this node with directly invoking commands via QRhi or directly via the underlying graphics API (OpenGL, Direct3D, etc.).
void	releaseResources () override
	This function is called when all custom graphics resources allocated by this node have to be freed immediately.
RenderingFlags	flags () const override
Public Member Functions inherited from QSGRenderNode
	QSGRenderNode ()
	~QSGRenderNode () override
	Destructs the render node.
virtual QRectF	rect () const
const QMatrix4x4 *	projectionMatrix () const
const QMatrix4x4 *	projectionMatrix (qsizetype index) const
const QMatrix4x4 *	matrix () const
const QSGClipNode *	clipList () const
qreal	inheritedOpacity () const
QRhiRenderTarget *	renderTarget () const
QRhiCommandBuffer *	commandBuffer () const
Public Member Functions inherited from QSGNode
	QSGNode ()
	Constructs a new node.
virtual	~QSGNode ()
	Destroys the node.
QSGNode *	parent () const
	Returns the parent node of this node.
void	removeChildNode (QSGNode *node)
	Removes node from this node's list of children.
void	removeAllChildNodes ()
	Removes all child nodes from this node's list of children.
void	prependChildNode (QSGNode *node)
	Prepends node to this node's the list of children.
void	appendChildNode (QSGNode *node)
	Appends node to this node's list of children.
void	insertChildNodeBefore (QSGNode node, QSGNode before)
	Inserts node to this node's list of children before the node specified with before.
void	insertChildNodeAfter (QSGNode node, QSGNode after)
	Inserts node to this node's list of children after the node specified with after.
void	reparentChildNodesTo (QSGNode *newParent)
int	childCount () const
	Returns the number of child nodes.
QSGNode *	childAtIndex (int i) const
	Returns the child at index i.
QSGNode *	firstChild () const
	Returns the first child of this node.
QSGNode *	lastChild () const
	Returns the last child of this node.
QSGNode *	nextSibling () const
	Returns the node after this in the parent's list of children.
QSGNode *	previousSibling () const
	Returns the node before this in the parent's list of children.
NodeType	type () const
	Returns the type of this node.
QT_DEPRECATED void	clearDirty ()
void	markDirty (DirtyState bits)
	Notifies all connected renderers that the node has dirty bits.
QT_DEPRECATED DirtyState	dirtyState () const
virtual bool	isSubtreeBlocked () const
	Returns whether this node and its subtree is available for use.
Flags	flags () const
	Returns the set of flags for this node.
void	setFlag (Flag, bool=true)
	Sets the flag f on this node if enabled is true; otherwise clears the flag.
void	setFlags (Flags, bool=true)
	Sets the flags f on this node if enabled is true; otherwise clears the flags.
virtual void	preprocess ()
	Override this function to do processing on the node before it is rendered.

Public Attributes
QQuickWindow *	window = nullptr
QQuick3DSceneRenderer *	renderer = nullptr

Additional Inherited Members
Public Types inherited from QSGRenderNode
enum	StateFlag { DepthState = 0x01 , StencilState = 0x02 , ScissorState = 0x04 , ColorState = 0x08 , BlendState = 0x10 , CullState = 0x20 , ViewportState = 0x40 , RenderTargetState = 0x80 }
	This enum contains the possible values for use in the bitmask returned from changedStates(). More...
enum	RenderingFlag { BoundedRectRendering = 0x01 , DepthAwareRendering = 0x02 , OpaqueRendering = 0x04 , NoExternalRendering = 0x08 }
	Possible values for the bitmask returned from flags(). More...
Public Types inherited from QSGNode
enum	NodeType { BasicNodeType , GeometryNodeType , TransformNodeType , ClipNodeType , OpacityNodeType , RootNodeType , RenderNodeType }
	Can be used to figure out the type of node. More...
enum	Flag { OwnedByParent = 0x0001 , UsePreprocess = 0x0002 , OwnsGeometry = 0x00010000 , OwnsMaterial = 0x00020000 , OwnsOpaqueMaterial = 0x00040000 , IsVisitableNode = 0x01000000 }
	The QSGNode::Flag enum describes flags on the QSGNode. More...
enum	DirtyStateBit { DirtySubtreeBlocked = 0x0080 , DirtyMatrix = 0x0100 , DirtyNodeAdded = 0x0400 , DirtyNodeRemoved = 0x0800 , DirtyGeometry = 0x1000 , DirtyMaterial = 0x2000 , DirtyOpacity = 0x4000 , DirtyForceUpdate = 0x8000 , DirtyUsePreprocess = UsePreprocess , DirtyPropagationMask }
	Used in QSGNode::markDirty() to indicate how the scene graph has changed. More...
Protected Member Functions inherited from QSGNode
	QSGNode (NodeType type)
	Constructs a new node with the given node type.
	QSGNode (QSGNodePrivate &dd, NodeType type)
	Constructs a new node with the given node type.
Protected Attributes inherited from QSGNode
QScopedPointer< QSGNodePrivate >	d_ptr

Detailed Description

Definition at line 186 of file qquick3dscenerenderer_p.h.

Constructor & Destructor Documentation

◆ ~QQuick3DSGRenderNode()

QQuick3DSGRenderNode::~QQuick3DSGRenderNode ( )

Definition at line 1606 of file qquick3dscenerenderer.cpp.

References renderer.

Member Function Documentation

◆ changedStates()

QSGRenderNode::StateFlags QQuick3DSGRenderNode::changedStates ( ) const

overridevirtual

This function should return a mask where each bit represents graphics states changed by the \l render() function.

Note: With Qt 6 and QRhi-based rendering the only relevant values are ViewportState and ScissorState. Other values can be returned but are ignored in practice.

\value ViewportState Viewport \value ScissorState Scissor test enabled state, scissor rectangle \value DepthState This value has no effect in Qt 6. \value StencilState This value has no effect in Qt 6. \value ColorState This value has no effect in Qt 6. \value BlendState This value has no effect in Qt 6. \value CullState This value has no effect in Qt 6. \value RenderTargetState This value has no effect in Qt 6.

Note: The software backend exposes its QPainter and saves and restores before and after invoking render(). Therefore reporting any changed states from here is not necessary.

The default implementation returns 0, meaning no relevant state was changed in render().

Note: This function may be called before render().

Reimplemented from QSGRenderNode.

Definition at line 1514 of file qquick3dscenerenderer.cpp.

◆ flags()

QSGRenderNode::RenderingFlags QQuick3DSGRenderNode::flags ( ) const

overridevirtual

Returns: flags describing the behavior of this render node.

The default implementation returns 0.

See also: RenderingFlag, rect()

Reimplemented from QSGRenderNode.

Definition at line 1657 of file qquick3dscenerenderer.cpp.

◆ prepare()

void QQuick3DSGRenderNode::prepare ( )

overridevirtual

Called from the frame preparation phase.

There is a call to this function before each invocation of render().

Unlike render(), this function is called before the scenegraph starts recording the render pass for the current frame on the underlying command buffer. This is useful when doing rendering with graphics APIs, such as Vulkan, where copy type of operations will need to be recorded before the render pass.

The default implementation is empty.

When implementing a QSGRenderNode that uses QRhi to render, query the QRhi object from the QQuickWindow via \l{QQuickWindow::rhi()}. To get a QRhiCommandBuffer for submitting work to, call commandBuffer(). To query information about the active render target, call renderTarget(). See the \l{{Scene Graph - Custom QSGRenderNode}} example for details.

Since: 6.0

Reimplemented from QSGRenderNode.

Definition at line 1611 of file qquick3dscenerenderer.cpp.

References QQuick3DSceneRenderer::beginFrame(), and renderer.

Here is the call graph for this function:

◆ releaseResources()

void QQuick3DSGRenderNode::releaseResources ( )

overridevirtual

This function is called when all custom graphics resources allocated by this node have to be freed immediately.

In case the node does not directly allocate graphics resources (buffers, textures, render targets, fences, etc.) through the graphics API that is in use, there is nothing to do here.

Failing to release all custom resources can lead to incorrect behavior in graphics device loss scenarios on some systems since subsequent reinitialization of the graphics system may fail.

Note: Some scenegraph backends may choose not to call this function. Therefore it is expected that QSGRenderNode implementations perform cleanup both in their destructor and in releaseResources().

Unlike with the destructor, it is expected that render() can reinitialize all resources it needs when called after a call to releaseResources().

With OpenGL, the scenegraph's OpenGL context will be current both when calling the destructor and this function.

Reimplemented from QSGRenderNode.

Definition at line 1653 of file qquick3dscenerenderer.cpp.

◆ render()

void QQuick3DSGRenderNode::render ( const RenderState * state )

overridevirtual

This function is called by the renderer and should paint this node with directly invoking commands via QRhi or directly via the underlying graphics API (OpenGL, Direct3D, etc.).

The effective opacity can be retrieved with \l inheritedOpacity().

The projection matrix is available through state, while the model-view matrix can be fetched with \l matrix(). The combined matrix is then the projection matrix times the model-view matrix. The correct stacking of the items in the scene is ensured by the projection matrix.

When using the provided matrices, the coordinate system for vertex data follows the usual QQuickItem conventions: top-left is (0, 0), bottom-right is the corresponding QQuickItem's width() and height() minus one. For example, assuming a two float (x-y) per vertex coordinate layout, a triangle covering half of the item can be specified as (width - 1, height - 1), (0, 0), (0, height - 1) using counter-clockwise direction.

Note: QSGRenderNode is provided as a means to implement custom 2D or 2.5D Qt Quick items. It is not intended for integrating true 3D content into the Qt Quick scene. That use case is better supported by the other methods for integrating custom rendering.; QSGRenderNode can perform significantly better than texture-based approaches (such as, QQuickRhiItem), especially on systems where the fragment processing power is limited. This is because it avoids rendering to a texture and then drawing a textured quad. Rather, QSGRenderNode allows recording draw calls in line with the scenegraph's other commands, avoiding an additional render target and the potentially expensive texturing and blending.

Clip information is calculated before the function is called. Implementations wishing to take clipping into account can set up scissoring or stencil based on the information in state. The stencil buffer is filled with the necessary clip shapes, but it is up to the implementation to enable stencil testing.

Some scenegraph backends, software in particular, use no scissor or stencil. There the clip region is provided as an ordinary QRegion.

When implementing a QSGRenderNode that uses QRhi to render, query the QRhi object from the QQuickWindow via \l{QQuickWindow::rhi()}. To get a QRhiCommandBuffer for submitting work to, call commandBuffer(). To query information about the active render target, call renderTarget(). See the \l{{Scene Graph - Custom QSGRenderNode}} example for details.

With Qt 6 and its QRhi-based scene graph renderer, no assumptions should be made about the active (OpenGL) state when this function is called, even when OpenGL is in use. Assume nothing about the pipelines and dynamic states bound on the command list/buffer when this function is called.

Note: Depth writes are expected to be disabled. Enabling depth writes can lead to unexpected results, depending on the scenegraph backend in use and the content in the scene, so exercise caution with this.; In Qt 6, \l changedStates() has limited use. See the documentation for changedStates() for more information.

With some graphics APIs, including when using QRhi directly, it can be necessary to reimplement prepare() in addition, or alternatively connect to the QQuickWindow::beforeRendering() signal. These are called/emitted before recording the beginning of a renderpass on the command buffer (vkCmdBeginRenderPass with Vulkan, or starting to encode via MTLRenderCommandEncoder in case of Metal. Recording copy operations cannot be done inside render() with such APIs. Rather, do such operations either in prepare() or the slot connected to beforeRendering (with DirectConnection).