QSGGeometryNode ¶

概要 ¶

详细描述 ¶

QSGGeometryNode consists of geometry and material. The geometry defines the mesh, the vertices and their structure, to be drawn. The Material defines how the shape is filled.

The following is a code snippet illustrating how to create a red line using a QSGGeometryNode :

QSGGeometry *geometry = new QSGGeometry(QSGGeometry::defaultAttributes_Point2D(), 2);
geometry->setDrawingMode(GL_LINES);
geometry->setLineWidth(3);
geometry->vertexDataAsPoint2D()[0].set(0, 0);
geometry->vertexDataAsPoint2D()[1].set(width(), height());
QSGFlatColorMaterial *material = new QSGFlatColorMaterial;
material->setColor(QColor(255, 0, 0));
QSGGeometryNode *node = new QSGGeometryNode;
node->setGeometry(geometry);
node->setFlag(QSGNode::OwnsGeometry);
node->setMaterial(material);
node->setFlag(QSGNode::OwnsMaterial);
											

A geometry node must have both geometry and a normal material before it is added to the scene graph. When the geometry and materials are changed after the node has been added to the scene graph, the user should also mark them as dirty using markDirty() .

The geometry node supports two types of materials, the opaqueMaterial and the normal material. The opaqueMaterial is used when the accumulated scene graph opacity at the time of rendering is 1. The primary use case is to special case opaque rendering to avoid an extra operation in the fragment shader can have significant performance impact on embedded graphics chips. The opaque material is optional.

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。

另请参阅

QSGGeometry QSGMaterial QSGSimpleMaterial

class QSGGeometryNode ¶

Creates a new geometry node without geometry and material.

PySide2.QtQuick.QSGGeometryNode. inheritedOpacity ( ) ¶

返回类型

qreal

PySide2.QtQuick.QSGGeometryNode. renderOrder ( ) ¶

返回类型

int

PySide2.QtQuick.QSGGeometryNode. setInheritedOpacity ( opacity ) ¶

参数

opacity – qreal

Sets the inherited opacity of this geometry to 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.

PySide2.QtQuick.QSGGeometryNode. setRenderOrder ( order ) ¶

参数

order – int

Sets the render order of this node to be order .

Geometry nodes 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 .