使用自定义QGLWidget调用Qt的QGraphicsView :: setViewport [英] calling Qt's QGraphicsView::setViewport with a custom QGLWidget

问题描述

我以前是从QGLWidget派生的，就像这样:

I've derived from QGLWidget before, like so:

class MyGLWidget : public QGLWidget
{
public:
   // stuff...

   virtual void initializeGL() { /* my custom OpenGL initialization routine */ }

   // more stuff...
};

但是，我发现如果尝试使用自定义QGLWidget作为视口初始化QGraphicsView，则不会调用initializeGL(在Qt库中设置断点，创建纯文本时QGLWidget :: initializeGL()也不会)

However, I find that if I try to initialize a QGraphicsView with my custom QGLWidget as the viewport, initializeGL doesn't get called (setting a breakpoint within the Qt library, neither does QGLWidget::initializeGL() when created plain).

// initializeGL, resizeGL, paintGL not called
ui.graphicsView->setViewport(new MyGLWidget(QGLFormat(QGL::DoubleBuffer)));

// initializeGL, resizeGL, paintGL *still* not called
ui.graphicsView->setViewport(new QGLWidget(QGLFormat(QGL::DoubleBuffer)));

当前将代码驻留在MyGLWidget :: initializeGL()中的正确位置在哪里?

Where is the correct location to place the code that currently resides in MyGLWidget::initializeGL()?

推荐答案

我将继续回答我自己的问题.这不是最佳选择，但这就是我解决问题的方法.

I'm going to go ahead and answer my own question. This isn't optimal, but this is how I've gotten around the problem.

代替

ui.graphicsView->setViewport(new MyGLWidget(QGLFormat(QGL::DoubleBuffer)));

我得到了这个

ui.graphicsView->setViewport(new QGLWidget(new CustomContext(QGLFormat(QGL::SampleBuffers))));

CustomContext是从QGLContext派生的类.我已经覆盖了create成员，就像这样:

CustomContext is a class that derives from QGLContext. I've overridden the create member, like so:

virtual bool create(const QGLContext *shareContext = 0)
{
    if(QGLContext::create(shareContext))
    {
        makeCurrent();

        /* do my initialization here */

        doneCurrent();

        return true;
    }

    return false;
}

我不认为这是实现此目的的最佳方法，但是它比完全没有特定初始化步骤的替代方法要好.我仍然很高兴有人能留下更好的答案！

I don't think this is the optimal way to do this, but it's better than the alternative of not having a specific initialization step at all. I'd still be happy to have someone leave a better answer!

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