QQuickFrameBufferObject 导致 PySide2 崩溃

Question

我正在尝试创建一个简单的 QQuickFrameBufferObject 以便在 Qt Quick 中渲染一些自定义 opengl 纹理。所以我决定用 PySide2 测试一下。这是一个简单的实现：

from PySide2.QtQuick import QQuickFramebufferObject
from PySide2.QtGui import QOpenGLFramebufferObjectFormat, QOpenGLFramebufferObject
from PySide2.QtCore import QSize, Qt

class FboRenderer(QQuickFramebufferObject.Renderer):
    def __init__(self, parent=None):
        super().__init__(parent)
        print("Creating renderer")

    def createFrameBufferObject(self, size):
        format = QOpenGLFramebufferObjectFormat()
        format.setAttachment(QOpenGLFramebufferObject.Depth)
        return QOpenGLFramebufferObject(size, format)

    def synchronize(self, item):
        print("Synchronizing")

    def render(self):
        print("Rendering")

class OpenGLCanvas(QQuickFramebufferObject):
    def __init__(self, parent=None):
        super().__init__(parent)

    def createRenderer(self):
        return FboRenderer()

然后为了在 QML 中使用它，我使用了：

    qmlRegisterType(OpenGLCanvas,"OpenGLCanvas", 1, 0, "OpenGLCanvas")

import QtQuick 2.12
import QtQuick.Window 2.12
import OpenGLCanvas 1.0

Window{
    id: win
    visible: true

    OpenGLCanvas{
        anchors.fill: parent
    }
}

现在应用程序运行并显示 "Creating renderer" 但几秒钟后它崩溃了。

Answer 1

问题是FboRenderer()是一个局部变量，会被立即销毁，因此它也会销毁C++对象，导致段错误，因为未保留内存已访问。

另一方面，你在 createFrameBufferObject 中有一个错字，因为它必须是 createFramebufferObject，这也揭示了一个类似于初始错误的错误，为此解决方案是相似的。

class FboRenderer(QQuickFramebufferObject.Renderer):
    def __init__(self):
        super().__init__()
        print("Creating renderer")
        self._fbos = []

    def createFramebufferObject(self, size):
        fmt = QOpenGLFramebufferObjectFormat()
        fmt.setAttachment(QOpenGLFramebufferObject.Depth)
        fbo = QOpenGLFramebufferObject(size, fmt)
        self._fbos.append(fbo)
        return fbo

    def synchronize(self, item):
        print("Synchronizing")

    def render(self):
        print("Rendering")


class OpenGLCanvas(QQuickFramebufferObject):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._renderer = None

    def createRenderer(self):
        if self._renderer is None:
            self.renderer = FboRenderer()
        return self.renderer

QQuickFrameBufferObject 导致 PySide2 崩溃

QQuickFrameBufferObject causes crash in PySide2

python

qt

qt5

qtquick2

pyside2